As filed with the Securities and Exchange Commission on April 30, 2010
Registration Nos. 33-54126
811-07332

SECURITIES AND EXCHANGE COMMISSION
                           Washington, DC 20549

                                 FORM N-1A

        REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933   [X]

                   Pre-Effective Amendment No.                    [_]

                   Post-Effective Amendment No. 88                [X]

                                    and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940   [X]

                             Amendment No. 92                     [X]

                             -----------------

BLACKROCK FUNDS III
(Exact Name of Registrant as Specified in Charter)

400 Howard Street
San Francisco, CA 94105
(Address of Principal Executive Offices)

Registrant's Telephone Number: 1-800-882-0052


Anne F. Ackerley
BlackRock Funds III
55 East 52nd Street
New York, New York 10055
United States of America
(Name and Address of Agent for Service)


                            With copies to:

 John A. MacKinnon, Esq.                   Andrew Josef, Esq.
    Sidley Austin LLP          BlackRock Institutional Trust Company, N.A.
   787 Seventh Avenue                       400 Howard Street
New York, New York 10019                 San Francisco, CA 94105

                           -----------------

It is proposed that this filing will become effective (check appropriate box)

[_] Immediately upon filing pursuant to paragraph (b)

[X] On May 1, 2010 pursuant to paragraph (b)

[_] 60 days after filing pursuant to paragraph (a)(1)

[_] On (date) pursuant to paragraph (a)(1)

[_] 75 days after filing pursuant to paragraph (a)(2)

[_] On (date) pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

[_] This post-effective amendment designates a new effective date for a
previously filed post-effective amendment.

Title of Securities Being Registered: Shares of Beneficial Interest.


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVES BLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III

PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                               TICKER SYMBOL
------------------------------     -------------
BlackRock S&P 500 Stock Fund               WFSPX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

  KEY FACTS AND DETAILS ABOUT THE FUND, INCLUDING
INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE
INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  INVESTMENT OBJECTIVE............................... 1
  PRINCIPAL INVESTMENT STRATEGIES OF THE FUND........ 2
  PRINCIPAL RISKS OF INVESTING IN THE FUND........... 2
  PERFORMANCE INFORMATION............................ 2
  INVESTMENT ADVISER................................. 3
  PORTFOLIO MANAGERS................................. 3
  PURCHASE AND SALE OF FUND SHARES................... 3
  TAX INFORMATION.................................... 4

DETAILS ABOUT THE FUND

DETAILS ABOUT THE FUND'S INVESTMENT STRATEGIES........ 5
A FURTHER DISCUSSION OF RISKS......................... 5

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.....................  8
HOW TO BUY, SELL AND TRANSFER SHARES........  8
SHAREHOLDER SERVICING PAYMENTS.............. 12
CALCULATING THE FUND'S SHARE PRICE.......... 13
FUND DISTRIBUTIONS.......................... 13
SHORT TERM TRADING POLICY................... 13
TAXES....................................... 14
MASTER/FEEDER MUTUAL FUND STRUCTURE......... 15

MANAGEMENT OF THE FUND

INVESTMENT ADVISER.................. 16
PORTFOLIO MANAGERS.................. 16
ADMINISTRATIVE SERVICES............. 17
CONFLICTS OF INTEREST............... 17
VALUATION OF FUND INVESTMENTS....... 18
CERTAIN FUND POLICIES............... 18

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUND........ 20

FOR MORE INFORMATION   ADDITIONAL INFORMATION............BACK COVER


[THIS PAGE INTENTIONALLY LEFT BLANK]


Fund Overview

KEY FACTS ABOUT BLACKROCK S&P 500 STOCK FUND

INVESTMENT OBJECTIVE

BlackRock S&P 500 Stock Fund (the "Fund"), a series of BlackRock Funds III (the "Trust"), seeks to provide investment results that correspond to the total return performance of publicly-traded common stocks in the aggregate, as represented by the Standard & Poor's 500 Index ("S&P 500 Index"). The Fund's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

ANNUAL FUND OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee                                                                          0.05%
 Distribution and/or Service (12b-1) Fees                                                 None
 Other Expenses                                                                          0.16%
  Administration Fees                                                                    0.15%
  Independent Expenses(1)(2)                                                             0.01%
 Total Annual Fund Operating Expenses(3)                                              0.21%
 Fee Waivers and/or Expense Reimbursements(2)                                           (0.01%)
 Total Annual Fund Operating Expenses After Fee Waivers and/or Expense                   0.20%
  Reimbursements(2)(3)


(1) Independent Expenses have been restated to reflect current fees.

(2) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and Master Investment Portfolio ("MIP"), counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and S&P 500 Stock Master Portfolio (the "Master Portfolio"), a series of MIP. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors) have contractually agreed to reimburse, or provide offsetting credits to, the Fund and the Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) Total Annual Fund Operating Expenses in the table above and the following example reflect the expenses of both the Fund and the Master Portfolio in which the Fund invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  20         $  66        $  116        $  266

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PORTFOLIO TURNOVER

The Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Master Portfolio's portfolio turnover rate was 5% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND


The Fund pursues its investment objective by seeking to replicate the total return performance of the S&P 500 Index, which is composed of 500 selected common stocks, most of which are listed on the New York Stock Exchange ("NYSE"). The S&P 500 Index is a capitalization-weighted index from a broad range of industries chosen for market size, liquidity and industry group representation. The component stocks are weighted according to the total float- adjusted market value of their outstanding shares (I.E., they are weighted according to the public float which is the total market value of their outstanding shares readily available to the general marketplace for trading purposes). The percentage of the Fund's assets invested in a given stock is approximately the same as the percentage such stock represents in the S&P 500 Index.

The Fund is managed by determining which securities are to be purchased or sold to reflect, to the extent feasible, the investment characteristics of its benchmark index. Under normal circumstances, at least 90% of the value of the Fund's assets, plus the amount of any borrowing for investment purposes, is invested in securities comprising the S&P 500 Index.

The Fund is a "feeder" fund that invests all of its investable assets in the Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include the Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency. The following is a summary description of certain risks of investing in the Fund.

. EQUITY SECURITIES RISK - Stock markets are volatile. The prices of equity securities fluctuate based on changes in a company's financial condition and overall market and economic conditions.

. INDEX FUND RISK - An index fund has operating and other expenses while an index does not. As a result, while the Fund will attempt to track the S&P 500 Index as closely as possible, it will tend to underperform the index to some degree over time.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of the Fund for each of the last ten calendar years. The average annual total return table (before and after taxes) compares the Fund's average annual total return to that of the S&P 500 Index. How the Fund has performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

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ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -9.34%
2001   -12.11%
2002   -22.20%
2003    28.37%
2004    10.67%
2005     4.72%
2006    15.60%
2007     5.39%
2008   -37.01%
2009    26.48%

During the periods shown in the bar chart, the highest return for a quarter was 15.95% (quarter ended June 30, 2009) and the lowest return for a quarter was -21.81% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 5.37%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                1 YEAR          5 YEARS         10 YEARS
 BLACKROCK S&P 500 STOCK FUND
  Return Before Taxes                                                        26.48%            0.32%          -1.11%
  Return After Taxes on Distributions                                        26.02%           -0.07%          -1.86%
  Return After Taxes on Distributions and Sale of Fund Shares                17.58%            0.21%          -1.16%
 S&P 500 INDEX (Reflects no deduction for fees, expenses or taxes)           26.46%            0.42%          -0.95%

After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The Master Portfolio's investment adviser is BFA.

PORTFOLIO MANAGERS

                          PORTFOLIO
                          MANAGER OF
                          THE MASTER
                          PORTFOLIO
NAME                        SINCE        TITLE
 Diane Hsiung               2008            Director of BTC
 Greg Savage                2008            Managing Director of BTC
 Edward Corallo             2009            Managing Director of BTC
 Christopher Bliss          2009            Managing Director of BTC
 Jennifer Hsui              2009            Director of BTC

PURCHASE AND SALE OF FUND SHARES

The Fund's minimum initial investment is $1 million, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange ("NYSE" or the "Exchange") is open. To purchase or sell shares, you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at (800) 441-7762, by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019, or by the internet at www.blackrock.com/funds).

3

To be eligible to purchase Fund shares, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an IRA; maintain an account with PNC Global Investment Servicing (U.S.) Inc., the Fund's transfer agent ("PNC GIS" or the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"); or initially invest a minimum of $1 million directly through the Transfer Agent (in certain situations this minimum initial investment may be reduced or waived; please contact your Shareholder Servicing Agent or the Transfer Agent for more information).

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the NYSE (generally 4:00 p.m. Eastern time) (or, if regular trading on the NYSE closes early, by such closing time) on any day the Fund is open (a "Business Day").

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and BlackRock Investments, LLC (the "Distributor"), the Fund's distributor, or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Details About the Fund

DETAILS ABOUT THE FUND'S INVESTMENT STRATEGIES


The Fund invests all of its assets in the Master Portfolio, a series of MIP, which has an investment objective and strategies substantially identical to those of the Fund. All discussion of the investment objective, strategies and risks of the Fund refers also to the investment objective, strategies and risks of the Master Portfolio, unless otherwise indicated. A description of the relationship of the Fund to the Master Portfolio appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

The Fund attempts to achieve, in both rising and falling markets, a correlation of at least 95% between the total return of its net assets before fees and expenses and the total return of the Fund's benchmark index, the S&P 500 Index. Notwithstanding the factors described below, perfect (100%) correlation would be achieved if the total return of the Fund's net assets, before fees and expenses, increased or decreased exactly as the total return of the Fund's benchmark index increased or decreased. The Fund's ability to match its investment performance to the investment performance of its benchmark index may be affected by, among other things, the Fund's expenses, the amount of cash and cash equivalents held by the Fund, the manner in which the total return of the Fund's benchmark index is calculated; the size of the Fund's investment portfolio; and the timing, frequency and size of shareholder purchases and redemptions.

The Fund seeks to replicate the total return performance of the S&P 500 Index by investing the Fund's assets so that the percentage of Fund assets invested in a given stock is approximately the same as the percentage such stock represents in the S&P 500 Index. No attempt is made to manage the Fund using economic, financial or market analysis. In addition, at times, the portfolio composition of the Fund may be altered (or "rebalanced") to reflect changes in the characteristics of the index that the Fund tracks.

The Fund also may engage in futures and options transactions and other derivative securities transactions and lend its portfolio securities, each of which involves risk. The Fund may use futures contracts, options and other derivative transactions to manage its short-term liquidity and/or as substitutes for comparable market positions in the securities in its benchmark index. The Fund may also invest in high-quality money market instruments, including shares of money market funds advised by BFA or its affiliates.

Investors look to indexes as a standard of market performance. Indexes are model portfolios, that is, groups of stocks or bonds selected to represent an entire market or market segment. One way an index fund seeks to match an index's performance, before fees and expenses, is by buying and selling all of the index's securities in the same proportion as they are reflected in the index. This is what the Fund does.

The Fund is designed for investors who desire a convenient way to invest in a broad spectrum of U.S. large cap stocks. Although this market has increased in value over the long-term, it fluctuates and has also decreased in value over shorter time periods. This volatility is particularly characteristic of stocks.

The Fund does not by itself constitute a balanced investment program. Diversifying your investments by buying shares in other funds may improve your long-term return as well as reduce volatility.

Standard & Poor's ("S&P") does not sponsor, endorse, sell or promote the Fund or the Master Portfolio, nor is it affiliated in any way with BTC, BFA, the Fund or the Master Portfolio. "Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," and "S&P 500(Reg. TM)" are trademarks of Standard & Poor's (a division of The McGraw-Hill Companies, Inc.) licensed for use for certain purposes by BTC. S&P makes no representation or warranty, expressed or implied, regarding the advisability of investing in the Fund or the Master Portfolio.

A FURTHER DISCUSSION OF RISKS

This section contains a discussion of the general risks of investing in the Fund. "Description of the Fund and its Investments and Risks" in the Fund's Statement of Additional Information ("SAI") also includes more information about the Fund, its investments and the related risks. There can be no guarantee that the Fund will meet its objective or that the Fund's performance will be positive for any period of time. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the FDIC or by any bank or governmental agency.

MAIN RISKS OF INVESTING IN THE FUND:

5

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the Fund could decline if the financial condition of the companies the Fund invests in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

INDEX FUND RISK - An index fund has operating and other expenses while an index does not. As a result, while the Fund will attempt to track the S&P 500 Index as closely as possible, it will tend to underperform the index to some degree over time.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

OTHER RISKS OF INVESTING IN THE FUND:

The Fund may also be subject to certain other risks associated with its investments and investment strategies, including:

CONCENTRATION RISK - The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) to approximately the same extent that its benchmark index concentrates in a particular industry. To the extent the Fund concentrates in a particular industry, it may be more susceptible to economic conditions and risks affecting that industry.

DERIVATIVES RISK - The Fund's use of derivatives may reduce the Fund's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund's derivatives positions to lose value. When a derivative is used as a hedge against a position that the Fund holds, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund's hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EXPENSE RISK - Fund expenses are subject to a variety of factors, including fluctuations in the Fund's net assets. Accordingly, actual expenses may be greater or less than those indicated. For example, to the extent that the Fund's net assets decrease due to market declines or redemptions, the Fund's expenses will increase as a percentage of Fund net assets. During periods of high market volatility, these increases in the Fund's expense ratio could be significant.

LIQUIDITY RISK - Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund's investments in illiquid securities may reduce the returns of the Fund because it may be difficult to sell the illiquid securities at an advantageous time or price. To the extent that the Fund's principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the index that the Fund tracks, the Fund may hold securities of companies that present risks that an investment adviser researching individual securities might seek to avoid.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the Fund may lose money and there may be a delay in recovering the loaned

6

securities. The Fund could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the Fund.

As with all mutual funds, the Fund must maintain cash balances to meet redemption requests, which may lower its overall performance.

FOR A DESCRIPTION OF THE FUND'S POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE MASTER PORTFOLIO'S PORTFOLIO HOLDINGS AND A FURTHER DISCUSSION OF THE FUND'S INVESTMENTS AND RISKS, PLEASE REFER TO THE FUND'S SAI.

7

Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

To be eligible to purchase Fund shares, you must:

. Invest through an employer-sponsored or individual retirement savings plan;

. Invest the proceeds rolled over from such retirement savings plan into an IRA;

. Maintain an account with the Transfer Agent or with one of the Fund's Shareholder Servicing Agents; or

. Initially invest a minimum of $1 million directly through the Transfer Agent (in certain situations this minimum initial investment may be reduced or waived; please contact your Shareholder Servicing Agent or the Transfer Agent for more information).

HOW TO BUY, SELL AND TRANSFER SHARES


The following chart summarizes how to buy, sell and transfer shares through your financial professional or other financial intermediary. You may also buy, sell and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling or transferring shares through BlackRock, call (800) 537-4942. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

The Fund may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders, and suspend and resume the sale of Fund shares at any time and for any reason.

In addition, the Fund may waive certain requirements regarding the purchase, sale or transfer of shares described below.

          HOW TO BUY SHARES
                   YOUR CHOICES        IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE   Determine           The minimum initial investment in the Fund is $1 million.
                   the amount of
                   your investment
                   Have your           The price of your shares is based on the next calculation of the Fund's net
                   financial           asset value ("NAV") after your order is placed. Any purchase orders placed
                   intermediary        prior to the close of business on a Business Day will be priced at the NAV
                   submit your         determined that day. Certain financial intermediaries, however, may
                   purchase order      require submission of orders prior to that time. A broker-dealer or financial
                                       institution maintaining the account in which you hold shares may charge
                                       a separate account, service or transaction fee on the purchase or sale of
                                       Fund shares that would be in addition to the fees and expenses shown in
                                       the Fund's "Fees and Expenses" table.
                                       Purchase orders placed after that time will be priced at the NAV
                                       determined on the next Business Day. The Fund may reject any order to
                                       buy shares and may suspend the sale of shares at any time. Financial
                                       intermediaries may charge a processing fee to confirm a purchase.
                   Or contact          To purchase shares directly with BlackRock, call (800) 537-4942 and
                   BlackRock (for      request a new account application. Mail the completed application, along
                   accounts held       with a check payable to "BlackRock Funds," to the Transfer Agent at the
                   directly with       address on the application.
                   BlackRock)
ADD TO YOUR        Purchase            There is no minimum investment for additional purchases.
INVESTMENT         additional shares

8

            HOW TO BUY SHARES
                 YOUR CHOICES              IMPORTANT INFORMATION FOR YOU TO KNOW
                 Have your                 To purchase additional shares, you may contact your financial professional
                 financial                 or financial intermediary. For more details on purchasing by Internet, see
                 professional              below.
                 or financial
                                           PURCHASE BY TELEPHONE: Call (800) 537-4942 and speak with one of our
                 intermediary
                                           representatives. The Fund has the right to reject any telephone request for
                 submit your
                                           any reason.
                 purchase order
                 for additional shares
                                           PURCHASE IN WRITING: You may send a written request to BlackRock at the
                                           address on the back cover of this Prospectus.
                                           PURCHASE BY VRU: Shares may also be purchased by use of the Fund's
                                           automated voice response unit service ("VRU") at (800) 537-4942.
                 Or contact                PURCHASE BY INTERNET: You may purchase your shares, and view activities
                 BlackRock                 in your account, by logging onto the BlackRock website at
                 (for accounts held        www.blackrock.com/funds. Purchases made on the Internet using the
                 directly with             Automated Clearing House Network ("ACH") will have a trade date that is
                 BlackRock)                the day after the purchase is made. Certain institutional clients' purchase
                                           orders for shares placed by wire prior to the close of business on a
                                           Business Day will be placed at the NAV determined that day. Contact your
                                           financial intermediary or BlackRock for further information. The Fund limits
                                           Internet purchases in shares of the Fund to $25,000 per trade. Please read
                                           the On-Line Services Disclosure Statement and User Agreement, the
                                           Terms and Conditions page and the Consent to Electronic Delivery
                                           Agreement (if you consent to electronic delivery), before attempting to
                                           transact online.
                                           The Fund employs reasonable procedures to confirm that transactions
                                           entered over the Internet are genuine. By entering into the User
                                           Agreement with the Fund in order to open an account through the
                                           website, the shareholder waives any right to reclaim any losses from the
                                           Fund or any of its affiliates incurred through fraudulent activity.
                 Acquire additional        All dividends and capital gains distributions are automatically reinvested
                 shares by                 without a sales charge. To make any changes to your dividend and/or
                 reinvesting               capital gains distributions options, please call (800) 537-4942, or contact
                 dividends and             your financial professional (if your account is not held directly with
                 capital gains             BlackRock).
                 Participate               BlackRock's AIP allows you to invest a specific amount on a periodic basis
                 in the Automatic          from your checking or savings account into your investment account.
                 Investment Plan ("AIP")
HOW TO PAY FOR   Making payment            Payment for an order must be made in Federal funds or other immediately
SHARES           for                       available funds by the time specified by your financial professional or other
                 purchases                 financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                           on the first business day (in the case of shares) following BlackRock's
                                           receipt of the order. If payment is not received by this time, the order will
                                           be canceled and you and your financial professional or other financial
                                           intermediary will be responsible for any loss to the Fund.
                                           For shares purchased directly from the Fund, a check payable to
                                           "BlackRock Funds," which bears the name of the Fund you are purchasing,
                                           must accompany a completed purchase application. There is a $20 fee for
                                           each purchase check that is returned due to insufficient funds.
                                           The Fund does not accept third-party checks. You may also wire Federal
                                           funds to the Fund to purchase shares, but you must call (800) 537-4942
                                           before doing so to confirm the wiring instructions.

9

       HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL   Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       The price of your shares is based on the next calculation of the Fund's
SHARES            intermediary    NAV after your order is placed. For your redemption request to be priced at
                  submit your     the NAV on the day of your request, you must submit your request to your
                  sales order     financial intermediary prior to that day's close of business on a Business
                                  Day. Certain financial intermediaries, however, may require submission of
                                  orders prior to that time. Any redemption request placed after that time
                                  will be priced at the NAV at the close of business on the next Business
                                  Day.
                                  Financial intermediaries may charge a fee to process a redemption of
                                  shares.
                                  The Fund may reject an order to sell shares under certain circumstances.
                  Selling         METHODS OF REDEEMING:
                  shares held
                                  REDEEM BY TELEPHONE: You may sell shares of the Fund held directly at
                  directly
                                  BlackRock by telephone request if certain conditions are met and if the
                  with
                                  amount being sold is less than (i) $100,000 for payments by check or (ii)
                  BlackRock
                                  $250,000 for payments through the ACH or wire transfer. Certain
                                  redemption requests may require written instructions with a medallion
                                  signature guarantee. Call (800) 537-4942 for details.
                                  Certain redemption requests, such as those in excess of these amounts,
                                  must be in writing with a medallion signature guarantee.
                                  You can obtain a medallion signature guarantee stamp from a bank,
                                  securities dealer, securities broker, credit union, savings and loan
                                  association, national securities exchange or registered securities
                                  association. A notary public seal will not be acceptable.
                                  The Fund, its administrator and the Distributor will employ reasonable
                                  procedures to confirm that instructions communicated by telephone are
                                  genuine. The Fund and its service providers will not be liable for any loss,
                                  liability, cost or expense for acting upon telephone instructions that are
                                  reasonably believed to be genuine in accordance with such procedures.
                                  The Fund may refuse a telephone redemption request if it believes it is
                                  advisable to do so.
                                  During periods of substantial economic or market change, telephone
                                  redemptions may be difficult to complete. Please find below alternative
                                  redemption methods.
                                  REDEEM BY VRU: Shares may also be redeemed by use of the Fund's VRU.
                                  Payment for shares redeemed by VRU may be made for non-retirement
                                  accounts in amounts up to $25,000, either through check, ACH or wire.
                                  REDEEM BY INTERNET: You may redeem in your account by logging onto
                                  the BlackRock website at www.blackrock.com/funds. Proceeds from
                                  Internet redemptions may be sent via check, ACH or wire to the bank
                                  account of record. Payment for shares redeemed via Internet may be
                                  made for non-retirement accounts in amounts up to $25,000, either
                                  through check, ACH or wire.

10

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                            REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                            BlackRock, P.O. Box 9819, Providence, RI 02940-8019 or, for overnight
                            delivery, 101 Sabin Street, Pawtucket, RI 02860-1427. All shareholders on
                            the account must sign the letter. A medallion signature guarantee will
                            generally be required but may be waived in certain limited circumstances.
                            You can obtain a medallion signature guarantee stamp from a bank,
                            securities dealer, securities broker, credit union, savings and loan
                            association, national securities exchange or registered securities
                            association. A notary public seal will not be acceptable. If you hold stock
                            certificates, return the certificates with the letter. Proceeds from
                            redemptions may be sent via check, ACH or wire to the bank account of
                            record.
                            PAYMENT OF REDEMPTION PROCEEDS: Redemption proceeds may be paid by
                            check or, if the Fund has verified banking information on file, through ACH
                            or by wire transfer.
                            PAYMENT BY CHECK: BlackRock will normally mail redemption proceeds
                            within seven days following receipt of a properly completed request.
                            Shares can be redeemed by telephone and the proceeds sent by check to
                            the shareholder at the address on record. Shareholders will pay $15 for
                            redemption proceeds sent by check via overnight mail. You are responsible
                            for any additional charges imposed by your bank for this service.
                            PAYMENT BY WIRE TRANSFER: Payment for redeemed shares for which a
                            redemption order is received before 4:00 p.m. (Eastern time) on a
                            Business Day is normally made in Federal funds wired to the redeeming
                            shareholder on the next Business Day, provided that the Fund's custodian
                            is also open for business. Payment for redemption orders received after
                            4:00 p.m. (Eastern time) or on a day when the Fund's custodian is closed
                            is normally wired in Federal funds on the next Business Day following
                            redemption on which the Fund's custodian is open for business. The Fund
                            reserves the right to wire redemption proceeds within seven days after
                            receiving a redemption order if, in the judgment of the Fund, an earlier
                            payment could adversely affect the Fund.
                            If a shareholder has given authorization for expedited redemption, shares
                            can be redeemed by Federal wire transfer to a single previously designated
                            bank account. Shareholders will pay $7.50 for redemption proceeds sent
                            by Federal wire transfer. You are responsible for any additional charges
                            imposed by your bank for this service. No charge for wiring redemption
                            payments with respect to the Fund is imposed by the Fund.
                            The Fund is not responsible for the efficiency of the Federal wire system or
                            the shareholder's firm or bank. To change the name of the single,
                            designated bank account to receive wire redemption proceeds, it is
                            necessary to send a written request to the Fund at the address on the
                            back cover of this Prospectus.

11

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                            PAYMENT BY ACH: Redemption proceeds may be sent to the shareholder's
                            bank account (checking or savings) via ACH. Payment for redeemed
                            shares for which a redemption order is received before 4:00 p.m. (Eastern
                            time) on a Business Day is normally sent to the redeeming shareholder
                            the next Business Day, with receipt at the receiving bank within the next
                            two business days (48-72 hours), provided that the Fund's custodian is
                            also open for business. Payment for redemption orders received after 4:00
                            p.m. (Eastern time) or on a day when the Fund's custodian is closed is
                            normally sent on the next Business Day following redemption on which
                            the Fund's custodian is open for business.
                            The Fund reserves the right to send redemption proceeds within seven
                            days after receiving a redemption order if, in the judgment of the Fund, an
                            earlier payment could adversely affect the Fund. No charge for sending
                            redemption payments via ACH is imposed by the Fund. If you make a
                            redemption request before the Fund has collected payment for the
                            purchase of shares, the Fund may delay mailing your proceeds. This delay
                            will usually not exceed ten days.

                                               HOW TO TRANSFER YOUR ACCOUNT
                     YOUR CHOICES             IMPORTANT INFORMATION FOR YOU TO KNOW
TRANSFER SHARES TO   Transfer to a            You may transfer your shares of the Fund only to another financial
ANOTHER SECURITIES   participating            professional or financial intermediary that has an agreement with the
DEALER OR OTHER      financial                Distributor. Certain shareholder services may not be available for the
FINANCIAL            professional or          transferred shares. All future trading of these assets must be coordinated
INTERMEDIARY         other                    by the receiving firm.
                     financial
                                              If your account is held directly with BlackRock, you may call (800) 537-
                     intermediary
                                              4942 with any questions; otherwise please contact your financial
                                              intermediary to accomplish the transfer of shares.
                     Transfer to a            You must either:
                     non-participating
                                              oTransfer your shares to an account with the Fund; or
                     financial professional
                     or other
                                              oSell your shares, paying any applicable deferred sales charge.
                     financial intermediary
                                              If your account is held directly with BlackRock, you may call (800) 537-4942
                                              with any questions; otherwise please contact your financial intermediary to
                                              accomplish the transfer of shares.

SHAREHOLDER SERVICING PAYMENTS


The Fund has adopted a shareholder servicing plan (the "Plan") that allows the Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of the Fund's shares. Because the fees paid by the Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Fund and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that the Fund may pay to a Financial Intermediary pursuant to the Plan and fees the Fund pays to the Transfer Agent, BFA, on behalf of the Fund, may enter into non-Plan

12

agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Fund and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Financial Intermediary for details about payments it may receive from the Fund or from BFA or its affiliates. For more information, see the Fund's SAI.

CALCULATING THE FUND'S SHARE PRICE


The Fund's share price (also known as the Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

The Fund's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating the Fund's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of the Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Fund's SAI includes a description of the methods for valuing the Master Portfolio's investments, including a description of the circumstances in which the Master Portfolio's investments would be valued using fair value pricing and the effects of using fair value pricing.

FUND DISTRIBUTIONS


The Fund makes distributions of its net investment income to investors every quarter. The Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by the Fund will be automatically reinvested in additional shares of the Fund, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and the Fund's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The Fund is not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of the Fund and its shareholders. For example, large flows of cash into and out of the Fund may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the Fund's investment goal. Frequent trading may cause the Fund to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the Fund's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. The Fund will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of Fund Investments" below.

The Fund discourages market timing and seeks to prevent frequent purchases and sales or exchanges of Fund shares that it determines may be detrimental to the Fund or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of Fund shares because certain legitimate strategies will not result in harm to the Fund or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, the Fund believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If the Fund rejects your purchase or exchange order, you will not be able to execute that transaction, and the Fund will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with the Fund, the Fund may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by the Fund. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide the Fund with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the Fund. While the Fund monitors for market timing activity, the Fund may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the Fund. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in the Fund's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by the Fund to be engaged in market timing or other improper trading activity, the Fund's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

The Fund may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

13

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Fund and its U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Fund's SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the Fund's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the Fund generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the Fund's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S. and certain foreign corporations. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) A portion of distributions paid to corporate shareholders of the Fund may qualify for the dividends-received deduction available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

In addition, if you sell your Fund shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

Sale proceeds generally are taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

If you buy the Fund's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of the Fund and the Fund holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the Fund sells the appreciated securities and distributes the realized gain on the sale. The Fund has built up, or has the potential to build up, high levels of unrealized appreciation in its investments.

After the end of each year, the Fund will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

14

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Fund if you fail to provide the Fund with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE


The Fund does not have its own investment adviser. Instead, the Fund invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to the Master Portfolio. The Master Portfolio may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolio and, therefore, the Fund.

FEEDER FUND EXPENSES

Feeder funds, including the Fund, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw the Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw the Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

15

Management of the Fund

INVESTMENT ADVISER


The Fund is a "feeder" fund that invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolio. BFA manages the investment of the Master Portfolio's assets and provides the Master Portfolio with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolio, BFA is entitled to receive a management fee at the annual rate of 0.05% of the Master Portfolio's average daily net assets.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolio invests.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreement with BFA is available in the Fund's annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS


BFA uses teams of portfolio managers, investment strategists and other investment specialists (the "Portfolio Management Team") to manage the Master Portfolio to reflect, to the extent feasible, the investment characteristics of its benchmark index, and BFA employs a combination of proprietary investment management systems and procedures to validate the consistent application of its investment methods. This team approach to portfolio management brings together many disciplines and leverages BFA's extensive resources. The team members act collaboratively with the other members of the Portfolio Management Team on all aspects concerning the Master Portfolio. Each member of the Portfolio Management Team, including the below-listed members, is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of his or her team to focus on certain asset classes, implementing investment strategies, researching and reviewing investment strategies, and overseeing members of the Portfolio Management Team with more limited responsibilities, but each member of the Portfolio Management Team has appropriate limitations on his or her authority for risk management and compliance purposes.

The members of the Portfolio Management Team for the Master Portfolio that have the most significant day-to-day management responsibility are: Diane Hsiung, Greg Savage, Edward Corallo, Christopher Bliss and Jennifer Hsui.

Diane Hsiung has been employed as a senior portfolio manager at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A. ("BGI")) since 2007 and a portfolio manager for BGFA and BGI from 2002 to 2006. Ms. Hsiung has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2008.

Greg Savage, CFA has been employed as a senior portfolio manager at BFA and BTC since 2009. Mr. Savage was previously a senior portfolio manager for BGFA and BGI from 2006 to 2009 and a portfolio manager for BGFA and BGI from 2001 to 2006. Mr. Savage has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2008.

Edward Corallo has been employed as the head of portfolio management in the Index Equity Group at BFA and BTC since 2009. Previously, Mr. Corallo was the head of portfolio management in the Index Equity Group at BGI and BGFA from 2007 to 2009. Prior to that time, he was a senior portfolio manager for BGFA and BGI from 2001 to 2007. Mr. Corallo has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2009.

Christopher Bliss, CFA has been employed as a senior portfolio manager at BFA and BTC since 2009. Mr. Bliss previously was a senior portfolio manager for BGI from 2005 to 2009 and a portfolio manager for BGI from 2004 to 2005. Mr. Bliss has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2009.

Jennifer Hsui has been employed as a senior portfolio manager at BFA and BTC since 2009. Ms. Hsui was previously a senior portfolio manager for BGI from 2007 to 2009 and a portfolio manager for BGI from 2006 to 2007. Prior to

16

joining BGI, Ms. Hsui was a research analyst for RBC Capital Markets from 2003 to 2006. Ms. Hsui has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2009.

The Fund's SAI provides additional information about the compensation of the above-listed members of the Portfolio Management Team, other accounts they manage and their ownership of shares of the Fund.

ADMINISTRATIVE SERVICES


BTC provides the following services, among others, as the Fund's administrator:

. Supervises the Fund's administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.15% of the average daily net assets of the Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Fund, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Fund or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Fund. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Fund directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Fund and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Fund and may result in an Affiliate or an Entity having positions that are adverse to those of the Fund.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, an Affiliate or an Entity may compete with the Fund for appropriate investment opportunities. The results of the Fund's investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Fund may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Fund. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Fund.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Fund's activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Fund may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Fund also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Fund or who engage in transactions with or for the Fund, and may receive compensation for such services. The Fund may also make brokerage and other payments to Affiliates or Entities in connection with the Fund's portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Fund and its shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

17

Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolio has retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolio to the extent that the Master Portfolio participates in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolio, including a fee based on the returns earned on the Master Portfolio's investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolio may lend its portfolio securities under the securities lending program.

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. The Fund calculates the net asset value of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00 p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

The Fund's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. The Fund values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If the Fund invests in foreign securities, these securities may trade on weekends or other days when the Fund does not price its shares. As a result, the Fund's net asset value may change on days when you will not be able to purchase or redeem the Fund's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, the Fund's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing the Fund's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the Fund. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining the Fund's net asset value.

The Fund may accept orders from certain authorized financial intermediaries or their designees. The Fund will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Fund is subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, the Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Fund reserves the right to reject purchase orders from persons who have not submitted information sufficient to allow the Fund to verify their identity. The Fund also reserves the right to redeem any amounts in the Fund from persons whose identity it is unable to verify on a timely basis. It is the Fund's policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

18

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

19

Financial Highlights

The financial highlights table is intended to help investors understand the financial performance of the shares of the Fund for the past five years. Certain information reflects financial results for a single share of the Fund. The total returns in the table represent the rate of return that an investor would have earned (or lost) on an investment in shares of the Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with the Fund's financial statements, is included in the Fund's annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-537-4942 (toll-free) from 8:30 a.m. to 6:30 p.m. Eastern time on any business day.

BLACKROCK S&P 500 STOCK INDEX FUND

FINANCIAL HIGHLIGHTS

                                                                    YEAR ENDED DECEMBER 31,
                                             ---------------------------------------------------------------------
                                                  2009          2008          2007          2006          2005
                                             ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year            $  107.85     $  175.47     $  169.53     $  150.07     $  145.95
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
Net investment income                              2.501          3.28         3.14          3.04          2.66
 Net realized and unrealized gain (loss)          25.60         (67.60)        5.94         20.11          4.07
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
Net increase (decrease) from investment
 operations                                       28.10         (64.32)        9.08         23.15          6.73
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Dividends and distributions from:
  Net investment income                            (2.46)        (3.27)        (3.14)        (3.68)        (2.61)
  Return of capital                                    -         (0.03)            -         (0.01)            -
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
Total dividends and distributions                  (2.46)        (3.30)        (3.14)        (3.69)        (2.61)
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Net asset value, end of year                  $  133.49     $  107.85     $  175.47     $  169.53     $  150.07
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
TOTAL INVESTMENT RETURN/2/
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Based on net asset value                          26.48%       (37.01)%        5.39%        15.60%         4.72%
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/3/
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Total expenses                                     0.21%         0.21%         0.21%         0.21%         0.20%
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
Total expenses after expense reductions             0.20%         0.20%         0.20%         0.20%       n/a
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Net investment income                              2.20%         2.16%         1.83%         1.78%         1.69%
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
SUPPLEMENTAL DATA
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
 Net assets, end of year (000)                 $ 215,333     $ 169,425     $ 330,892     $ 270,407     $ 308,836
--------------------------------------------   ---------     ---------     ---------     ---------     ---------
Portfolio turnover of the Master Portfolio             5%            8%            7%           14%           10%
--------------------------------------------   ---------     ---------     ---------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Includes the reinvestment of dividends and distributions.

/3/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

20

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the Fund is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about the Fund, may be obtained free of charge, along with the Fund's annual and semi-annual reports, by calling (800) 537-4942 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS

If you have any questions about the Fund, please:
Call: 1-800-537-4942 (toll-free)
8:30 a.m. to 6:30 p.m. (Eastern time) on any business day.

WORLD WIDE WEB
The Fund currently does not have a Fund website, but the Fund's annual and semi- annual shareholder reports, Prospectus and SAI are available free of charge online at the SEC'S website www.sec.gov.

WRITTEN CORRESPONDENCE

BlackRock Funds III
P.O. Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about the Fund, including the SAI, by visiting the EDGAR database on the SEC website (www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at
(202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-S&P500-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III

PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                            TICKER SYMBOL
---------------------------     --------------
BlackRock Bond Index Fund                WFBIX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

  KEY FACTS AND DETAILS ABOUT THE FUND, INCLUDING
INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE
INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  INVESTMENT OBJECTIVE............................... 1
  PRINCIPAL INVESTMENT STRATEGIES OF THE FUND........ 2
  PRINCIPAL RISKS OF INVESTING IN THE FUND........... 2
  PERFORMANCE INFORMATION............................ 3
  INVESTMENT ADVISER................................. 3
  PORTFOLIO MANAGERS................................. 4
  PURCHASE AND SALE OF FUND SHARES................... 4
  TAX INFORMATION.................................... 4

DETAILS ABOUT THE FUND

DETAILS ABOUT THE FUND'S INVESTMENT STRATEGIES........ 5
A FURTHER DISCUSSION OF RISKS......................... 6

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.....................  9
HOW TO BUY, SELL AND TRANSFER SHARES........  9
SHAREHOLDER SERVICING PAYMENTS.............. 13
CALCULATING THE FUND'S SHARE PRICE.......... 14
FUND DISTRIBUTIONS.......................... 14
SHORT TERM TRADING POLICY................... 14
TAXES....................................... 15
MASTER/FEEDER MUTUAL FUND STRUCTURE......... 16

MANAGEMENT OF THE FUND

INVESTMENT ADVISER.............. 17
PORTFOLIO MANAGERS.............. 17
ADMINISTRATIVE SERVICES......... 17
CONFLICTS OF INTEREST........... 18
VALUATION OF FUND INVESTMENTS... 18
CERTAIN FUND POLICIES........... 19

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUND........ 20

FOR MORE INFORMATION   ADDITIONAL INFORMATION............BACK COVER


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Fund Overview

KEY FACTS ABOUT BLACKROCK BOND INDEX FUND

INVESTMENT OBJECTIVE

BlackRock Bond Index Fund (the "Fund"), a series of BlackRock Funds III (the "Trust"), seeks to provide investment results that correspond to the total return performance of fixed-income securities in the aggregate, as represented by the Barclays Capital U.S. Aggregate Bond Index (the "Barclays Aggregate Index"). The Fund's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

ANNUAL FUND OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee                                                                          0.08%
 Distribution and/or Service (12b-1) Fees                                                 None
 Other Expenses                                                                          0.19%
  Administration Fees                                                                    0.15%
  Independent Expenses(1)(2)                                                             0.03%
  Acquired Fund Fees and Expenses (Underlying Funds)(3)                                  0.01%
 Total Annual Fund Operating Expenses(4)                                                 0.27%
 Fee Waivers and/or Expense Reimbursements(2)                                           (0.03%)
 Total Annual Fund Operating Expenses After Fee Waivers and/or Expense                   0.24%
  Reimbursements(2)(4)


(1) Independent Expenses have been restated to reflect current fees.

(2) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and Master Investment Portfolio ("MIP"), counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Bond Index Master Portfolio (the "Master Portfolio"), a series of MIP. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors) have contractually agreed to reimburse, or provide offsetting credits to, the Fund and the Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect the Fund's PRO RATA share of the fees and expenses incurred by investing in the underlying funds or certain other funds.

(4) Total Annual Fund Operating Expenses in the table above and the following example reflect the expenses of both the Fund and the Master Portfolio in which the Fund invests.

1

EXAMPLE

This Example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  25         $  81        $  146        $  337

PORTFOLIO TURNOVER

The Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Master Portfolio's portfolio turnover rate was 103% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND


The Fund pursues its investment objective by seeking to match the total return performance of the Barclays Capital U.S. Aggregate Bond Index (the "Barclays Aggregate Index"), which is composed of approximately 8,253 fixed-income securities. The fixed-income securities that comprise the Barclays Aggregate Index include U.S. government securities and investment- grade corporate bonds, as well as mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. The Fund invests in a representative sample of these securities. Securities are selected for investment by the Fund in accordance with their relative proportion within the Barclays Aggregate Index as well as based on credit quality, issuer sector, maturity structure, coupon rates and callability, among other factors. BFA, the investment adviser to the Master Portfolio in which the Fund invests, considers investments that provide substantially similar exposure to securities in the Barclays Aggregate Index to be investments comprising the Fund's benchmark index.

The Fund is managed by determining which securities are to be purchased or sold to reflect, to the extent feasible, the investment characteristics of its benchmark index. Under normal circumstances, at least 90% of the value of the Fund's assets, plus the amount of any borrowing for investment purposes, is invested in securities comprising the Barclays Aggregate Index, which, for the Fund, are considered bonds.

The Fund is a "feeder" fund that invests all of its investable assets in the Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include the Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency. The following is a summary description of certain risks of investing in the Fund.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. INDEX FUND RISK - An index fund has operating and other expenses while an index does not. As a result, while the Fund will attempt to track the Barclays Aggregate Index as closely as possible, it will tend to underperform the index to some degree over time.

2

. MORTGAGE- AND ASSET-BACKED SECURITIES RISKS - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of the Fund for each of the last ten calendar years. The average annual total return table (before and after taxes) compares the Fund's average annual total return to that of the Barclays Aggregate Index. How the fund has performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    11.76%
2001     8.80%
2002     9.90%
2003     3.92%
2004     4.05%
2005     2.12%
2006     4.76%
2007     7.16%
2008     5.91%
2009     5.21%

During the periods shown in the bar chart, the highest return for a quarter was 4.93% (quarter ended September 30, 2001) and the lowest return for a quarter was -2.50% (quarter ended June 30, 2004). The year-to-date return as of March 31, 2010 was 1.93%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                        1 YEAR         5 YEARS         10 YEARS
 BLACKROCK BOND INDEX FUND
  Return Before Taxes                                                                 5.21%           5.02%           6.32%
  Return After Taxes on Distributions                                                 3.65%           3.22%           4.27%
  Return After Taxes on Distributions and Sale of Fund Shares                         3.36%           3.21%           4.18%
 BARCLAYS CAPITAL U.S. AGGREGATE BOND INDEX (Reflects no deduction for fees,
 expenses or taxes)                                                                   5.93%           4.97%           6.33%

After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The Master Portfolio's investment adviser is BFA.

3

PORTFOLIO MANAGERS

                     PORTFOLIO
                     MANAGER OF
                     THE MASTER
                     PORTFOLIO
NAME                   SINCE        TITLE
 Lee Sterne            1996            Managing Director of BTC
 John Sulski           2009            Director of BTC
 Scott Radell          2009            Managing Director of BTC

PURCHASE AND SALE OF FUND SHARES

The Fund's minimum initial investment is $1 million, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange ("NYSE" or the "Exchange") is open. To purchase or sell shares, you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at (800) 441-7762, by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019, or by the internet at www.blackrock.com/funds).

To be eligible to purchase Fund shares, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an IRA; maintain an account with PNC Global Investment Servicing (U.S.) Inc., the Fund's transfer agent ("PNC GIS" or the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"); or initially invest a minimum of $1 million directly through the Transfer Agent (in certain situations this minimum initial investment may be reduced or waived; please contact your Shareholder Servicing Agent or the Transfer Agent for more information).

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the NYSE (generally 4:00 p.m. Eastern time) (or, if regular trading on the NYSE closes early, by such closing time) on any day the Fund is open (a "Business Day").

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and BlackRock Investments, LLC (the "Distributor"), the Fund's distributor, or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Details About the Fund

DETAILS ABOUT THE FUND'S INVESTMENT STRATEGIES


The Fund invests all of its assets in the Master Portfolio, a series of MIP, which has an investment objective and strategies substantially identical to those of the Fund. All discussion of the investment objective, strategies and risks of the Fund refers also to the investment objective, strategies and risks of the Master Portfolio, unless otherwise indicated. A description of the relationship of the Fund to the Master Portfolio appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

The Fund attempts to achieve, in both rising and falling markets, a correlation of at least 95% between the total return of its net assets before fees and expenses and the total return of the Fund's benchmark index, the Barclays Aggregate Index. Notwithstanding the factors described below, perfect (100%) correlation would be achieved if the total return of the Fund's net assets, before fees and expenses, increased or decreased exactly as the total return of the Fund's benchmark index increased or decreased. The Fund's ability to match its investment performance to the investment performance of its benchmark index may be affected by, among other things, the Fund's expenses, the amount of cash and cash equivalents held by the Fund, the manner in which the total return of the Fund's benchmark index is calculated; the size of the Fund's investment portfolio; and the timing, frequency and size of shareholder purchases and redemptions.

The Fund utilizes sampling techniques that are designed to allow the Fund to duplicate substantially the investment performance of the Barclays Aggregate Index. However, the Fund is not expected to track the Barclays Aggregate Index with the same degree of accuracy that complete replication of the Barclays Aggregate Index would provide. No attempt is made to manage the Fund using economic, financial or market analysis. In addition, at times, the portfolio composition of the Fund may be altered (or "rebalanced") to reflect changes in the characteristics of the index that the Fund tracks.

The Fund also may engage in futures and options transactions and other derivative securities transactions and lend its portfolio securities, each of which involves risk. The Fund may use futures contracts, options and other derivative transactions to manage its short-term liquidity and/or as substitutes for comparable market positions in the securities in its benchmark index. The Fund may also invest in high-quality money market instruments, including shares of money market funds advised by BFA.

Investors look to indexes as a standard of market performance. Indexes are model portfolios, that is, groups of stocks or bonds selected to represent an entire market or market segment. One way an index fund seeks to match an index's performance, before fees and expenses, is by buying and selling all of the index's securities in the same proportion as they are reflected in the index.

Since, as of March 31, 2010, there were over 9,000 securities included in the Barclays Aggregate Index, as a practical matter, it would be inefficient for the Fund to hold each security included in the Barclays Aggregate Index. The Fund can, however, substantially replicate the Barclays Aggregate Index's profile by holding a representative sample of securities in the Barclays Aggregate Index. It may, for example, hold U.S. government obligations and corporate bonds in a similar proportion to the Barclays Aggregate Index. Additionally, it can match certain Barclays Aggregate Index features such as:

. Average time to maturity for both government and corporate securities;

. Securities' coupon rates, which are the interest rates securities pay based on their face values;

. Economic sectors represented by securities;

. Credit quality of securities; and

. Whether or not securities are callable, which means the issuer has the right to repay principal and interest before maturity.

The Fund is designed for investors who desire a convenient way to invest in bonds issued in the United States. Although this market has increased in value over the long-term, it fluctuates and has also decreased in value over shorter time periods.

The Fund does not by itself constitute a balanced investment program. Diversifying your investments by buying shares in other funds may improve your long-term return as well as reduce volatility.

5

The Barclays Aggregate Index is maintained by Barclays Capital Inc. ("Barclays Capital"). Barclays Capital does not sponsor, endorse, sell or promote the Fund or the Master Portfolio. Barclays Capital makes no representation or warranty, expressed or implied, regarding the advisability of investing in the Fund or its Master Portfolio. Neither BFA nor BTC has or will have a role in maintaining the Barclays Aggregate Index.

A FURTHER DISCUSSION OF RISKS

This section contains a discussion of the general risks of investing in the Fund. "Description of the Fund and its Investments and Risks" in the Fund's Statement of Additional Information ("SAI") also includes more information about the Fund, its investments and the related risks. There can be no guarantee that the Fund will meet its objective or that the Fund's performance will be positive for any period of time. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the FDIC or by any bank or governmental agency.

MAIN RISKS OF INVESTING IN THE FUND:

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The Fund's use of derivatives may reduce the Fund's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund's derivatives positions to lose value. When a derivative is used as a hedge against a position that the Fund holds, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund's hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

INDEX FUND RISK - An index fund has operating and other expenses while an index does not. As a result, while the Fund will attempt to track the Barclays Aggregate Index as closely as possible, it will tend to underperform the index to some degree over time.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Although asset-backed and commercial mortgage-backed securities ("CMBS") generally experience less prepayment than residential mortgage-backed securities, mortgage-backed and asset-backed securities, like traditional fixed-income securities, are subject to credit, interest rate, prepayment and extension risks.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The Fund's investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The Fund's investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

6

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only ("IOs"), principal only ("POs") or an amount that remains after floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the Fund invests in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by fund management, it is possible that the Fund could lose all or substantially all of its investment.

The mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the Fund's mortgage-related investments. Delinquencies and losses on mortgage loans (including subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of real-estate values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the Fund may invest may also provide a degree of investment leverage, which could cause the Fund to lose all or substantially all of its investment.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

OTHER RISKS OF INVESTING IN THE FUND:

The Fund may also be subject to certain other risks associated with its investments and investment strategies, including:

CONCENTRATION RISK - The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) to approximately the same extent that its benchmark index concentrates in a particular industry. To the extent the Fund concentrates in a particular industry, it may be more susceptible to economic conditions and risks affecting that industry.

EXPENSE RISK - Fund expenses are subject to a variety of factors, including fluctuations in the Fund's net assets. Accordingly, actual expenses may be greater or less than those indicated. For example, to the extent that the Fund's net assets decrease due to market declines or redemptions, the Fund's expenses will increase as a percentage of Fund net assets. During periods of high market volatility, these increases in the Fund's expense ratio could be significant.

FOREIGN SECURITIES RISK - Because the Fund may invest in companies located in countries other than the United States, the Fund may be exposed to risks associated with foreign investments.

. The value of holdings traded outside the U.S. (and any hedging transactions in foreign currencies) will be affected by changes in currency exchange rates.

. The costs of non-U.S. securities transactions tend to be higher than those of U.S. transactions.

. Foreign holdings may be adversely affected by foreign government action.

7

. International trade barriers or economic sanctions against certain non-U.S. countries may adversely affect these holdings.

. The economies of certain countries may compare unfavorably with the U.S. economy.

. Foreign securities markets may be smaller than the U.S. markets, which may make trading more difficult.

LIQUIDITY RISK - Liquidity risk exists when particular investments are difficult to purchase or sell. The Fund's investments in illiquid securities may reduce the returns of the Fund because it may be difficult to sell the illiquid securities at an advantageous time or price. To the extent that the Fund's principal investment strategies involve derivatives or securities with substantial market and/or credit risk, the Fund will tend to have the greatest exposure to liquidity risk.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the index that the Fund tracks, the Fund may hold securities of companies that present risks that an investment adviser researching individual securities might seek to avoid.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the Fund may lose money and there may be a delay in recovering the loaned securities. The Fund could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the Fund.

As with all mutual funds, the Fund must maintain cash balances to meet redemption requests, which may lower its overall performance.

FOR A DESCRIPTION OF THE FUND'S POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE MASTER PORTFOLIO'S PORTFOLIO HOLDINGS AND A FURTHER DISCUSSION OF THE FUND'S INVESTMENTS AND RISKS, PLEASE REFER TO THE FUND'S SAI.

8

Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

To be eligible to purchase Fund shares, you must:

. Invest through an employer-sponsored or individual retirement savings plan;

. Invest the proceeds rolled over from such retirement savings plan into an IRA;

. Maintain an account with the Transfer Agent or with one of the Fund's Shareholder Servicing Agents; or

. Initially invest a minimum of $1 million directly through the Transfer Agent (in certain situations this minimum initial investment may be reduced or waived; please contact your Shareholder Servicing Agent or the Transfer Agent for more information).

HOW TO BUY, SELL AND TRANSFER SHARES


The following chart summarizes how to buy, sell and transfer shares through your financial professional or other financial intermediary. You may also buy, sell and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling or transferring shares through BlackRock, call (800) 537-4942. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

The Fund may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders, and suspend and resume the sale of Fund shares at any time and for any reason.

In addition, the Fund may waive certain requirements regarding the purchase, sale or transfer of shares described below.

          HOW TO BUY SHARES
                   YOUR CHOICES        IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE   Determine           The minimum initial investment in the Fund is $1 million.
                   the amount of
                   your investment
                   Have your           The price of your shares is based on the next calculation of the Fund's net
                   financial           asset value ("NAV") after your order is placed. Any purchase orders placed
                   intermediary        prior to the close of business on a Business Day will be priced at the NAV
                   submit your         determined that day. Certain financial intermediaries, however, may
                   purchase order      require submission of orders prior to that time. A broker-dealer or financial
                                       institution maintaining the account in which you hold shares may charge
                                       a separate account, service or transaction fee on the purchase or sale of
                                       Fund shares that would be in addition to the fees and expenses shown in
                                       the Fund's "Fees and Expenses" table.
                                       Purchase orders placed after that time will be priced at the NAV
                                       determined on the next Business Day. The Fund may reject any order to
                                       buy shares and may suspend the sale of shares at any time. Financial
                                       intermediaries may charge a processing fee to confirm a purchase.
                   Or contact          To purchase shares directly with BlackRock, call (800) 537-4942 and
                   BlackRock (for      request a new account application. Mail the completed application, along
                   accounts held       with a check payable to "BlackRock Funds," to the Transfer Agent at the
                   directly with       address on the application.
                   BlackRock)
ADD TO YOUR        Purchase            There is no minimum investment for additional purchases.
INVESTMENT         additional shares

9

HOW TO BUY SHARES
                 YOUR CHOICES              IMPORTANT INFORMATION FOR YOU TO KNOW
                 Have your                 To purchase additional shares, you may contact your financial professional
                 financial                 or financial intermediary. For more details on purchasing by Internet, see
                 professional              below.
                 or financial
                                           PURCHASE BY TELEPHONE: Call (800) 537-4942 and speak with one of our
                 intermediary
                                           representatives. The Fund has the right to reject any telephone request for
                 submit your
                                           any reason.
                 purchase order
                 for additional shares
                                           PURCHASE IN WRITING: You may send a written request to BlackRock at the
                                           address on the back cover of this Prospectus.
                                           PURCHASE BY VRU: Shares may also be purchased by use of the Fund's
                                           automated voice response unit service ("VRU") at (800) 537-4942.
                 Or contact                PURCHASE BY INTERNET: You may purchase your shares, and view activities
                 BlackRock                 in your account, by logging onto the BlackRock website at
                 (for accounts held        www.blackrock.com/funds. Purchases made on the Internet using the
                 directly with             Automated Clearing House Network ("ACH") will have a trade date that is
                 BlackRock)                the day after the purchase is made. Certain institutional clients' purchase
                                           orders for shares placed by wire prior to the close of business on a
                                           Business Day will be placed at the NAV determined that day. Contact your
                                           financial intermediary or BlackRock for further information. The Fund limits
                                           Internet purchases in shares of the Fund to $25,000 per trade. Please read
                                           the On-Line Services Disclosure Statement and User Agreement, the
                                           Terms and Conditions page and the Consent to Electronic Delivery
                                           Agreement (if you consent to electronic delivery), before attempting to
                                           transact online.
                                           The Fund employs reasonable procedures to confirm that transactions
                                           entered over the Internet are genuine. By entering into the User
                                           Agreement with the Fund in order to open an account through the
                                           website, the shareholder waives any right to reclaim any losses from the
                                           Fund or any of its affiliates incurred through fraudulent activity.
                 Acquire additional        All dividends and capital gains distributions are automatically reinvested
                 shares by                 without a sales charge. To make any changes to your dividend and/or
                 reinvesting               capital gains distributions options, please call (800) 537-4942, or contact
                 dividends and             your financial professional (if your account is not held directly with
                 capital gains             BlackRock).
                 Participate               BlackRock's AIP allows you to invest a specific amount on a periodic basis
                 in the Automatic          from your checking or savings account into your investment account.
                 Investment Plan ("AIP")
HOW TO PAY FOR   Making payment            Payment for an order must be made in Federal funds or other immediately
SHARES           for                       available funds by the time specified by your financial professional or other
                 purchases                 financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                           on the first business day (in the case of shares) following BlackRock's
                                           receipt of the order. If payment is not received by this time, the order will
                                           be canceled and you and your financial professional or other financial
                                           intermediary will be responsible for any loss to the Fund.
                                           For shares purchased directly from the Fund, a check payable to
                                           "BlackRock Funds," which bears the name of the Fund you are purchasing,
                                           must accompany a completed purchase application. There is a $20 fee for
                                           each purchase check that is returned due to insufficient funds.
                                           The Fund does not accept third-party checks. You may also wire Federal
                                           funds to the Fund to purchase shares, but you must call (800) 537-4942
                                           before doing so to confirm the wiring instructions.

10

       HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL   Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       The price of your shares is based on the next calculation of the Fund's
SHARES            intermediary    NAV after your order is placed. For your redemption request to be priced at
                  submit your     the NAV on the day of your request, you must submit your request to your
                  sales order     financial intermediary prior to that day's close of business on a Business
                                  Day. Certain financial intermediaries, however, may require submission of
                                  orders prior to that time. Any redemption request placed after that time
                                  will be priced at the NAV at the close of business on the next Business
                                  Day.
                                  Financial intermediaries may charge a fee to process a redemption of
                                  shares.
                                  The Fund may reject an order to sell shares under certain circumstances.
                  Selling         METHODS OF REDEEMING:
                  shares held
                                  REDEEM BY TELEPHONE: You may sell shares of the Fund held directly at
                  directly
                                  BlackRock by telephone request if certain conditions are met and if the
                  with
                                  amount being sold is less than (i) $100,000 for payments by check or (ii)
                  BlackRock
                                  $250,000 for payments through the ACH or wire transfer. Certain
                                  redemption requests may require written instructions with a medallion
                                  signature guarantee. Call (800) 537-4942 for details.
                                  Certain redemption requests, such as those in excess of these amounts,
                                  must be in writing with a medallion signature guarantee.
                                  You can obtain a medallion signature guarantee stamp from a bank,
                                  securities dealer, securities broker, credit union, savings and loan
                                  association, national securities exchange or registered securities
                                  association. A notary public seal will not be acceptable.
                                  The Fund, its administrator and the Distributor will employ reasonable
                                  procedures to confirm that instructions communicated by telephone are
                                  genuine. The Fund and its service providers will not be liable for any loss,
                                  liability, cost or expense for acting upon telephone instructions that are
                                  reasonably believed to be genuine in accordance with such procedures.
                                  The Fund may refuse a telephone redemption request if it believes it is
                                  advisable to do so.
                                  During periods of substantial economic or market change, telephone
                                  redemptions may be difficult to complete. Please find below alternative
                                  redemption methods.
                                  REDEEM BY VRU: Shares may also be redeemed by use of the Fund's VRU.
                                  Payment for shares redeemed by VRU may be made for non-retirement
                                  accounts in amounts up to $25,000, either through check, ACH or wire.
                                  REDEEM BY INTERNET: You may redeem in your account by logging onto
                                  the BlackRock website at www.blackrock.com/funds. Proceeds from
                                  Internet redemptions may be sent via check, ACH or wire to the bank
                                  account of record. Payment for shares redeemed via Internet may be
                                  made for non-retirement accounts in amounts up to $25,000, either
                                  through check, ACH or wire.

11

HOW TO SELL SHARES
                   YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                                   REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                                   BlackRock, P.O. Box 9819, Providence, RI 02940-8019 or, for overnight
                                   delivery, 101 Sabin Street, Pawtucket, RI 02860-1427. All shareholders on
                                   the account must sign the letter. A medallion signature guarantee will
                                   generally be required but may be waived in certain limited circumstances.
                                   You can obtain a medallion signature guarantee stamp from a bank,
                                   securities dealer, securities broker, credit union, savings and loan
                                   association, national securities exchange or registered securities
                                   association. A notary public seal will not be acceptable. If you hold stock
                                   certificates, return the certificates with the letter. Proceeds from
                                   redemptions may be sent via check, ACH or wire to the bank account of
                                   record.
                                   PAYMENT OF REDEMPTION PROCEEDS
                                   Redemption proceeds may be paid by check or, if the Fund has verified banking
                                   information on file, through ACH or by wire transfer.
                                   PAYMENT BY CHECK: BlackRock will normally mail redemption proceeds
                                   within seven days following receipt of a properly completed request.
                                   Shares can be redeemed by telephone and the proceeds sent by check to
                                   the shareholder at the address on record. Shareholders will pay $15 for
                                   redemption proceeds sent by check via overnight mail. You are responsible
                                   for any additional charges imposed by your bank for this service.
                                   PAYMENT BY WIRE TRANSFER: Payment for redeemed shares for which a
                                   redemption order is received before 4:00 p.m. (Eastern time) on a
                                   Business Day is normally made in Federal funds wired to the redeeming
                                   shareholder on the next Business Day, provided that the Fund's custodian
                                   is also open for business. Payment for redemption orders received after
                                   4:00 p.m. (Eastern time) or on a day when the Fund's custodian is closed
                                   is normally wired in Federal funds on the next Business Day following
                                   redemption on which the Fund's custodian is open for business. The Fund
                                   reserves the right to wire redemption proceeds within seven days after
                                   receiving a redemption order if, in the judgment of the Fund, an earlier
                                   payment could adversely affect the Fund.
                                   If a shareholder has given authorization for expedited redemption, shares
                                   can be redeemed by Federal wire transfer to a single previously designated
                                   bank account. Shareholders will pay $7.50 for redemption proceeds sent
                                   by Federal wire transfer. You are responsible for any additional charges
                                   imposed by your bank for this service. No charge for wiring redemption
                                   payments with respect to the Fund is imposed by the Fund.
                                   The Fund is not responsible for the efficiency of the Federal wire system or
                                   the shareholder's firm or bank. To change the name of the single,
                                   designated bank account to receive wire redemption proceeds, it is
                                   necessary to send a written request to the Fund at the address on the
                                   back cover of this Prospectus.

12

HOW TO SELL SHARES
                   YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                                   PAYMENT BY ACH: Redemption proceeds may be sent to the shareholder's
                                   bank account (checking or savings) via ACH. Payment for redeemed
                                   shares for which a redemption order is received before 4:00 p.m. (Eastern
                                   time) on a Business Day is normally sent to the redeeming shareholder
                                   the next Business Day, with receipt at the receiving bank within the next
                                   two business days (48-72 hours), provided that the Fund's custodian is
                                   also open for business. Payment for redemption orders received after 4:00
                                   p.m. (Eastern time) or on a day when the Fund's custodian is closed is
                                   normally sent on the next Business Day following redemption on which
                                   the Fund's custodian is open for business.
                                   The Fund reserves the right to send redemption proceeds within seven
                                   days after receiving a redemption order if, in the judgment of the Fund, an
                                   earlier payment could adversely affect the Fund. No charge for sending
                                   redemption payments via ACH is imposed by the Fund. If you make a
                                   redemption request before the Fund has collected payment for the
                                   purchase of shares, the Fund may delay mailing your proceeds. This delay
                                   will usually not exceed ten days.

                                               HOW TO TRANSFER YOUR ACCOUNT
                     YOUR CHOICES             IMPORTANT INFORMATION FOR YOU TO KNOW
TRANSFER SHARES TO   Transfer to a            You may transfer your shares of the Fund only to another financial
ANOTHER SECURITIES   participating            professional or financial intermediary that has an agreement with the
DEALER OR OTHER      financial                Distributor. Certain shareholder services may not be available for the
FINANCIAL            professional or          transferred shares. All future trading of these assets must be coordinated
INTERMEDIARY         other                    by the receiving firm.
                     financial
                                              If your account is held directly with BlackRock, you may call (800) 537-
                     intermediary
                                              4942 with any questions; otherwise please contact your financial
                                              intermediary to accomplish the transfer of shares.
                     Transfer to a            You must either:
                     non-participating
                                              oTransfer your shares to an account with the Fund; or
                     financial professional
                     or other
                                              oSell your shares, paying any applicable deferred sales charge.
                     financial intermediary
                                              If your account is held directly with BlackRock, you may call (800) 537-4942
                                              with any questions; otherwise please contact your financial intermediary to
                                              accomplish the transfer of shares.

SHAREHOLDER SERVICING PAYMENTS


The Fund has adopted a shareholder servicing plan (the "Plan") that allows the Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of the Fund's shares. Because the fees paid by the Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Fund and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that the Fund may pay to a Financial Intermediary pursuant to the Plan and fees the Fund pays to the Transfer Agent, BFA, on behalf of the Fund, may enter into non-Plan

13

agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Fund and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Financial Intermediary for details about payments it may receive from the Fund or from BFA or its affiliates. For more information, see the Fund's SAI.

CALCULATING THE FUND'S SHARE PRICE

The Fund's share price (also known as the Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

The Fund's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating the Fund's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of the Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Fund's SAI includes a description of the methods for valuing the Master Portfolio's investments, including a description of the circumstances in which the Master Portfolio's investments would be valued using fair value pricing and the effects of using fair value pricing.

FUND DISTRIBUTIONS

The Fund makes distributions of its net investment income to shareholders every month. The Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by the Fund will be automatically reinvested in additional shares of the Fund, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and the Fund's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The Fund is not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of the Fund and its shareholders. For example, large flows of cash into and out of the Fund may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the Fund's investment goal. Frequent trading may cause the Fund to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the Fund's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. The Fund will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of Fund Investments" below.

The Fund discourages market timing and seeks to prevent frequent purchases and sales or exchanges of Fund shares that it determines may be detrimental to the Fund or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of Fund shares because certain legitimate strategies will not result in harm to the Fund or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, the Fund believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If the Fund rejects your purchase or exchange order, you will not be able to execute that transaction, and the Fund will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with the Fund, the Fund may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by the Fund. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide the Fund with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the Fund. While the Fund monitors for market timing activity, the Fund may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the Fund. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in the Fund's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by the Fund to be engaged in market timing or other improper trading activity, the Fund's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

The Fund may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

14

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Fund and its U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Fund's SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the Fund's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the Fund generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the Fund's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S and certain foreign corporations. Distributions of the Fund are not expected to be attributable to qualified dividend income. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) None of the distributions of the Fund are expected to qualify for the dividends received deductions available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

In addition, if you sell your Fund shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

Sales proceeds generally are taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

If you buy the Fund's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of the Fund and the Fund holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the Fund sells the appreciated securities and distributes the realized gain on the sale. The Fund has built up, or has the potential to build up, high levels of unrealized appreciation in its investments.

After the end of each year, the Fund will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

15

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Fund if you fail to provide the Fund with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE


The Fund does not have its own investment adviser. Instead, the Fund invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to the Master Portfolio. The Master Portfolio may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolio and, therefore, the Fund.

FEEDER FUND EXPENSES

Feeder funds, including the Fund, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw the Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw the Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

16

Management of the Fund

INVESTMENT ADVISER


The Fund is a "feeder" fund that invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolio. BFA manages the investment of the Master Portfolio's assets and provides the Master Portfolio with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolio, BFA is entitled to receive a management fee at the annual rate of 0.08% of the Master Portfolio's average daily net assets.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolio invests.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreement with BFA is available in the Fund's annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS


BFA uses teams of portfolio managers, investment strategists and other investment specialists (the "Portfolio Management Team") to manage the Master Portfolio to reflect, to the extent feasible, the investment characteristics of its respective benchmark index, and BFA employs a combination of proprietary investment management systems and procedures to validate the consistent application of its investment methods. This team approach to portfolio management brings together many disciplines and leverages BFA's extensive resources. The team members act collaboratively with the other members of the Portfolio Management Team on all aspects concerning the Master Portfolio. Each member of the Portfolio Management Team, including the below-listed members, is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of the team to focus on certain asset classes, implementing investment strategies, researching and reviewing investment strategies, and overseeing members of the Portfolio Management Team with more limited responsibilities, but each member of the Portfolio Management Team has appropriate limitations on his authority for risk management and compliance purposes.

The members of the Portfolio Management Team for the Master Portfolio that have the most significant day-to-day management responsibility are: Lee Sterne, John Sulski and Scott Radell.

Mr. Sterne has been employed as a senior portfolio manager with BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A. ("BGI")) since 2004. Mr. Sterne has been a member of the Portfolio Management Team for the Master Portfolio since 1996.

Mr. Sulski has been employed as a portfolio manager with BFA and BTC since 2009. Previously, Mr. Sulski was a portfolio manager and credit trader with BGFA and BGI from June 2004 to November 2009. Mr. Sulski has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2009.

Mr. Radell has been employed as a portfolio manager with BFA and BTC since 2009. Mr. Radell was a credit strategist from 2003 to 2004 before becoming a portfolio manager at BGFA and BGI in 2004. Mr. Radell has been one of the portfolio managers primarily responsible for the day-to-day management of the Master Portfolio since 2009.

The Fund's SAI provides additional information about the compensation of the above-listed members of the Portfolio Management Team, other accounts they manage and their ownership of shares of the Fund.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Fund's administrator:

. Supervises the Fund's administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

17

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.15% of the average daily net assets of the Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Fund, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Fund or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Fund. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Fund directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Fund and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Fund and may result in an Affiliate or an Entity having positions that are adverse to those of the Fund.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, an Affiliate or an Entity may compete with the Fund for appropriate investment opportunities. The results of the Fund's investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Fund may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Fund. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Fund.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Fund's activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Fund may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Fund also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Fund or who engage in transactions with or for the Fund, and may receive compensation for such services. The Fund may also make brokerage and other payments to Affiliates or Entities in connection with the Fund's portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Fund and its shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

18

Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolio has retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolio to the extent that the Master Portfolio participates in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolio, including a fee based on the returns earned on the Master Portfolio's investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolio may lend its portfolio securities under the securities lending program.

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. The Fund calculates the net asset value of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00 p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

The Fund's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. The Fund values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If the Fund invests in foreign securities, these securities may trade on weekends or other days when the Fund does not price its shares. As a result, the Fund's net asset value may change on days when you will not be able to purchase or redeem the Fund's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, the Fund's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing the Fund's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the Fund. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining the Fund's net asset value.

The Fund may accept orders from certain authorized financial intermediaries or their designees. The Fund will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Fund is subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, the Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Fund reserves the right to reject purchase orders from persons who have not submitted information sufficient to allow the Fund to verify their identity. The Fund also reserves the right to redeem any amounts in the Fund from persons whose identity it is unable to verify on a timely basis. It is the Fund's policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

19

Financial Highlights

The financial highlights table is intended to help investors understand the financial performance of the shares of the Fund for the past five years. Certain information reflects financial results for a single share of the Fund. The total returns in the table represent the rate of return that an investor would have earned (or lost) on an investment in shares of the Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with the Fund's financial statements, is included in the Fund's annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-537-4942 (toll-free) from 8:30 a.m. to 6:30 p.m. Eastern time on any business day.

BLACKROCK BOND INDEX FUND

FINANCIAL HIGHLIGHTS

                                                                          YEAR ENDED DECEMBER 31,
                                                ---------------------------------------------------------------------------
                                                     2009             2008           2007          2006          2005
                                                ---------------- ---------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------------           -                ---              -             -             -
 Net asset value, beginning of year                 $  9.82         $  9.74         $   9.59      $   9.64      $   9.93
-----------------------------------------------     -------         ----------      --------      --------      --------
Net investment income                                 0.401           0.47              0.48          0.46          0.44
 Net realized and unrealized gain (loss)              0.10            0.09              0.19          (0.02)        (0.23)
-----------------------------------------------     -------         ----------      --------      --------      --------
Net increase from investment operations               0.50            0.56              0.67          0.44          0.21
-----------------------------------------------     -------         ----------      --------      --------      --------
 Dividends and distributions from:
  Net investment income                              ( 0.42)           (0.48)           (0.52)        (0.49)        (0.50)
  Return of capital                                       -            (0.00)/2/            -             -             -
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
Total dividends and distributions                     (0.42)           (0.48)           (0.52)        (0.49)        (0.50)
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
 Net asset value, end of year                       $  9.90         $  9.82         $   9.74      $   9.59      $   9.64
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
TOTAL INVESTMENT RETURN/3/
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
 Based on net asset value                              5.21%          5.91   %           7.16%         4.76%         2.12%
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/4/
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
 Total expenses                                        0.25%          0.26   %           0.28%         0.26%         0.23%
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
Total expenses after expense reductions                0.23%          0.23   %           0.23%         0.23%       n/a
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
 Net investment income                                 4.05%          4.84   %           5.00%         4.83%         4.42%
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
SUPPLEMENTAL DATA
-----------------------------------------------     -------         -----------     ---------     ---------     ---------
 Net assets, end of year (000)                      $156,688        $132,997        $ 111,847     $ 103,592     $ 203,771
-----------------------------------------------     ---------       -----------     ---------     ---------     ---------
Portfolio turnover of the Master Portfolio/5/           103%/6/           89%              61%           57%           76%
-----------------------------------------------     ----------      -----------     ---------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Rounds to less than $0.01.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/5/ Includes TBA transactions.

/6/ Excluding TBA transactions, the portfolio turnover rate would have been 87%.

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the Fund is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about the Fund, may be obtained free of charge, along with the Fund's annual and semi-annual reports, by calling (800) 537-4942 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS

If you have any questions about the Fund, please:
Call: 1-800-537-4942 (toll-free)
8:30 a.m. to 6:30 p.m. (Eastern time) on any business day.

WORLD WIDE WEB
The Fund currently does not have a Fund website, but the Fund's annual and semi- annual shareholder reports, Prospectus and SAI are available free of charge online at the SEC's website www.sec.gov.

WRITTEN CORRESPONDENCE

BlackRock Funds III
P.O. Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about the Fund, including the SAI, by visiting the EDGAR database on the SEC website (www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at
(202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-BONDIND-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
LIFEPATH(Reg. TM) PORTFOLIOS

INVESTOR A SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

PORTFOLIO                                                        TICKER SYMBOL
------------------------------------------------------------     --------------
LifePath(Reg. TM) Retirement Portfolio - Investor A Shares                LPRAX
LifePath 2020 Portfolio(Reg. TM) - Investor A Shares                      LPRCX
LifePath 2030 Portfolio(Reg. TM) - Investor A Shares                      LPRDX
LifePath 2040 Portfolio(Reg. TM) - Investor A Shares                      LPREX
LifePath(Reg. TM) 2050 Portfolio - Investor A Shares                      LPRFX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

LIFEPATH PORTFOLIO

  KEY FACTS AND DETAILS ABOUT THE LIFEPATH PORTFOLIOS, INCLUDING
OVERVIEW
  INVESTMENT OBJECTIVES, PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND
  EXPENSE INFORMATION, AND HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO.....................  1
  KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO...........................  7
  KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO........................... 14
  KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO........................... 21
  KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO........................... 28

DETAILS ABOUT THE LIFEPATH PORTFOLIOS

INVESTMENT TIME HORIZONS....................................... 35
A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES........ 36
A FURTHER DISCUSSION OF RISK FACTORS........................... 42

ACCOUNT INFORMATION

DETAILS ABOUT INVESTOR A SHARES......................... 48
DISTRIBUTION AND SERVICE PAYMENTS....................... 50
HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES.......... 51
ACCOUNT SERVICES AND PRIVILEGES......................... 57
LIFEPATH PORTFOLIOS' RIGHTS............................. 58
CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE........ 59
LIFEPATH PORTFOLIO DISTRIBUTIONS........................ 59
SHORT TERM TRADING POLICY............................... 59
TAXES................................................... 60
MASTER/FEEDER AND FUND OF FUNDS STRUCTURES.............. 61

MANAGEMENT OF THE LIFEPATH PORTFOLIOS

INVESTMENT ADVISER......................... 62
PORTFOLIO MANAGERS......................... 62
ADMINISTRATIVE SERVICES.................... 63
CONFLICTS OF INTEREST...................... 63
CERTAIN LIFEPATH PORTFOLIO POLICIES........ 64

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE LIFEPATH PORTFOLIOS........ 66
DISCLAIMERS............................................. 71

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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LifePath Retirement Portfolio Overview

KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO

INVESTMENT OBJECTIVE

LifePath Retirement Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors seeking income and moderate long-term growth of capital. LifePath Retirement Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH RETIREMENT PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor A Shares (formerly, Class R Shares) of LifePath Retirement Portfolio. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in certain funds in the fund complex advised by BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors) and its affiliates (the "BlackRock Funds"). More information about these and other discounts is available from your financial professional and in the "Details About Investor A Shares" section of the prospectus ("Prospectus") and in the "Purchase, Redemption and Pricing of Shares" section of the Statement of Additional Information ("SAI").

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Sales Charge (Load) Imposed on Purchases                                             5.25%
 (as percentage of offering price)
 Maximum Deferred Sales Charge (Load) (as                                                     None(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.25%
 Other Expenses                                                                               0.52%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.02%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.33%
 Total Annual Class Operating Expenses(6)                                                     1.45%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.10%
  Reimbursements(2)(4)(6)


(1) A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $1,000,000 or more.

(2) BFA, the investment adviser to LifePath Retirement Master Portfolio (the "Retirement Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Retirement Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the Retirement Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of those fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath Retirement Portfolio and the Retirement Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath Retirement Portfolio and Retirement Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

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(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath Retirement Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor A Shares of LifePath Retirement Portfolio and the Retirement Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the Retirement Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor A Shares of LifePath Retirement Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor A Shares of LifePath Retirement Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor A Shares of LifePath Retirement Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  631       $  893        $  1,211        $  2,110

PORTFOLIO TURNOVER

The Retirement Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath Retirement Portfolio's performance. During the most recent fiscal year, the Retirement Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH RETIREMENT PORTFOLIO


LifePath Retirement Portfolio invests all of its assets in the Retirement Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath Retirement Portfolio is designed for investors seeking current income and moderate long-term growth of capital. As of March 31, 2010, LifePath Retirement Portfolio held approximately 39% of its assets in Underlying Funds that invest primarily in equity securities, 61% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in real estate investment trusts ("REITs"), foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. Because LifePath Retirement Portfolio is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain LifePath Retirement Portfolio's risk profile.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH RETIREMENT PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath Retirement Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath Retirement Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath Retirement Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath Retirement Portfolio.

. ALLOCATION RISK - LifePath Retirement Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath Retirement Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

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. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath Retirement Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath Retirement Portfolio's use of derivatives may reduce LifePath Retirement Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath Retirement Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath Retirement Portfolio will lose money. These risks include:

. LifePath Retirement Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath Retirement Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath Retirement Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath Retirement Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath Retirement Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath Retirement Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath Retirement Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath Retirement Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath Retirement Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are

3

subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath Retirement Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath Retirement Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath Retirement Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath Retirement Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath Retirement Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Investor A Shares of LifePath Retirement Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Investor A Shares of LifePath Retirement Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Investor A Shares were designated Class R Shares and were subject to different sales charges and service and distribution fees. Class R Shares commenced operations on April 30, 2001. For the period January 1, 2000 to April 30, 2001, the performance information shown is based on the returns of LifePath Retirement Portfolio's Institutional Shares, and for the period April 30, 2001 to December 31, 2009, is based on LifePath Retirement Portfolio's Class R Shares, in each case adjusted to reflect the fees and expenses of Investor A Shares. The average annual total return table compares the performance of Investor A Shares of LifePath Retirement Portfolio to that of the LifePath Retirement Portfolio Custom Benchmark. The LifePath Retirement Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath Retirement Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath Retirement Portfolio reflect the Retirement Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath Retirement Portfolio reflect the direct investment by the Retirement Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath Retirement Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BFA and its affiliates had not waived or reimbursed certain LifePath Retirement Portfolio expenses during these periods, LifePath Retirement Portfolio's returns would have been lower.

LIFEPATH RETIREMENT PORTFOLIO - INVESTOR A SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000      4.48%
2001      1.40%
2002     -4.98%
2003     15.51%
2004      6.07%
2005      4.05%
2006      8.52%
2007      4.17%
2008    -15.24%
2009     17.96%

During the periods shown in the bar chart, the highest return for a quarter was 11.32% (quarter ended June 30, 2003) and the lowest return for a quarter was -7.90% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 2.76%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath Retirement Portfolio - Investor A Shares
  Return Before Taxes                                                                       17.96%       3.30%       3.79%
  Return After Taxes on Distributions                                                       16.80%       2.11%       2.56%
  Return After Taxes on Distributions and Sale of Fund Shares                               11.71%       2.26%       2.67%
 LifePath Retirement Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         16.75%       4.06%       5.09%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER


The Retirement Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                         THE
                      RETIREMENT
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon          2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw           2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath Retirement Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath Retirement Portfolio, you should contact LifePath Retirement Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath Retirement Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath Retirement Portfolio may reduce or waive these investment minimums in some cases:

5

                                INVESTOR A SHARES
                                =======================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                . $250 for certain fee-based programs
                                . $100 for retirement plans
                                . $50, if establishing Automatic Investment Plan
Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath Retirement Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath Retirement Portfolio through a broker-dealer or other financial intermediary, LifePath Retirement Portfolio and BlackRock Investments, LLC, LifePath Retirement Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath Retirement Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath Retirement Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

6

LifePath 2020 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2020 Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020. LifePath 2020 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2020 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor A Shares of LifePath 2020 Portfolio. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in certain funds in the fund complex advised by BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), and its affiliates. More information about these and other discounts is available from your financial professional and in the "Details About Investor A Shares" section of the Prospectus and in the "Purchase, Redemption and Pricing of Shares" section of the Statement of Additional Information ("SAI").

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Sales Charge (Load) Imposed on Purchases          5.25%
 (as percentage of offering price)
 Maximum Deferred Sales Charge (Load) (as                  None(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                       0.35%
 Distribution and/or Service (12b-1) Fees                                                0.25%
 Other Expenses                                                                          0.51%
  Administration Fees                                                                    0.50%
  Independent Expenses(3)(4)                                                             0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                   0.33%
 Total Annual Class Operating Expenses(6)                                                1.44%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                        (0.34)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                  1.10%
  Reimbursements(2)(4)(6)


(1) A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $1,000,000 or more.

(2) BFA, the investment adviser to LifePath 2020 Master Portfolio (the "2020 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2020 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2020 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3)

Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2020 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to the such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2020 Portfolio and the 2020 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2020 Portfolio and 2020 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2020 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

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(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor A Shares of LifePath 2020 Portfolio and the 2020 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2020 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor A Shares of LifePath 2020 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor A Shares of LifePath 2020 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor A Shares of LifePath 2020 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  631       $  892        $  1,208        $  2,102

PORTFOLIO TURNOVER

The 2020 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2020 Portfolio's performance. During the most recent fiscal year, the 2020 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2020 PORTFOLIO


LifePath 2020 Portfolio invests all of its assets in the 2020 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2020 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2020. As of March 31, 2010, LifePath 2020 Portfolio held approximately 60% of its assets in Underlying Funds that invest primarily in equity securities, 40% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2020 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2020 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2020 Portfolio, which may be a primary source of income after retirement.

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The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their respective target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2020 Portfolio, and determine whether any changes are required to enable LifePath 2020 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2020 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2020 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2020 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2020 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2020 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2020 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2020 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2020 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

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PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2020 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2020 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2020 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2020 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2020 Portfolio.

. ALLOCATION RISK - LifePath 2020 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2020 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2020 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2020 Portfolio's use of derivatives may reduce LifePath 2020 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2020 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2020 Portfolio will lose money. These risks include:

. LifePath 2020 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2020 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

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. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2020 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2020 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2020 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2020 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2020 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2020 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2020 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2020 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2020 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2020 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2020 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2020 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Investor A Shares of LifePath 2020 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Investor A Shares of LifePath 2020 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Investor A Shares were designated Class R Shares and were subject to different sales charges and service and distribution fees. Class R Shares commenced operations on April 30, 2001. For the period January 1, 2000 to April 30, 2001, the performance information shown is based on the returns of LifePath 2020 Portfolio's Class I Shares, and for the period April 30, 2001 to December 31, 2009, is based on LifePath 2020 Portfolio's Class R Shares, in each case adjusted to reflect the fees and expenses of Investor A Shares. The average annual total return table compares the performance of Investor A Shares of LifePath 2020 Portfolio to that of the LifePath 2020 Portfolio Custom Benchmark. The LifePath 2020 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2020 Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for LifePath 2020 Portfolio reflect the 2020 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2020 Portfolio reflect the direct investment by the 2020 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2020 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Sales charges are not reflected in

11

the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BFA and its affiliates had not waived or reimbursed certain LifePath 2020 Portfolio expenses during these periods, LifePath 2020 Portfolio's returns would have been lower.

LIFEPATH 2020 PORTFOLIO - INVESTOR A SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -3.99%
2001    -7.43%
2002   -13.01%
2003    20.37%
2004     9.01%
2005     6.28%
2006    12.77%
2007     3.06%
2008   -25.57%
2009    22.42%

During the periods shown in the bar chart, the highest return for a quarter was 13.74% (quarter ended June 30, 2009) and the lowest return for a quarter was -14.22% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.21%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2020 Portfolio - Investor A Shares
  Return Before Taxes                                                                       22.42%       2.39%       1.33%
  Return After Taxes on Distributions                                                       21.24%       1.59%       0.63%
  Return After Taxes on Distributions and Sale of Fund Shares                               14.65%       1.75%       0.94%
 LifePath 2020 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         22.84%       3.27%       2.78%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

BFA and BTC have in the past waived and may from time to time agree to waive all or a portion of their fees or reimburse expenses to the Master Portfolio or LifePath 2020 Portfolio. When they do so, LifePath 2020 Portfolio's operating expenses are reduced so that LifePath 2020 Portfolio's total return is increased. These waivers and reimbursements may be discontinued at any time, except as described above in "Fees and Expenses of LifePath 2020 Portfolio." In the absence of such waivers and/or reimbursements, LifePath 2020 Portfolio's total return would be lower.

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INVESTMENT ADVISER

The 2020 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2020
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005         Director of BTC
 Leslie Gambon          2007         Director of BTC
 Alan Mason             2009         Managing Director of BTC
 Amy Whitelaw           2010         Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2020 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2020 Portfolio, you should contact LifePath 2020 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2020 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2020 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR A SHARES
                                =======================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                . $250 for certain fee-based programs
                                . $100 for retirement plans
                                . $50, if establishing Automatic Investment Plan
Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2020 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2020 Portfolio through a broker-dealer or other financial intermediary, LifePath 2020 Portfolio and BlackRock Investments, LLC, LifePath 2020 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2020 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2020 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

13

LifePath 2030 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2030 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030. LifePath 2030 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2030 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor A Shares of LifePath 2030 Portfolio. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in certain funds in the fund complex advised by BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), and its affiliates. More information about these and other discounts is available from your financial professional and in the "Details About Investor A Shares" section of the prospectus ("Prospectus") and in the "Purchase, Redemption and Pricing of Shares" section of the Statement of Additional Information ("SAI").

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Sales Charge (Load) Imposed on Purchases               5.25%
 (as percentage of offering price)
 Maximum Deferred Sales Charge (Load) (as                  None(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                       0.35%
 Distribution and/or Service (12b-1) Fees                                                0.25%
 Other Expenses                                                                          0.51%
  Administration Fees                                                                    0.50%
  Independent Expenses(3)(4)                                                             0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                   0.34%
 Total Annual Class Operating Expenses(6)                                                1.45%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                        (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                  1.10%
  Reimbursements(2)(4)(6)


(1) A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $1,000,000 or more.

(2) BFA, the investment adviser to LifePath 2030 Master Portfolio (the "2030 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2030 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2030 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2030 Portfolio and the 2030 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2030 Portfolio and 2030 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2030 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

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(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor A Shares of LifePath 2030 Portfolio and the 2030 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2030 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor A Shares of LifePath 2030 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor A Shares of LifePath 2030 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor A Shares of LifePath 2030 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  631       $  893        $  1,211        $  2,110

PORTFOLIO TURNOVER

The 2030 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2030 Portfolio's performance. During the most recent fiscal year, the 2030 Master Portfolio's portfolio turnover rate was 7% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2030 PORTFOLIO


LifePath 2030 Portfolio invests all of its assets in the 2030 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2030 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2030. As of March 31, 2010, LifePath 2030 Portfolio held approximately 75% of its assets in Underlying Funds that invest primarily in equity securities, 25% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2030 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2030 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2030 Portfolio, which may be a primary source of income after retirement.

15

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their respective target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2030 Portfolio, and determine whether any changes are required to enable LifePath 2030 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2030 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2030 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2030 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2030 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2030 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2030 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2030 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2030 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

16

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2030 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2030 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2030 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2030 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2030 Portfolio.

. ALLOCATION RISK - LifePath 2030 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2030 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2030 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2030 Portfolio's use of derivatives may reduce LifePath 2030 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2030 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2030 Portfolio will lose money. These risks include:

. LifePath 2030 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2030 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

17

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2030 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2030 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2030 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2030 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2030 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2030 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2030 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2030 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2030 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2030 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2030 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2030 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Investor A Shares of LifePath 2030 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Investor A Shares of LifePath 2030 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Investor A Shares were designated Class R Shares and were subject to different sales charges and service and distribution fees. Class R Shares commenced operations on April 30, 2001. For the period January 1, 2000 to April 30, 2001, the performance information shown is based on the returns of LifePath Retirement Portfolio's Institutional Shares, and for the period April 30, 2001 to December 31, 2009, is based on LifePath Retirement Portfolio's Class R Shares, in each case adjusted to reflect the fees and expenses of Investor A Shares. The average annual total return table compares the performance of Investor A Shares of LifePath 2030 Portfolio to that of the LifePath 2030 Portfolio Custom Benchmark. The LifePath 2030 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2030 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2030 Portfolio reflect the 2030 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2030 Portfolio reflect the direct investment by the 2030 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2030 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges.

18

If BFA and its affiliates had not waived or reimbursed certain LifePath 2030 Portfolio expenses during these periods, LifePath 2030 Portfolio's returns would have been lower.

LIFEPATH 2030 PORTFOLIO - INVESTOR A SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -5.90%
2001   -10.54%
2002   -16.04%
2003    23.48%
2004    10.51%
2005     7.37%
2006    14.83%
2007     2.38%
2008   -31.19%
2009    25.51%

During the periods shown in the bar chart, the highest return for a quarter was 16.67% (quarter ended June 30, 2009) and the lowest return for a quarter was -17.93% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.49%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5YEARS      10YEARS
 LifePath 2030 Portfolio - Investor A Shares
  Return Before Taxes                                                                       25.51%      1.74%        0.50%
  Return After Taxes on Distributions                                                       24.49%      0.90%       -0.25%
  Return After Taxes on Distributions and Sale of Fund Shares                               16.70%      1.29%        0.31%
 LifePath 2030 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         27.05%      2.70%        1.82%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%      0.69%       -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%      4.97%        6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%      6.04%        2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%      2.88%        2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%      4.63%        7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%      2.00%        9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

19

INVESTMENT ADVISER

The 2030 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2030
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2030 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2030 Portfolio, you should contact LifePath 2030 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2030 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2030 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR A SHARES
                                =======================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan
Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2030 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2030 Portfolio through a broker-dealer or other financial intermediary, LifePath 2030 Portfolio and BlackRock Investments, LLC, LifePath 2030 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2030 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2030 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

20

LifePath 2040 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2040 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040. LifePath 2040 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2040 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor A Shares of LifePath 2040 Portfolio. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in certain funds in the fund complex advised by BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), and its affiliates. More information about these and other discounts is available from your financial professional and in the "Details About Investor A Shares" section of the prospectus ("Prospectus") and in the "Purchase, Redemption and Pricing of Shares" section of the Statement of Additional Information ("SAI").

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Sales Charge (Load) Imposed on Purchases               5.25%
 (as percentage of offering price)
 Maximum Deferred Sales Charge (Load) (as                  None(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                      0.35%
 Distribution and/or Service (12b-1) Fees                                               0.25%
 Other Expenses                                                                         0.51%
  Administration Fees                                                                   0.50%
  Independent Expenses(3)(4)                                                            0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                  0.34%
 Total Annual Class Operating Expenses(6)                                               1.45%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                       (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                 1.10%
  Reimbursements(2)(4)(6)


(1) A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $1,000,000 or more.

(2) BFA, the investment adviser to LifePath 2040 Master Portfolio (the "2040 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2040 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2040 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2040 Portfolio and the 2040 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2040 Portfolio and the 2040 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2040 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

21

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor A Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2040 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor A Shares of LifePath 2040 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor A Shares of LifePath 2040 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor A Shares of LifePath 2040 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  631       $  893        $  1,211        $  2,110

PORTFOLIO TURNOVER

The 2040 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2040 Portfolio's performance. During the most recent fiscal year, the 2040 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2040 PORTFOLIO


LifePath 2040 Portfolio invests all of its assets in the 2040 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of the equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2040 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2040. As of March 31, 2010, LifePath 2040 Portfolio held approximately 88% of its assets in Underlying Funds that invest primarily in equity securities, 12% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2040 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2040 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2040 Portfolio, which may be a primary source of income after retirement.

22

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their respective target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2040 Portfolio, and determine whether any changes are required to enable LifePath 2040 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2040 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2040 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2040 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2040 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2040 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2040 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2040 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2040 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

23

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2040 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2040 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2040 Portfolio or your investment may not perform as well as other similar investments. The following is a summary description of certain risks of investing in LifePath 2040 Portfolio. An investment in LifePath 2040 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

. ALLOCATION RISK - LifePath 2040 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2040 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2040 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2040 Portfolio's use of derivatives may reduce LifePath 2040 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2040 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2040 Portfolio will lose money. These risks include:

. LifePath 2040 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2040 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

24

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2040 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2040 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2040 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2040 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2040 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2040 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2040 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2040 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2040 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2040 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2040 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2040 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Investor A Shares of LifePath 2040 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Investor A Shares of LifePath 2040 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Investor A Shares were designated Class R Shares and were subject to different sales charges and service and distribution fees. Class R Shares commenced operations on April 30, 2001. For the period January 1, 2000 to April 30, 2001, the performance information shown is based on the returns of LifePath Retirement Portfolio's Institutional Shares, and for the period April 30, 2001 to December 31, 2009, is based on LifePath Retirement Portfolio's Class R Shares, in each case adjusted to reflect the fees and expenses of Investor A Shares. The average annual total return table compares the performance of Investor A Shares of LifePath 2040 Portfolio to that of the LifePath 2040 Portfolio Custom Benchmark. The LifePath 2040 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2040 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2040 Portfolio reflect 2040 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2040 Portfolio reflect the direct investment by 2040 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2040 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges.

25

If BFA and its affiliates had not waived or reimbursed certain LifePath 2040 Portfolio expenses during these periods, LifePath 2040 Portfolio's returns would have been lower.

LIFEPATH 2040 PORTFOLIO - INVESTOR A SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -9.96%
2001   -13.64%
2002   -18.58%
2003    27.66%
2004    11.08%
2005     8.01%
2006    16.64%
2007     1.78%
2008   -35.56%
2009    27.85%

During the periods shown in the bar chart, the highest return for a quarter was 19.06% (quarter ended June 30, 2009) and the lowest return for a quarter was -20.88% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.75%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2040 Portfolio - Investor A Shares
  Return Before Taxes                                                                       27.85%       1.10%      -0.53%
  Return After Taxes on Distributions                                                       26.99%       0.66%      -1.02%
  Return After Taxes on Distributions and Sale of Fund Shares                               18.29%       0.88%      -0.40%
 LifePath 2040 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         30.52%       2.15%       0.87%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

26

INVESTMENT ADVISER

The 2040 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2040
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2040 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2040 Portfolio, you should contact LifePath 2040 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2040 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2040 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR A SHARES
                                =======================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan
Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2040 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2040 Portfolio through a broker-dealer or other financial intermediary, LifePath 2040 Portfolio and BlackRock Investments, LLC, LifePath 2040 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2040 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2040 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

27

LifePath 2050 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2050 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050. LifePath 2050 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2050 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor A Shares of LifePath 2050 Portfolio. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in certain funds in the fund complex advised by BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), and its affiliates. More information about these and other discounts is available from your financial professional and in the "Details About Investor A Shares" section of the prospectus ("Prospectus") and in the "Purchase, Redemption and Pricing of Shares" section of the Statement of Additional Information ("SAI").

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Sales Charge (Load) Imposed on Purchases               5.25%
 (as percentage of offering price)
 Maximum Deferred Sales Charge (Load) (as                  None(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.25%
 Other Expenses                                                                               0.83%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.33%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.34%
 Total Annual Class Operating Expenses(6)                                                     1.77%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                             (0.67)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.10%
  Reimbursements(2)(4)(6)


(1) A contingent deferred sales charge ("CDSC") of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $1,000,000 or more.

(2) BFA, the investment adviser to LifePath 2050 Master Portfolio (the "2050 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2050 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2050 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2050 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2050 Portfolio and the 2050 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2050 Portfolio and the 2050 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2050 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

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(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor A Shares of LifePath 2050 Portfolio and the 2050 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2050 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor A Shares of LifePath 2050 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor A Shares of LifePath 2050 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor A Shares of LifePath 2050 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  631       $  926        $  1,312        $  2,391

PORTFOLIO TURNOVER

The 2050 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2050 Portfolio's performance. During the most recent fiscal year, the 2050 Master Portfolio's portfolio turnover rate was 12% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2050 PORTFOLIO


LifePath 2050 Portfolio invests all of its assets in the 2050 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2050 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2050. As of March 31, 2010, LifePath 2050 Portfolio held approximately 98% of its assets in Underlying Funds that invest primarily in equity securities, 1% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2050 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2050 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2050 Portfolio, which may be a primary source of income after retirement.

29

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their respective target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2050 Portfolio, and determine whether any changes are required to enable LifePath 2050 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2050 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2050 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2050 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2050 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2050 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2050 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2050 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2050 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

30

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2050 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2050 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2050 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2050 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2050 Portfolio.

. ALLOCATION RISK - LifePath 2050 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2050 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2050 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2050 Portfolio's use of derivatives may reduce LifePath 2050 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2050 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2050 Portfolio will lose money. These risks include:

. LifePath 2050 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2050 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

31

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2050 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2050 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2050 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2050 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2050 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2050 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2050 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2050 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2050 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2050 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2050 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2050 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Investor A Shares of LifePath 2050 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Investor A Shares of LifePath 2050 Portfolio for the last calendar year. Prior to May 1, 2010, Investor A Shares were designated Class R Shares and were subject to different sales charges and service and distribution fees. Class R Shares for LifePath 2050 Portfolio commenced operations on June 30, 2008. The performance information shown is based on the returns of LifePath 2050 Portfolio's Class R Shares, adjusted to reflect the fees and expenses of Investor A Shares. The average annual total return table compares the performance of Investor A Shares of LifePath 2050 Portfolio to that of the LifePath 2050 Portfolio Custom Benchmark. The LifePath 2050 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2050 Portfolio invests according to their weightings as of the most recent quarter-end. How LifePath 2050 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. If BFA and its affiliates had not waived or reimbursed certain LifePath 2050 Portfolio expenses during these periods, LifePath 2050 Portfolio's returns would have been lower.

32

LIFEPATH 2050 PORTFOLIO - INVESTOR A SHARES

ANNUAL TOTAL RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   30.08%

During the period shown in the bar chart, the highest return for a quarter was 20.89% (quarter ended June 30, 2009) and the lowest return for a quarter was -12.76% (quarter ended March 31, 2009). The year-to-date return as of March 31, 2010 was 4.06%.

                                                                                                                 SINCE
AS OF 12/31/09                                                                                               INCEPTION JUNE
AVERAGE ANNUAL TOTAL RETURNS                                                                   1 YEAR           30, 2008
 LifePath 2050 Portfolio - Investor A Shares
  Return Before Taxes                                                                           30.08%          -8.07%
  Return After Taxes on Distributions                                                           28.41%          -8.93%
  Return After Taxes on Distributions and Sale of Fund Shares                                   19.68%          -7.29%
 LifePath 2050 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                             34.11%          -6.38%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                            27.25%            N/A
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                              5.93%             N/A
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             43.60%            N/A
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                          0.16%             N/A
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                           11.41%            N/A
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             38.25%             N/A

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

33

INVESTMENT ADVISER

The 2050 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2050
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2050 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2050 Portfolio, you should contact LifePath 2050 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2050 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2050 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR A SHARES
                                =======================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan
Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2050 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2050 Portfolio through a broker-dealer or other financial intermediary, LifePath 2050 Portfolio and BlackRock Investments, LLC, LifePath 2050 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2050 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2050 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the LifePath Portfolios

INVESTMENT TIME HORIZONS

Each LifePath Portfolio seeks to maximize return consistent with the quantitatively measured risk that investors on average may be willing to accept given a particular investment time horizon. An investor's time horizon marks the point when the investor plans to start making net withdrawals from his or her investments, in other words, the time when they will cease making new contributions to their investments. For many LifePath Portfolio investors, their time horizon is tied to the date that they plan to retire and begin gradually utilizing their investment to support themselves in retirement. For other LifePath Portfolio investors, their time horizon may represent the date when they plan to make substantial withdrawals for another purpose, such as a major purchase.

As a general rule, investors with a longer time horizon have a greater tolerance for risk than investors with a shorter time horizon. Long-term investors are more likely to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns. Each LifePath Portfolio has its own time horizon, as described in its investment objective in each LifePath Portfolio's "Key Facts" section in this Prospectus, which affects the targeted risk level of that LifePath Portfolio and, in turn, its asset allocation.

The allocations for LifePath Retirement Portfolio reflect the expectation that investors in or near retirement, or otherwise seeking current income, are willing to take some risk of loss of their investment in hopes of achieving moderate long term growth of capital. LifePath Retirement Portfolio is designed to help balance two risk factors that investors face during retirement: market risk (potential declines in market values) and longevity risk (living longer than expected). Specifically, the portfolio seeks to enable investors to maintain a steady withdrawal rate (about 3-5% per year) throughout their retirement without exhausting their investment. There is no guarantee that the performance of LifePath Retirement Portfolio will be sufficient to enable this withdrawal rate or that any one withdrawal rate is appropriate for all investors. Investors should work with a financial advisor or other expert to determine a sustainable withdrawal rate for their circumstances, and that withdrawal rate should be periodically reassessed throughout retirement as the value of the investor's portfolio changes.

Each LifePath Portfolio has a distinct investment objective tied to its time horizon:

. LifePath Retirement Portfolio is managed for investors seeking income and moderate long-term growth of capital.

. LifePath 2020 Portfolio is managed for investors planning to retire
(or begin to withdraw substantial portions of their investment) approximately in the year 2020.

. LifePath 2030 Portfolio is managed for investors planning to retire
(or begin to withdraw substantial portions of their investment) approximately in the year 2030.

. LifePath 2040 Portfolio is managed for investors planning to retire
(or begin to withdraw substantial portions of their investment) approximately in the year 2040.

. LifePath 2050 Portfolio is managed for investors planning to retire
(or begin to withdraw substantial portions of their investment) approximately in the year 2050.

You should carefully consider the asset allocation and risks of each LifePath Portfolio before deciding whether to invest.

The LifePath Portfolios are designed to offer individual investors comprehensive asset allocation strategies tailored to the time when they expect to begin withdrawing assets. Asset allocation is the distribution of investments among broad types of asset classes: equity securities, bonds and money market instruments. Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has the same objective and strategies as the applicable LifePath Portfolio. LifePath Retirement Portfolio invests all of its assets in Retirement Master Portfolio. LifePath 2020 Portfolio invests all of its assets in 2020 Master Portfolio. LifePath 2030 Portfolio invests all of its assets in 2030 Master Portfolio. LifePath 2040 Portfolio invests all of its assets in 2040 Master Portfolio. LifePath 2050 Portfolio invests all of its assets in 2050 Master Portfolio. To implement the asset allocation strategy, each Master Portfolio, in turn, invests in a combination of Underlying Funds in proportions based on its own comprehensive investment strategy that gradually becomes more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase. BFA is the investment adviser to the Master Portfolios. For simplicity's sake, all discussion of investment objective, strategies and risks of a particular LifePath Portfolio refers also to the

35

investment objective, strategies and risks of the applicable Master Portfolio, unless otherwise indicated. A description of the relationship of the LifePath Portfolios to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder and Fund of Funds Structures."

WHICH LIFEPATH PORTFOLIO TO CONSIDER

The first step in choosing which LifePath Portfolio to consider is answering a key question: When will you need the money you are thinking of investing? Will it be in ten years, when your kids are ready for college? Or 30 years, when you retire?

The number in the name of most of the LifePath Portfolios is actually a year - a "target year" when you might expect to begin withdrawing your money. Selecting the LifePath Portfolio that may be most appropriate for your investment may be as simple as matching your target year with the closest LifePath Portfolio target year.

For example, let's say that you are investing for retirement purposes, and that you expect to retire at age 60. If you are 45 years old, you have 15 years before retirement. By adding 15 to the current year, you can define your "target year." If you expect to retire in the year 2025, as in this example, you may conclude that LifePath 2020 Portfolio is the most appropriate LifePath Portfolio for you.

The investment mix of the LifePath Portfolios gradually shifts from a greater concentration of higher-risk investments (namely, equity securities funds) to a greater concentration of lower-risk investments (namely, bond funds), thereby making the LifePath Portfolios increasingly conservative.

In making your investment decision, you should keep in mind:

. The LifePath Portfolios' investment strategies derive from the risk tolerance of average investors with a particular time horizon.

. The LifePath Portfolios' time horizons are based on the year in their name, except for LifePath Retirement Portfolio, which is designed for investors who are currently withdrawing, or plan in the near future to begin withdrawing, a substantial portion of their investment.

If you are willing to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns, you may invest some or all of your assets in a LifePath Portfolio with a longer time horizon. If you desire a more conservative investment and are willing to forego some potential returns, you may invest some or all of your assets in a LifePath Portfolio with a shorter time horizon. The final choice is yours.

A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES

Each LifePath Portfolio invests all of its assets in a corresponding Master Portfolio which allocates and reallocates its assets among the Underlying Funds. The Master Portfolios with longer time horizons invest a greater portion of their assets in Underlying Funds that invest in equity securities, which provide a greater opportunity for capital appreciation over the long-term but have a greater risk of loss. The Master Portfolios with shorter time horizons invest a greater portion of their assets in Underlying Funds that invest in bonds and money market instruments, which typically offer reduced risk and price volatility but forego some potential returns. Accordingly, under normal circumstances, the Master Portfolios with shorter time horizons have lower expected returns than the Master Portfolios with longer time horizons. In addition to investing in Underlying Funds, each Master Portfolio may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and invest the collateral in certain short-term instruments either directly or through one or more joint accounts or money market funds, as described in greater detail in the LifePath Portfolios' SAI.

As each Master Portfolio approaches its designated time horizon, it systematically seeks to reduce the level of risk by allocating assets more conservatively among the Underlying Funds. This systematic shift toward more conservative investments is designed to reduce the risk of significant reductions in the value of an investment in a Master Portfolio as it approaches its time horizon.

For example, LifePath Retirement Portfolio has entered its "retirement phase" and seeks to maximize returns consistent with the risk that an average investor in retirement may be willing to accept. This does not mean, however, that it invests exclusively, or primarily, in Underlying Funds that are money market funds. Rather, because BFA believes that most investors are still willing to take some risks in pursuing returns even while drawing on their investments, almost all of LifePath Retirement Portfolio's assets will continue to be allocated to Underlying Funds that are equity and bond funds.

In determining the allocation of assets to the Underlying Funds, BFA uses a proprietary investment model that analyzes securities market data, including risk, asset class correlations, and expected returns, to provide portfolio

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allocations among the asset classes represented by the Underlying Funds. The allocations are periodically monitored and rebalanced in an effort to maximize expected return for a given level of risk. In managing the LifePath Portfolios, BFA focuses on long-term targets and objectives. The progression over time of a LifePath Portfolio's asset allocation to more conservative asset classes is a relatively steady process resulting in only gradual changes to the asset allocation from quarter to quarter. The Underlying Funds invest in a mix of equity securities, bonds and money market instruments. Certain Underlying Funds invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivatives, which are subject to additional risks, as described in the "Details About the LifePath Portfolios - A Further Discussion of Risk Factors" section of this Prospectus. The investment model adjusts each LifePath Portfolio's risk level by gradually making it more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase.

When a LifePath Portfolio reaches its stated time horizon and enters its most conservative phase, the allocation of its assets is expected to be similar to that of LifePath Retirement Portfolio. Such LifePath Portfolio and LifePath Retirement Portfolio may then continue to operate as separate funds or, subject to approval by the Trust's Board of Trustees, they may be merged into a single fund.

THE UNDERLYING FUNDS

Two of the Underlying Funds - Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio - are diversified portfolios of MIP. Active Stock Master Portfolio seeks to provide long-term appreciation of capital. BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors. CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return.

The remaining Underlying Funds, other than BlackRock Cash Funds: Institutional (the "Underlying Money Market Fund"), are ETFs that are part of the iShares family of funds ("Underlying iShares Funds"). Each of the Underlying iShares Funds seeks investment results that correspond generally to the performance, before fees and expenses, of its underlying index. As a result, adverse performance of a particular security in an Underlying iShares Fund's portfolio will ordinarily not result in the elimination of the security from the Underlying iShares Fund's portfolio. Each Underlying iShares Fund offers and issues iShares at their NAV per share only to certain institutional investors in aggregations of a specified number of iShares, generally in exchange for a basket of securities included in its underlying index, together with the deposit of a specified cash payment. The iShares for these Underlying iShares Funds are listed and traded on national securities exchanges and also may be listed on certain non-U.S. exchanges. BFA purchases iShares on behalf of the Master Portfolios in the secondary market.

The relative weightings for each Master Portfolio in the various Underlying Funds will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time.

Each Master Portfolio currently expects to invest in some or all of the Underlying Funds described below:

ACTIVE STOCK MASTER PORTFOLIO

Active Stock Master Portfolio seeks to provide long-term appreciation of capital. Active Stock Master Portfolio invests, under normal circumstances, at least 80% of its assets in common stocks. Active Stock Master Portfolio invests primarily in equity securities of U.S. companies with market capitalizations similar to the range of market capitalizations represented in the Standard & Poor's ("S&P") 500 Index(Reg. TM). BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors, such as relative values based on earnings and cash flows; earnings quality as measured by the company's financial condition and earnings reports; sentiment as expressed through management and market participant behavior; and industry classification. BFA considers risk parameters in deciding upon Active Stock Master Portfolio's aggregate holdings, and factors trading costs into its stock selection process.

COREALPHA BOND MASTER PORTFOLIO

CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return. BFA's models also allocate assets among bonds of different maturities based on yield characteristics and expectations. Specific investment selection decisions are made on the basis of evaluations of relative value, credit quality and other factors. CoreAlpha Bond Master Portfolio invests, under normal circumstances, at least 80% of its assets in bonds. For the purposes of this strategy, "bonds" include the following:
obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial

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mortgage-backed securities; debt obligations of U.S. corporations; U.S. dollar-denominated debt obligations of foreign issuers; municipal securities; and asset-backed securities. CoreAlpha Bond Master Portfolio invests a substantial portion of its assets in U.S.-registered, dollar-denominated bonds. CoreAlpha Bond Master Portfolio may invest in bonds of any maturity or duration.

BLACKROCK CASH FUNDS: INSTITUTIONAL

BlackRock Cash Funds: Institutional seeks a high level of income consistent with liquidity and the preservation of capital. BlackRock Cash Funds:
Institutional invests in high-quality, short-term money market instruments that include fixed-rate, floating-rate and variable-rate debt securities. BlackRock Cash Funds: Institutional also may invest in high-quality, short-term U.S. and foreign government debt, including the debt of agencies and instrumentalities, such as the Federal National Mortgage Association ("Fannie Mae"), U.S. and foreign bank obligations, corporate obligations, repurchase agreements and asset-backed securities.

UNDERLYING ISHARES FUNDS

In managing each of the Underlying iShares Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that has an investment profile similar to the underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the applicable underlying index. Underlying iShares Funds that use representative sampling may or may not hold all of the securities in the relevant underlying index.

ISHARES S&P 500 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P 500 Index(Reg. TM), which measures the performance of the large-capitalization sector of the U.S. equity market. The component stocks are weighted according to the float-adjusted market value of their outstanding shares.

ISHARES S&P MIDCAP 400 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P MidCap 400 IndexTM, which measures the performance of the mid-capitalization sector of the U.S. equity market. The stocks in the S&P MidCap 400 IndexTM have a market capitalization between $750 million and $3.3 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation. The S&P MidCap 400 IndexTM consists of stocks from a broad range of industries.

ISHARES S&P SMALLCAP 600 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P SmallCap 600 IndexTM, which measures the performance of the small-capitalization sector of the U.S. equity market. The stocks in the S&P SmallCap 600 IndexTM have a market capitalization between $200 million and $1 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation.

ISHARES S&P NATIONAL AMT-FREE MUNICIPAL BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P National AMT-Free Municipal Bond Index, which measures the performance of the investment-grade segment of the U.S. municipal bond market. As of May 31, 2009, there were 8,709 issues in the S&P National AMT-Free Municipal Bond Index.

ISHARES S&P NORTH AMERICAN NATURAL RESOURCES SECTOR INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P North American Natural Resources Sector IndexTM, which measures the performance of U.S.-traded stocks of natural resource-related companies in the U.S. and Canada, and includes companies in the following categories: producers of oil, gas and consumable fuels, energy equipment and services, metals and mining, manufacturers of paper and forest products, and producers of construction materials, containers and packaging.

ISHARES RUSSELL MIDCAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell Midcap Index, which measures the performance of the mid-capitalization sector of the U.S. equity market. The Russell Midcap Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000(Reg. TM) Index.

ISHARES RUSSELL 2000 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell 2000 Index, which measures the performance of the small capitalization sector of the U.S. equity market. The Russell 2000 Index is a float-adjusted, capitalization-weighted index of equity securities issued by the approximately 2,000 smallest issuers in the Russell 3000(Reg. TM) Index.

ISHARES COHEN & STEERS REALTY MAJORS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Cohen & Steers Realty Major Index (the "Cohen & Steers Index"),

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which consists of selected U.S. REITs. The objective of the Cohen & Steers Index is to represent relatively large and liquid REITs that may benefit from future consolidation and securitization of the U.S. real estate industry. REITs are selected for inclusion in the Cohen & Steers Index based on a rigorous review of several factors, including management, portfolio quality, and sector and geographic diversification. The REITs selected for inclusion in the Cohen & Steers Index must meet minimum market capitalization and liquidity requirements. The Cohen & Steers Index is weighted according to the total market value of each REIT's outstanding shares and is adjusted quarterly so that no REIT represents more than 8% of the Cohen & Steers Index. Within the REIT market, the Cohen & Steers Index is diversified across property sectors that represent the current market.

ISHARES FTSE EPRA/NAREIT DEVELOPED REAL ESTATE EX-U.S. INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which measures the stock performance of companies engaged in the ownership and development of the following real estate markets defined as developed by FTSE EPRA/NAREIT: Canada, Europe (including Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom (including the Channel Islands)), Middle East (Israel) and Asia (including Australia, Hong Kong, Japan, New Zealand and Singapore). As of May 29, 2009, the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index was comprised of stocks of companies in the following markets: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Italy, Japan, Netherlands, New Zealand, Norway, Poland, Singapore, Spain, Sweden, Switzerland and the United Kingdom.

ISHARES MSCI CANADA INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Canada Index developed by MSCI, Inc. ("MSCI"). The MSCI Canada Index consists of stocks traded primarily on the Toronto Stock Exchange.

ISHARES MSCI EAFE INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE(Reg. TM) Index, which has been developed by MSCI as an equity benchmark for its international stock performance. The MSCI EAFE Index includes stocks from Europe, Australasia and the Far East.

ISHARES MSCI EAFE SMALL CAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE Small Cap Index, which represents the small cap size segment of the MSCI EAFE Index. The MSCI EAFE(Reg. TM) Index includes securities from Europe, Australasia and the Far East. Under MSCI's Global Investable Market Index methodology, the small cap universe consists of the securities of those companies whose securities are not included in the large cap or mid cap segments of a particular market, which together comprise approximately 85% of each market's free float-adjusted market capitalization. The small cap segment covers the 85%-99% range of each market's free float-adjusted market capitalization.

ISHARES MSCI EMERGING MARKETS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Emerging Markets Index, which is designed to measure equity market performance in the global emerging markets. As of September 30, 2009, the MSCI Emerging Markets Index consisted of the following 22 emerging market country indexes: Brazil, Chile, China, Colombia, the Czech Republic, Egypt, Hungary, India, Indonesia, Israel, Malaysia, Mexico, Morocco, Peru, the Philippines, Poland, Russia, South Africa, South Korea, Taiwan, Thailand and Turkey. Emerging market country indexes may be added to or deleted from the MSCI Emerging Markets Index from time to time. The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares funds that invest in securities in the MSCI Emerging Markets Index. BFA waives a portion of its advisory fees otherwise due from the iShares MSCI Emerging Markets Index Fund in an amount equal to the portfolio management fees incurred by assets that are invested in shares of other iShares funds.

ISHARES BARCLAYS 1-3 YEAR CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 1-3 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 3-7 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 3-7 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to three years and less than seven years.

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ISHARES BARCLAYS 7-10 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 7-10 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years.

ISHARES BARCLAYS 10-20 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 10-20 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to ten years and less than 20 years.

ISHARES BARCLAYS 20+ YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 20+ Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of 20 years or more.

ISHARES BARCLAYS AGGREGATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Aggregate Bond Index, which measures the performance of the total U.S. investment-grade bond market, which includes investment-grade U.S. Treasury bonds, government-related bonds, investment-grade corporate bonds, mortgage pass-through securities, commercial mortgage-backed securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Barclays Capital U.S. Aggregate Bond Index have $250 million or more of outstanding face value and have at least one year remaining to maturity. In addition, the securities must be U.S. dollar-denominated, fixed-rate and non-convertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and Eurobonds are excluded from the Barclays Capital U.S. Aggregate Bond Index. The Barclays Capital U.S. Aggregate Bond Index is market capitalization weighted and the securities are updated on the last calendar day of each month.

ISHARES BARCLAYS CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Government/Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS INTERMEDIATE CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS INTERMEDIATE GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Government/

Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS MBS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. MBS Index, which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Government National Mortgage Association, Fannie Mae and the Federal Home Loan Mortgage Corporation.

ISHARES BARCLAYS SHORT TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Short Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of between one and 12 months.

ISHARES BARCLAYS TIPS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L), which measures the performance of the inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS."

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ISHARES JPMORGAN USD EMERGING MARKETS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the JPMorgan EMBI Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark which tracks the total return of actively traded external debt instruments in emerging market countries.

ISHARES IBOXX $ HIGH YIELD CORPORATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the iBoxx(Reg. TM) $ Liquid High Yield Index, which is a rules-based index consisting of liquid U.S. dollar-denominated, high yield corporate bonds for sale in the United States, as determined by the International Index Company Limited ("IIC"). The iBoxx(Reg. TM) $ Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated high yield liquid corporate bond market. The iBoxx(Reg. TM) $ Liquid High Yield Index is a modified market value weighted index. There is no limit to the number of issues in the iBoxx(Reg. TM) $ Liquid High Yield Index, but as of June 30, 2009, the iBoxx(Reg. TM) $ Liquid High Yield Index included approximately 281 constituents.

The following table lists the Underlying Funds and the asset allocation for each Master Portfolio as of March 31, 2010. BFA allocates each Master Portfolio's assets among the Underlying Funds based on the Master Portfolio's investment objective and policies. The asset allocation for each Master Portfolio will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time:

UNDERLYING FUNDS
(as of March 31, 2010)

                                                    LIFEPATH     LIFEPATH    LIFEPATH    LIFEPATH    LIFEPATH
                                                   RETIREMENT      2020        2030        2040        2050
                                                    PORTFOLIO   PORTFOLIO   PORTFOLIO   PORTFOLIO    PORTFOLIO
CAPITAL GROWTH
MIP-Active Stock Master Portfolio                     19.45%       30.45%      38.39%      44.64%       49.18%
iShares S&P MidCap 400 Index Fund                      4.93%        5.87%       6.54%       7.14%        8.10%
iShares S&P SmallCap 600 Index Fund                    2.18%        2.58%       2.89%       3.16%        3.54%
iShares MSCI EAFE Index Fund                           6.74%       10.08%      12.60%      14.73%       17.01%
iShares Cohen & Steers Realty Majors Index Fund        0.62%        1.87%       2.73%       3.50%        4.01%
iShares FTSE EPRA/NAREIT Developed Real Estate         0.99%        2.99%       4.43%       5.62%        6.40%
ex-U.S. Index Fund
iShares MSCI Emerging Markets Index Fund               2.40%        3.70%       4.66%       5.47%        6.09%
iShares MSCI Canada Index Fund                         0.82%        1.25%       1.54%       1.82%        2.02%
iShares MSCI EAFE Small Cap Index Fund                 0.81%        1.25%       1.47%       1.72%        2.00%
CAPITAL GROWTH AND INCOME
MIP-CoreAlpha Bond Master Portfolio                   51.96%       34.27%      21.48%      10.89%        0.99%
iShares Barclays TIPS Bond Fund                        8.87%        5.49%       3.08%       1.08%       N/A
INCOME
BlackRock Cash Funds: Institutional - SL Agency        0.23%        0.20%       0.19%       0.23%        0.66%
Shares


Note: The allocation percentages may not add to, or may appear to exceed, 100% due to rounding.

"Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," "S&P 500 Index(Reg. TM)," "S&P MidCap 400 IndexTM," "S&P SmallCap 600 IndexTM," "S&P National AMT-Free Municipal Bond IndexTM," and "S&P North American Natural Resources Sector IndexTM" are trademarks of Standard & Poor's Financial Services LLC (a subsidiary of The McGraw-Hill Companies) licensed for use for certain purposes by BTC. The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P SmallCap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and iShares S&P North American Natural Resources Sector Index Fund that are based on S&P Indexes are not sponsored, endorsed, sold or promoted by S&P or its affiliates, and S&P and its affiliates make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"FTSE," "EPRA," "NAREIT" and "FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index" are marks that have been licensed for use for certain purposes by BTC. The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together the "FTSE Licensor Parties"), and the FTSE Licensor Parties make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Cohen & Steers" and "Cohen & Steers Realty Majors Index" are trademarks of Cohen & Steers Capital Management, Inc. ("Cohen & Steers") licensed for use for certain purposes by BTC. The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers, and Cohen & Steers makes no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Barclays Capital Inc.," "Barclays Capital U.S. 1-3 Year Credit Bond Index," "Barclays Capital U.S. 1-3 Year Treasury Bond Index," "Barclays Capital U.S. 3-7 Year Treasury Bond Index," "Barclays Capital U.S. 7-10 Year Treasury Bond Index," "Barclays Capital U.S. 10-20 Year Treasury Bond Index," "Barclays Capital U.S. 20+ Year Treasury Bond Index," "Barclays Capital U.S. Aggregate Bond Index," "Barclays Capital U.S. Credit Bond Index," "Barclays Capital U.S. Government/Credit Bond Index," "Barclays Capital U.S. Intermediate Credit Bond Index," "Barclays Capital U.S. Intermediate Government/Credit Bond Index," "Barclays Capital U.S. MBS Index," "Barclays Capital U.S. Short Treasury Bond Index," and the "Barclays Capital

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U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)" (collectively referred to as the "iShares Bond Fund Indexes") are trademarks of Barclays Bank PLC licensed for use for certain purposes by BTC. The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund are not sponsored, endorsed, sold or promoted by Barclays Capital Inc. ("Barclays Capital"), and Barclays Capital makes no representation or warranty, express or implied, regarding the advisability of investing in iShares. The iShares Bond Fund Indexes are maintained by Barclays Capital. Neither BTC nor BFA has or will have a role in maintaining the iShares Bond Fund Indexes.

"MSCI Canada Index/SM/," "MSCI EAFE(Reg. TM) Index" and "MSCI Emerging Markets Index/SM/" are servicemarks and "MSCI EAFE Small Cap Index" is a trademark of MSCI, and such marks have been licensed for use for certain purposes by BTC. The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI, and neither MSCI nor any other party makes any representation or warranty, express or implied, regarding the advisability of investing in iShares.

A FURTHER DISCUSSION OF RISK FACTORS

This section contains a description of the general risks of investing in the LifePath Portfolios. "Description of the LifePath Portfolios and their Investments and Risks" in the SAI also includes more information about the LifePath Portfolios, their investments and the related risks. There can be no guarantee that a LifePath Portfolio will meet its objective or that a LifePath Portfolio's performance will be positive for any period of time. An investment in a LifePath Portfolio is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

GENERAL

The NAV of each LifePath Portfolio's shares is neither insured nor guaranteed, is not fixed and will fluctuate.

GENERAL RISKS APPLICABLE TO THE LIFEPATH PORTFOLIOS

ALLOCATION RISK - The LifePath Portfolios' ability to achieve their investment goals depends upon BFA's skill in determining the LifePath Portfolios' strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, there is no guarantee that the Underlying Funds will achieve their investment objectives, and the Underlying Funds' performance may be lower than the performance of the asset class which they were selected to represent. The Underlying Funds may change their investment objectives or policies without the approval of the LifePath Portfolios. If an Underlying Fund were to change its investment objective or policies, the LifePath Portfolios might be forced to withdraw their investment from the Underlying Fund at a disadvantageous time and price.

CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the LifePath Portfolios' investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The LifePath Portfolios' use of derivatives may reduce the LifePath Portfolios' returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the LifePath Portfolios' use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the LifePath Portfolios to sell or otherwise close a derivatives position could expose the LifePath Portfolios to losses and could make derivatives more difficult for the LifePath Portfolios to value accurately. The LifePath Portfolios could also suffer losses related to their derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally,

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BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the LifePath Portfolios' derivatives positions to lose value. When a derivative is used as a hedge against a position that the LifePath Portfolios hold, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the LifePath Portfolios' hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EMERGING MARKETS RISK - The risks of foreign investments are usually much greater for emerging markets. Investments in emerging markets may be considered speculative. Emerging markets include those in countries defined as emerging or developing by the World Bank, the International Finance Corporation or the United Nations. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain small markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards and requirements comparable to those to which U.S. companies are subject.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments are more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation, high rates of inflation or unfavorable diplomatic developments. In the past, governments of such nations have expropriated substantial amounts of private property, and most claims of the property owners have never been fully settled. There is no assurance that such expropriations will not reoccur. In such an event, it is possible that the LifePath Portfolio could lose the entire value of its investments in the affected market. Some countries have pervasiveness of corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth. National policies that may limit the LifePath Portfolio's investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other foreign or U.S. governmental laws or restrictions applicable to such investments. Sometimes, they may lack or be in the relatively early development of legal structures governing private and foreign investments and private property. In addition to withholding taxes on investment income, some countries with emerging markets may impose differential capital gains taxes on foreign investors.

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the LifePath Portfolios could decline if the financial condition of the companies the LifePath Portfolios invest in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

FOREIGN SECURITIES RISK - Securities traded in foreign markets have often (though not always) performed differently from securities traded in the United States. However, such investments often involve special risks not present in U.S. investments that can increase the chances that the LifePath Portfolio will lose money. In particular, the LifePath Portfolio is subject to the risk that because there may be fewer investors on foreign exchanges and a smaller number of securities traded each day, it may be more difficult for the LifePath Portfolio to buy and sell securities on those exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

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CERTAIN RISKS OF HOLDING FUND ASSETS OUTSIDE THE UNITED STATES - The LifePath Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories. Some foreign banks and securities depositories may be recently organized or new to the foreign custody business. In addition, there may be limited or no regulatory oversight of their operations. Also, the laws of certain countries limit the LifePath Portfolio's ability to recover its assets if a foreign bank, depository or issuer of a security, or any of their agents, goes bankrupt. In addition, it is often more expensive for the LifePath Portfolio to buy, sell and hold securities in certain foreign markets than in the United States. The increased expense of investing in foreign markets reduces the amount the LifePath Portfolio can earn on its investments and typically results in a higher operating expense ratio for the LifePath Portfolio than for investment companies invested only in the United States.

CURRENCY RISK - Securities and other instruments in which the LifePath Portfolio invests may be denominated or quoted in currencies other than the U.S. dollar. For this reason, changes in foreign currency exchange rates can affect the value of the LifePath Portfolio.

Generally, when the U.S. dollar rises in value against a foreign currency, a security denominated in that currency loses value because the currency is worth fewer U.S. dollars. Conversely, when the U.S. dollar decreases in value against a foreign currency, a security denominated in that currency gains value because the currency is worth more U.S. dollars. This risk, generally known as "currency risk," means that a strong U.S. dollar will reduce returns for U.S. investors while a weak U.S. dollar will increase those returns.

FOREIGN ECONOMY RISK - The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. Certain foreign economies may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. In addition, the governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Any of these actions could severely affect securities prices or impair the LifePath Portfolio's ability to purchase or sell foreign securities or transfer the LifePath Portfolio's assets or income back into the United States, or otherwise adversely affect the LifePath Portfolio's operations.

Other potential foreign market risks include foreign exchange controls, difficulties in pricing securities, defaults on foreign government securities, difficulties in enforcing legal judgments in foreign courts and political and social instability. Diplomatic and political developments, including rapid and adverse political changes, social instability, regional conflicts, terrorism and war, could affect the economies, industries and securities and currency markets, and the value of the LifePath Portfolio's investments, in non-U.S. countries. These factors are extremely difficult, if not impossible, to predict and take into account with respect to the LifePath Portfolio's investments.

GOVERNMENTAL SUPERVISION AND REGULATION/ACCOUNTING STANDARDS - Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as such regulations exist in the United States. They also may not have laws to protect investors that are comparable to U.S. securities laws. For example, some foreign countries may have no laws or rules against insider trading. Insider trading occurs when a person buys or sells a company's securities based on material non-public information about that company. In addition, some countries may have legal systems that may make it difficult for the LifePath Portfolio to vote proxies, exercise shareholder rights, and pursue legal remedies with respect to its foreign investments. Accounting standards in other countries are not necessarily the same as in the United States. If the accounting standards in another country do not require as much detail as U.S. accounting standards, it may be harder for LifePath Portfolio management to completely and accurately determine a company's financial condition.

SETTLEMENT RISK - Settlement and clearance procedures in certain foreign markets differ significantly from those in the United States. Foreign settlement and clearance procedures and trade regulations also may involve certain risks (such as delays in payment for or delivery of securities) not typically associated with the settlement of U.S. investments.

At times, settlements in certain foreign countries have not kept pace with the number of securities transactions. These problems may make it difficult for the LifePath Portfolio to carry out transactions. If the LifePath Portfolio cannot settle or is delayed in settling a purchase of securities, it may miss attractive investment opportunities and certain of its assets may be uninvested with no return earned thereon for some period. If the LifePath Portfolio cannot settle or is delayed in settling a sale of securities, it may lose money if the value of the security then declines or, if it has contracted to sell the security to another party; the LifePath Portfolio could be liable for any losses incurred.

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INVESTMENTS IN MUTUAL FUNDS AND ETFS RISK - Each LifePath Portfolio will invest substantially all of its assets in Underlying Funds, so the LifePath Portfolio's investment performance is directly related to the performance of the Underlying Funds. The LifePath Portfolios may also directly invest in ETFs. The LifePath Portfolio's net asset value will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in the LifePath Portfolios will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs. For example, the LifePath Portfolios indirectly pay a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds and ETFs.

One Underlying Fund may buy the same securities that another Underlying Fund sells. In addition, a LifePath Portfolio may buy the same securities that an Underlying Fund sells, or vice-versa. If this happens, an investor in the LifePath Portfolio would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in a LifePath Portfolio may receive taxable gains from portfolio transactions by an Underlying Fund, as well as taxable gains from transactions in shares of the Underlying Fund by the LifePath Portfolio. Certain of the Underlying Funds may hold common portfolio securities, thereby reducing the diversification benefits of the LifePath Portfolios.

In order to minimize expenses, the LifePath Portfolios intend to invest in the class of shares of each Underlying Fund with the lowest shareholder fees and net fund operating expenses. As the Underlying Funds or the LifePath Portfolios' allocations among the Underlying Funds change from time to time, or to the extent that the expense ratio of the Underlying Funds changes, the weighted average operating expenses borne by the LifePath Portfolios may increase or decrease.

Underlying iShares Funds are subject to additional risks due to their shares being listed and traded on securities exchanges. There can be no assurance that an active trading market for these particular ETFs will develop or be maintained. Trading in ETFs may be halted because of market conditions or for reasons that, in the view of the listing exchange, make trading in ETFs inadvisable. In addition, trading in ETFs is subject to trading halts caused by extraordinary market volatility pursuant to "circuit breaker" rules. There can be no assurance that the requirements necessary to maintain the listing of ETFs will continue to be met or will remain unchanged. An ETF may trade at, above or below its NAV. The NAV of an ETF will fluctuate with changes in the market value of its holdings. The trading price of an ETF will generally fluctuate in accordance with changes in its NAV, as well as market supply and demand.

JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the LifePath Portfolios. The major risks of junk bond investments include:

. Junk bonds may be issued by less creditworthy issuers. Issuers of junk bonds may have a larger amount of outstanding debt relative to their assets than issuers of investment grade bonds. In the event of an issuer's bankruptcy, claims of other creditors may have priority over the claims of junk bond holders, leaving few or no assets available to repay junk bond holders.

. Prices of junk bonds are subject to extreme price fluctuations. Adverse changes in an issuer's industry and general economic conditions may have a greater impact on the prices of junk bonds than on other higher rated fixed-income securities.

. Issuers of junk bonds may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.

. Junk bonds frequently have redemption features that permit an issuer to repurchase the security from the LifePath Portfolios before it matures. If the issuer redeems junk bonds, the LifePath Portfolios may have to invest the proceeds in bonds with lower yields and may lose income.

. Junk bonds may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the junk bond market, and there may be significant differences in the prices quoted for junk bonds by the dealers. Because they are less liquid, judgment may play a greater role in valuing certain of the LifePath Portfolios' securities than is the case with securities trading in a more liquid market.

. The LifePath Portfolios may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the LifePath Portfolios invest will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection

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risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. The characteristics of these mortgage-backed and asset-backed securities differ from traditional fixed-income securities. Like traditional fixed-income securities, the value of asset-backed securities typically increases when interest rates fall and decreases when interest rates rise. However, a main difference is that the principal on mortgage- or asset-backed securities may normally be prepaid at any time, which will reduce the yield and market value of these securities. Therefore, mortgage- and asset-backed backed securities are subject to "prepayment risk" and "extension risk." Because of prepayment risk and extension risk, mortgage-backed securities react differently to changes in interest rates than other fixed-income securities.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The LifePath Portfolios' investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The LifePath Portfolios' investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only (IOs), principal only (POs) or an amount that remains after other floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the LifePath Portfolios invest in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by BFA, it is possible that the LifePath Portfolios could lose all or substantially all of their investment.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the LifePath Portfolios' mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the LifePath Portfolios may invest may also provide a degree of investment leverage, which could cause the LifePath Portfolios to lose all or substantially all of their investment.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for the Underlying iShares Funds, those Underlying iShares Funds may hold stocks in companies that present risks that an investment adviser researching individual stocks might seek to avoid.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the LifePath Portfolios may have to invest their proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment

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proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

REIT INVESTMENT RISK - In addition to the risks facing real estate-related securities, such as a decline in property values due to increasing vacancies, a decline in rents resulting from unanticipated economic, legal or technological developments or a decline in the price of securities of real estate companies due to a failure of borrowers to pay their loans or poor management, investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the LifePath Portfolios may lose money and there may be a delay in recovering the loaned securities. The LifePath Portfolios could also lose money if they do not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the LifePath Portfolios.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

Each LifePath Portfolio must maintain cash balances to meet redemption requests, which may lower overall portfolio performance.

FOR A DESCRIPTION OF THE LIFEPATH PORTFOLIOS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THEIR MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A FURTHER DISCUSSION OF THE LIFEPATH PORTFOLIOS' INVESTMENTS AND RISKS, PLEASE REFER TO THE LIFEPATH PORTFOLIOS' SAI.

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Account Information

DETAILS ABOUT INVESTOR A SHARES

Effective May 3, 2010, current Class R Shares of the LifePath Portfolios will be reclassified as Investor A Shares. EXISTING CLASS R SHAREHOLDER ACCOUNTS WILL BE GRANDFATHERED TO PURCHASE INVESTOR A SHARES AT NET ASSET VALUE.

MINIMUM INVESTMENT

The initial and subsequent investment minimums for Investor A Shares of the LifePath Portfolios generally are as follows, although Investor A Shares of the LifePath Portfolios may reduce or waive these investment minimums in some cases:

MINIMUM INITIAL         $1,000 for all accounts except:
INVESTMENT              . $250 for certain fee based programs
                        . $100 for retirement plans
                        . $50, if establishing Automatic Investment Plan
MINIMUM ADDITIONAL      $50 for all accounts except certain retirement plans and payroll deduction
INVESTMENT              programs may have a lower minimum

INITIAL SALES CHARGE OPTIONS

The following table shows the front-end sales charges that you may pay if you buy Investor A Shares. The offering price for Investor A Shares includes any front-end sales charge. The front-end sales charge expressed as a percentage of the offering price may be higher or lower than the charge described below due to rounding. Similarly, any contingent deferred sales charge paid upon certain redemptions of Investor A Shares expressed as a percentage of the applicable redemption amount may be higher or lower than the charge described below due to rounding. You may qualify for a reduced front-end sales charge. Purchases of Investor A Shares at certain fixed dollar levels, known as "breakpoints," cause a reduction in the front-end sales charge. Once you achieve a breakpoint, you pay that sales charge on your entire purchase amount (and not just the portion above the breakpoint). If you select Investor A Shares, you will pay a sales charge at the time of purchase as shown in the following table.

                                                                                       DEALER
                                          SALES CHARGE         SALES CHARGE         COMPENSATION
                                            AS A % OF         AS A % OF YOUR         AS A % OF
YOUR INVESTMENT                          OFFERING PRICE        INVESTMENT(1)       OFFERING PRICE
===================================     ================     ================     ===============
Less than $25,000                              5.25%                5.54%              5.00%
$25,000 but less than $50,000                  4.75%                4.99%              4.50%
$50,000 but less than $100,000                 4.00%                4.17%              3.75%
$100,000 but less than $250,000                3.00%                3.09%              2.75%
$250,000 but less than $500,000                2.50%                2.56%              2.25%
$500,000 but less than $750,000                2.00%                2.04%              1.75%
$750,000 but less than $1,000,000              1.50%                1.52%              1.25%
$1,000,000 and over(2)                         0.00%                0.00%                --(2)


(1) Rounded to the nearest one-hundredth percent.

(2) If you invest $1,000,000 or more in Investor A Shares, you will not pay an initial sales charge. In that case, BFA compensates the financial intermediary from its own resources. However, if you redeem your shares within 18 months after purchase, you may be charged a deferred sales charge of 1.00% of the lesser of the original cost of the shares being redeemed or your redemption proceeds. Such deferred sales charge may be waived in connection with certain fee-based programs.

No initial sales charge applies to Investor A Shares that you buy through reinvestment of the LifePath Portfolios' dividends or capital gains.

SALES CHARGES REDUCED OR ELIMINATED FOR INVESTOR A SHARES

There are several ways in which the sales charge can be reduced or eliminated. Purchases of Investor A Shares at certain fixed dollar levels, known as "breakpoints," cause a reduction in the front-end sales charge (as described above in the "Investor A Shares - Initial Sales Charge Options" section). Additionally, the front-end sales charge can be reduced or eliminated through one or a combination of the following: a Letter of Intent, the right of accumulation,

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the reinstatement privilege (described under "Account Services and Privileges"), or a waiver of the sales charge (described below). Reductions or eliminations through the right of accumulation or Letter of Intent will apply to the value of all qualifying holdings in shares of BlackRock Funds owned by:
(a) the investor, (b) the investor's spouse and any children under the age of 21, or (c) a trustee or fiduciary of a single trust estate or single fiduciary account. For this purpose, the value of an investor's holdings means the offering price of the newly purchased shares (including any applicable sales charge) plus the current value (including any sales charges paid) of all other shares the investor already holds taken together. These may include shares held in accounts held at a financial intermediary, including personal accounts, certain retirement accounts, UGMA/UTMA accounts, Joint Tenancy accounts, trust accounts and Transfer on Death accounts, as well as shares purchased by a trust of which the investor is a beneficiary. For purposes of the right of accumulation and Letter of Intent the investor may not combine with the investor's other holdings shares held in pension, profit sharing or other employee benefit plans if those shares are held in the name of a nominee or custodian.

In order to receive a reduced sales charge, at the time an investor purchases shares of a LifePath Portfolio, the investor should inform the financial professional, financial intermediary or the BlackRock Funds of any other shares of the LifePath Portfolio or any other BlackRock Fund owned by: (a) the investor, (b) the investor's spouse and any children under the age of 21, or
(c) a trustee or fiduciary of a single trust estate or single fiduciary account. Failure by the investor to notify the financial professional, financial intermediary or the BlackRock Funds, may result in the investor not receiving the sales charge reduction to which the investor is otherwise entitled.

The financial professional, financial intermediary or the BlackRock Funds may request documentation - including account statements and records of the original cost of the shares owned by the investor, the investor's spouse and/or children under the age of 21 - showing that the investor qualifies for a reduced sales charge. The investor should retain these records because - depending on where an account is held or the type of account - the LifePath Portfolios' and/or the investor's financial professional, financial intermediary or BlackRock Funds may not be able to maintain this information.

For more information, see the LifePath Portfolios' SAI or contact your financial professional or financial intermediary.

LETTER OF INTENT

An investor may qualify for a reduced front-end sales charge immediately by signing a "Letter of Intent" stating the investor's intention to buy a specified amount of Investor A Shares, Investor C Shares or Institutional Shares in one or more BlackRock Funds within the next 13 months that would, if bought all at once, qualify the investor for a reduced sales charge. The initial investment must meet the minimum initial purchase requirement. The 13-month Letter of Intent period commences on the day that the Letter of Intent is received by a LifePath Portfolio, and the investor must tell the LifePath Portfolios that later purchases are subject to the Letter of Intent. Purchases submitted prior to the date the Letter of Intent is received by a LifePath Portfolio is not counted toward the sales charge reduction. During the term of the Letter of Intent, a LifePath Portfolio will hold Investor A Shares representing up to 5% of the indicated amount in an escrow account for payment of a higher sales load if the full amount indicated in the Letter of Intent is not purchased. If the full amount indicated is not purchased within the 13-month period, and the investor does not pay the higher sales load within 20 days, a LifePath Portfolio will redeem enough of Investor A Shares held in escrow to pay the difference.

RIGHT OF ACCUMULATION

Investors have a "right of accumulation" under which the current value of an investor's existing Investor A, Investor C and Institutional Shares in most BlackRock Funds and the investment in the BlackRock CollegeAdvantage 529 program by the investor or by or on behalf of the investor's spouse and minor children may be combined with the amount of the current purchase in determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge. Financial intermediaries may value current holdings of their customers differently for purposes of determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge, although customers of the same financial intermediary will be treated similarly. In order to use this right, the investor must alert BlackRock, Inc. ("BlackRock") to the existence of any previously purchased shares.

OTHER FRONT-END SALES CHARGE WAIVERS

A sales charge waiver on a purchase of Investor A Shares may also apply for:

. Authorized qualified employee benefit plans or savings plans and rollovers of current investments in a LifePath Portfolio through such plans

. Persons investing through an authorized payroll deduction plan

. Persons investing through an authorized investment plan for organizations that operate under Section 501(c)(3) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code")

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. Registered investment advisers, trust companies and bank trust departments exercising discretionary investment authority with respect to amounts to be invested in a LifePath Portfolio

. Persons associated with a LifePath Portfolio, BlackRock Investments, LLC, the LifePath Portfolios' distributor (the "Distributor"), or the LifePath Portfolios' transfer agent, PNC Global Investment Servicing (U.S.) Inc. (the "Transfer Agent") and their affiliates

. Persons participating in a fee-based program under which they (i) pay advisory fees to a broker-dealer or other financial institution or (ii) pay fees to a broker-dealer or other financial institution for providing transaction processing and other administrative services, but not investment advisory services

. Employees of MetLife

INVESTOR A SHARES AT NET ASSET VALUE

If you invest $1,000,000 or more in Investor A Shares, you will not pay any initial sales charge. However, if you redeem your Investor A Shares within 18 months after purchase, you may be charged a deferred sales charge of 1.00% of the lesser of the original cost of the shares being redeemed or your redemption proceeds. For a discussion on waivers, see "Contingent Deferred Sales Charge Waivers."

CONTINGENT DEFERRED SALES CHARGE WAIVERS

The deferred sales charge relating to Investor A Shares may be reduced or waived in certain circumstances, such as:

. Redemptions of shares purchased through authorized qualified employee benefit plans or savings plans and rollovers of current investments in a LifePath Portfolio through such plans

. Exchanges pursuant to the exchange privilege

. Redemptions made in connection with minimum required distributions from individual retirement accounts ("IRAs") or 403(b)(7) accounts due to the shareholder reaching the age of 70 1/2

. Certain post-retirement withdrawals from an IRA or other retirement plan if you are over 59 1/2 years old

. Redemptions made with respect to certain retirement plans sponsored by a LifePath Portfolio, BFA or an affiliate

. Redemptions resulting from shareholder death as long as the waiver request is made within one year of death or, if later, reasonably promptly following completion of probate (including in connection with the distribution of account assets to a beneficiary of the decedent)

. Withdrawals resulting from shareholder disability (as defined in the Internal Revenue Code) as long as the disability arose subsequent to the purchase of the shares

. Involuntary redemptions made of shares in accounts with low balances

. Certain redemptions made through the Systematic Withdrawal Plan offered by a LifePath Portfolio, BFA or an affiliate

. Redemptions related to the payment of PNC Trust Company custodial IRA fees

. Redemptions when a shareholder can demonstrate hardship, in the absolute discretion of the LifePath Portfolio

Please contact your Financial Intermediary for more details on contingent deferred sales charges.

DISTRIBUTION AND SERVICE PAYMENTS


The LifePath Portfolios have adopted a shareholder servicing plan (the "Plan") with respect to Investor A Shares that allow each LifePath Portfolio to pay shareholder servicing fees for certain services provided to its Investor A shareholders under Rule 12b-1 of the Investment Company Act of 1940, as amended (the "1940 Act").

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (including BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co., Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a LifePath Portfolio's shares. Because the fees paid by a LifePath Portfolio under the Plan are paid out of LifePath Portfolio assets on an ongoing basis, over time these fees will increase the cost of your investment in the LifePath Portfolios and may cost you more than paying other types of sales charges.

50

In addition to, rather than in lieu of, shareholder servicing fees that a LifePath Portfolio may pay to a Financial Intermediary pursuant to the Plan and fees a LifePath Portfolio pays to the Transfer Agent, BFA, on behalf of a LifePath Portfolio, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the LifePath Portfolio will pay the Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either
(1) a percentage of the average daily net assets of LifePath Portfolio shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

The Plan permits BFA, the Distributor and their affiliates to make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to the LifePath Portfolios). From time to time, BFA, the Distributor or their affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA, the Distributor and their affiliates may compensate affiliated and unaffiliated Financial Intermediaries for the sale and distribution of shares of the LifePath Portfolios or for these other services to the LifePath Portfolios and shareholders. These payments would be in addition to the LifePath Portfolio payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, the Distributor and their affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a LifePath Portfolio to you. Please contact your Financial Intermediary for details about payments it may receive from a LifePath Portfolio or from BFA, the Distributor or their affiliates. For more information, see the LifePath Portfolios' SAI.

HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES

The chart on the following pages summarizes how to buy, sell, exchange and transfer shares through your financial professional or other financial intermediary. You may also buy, sell, exchange and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling, transferring or exchanging shares through BlackRock, call
(800) 441-7762. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

Each LifePath Portfolio may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders and suspend and resume the sale of any share class of the LifePath Portfolio at any time for any reason.

In addition, the LifePath Portfolios may waive certain requirements regarding the purchase, sale, exchange or transfer of shares described below.

HOW TO BUY SHARES
                   YOUR CHOICES               IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE   First, select the          The LifePath Portfolios offer other classes of shares (Investor C Shares,
                   share class appropriate    Class K Shares, Class R Shares and Institutional Shares) with different
                   for you                    features and expense levels, which you may be eligible to buy. Please see
                                              the LifePath Portfolios' Investor C Shares, Class K Shares, Class R Shares
                                              and Institutional Shares prospectuses for more information.
                                              When you place your initial order, you must indicate which share class
                                              you select (if you do not specify a class and do not qualify to purchase
                                              Institutional Shares, you will receive Investor A Shares).
                                              Certain factors, such as the amount of your investment, your time
                                              frame for investing, and your financial goals, may affect which share
                                              class you choose. Your financial representative can help you determine
                                              which share class is appropriate for you.

51

HOW TO BUY SHARES
              YOUR CHOICES                  IMPORTANT INFORMATION FOR YOU TO KNOW
              Next, determine               Refer to the minimum initial investment in the "Account Information -
              the amount of                 Details About Investor A Shares" in this Prospectus.
              your investment
                                            See "Account Information - Details About Investor A Shares" for
                                            information on lower initial investment requirements for certain LifePath
                                            Portfolio investors if their purchase, combined with purchases by other
                                            investors received together by a LifePath Portfolio, meets the minimum
                                            investment requirement.
              Have your                     The price of your shares is based on the next calculation of a LifePath
              financial                     Portfolio's NAV after your order is placed. Any purchase orders placed prior
              intermediary                  to the close of business on the NYSE (generally 4:00 p.m. Eastern time)
              submit your                   will be priced at the NAV determined that day. Certain financial
              purchase order                intermediaries, however, may require submission of orders prior to that
                                            time. A broker-dealer or financial institution maintaining the account in
                                            which you hold shares may charge a separate account, service or
                                            transaction fee on the purchase or sale of Fund shares that would be in
                                            addition to the fees and expenses shown in each LifePath Portfolio's "Fees
                                            and Expenses" table.
                                            Purchase orders placed after that time will be priced at the NAV
                                            determined on the next business day. The LifePath Portfolios may reject
                                            any order to buy shares and may suspend the sale of shares at any time.
                                            Financial intermediaries may charge a processing fee to confirm a
                                            purchase.
              Or contact                    To purchase shares directly from BlackRock, call (800) 441-7762 and
              BlackRock (for                request a new account application. Mail the completed application along
              accounts held                 with a check payable to "BlackRock Funds" to the Transfer Agent at the
              directly with                 address on the application.
              BlackRock)
ADD TO YOUR   Purchase                      The minimum investment for additional purchases is generally $50 for all
INVESTMENT    additional shares             accounts, except that certain retirement plans may have a lower minimum
                                            for additional purchases and certain payroll deduction programs, such as
                                            automatic investment plans, may have higher minimums. (The minimums for
                                            additional purchases may be waived under certain circumstances.)
              Have your financial           To purchase additional shares you may contact your financial professional
              professional or               or financial intermediary. For more details on purchasing by Internet see
              financial intermediary        below.
              submit your purchase

52

HOW TO BUY SHARES
                 YOUR CHOICES                IMPORTANT INFORMATION FOR YOU TO KNOW
                                             PURCHASE BY TELEPHONE: Call (800) 441-7762 and speak with one of our order
                                             for additional shares representatives. The LifePath Portfolios have the
                                             right to   reject any telephone request for any reason.
                                             PURCHASE IN WRITING: You may send a written request to BlackRock at the
                                             address on the back cover of this Prospectus.
                                             PURCHASE BY VRU: Investor A Shares may also be purchased by use of the
                                             LifePath Portfolio's automated voice response unit service ("VRU") at
                                             (800) 441-7762
                 Or contact BlackRock        PURCHASE BY INTERNET: You may purchase your shares, and view activities
                 (for accounts held          in your account, by logging onto the BlackRock website at
                 directly with BlackRock)    www.blackrock.com/funds. Purchases made on the Internet using the
                                             Automated Clearing House Network ("ACH") will have a trade date that is
                                             the day after the purchase is made. Certain institutional clients' purchase
                                             orders for Investor A Shares placed by wire prior to the close of business
                                             on the NYSE will be placed at the NAV determined that day. Contact your
                                             financial intermediary or BlackRock for further information. Each LifePath
                                             Portfolio limits Internet purchases in shares of the LifePath Portfolio to
                                             $25,000 per trade. Different maximums may apply to certain institutional
                                             investors. Please read the On-Line Services Disclosure Statement and User
                                             Agreement, the Terms and Conditions page and the Consent to Electronic
                                             Delivery Agreement (if you consent to electronic delivery), before
                                             attempting to transact online.
                                             The LifePath Portfolios employ reasonable procedures to confirm that
                                             transactions entered over the Internet are genuine. By entering into the
                                             User Agreement with a LifePath Portfolio in order to open an account
                                             through the website, the shareholder waives any right to reclaim any
                                             losses from a LifePath Portfolio or any of its affiliates, incurred through
                                             fraudulent activity.
                 Acquire additional          All dividends and capital gains distributions are automatically reinvested
                 shares by                   without a sales charge. To make any changes to your dividend and/or
                 reinvesting                 capital gains distributions options, please call (800) 441-7762, or contact
                 dividends and               your financial professional (if your account is not held directly with
                 capital gains               BlackRock).
                 Participate                 BlackRock's AIP allows you to invest a specific amount on a periodic basis
                 in the Automatic            from your checking or savings account into your investment account.
                 Investment Plan ("AIP")     Refer to the "Account Services and Privileges" section of this Prospectus
                                             for additional information.
HOW TO PAY FOR   Making payment for          Payment for an order must be made in Federal funds or other immediately
SHARES           purchases                   available funds by the time specified by your financial professional or other
                                             financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                             on the first business day (in the case of Investor A Shares) following
                                             BlackRock's receipt of the order. If payment is not received by this time,
                                             the order will be canceled and you and your financial professional or other
                                             financial intermediary will be responsible for any loss to the LifePath
                                             Portfolios.
                                             For shares purchased directly from the LifePath Portfolio, a check payable
                                             to "BlackRock Funds," which bears the name of the LifePath Portfolio and
                                             Share Class you are purchasing must accompany a completed purchase
                                             application. There is a $20 fee for each purchase check that is returned
                                             due to insufficient funds.
                                             The LifePath Portfolios do not accept third-party checks. You may also
                                             wire Federal funds to a LifePath Portfolio to purchase shares, but you must
                                             call (800) 441-7762 before doing so to confirm the wiring instructions.

53

HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL   Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       Shareholders should indicate that they are redeeming Investor A Shares.
SHARES            intermediary    The price of your shares is based on the next calculation of a LifePath
                  submit your     Portfolio's NAV after your order is placed. For your redemption request to
                  sales order     be priced at the NAV on the day of your request, you must submit your
                                  request to your financial intermediary prior to that day's close of business
                                  on the NYSE (generally 4:00 p.m. Eastern time). Certain financial
                                  intermediaries, however, may require submission of orders prior to that
                                  time. Any redemption request placed after that time will be priced at the
                                  NAV at the close of business on the next business day.
                                  Financial intermediaries may charge a fee to process a redemption of
                                  shares. Shareholders should indicate which class of shares they are
                                  redeeming.
                                  The LifePath Portfolios may reject an order to sell shares under certain
                                  circumstances.
                  Selling         METHODS OF REDEEMING
                  shares held
                                  REDEEM BY TELEPHONE: You may sell Investor A Shares held directly at
                  directly
                                  BlackRock by telephone request if certain conditions are met and if the
                  with
                                  amount being sold is less than (i) $100,000 for payments by check or (ii)
                  BlackRock
                                  $250,000 for payments through the ACH or wire transfer. Certain
                                  redemption requests such as those in excess of these amounts, must be
                                  in writing with a medallion signature guarantee. You can obtain a
                                  medallion signature guarantee stamp from a bank, securities dealer,
                                  securities broker, credit union, savings and loan association, national
                                  securities exchange or registered securities association. A notary public
                                  seal will not be acceptable.
                                  The LifePath Portfolios, their administrator and the distributor will employ
                                  reasonable procedures to confirm that instructions communicated by
                                  telephone are genuine. The LifePath Portfolios and their service providers
                                  will not be liable for any loss, liability, cost or expense for acting upon
                                  telephone instructions that are reasonably believed to be genuine in
                                  accordance with such procedures. The LifePath Portfolios may refuse a
                                  telephone redemption request if they believe it is advisable to do so.
                                  During periods of substantial economic or market change, telephone
                                  redemptions may be difficult to complete. Please find below alternative
                                  redemption methods.
                                  REDEEM BY VRU: Investor A Shares may also be redeemed by use of the
                                  LifePath Portfolios' VRU. Payment for Investor A Shares redeemed by VRU
                                  may be made for non-retirement accounts in amounts up to $25,000,
                                  either through check, ACH or wire.
                                  REDEEM BY INTERNET: You may redeem in your account by logging onto
                                  the BlackRock website at www.blackrock.com/funds. Proceeds from
                                  Internet redemptions may be sent via check, ACH or wire to the bank
                                  account of record. Payment for Investor A Shares redeemed by VRU may
                                  be made for non-retirement accounts in amounts up to $25,000, either
                                  through check, ACH or wire.

54

HOW TO SELL SHARES
                   YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                                   REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                                   BlackRock, P.O. Box 9819, Providence, RI 02940-8019 or, for overnight
                                   delivery, 101 Sabin Street, Pawtucket, RI 02860-1427. All shareholders on
                                   the account must sign the letter. A medallion signature guarantee will
                                   generally be required but may be waived in certain limited circumstances.
                                   You can obtain a medallion signature guarantee stamp from a bank,
                                   securities dealer, securities broker, credit union, savings and loan
                                   association, national securities exchange or registered securities
                                   association. A notary public seal will not be acceptable. If you hold stock
                                   certificates, return the certificates with the letter. Proceeds from
                                   redemptions may be sent via check, ACH or wire to the bank account of
                                   record.
                                   PAYMENT OF REDEMPTION PROCEEDS: Redemption proceeds may be paid by
                                   check or, if a LifePath Portfolio has verified banking information on file,
                                   through ACH or by wire transfer.
                                   PAYMENT BY CHECK: BlackRock will normally mail redemption proceeds
                                   within seven days following receipt of a properly completed request.
                                   Shares can be redeemed by telephone and the proceeds sent by check to
                                   the shareholder at the address on record. Shareholders will pay $15 for
                                   redemption proceeds sent by check via overnight mail. You are responsible
                                   for any additional charges imposed by your bank for this service.
                                   PAYMENT BY WIRE TRANSFER: Payment for redeemed shares for which a
                                   redemption order is received before 4:00 p.m. (Eastern time) on a
                                   business day is normally made in Federal funds wired to the redeeming
                                   shareholder on the next business day, provided that the LifePath
                                   Portfolios' custodian is also open for business. Payment for redemption
                                   orders received after 4:00 p.m. (Eastern time) or on a day when the
                                   LifePath Portfolios' custodian is closed is normally wired in Federal funds
                                   on the next business day following redemption on which the LifePath
                                   Portfolios' custodian is open for business. The LifePath Portfolios reserve
                                   the right to wire redemption proceeds within seven days after receiving a
                                   redemption order if, in the judgment of the LifePath Portfolio, an earlier
                                   payment could adversely affect a LifePath Portfolio.
                                   If a shareholder has given authorization for expedited redemption, shares
                                   can be redeemed by Federal wire transfer to a single previously designated
                                   bank account. Shareholders will pay $7.50 for redemption proceeds sent
                                   by Federal wire transfer. You are responsible for any additional charges
                                   imposed by your bank for this service. No charge for wiring redemption
                                   payments with respect to Investor A Shares is imposed by the LifePath
                                   Portfolios.
                                   The LifePath Portfolios are not responsible for the efficiency of the Federal
                                   wire system or the shareholder's firm or bank. To change the name of the
                                   single, designated bank account to receive wire redemption proceeds, it is
                                   necessary to send a written request to the LifePath Portfolio at the
                                   address on the back cover of this Prospectus.
                                   PAYMENT BY ACH: Redemption proceeds may be sent to the shareholder's
                                   bank account (checking or savings) via ACH. Payment for redeemed
                                   shares for which a redemption order is received before 4:00 p.m. (Eastern
                                   time) on a business day is normally sent to the redeeming shareholder the
                                   next business day, with receipt at the receiving bank within the next two
                                   business days (48-72 hours); provided that the LifePath Portfolios'
                                   custodian is also open for business. Payment for redemption orders
                                   received after 4:00 p.m. (Eastern time) or on a day when the LifePath
                                   Portfolios' custodian is closed is normally sent on the next business day
                                   following redemption on which the LifePath Portfolios' custodian is open
                                   for business.

55

HOW TO SELL SHARES
                   YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                                   The LifePath Portfolios reserve the right to send redemption proceeds
                                   within seven days after receiving a redemption order if, in the judgment of
                                   a LifePath Portfolio, an earlier payment could adversely affect the LifePath
                                   Portfolio. No charge for sending redemption payments via ACH is imposed
                                   by the LifePath Portfolios. If you make a redemption request before a
                                   LifePath Portfolio has collected payment for the purchase of shares, the
                                   LifePath Portfolio may delay mailing your proceeds. This delay will usually
                                   not exceed ten days.

       HOW TO EXCHANGE SHARES OR TRANSFER YOUR ACCOUNT
                     Your Choices
EXCHANGE PRIVILEGE   Selling shares
                     of one LifePath Portfolio to
                     purchase shares
                     of another
                     BlackRock Fund
                     ("exchanging")

                     Important Information for You to Know
EXCHANGE PRIVILEGE    Investor A Shares of the LifePath Portfolios are generally exchangeable for
                     shares of the same class of another BlackRock Fund.
                     You can exchange $1,000 or more of Investor A Shares from one LifePath
                     Portfolio into the same class of another BlackRock Fund which offers that
                     class of shares (you can exchange less than $1,000 of Investor A Shares if
                     you already have an account in the BlackRock Fund into which you are
                     exchanging). You may only exchange into a share class and BlackRock
                     Fund that are open to new investors or in which you have a current
                     account, if the BlackRock Fund is closed to new investors. If you held the
                     exchanged shares for 30 days or less, you may be charged a redemption
                     fee (please refer to the "Redemption Fee" section of this Prospectus for
                     additional information).
                     Some of the BlackRock Funds impose a different deferred sales charge
                     schedule. The CDSC will continue to be measured from the date of the
                     original purchase. The CDSC schedule applicable to your original purchase
                     will apply to the shares you receive in the exchange and any subsequent
                     exchange.
                     To exercise the exchange privilege, you may contact your financial
                     professional or financial intermediary. Alternatively, if your account is held
                     directly with BlackRock, you may: (i) call (800) 441-7762 and speak with
                     one of our representatives, (ii) make the exchange via the Internet by
                     accessing your account online at www.blackrock.com/funds, or (iii) send
                     a written request to the LifePath Portfolio at the address on the back cover
                     of this Prospectus. Please note, if you indicated on your New Account
                     Application that you did not want the Telephone Exchange Privilege, you
                     will not be able to place exchanges via the telephone until you update this
                     option either in writing or by calling (800) 441-7762. The LifePath
                     Portfolios have the right to reject any telephone request for any reason.
                     Although there is currently no express limit on the number of exchanges
                     that you can make, the exchange privilege may be modified or terminated
                     at any time in the future. The LifePath Portfolios may suspend or
                     terminate your exchange privilege at any time for any reason, including if a
                     LifePath Portfolio believes, in its sole discretion that you are engaging in
                     market timing activities. See "Frequent Trading in LifePath Portfolio
                     Shares" below. For U.S. federal income tax purposes, a share exchange is a
                     taxable event and a capital gain or loss may be realized. Please consult
                     your tax adviser or other financial professional before making an exchange
                     request.

56

                                      HOW TO EXCHANGE SHARES OR TRANSFER YOUR ACCOUNT
                     Your Choices             Important Information for You to Know
TRANSFER SHARES TO    Transfer to a            You may transfer your Investor A Shares of a LifePath Portfolio only to
ANOTHER SECURITIES   participating            another financial professional or financial intermediary that has an
DEALER OR OTHER      financial                agreement with the Distributor. Certain shareholder services may not be
FINANCIAL            professional or          available for the transferred shares. All future trading of these assets must
INTERMEDIARY         other                    be coordinated by the receiving firm.
                     financial
                                              If your account is held directly with BlackRock, you may call (800) 441-
                     intermediary
                                              7762 with any questions; otherwise please contact your financial
                                              intermediary to accomplish the transfer of shares.
                      Transfer to a            You must either:
                     non-participating
                                              oTransfer your Investor A Shares to an account with a LifePath Portfolio; or
                     financial professional
                                              oSell your shares, paying any applicable deferred sales charge.
                     or other
                     financial intermediary
                                              If your account is held directly with BlackRock, you may call (800) 441-7762
                                              with any questions; otherwise please contact your financial intermediary to
                                              accomplish the transfer of shares.

ACCOUNT SERVICES AND PRIVILEGES


The following table provides examples of account services and privileges available in your BlackRock account. Certain of these account services and privileges are only available to shareholders of Investor A Shares whose accounts are held directly with BlackRock. If your account is held directly with BlackRock, please call (800) 441-7762 for additional information as well as forms and applications. Otherwise, please contact your financial professional for assistance in requesting one or more of the following services and privileges.

AIP                Allows systematic                  BlackRock's AIP allows you to invest a specific amount on a periodic basis
                  investments on a                   from your checking or savings account into your investment account. You
                  periodic basis from                may apply for this option upon account opening or by completing the AIP
                  your checking or savings           application. The minimum investment amount for an AIP is $50 per
                  account.                           portfolio.
DIVIDEND           Automatically invests your         Dividend and capital gains distributions may be reinvested in your
ALLOCATION PLAN   distributions into another         account to purchase additional shares or paid in cash. Using the
                  BlackRock Fund of your             Dividend Allocation Plan, you can direct your distributions to your bank
                  choice pursuant to your            account (checking or savings), to purchase shares of another fund at
                  instructions, without any          BlackRock without any fees or sales charges, or by check to special
                  fees or sales charges.             payee. Please call (800) 441-7762 for details. If investing into another
                                                     fund at BlackRock, the receiving fund must be open to new purchases.
EZ TRADER          Allows an investor to purchase     (NOTE: This option is offered to shareholders whose accounts are held
                  or sell Investor A Shares by       directly with BlackRock. Please speak with your financial professional if
                  telephone or                       your account is held elsewhere).
                  over the Internet
                                                     Prior to establishing an EZ Trader account, please contact your bank to
                  through ACH.
                                                     confirm that it is a member of the ACH system. Once confirmed,
                                                     complete an application, making sure to include the appropriate bank
                                                     information, and return the application to the address listed on the form.
                                                     Prior to placing a telephone or internet purchase or sale order, please
                                                     contact (800) 441-7762 to confirm that your bank information has been
                                                     updated on your account. Once this is established, you may place your
                                                     request to sell shares with the LifePath Portfolios by telephone or
                                                     Internet. Proceeds will be sent to your pre-designated bank account.

57

SYSTEMATIC       This feature can be used by
EXCHANGE        investors to systematically exchange
PLAN            money from one fund to up
                to four other funds.
SYSTEMATIC       This feature can be used by
WITHDRAWAL      investors who want to receive
PLAN ("SWP")    regular distributions from their
                accounts.
REINSTATEMENT
PRIVILEGE

SYSTEMATIC       A minimum of $10,000 in the initial BlackRock Fund is required and
EXCHANGE        investments in any additional funds must meet minimum initial
PLAN            investment requirements. For more information, please contact the
                LifePath Portfolio at (800) 441-7762.
SYSTEMATIC       To start a SWP, a shareholder must have a current investment of $10,000
WITHDRAWAL      or more in a BlackRock Fund.
PLAN ("SWP")
                Shareholders can elect to receive cash payments of $50 or more at any
                interval they choose. Shareholders may sign up by completing the SWP
                Application Form, which may be obtained from BlackRock.
                Shareholders should realize that if withdrawals exceed income the
                invested principal in their account will be depleted. To participate in the
                SWP, shareholders must have their dividends reinvested. Shareholders
                may change or cancel the SWP at any time, with a minimum of 24 hours
                notice. If a shareholder purchases additional Investor A Shares of a
                LifePath Portfolio at the same time he or she redeems shares through
                the SWP, that investor may lose money because of the sales charge
                involved. No CDSC will be assessed on redemptions of Investor A Shares
                made through the SWP that do not exceed 12% of the account's NAV on
                an annualized basis. For example, monthly, quarterly, and semi-annual
                SWP redemptions of Investor A Shares will not be subject to the CDSC if
                they do not exceed 1% of an account's NAV on the redemption date. SWP
                redemptions of Investor A Shares in excess of this limit will still pay any
                applicable CDSC. Ask your financial adviser or other financial
                intermediary for details.
REINSTATEMENT    If you redeem Investor A Shares, and within 60 days buy new Investor A
PRIVILEGE       Shares of the SAME LifePath Portfolio, you will not pay a sales charge
                on the new purchase amount. This right may be exercised once a year
                and within 60 days of the redemption, provided that Investor A Shares of
                that LifePath Portfolio is currently open to new investors or the
                shareholder has a current account in that closed LifePath Portfolio.
                Shares will be purchased at the NAV calculated at the close of trading
                on the day the request is received. To exercise this privilege, the
                LifePath Portfolios must receive written notification from the
                shareholder of record or the financial professional of record, at the time
                of purchase. Investors should consult a tax adviser concerning the tax
                consequences of exercising this reinstatement privilege.

LIFEPATH PORTFOLIOS' RIGHTS

Each LifePath Portfolio may:

. Suspend the right of redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act,

. Postpone date of payment upon redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act or if a redemption request is made before a LifePath Portfolio has collected payment for the purchase of shares,

. Redeem shares for property other than cash if conditions exist which make cash payments undesirable in accordance with its rights under the 1940 Act, and

. Redeem shares involuntarily in certain cases, such as when the value of a shareholder account falls below a specified level.

NOTE ON LOW BALANCE ACCOUNTS. Because of the high cost of maintaining smaller shareholder accounts, a LifePath Portfolio may redeem the shares in your account (without charging any deferred sales charge) if the NAV of your account falls below $500 due to redemptions you have made. You will be notified that the value of your account is less than $500 before a LifePath Portfolio makes an involuntary redemption. You will then have 60 days to make an additional investment to bring the value of your account to at least $500 before a LifePath Portfolio takes any action.

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This involuntary redemption does not apply to accounts of authorized qualified employee benefit plans, selected fee-based programs or accounts established under the Uniform Gifts or Transfers to Minors Acts.

CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE


Each LifePath Portfolio's share price (also known as a LifePath Portfolio's NAV) is calculated by dividing the value of the net assets of the LifePath Portfolio (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the LifePath Portfolio, generally rounded to the nearest cent.

Each LifePath Portfolio's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern Time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating each LifePath Portfolio's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of each LifePath Portfolio is calculated based on the NAV of the Master Portfolio in which the LifePath Portfolio invests. The LifePath Portfolios' SAI includes a description of the methods for valuing the Master Portfolios' investments, including a description of the circumstances in which the Master Portfolios' investments would be valued using fair value pricing and the effects of using fair value pricing.

LIFEPATH PORTFOLIO DISTRIBUTIONS

The LifePath Portfolios distribute their net investment income to shareholders quarterly. The LifePath Portfolios distribute their net realized capital gains, if any, to shareholders at least annually. Distributions payable to you will be automatically reinvested in additional Investor A Shares of your LifePath Portfolio, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and a LifePath Portfolio's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The LifePath Portfolios are not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. The exchange privilege is not intended as a vehicle for short-term trading. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of a LifePath Portfolio and its shareholders. For example, large flows of cash into and out of a LifePath Portfolio may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the LifePath Portfolio's investment goal. Frequent trading may cause a LifePath Portfolio to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the LifePath Portfolio's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. Each LifePath Portfolio will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of LifePath Portfolio Investments" below.

Each LifePath Portfolio discourages market timing and seeks to prevent frequent purchases and sales or exchanges of LifePath Portfolio shares that it determines may be detrimental to the LifePath Portfolio or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of LifePath Portfolio shares because certain legitimate strategies will not result in harm to a LifePath Portfolio or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, a LifePath Portfolio believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If a LifePath Portfolio rejects your purchase or exchange order, you will not be able to execute that transaction, and the LifePath Portfolio will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with a LifePath Portfolio, the LifePath Portfolio may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by a LifePath Portfolio. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide a LifePath Portfolio with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the LifePath Portfolio. While each LifePath Portfolio monitors for market timing activity, a LifePath Portfolio may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the LifePath Portfolio. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in a LifePath Portfolio's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by a LifePath Portfolio to be engaged in market timing or other improper trading activity, the LifePath Portfolio's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

A LifePath Portfolio may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

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The LifePath Portfolios may from time to time implement various methods that the LifePath Portfolios believe are appropriate to deter market timing, frequent trading or other activity that may be detrimental to the LifePath Portfolios or long-term investors in the LifePath Portfolios. There is no assurance that any such methods will prevent such detrimental trading activity.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the LifePath Portfolios and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the LifePath Portfolios' SAI for additional U.S. federal income tax information.

Distributions from your LifePath Portfolio's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional LifePath Portfolio shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the LifePath Portfolio's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the LifePath Portfolios generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the LifePath Portfolio's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S. and certain foreign corporations. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) A portion of distributions paid to corporate shareholders of the LifePath Portfolios may qualify for the dividends-received deduction available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

In addition, if you sell your LifePath Portfolio shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

If you buy a LifePath Portfolio's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of a LifePath Portfolio that holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the LifePath Portfolio sells the appreciated securities and distributes the realized gain on the sale. The LifePath Portfolios have built up, or have the potential to build up, high levels of unrealized appreciation in their investments.

After the end of each year, the LifePath Portfolios will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the LifePath Portfolios if you fail to provide the LifePath Portfolios with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Sales proceeds generally are taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

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Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code, unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING LIFEPATH PORTFOLIO SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL

INCOME TAX ON LIFEPATH PORTFOLIO DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF LIFEPATH PORTFOLIO SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER AND FUND OF FUNDS STRUCTURES


The LifePath Portfolios do not have their own investment adviser. Instead, each LifePath Portfolio invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the LifePath Portfolio. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the LifePath Portfolios.

FEEDER FUND EXPENSES

Feeder funds, including the LifePath Portfolios, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund- specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a LifePath Portfolio's assets from its Master Portfolio if it believes doing so is in the best interests of the LifePath Portfolio's shareholders. If the Trust's Board of Trustees decides to withdraw a LifePath Portfolio's assets, it would then consider whether the LifePath Portfolio should hire its own investment adviser, invest in another master portfolio or take other action.

FUND OF FUNDS

The Master Portfolios do not invest directly in a portfolio of securities. Instead, they invest in the Underlying Money Market Fund and other Underlying Funds that are also advised by BFA. Each Master Portfolio charges for its own direct expenses, in addition to bearing a PRO RATA share of the expenses charged by the Underlying Funds in which it invests.

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Management of the LifePath Portfolios

INVESTMENT ADVISER

Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the LifePath Portfolio. The Master Portfolios, in turn, invest in a combination of Underlying Funds. BFA, a registered investment adviser, serves as investment adviser to each Master Portfolio, and also serves as investment adviser to each Underlying Fund, with the exception of the Underlying Money Market Fund, which invests in a master portfolio advised by BFA. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive an annual management fee of 0.35% of each Master Portfolio's average daily net assets.

For its services to the Underlying Funds, BFA receives fees that differ from the fees described for the LifePath Portfolios in this Prospectus. BFA provides investment advisory services for the Underlying Funds that differ from the investment advisory services it provides for the Master Portfolios. For services provided to the Underlying Funds, BFA receives investment advisory fees from the Underlying Funds. In addition, BTC provides administration services to certain of the Underlying Funds and, for those services, may receive administration fees from those Underlying Funds. BFA has contractually agreed to waive its management fees at the Master Portfolio level in an amount equal to management and administration fees, if any, paid by the Underlying Funds to BFA and BTC, respectively, through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly- owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the LifePath Portfolios' annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS

Dagmar Nikles, Leslie Gambon, Alan Mason and Amy Whitelaw (the "Portfolio Managers") are jointly and primarily responsible for the day-to- day management of the Master Portfolios and act collaboratively on all aspects concerning the Master Portfolios. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of their team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy, and overseeing members of his or her portfolio management team with more limited responsibilities.

Ms. Nikles has been employed as a Senior Investment Strategist in the defined contributions team at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A ("BGI")) since December 2009. From July 2003 to November 2009, Ms. Nikles was a member of the asset allocation portfolio management team at BGFA and BGI. Ms. Nikles has been a one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since June 2005.

Ms. Gambon has been employed as a member of the asset allocation portfolio management team at BFA and BTC since April 2007. From October 2004 to April 2007, Ms. Gambon was Head of Defined Contribution Portfolio Management at BGI. Ms. Gambon has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since May 2007.

Mr. Mason has been employed by BFA and BTC since December 2009. Mr. Mason is responsible for multi-asset class solutions for institutional clients. From 1991 to 2009, Mr. Mason served a variety of roles at BGFA and BGI, including eight years devoted to the development of transition management products. Mr. Mason has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since September 2009.

Ms. Whitelaw has been employed as Head of Defined Contributions Portfolio Management at BFA and BTC since December 2009. From October 2009 to November 2009, Ms. Whitelaw was Head of Defined Contributions Portfolio Management at BGFA and BGI. Ms. Whitelaw had been employed as a member of the portfolio management team at

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BGFA and BGI since July 2006. From April 2002 to April 2005, Ms. Whitelaw worked as a transition manager and strategist in the Transition Services group at BGFA and BGI.

The LifePath Portfolios' SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers' ownership of shares in the LifePath Portfolios.

ADMINISTRATIVE SERVICES

Pursuant to an Administration Agreement between the Trust, on behalf of the LifePath Portfolios, and BTC, BTC provides the following services, among others, as the LifePath Portfolios' administrator:

. Supervises the LifePath Portfolios' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the shareholder servicing agent ("Shareholder Servicing Agent") on behalf of the LifePath Portfolios.

BTC is entitled to receive fees for these services at the annual rate of 0.50% of the average daily net assets of Investor A Shares of each LifePath Portfolio. In addition to performing these services, BTC has agreed to bear all costs of operating the LifePath Portfolios, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the LifePath Portfolios or the Trust as defined in the 1940 Act and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

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Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolios have retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolios to the extent that the Master Portfolios participate in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolios, including a fee based on the returns earned on the Master Portfolios' investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolios may lend their portfolio securities under the securities lending program.

VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. Each LifePath Portfolio calculates the net asset value of each class of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00
p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

Each LifePath Portfolio's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. Each LifePath Portfolio values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If a LifePath Portfolio invests in foreign securities, these securities may trade on weekends or other days when the LifePath Portfolio does not price its shares. As a result, a LifePath Portfolio's net asset value may change on days when you will not be able to purchase or redeem the LifePath Portfolio's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a LifePath Portfolio's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, a LifePath Portfolio's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the LifePath Portfolio. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value.

A LifePath Portfolio may accept orders from certain authorized financial intermediaries or their designees. A LifePath Portfolio will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the LifePath Portfolio after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN LIFEPATH PORTFOLIO POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The LifePath Portfolios are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a LifePath Portfolio may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The LifePath Portfolios reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the LifePath Portfolios to verify their identity. The LifePath Portfolios also reserve the right to redeem any amounts in a LifePath Portfolio from persons whose identity it is unable to verify on a timely basis. It is the LifePath Portfolios' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

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BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

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Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Investor A Shares of each LifePath Portfolio for the past five years or, if shorter, since inception. Certain information reflects financial results for a single Investor A Share of each LifePath Portfolio. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Investor A Shares of a given LifePath Portfolio, assuming reinvestment of all distributions. PRIOR TO MAY 1, 2010, INVESTOR A SHARES WERE DESIGNATED CLASS R SHARES AND WERE SUBJECT TO DIFFERENT SALES CHARGES AND SERVICE AND DISTRIBUTION FEES. THE TABLES BELOW SET FORTH SELECTED FINANCIAL DATA FOR A CLASS R SHARES OF EACH LIFEPATH PORTFOLIO OUTSTANDING THROUGHOUT EACH PERIOD PRESENTED. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each LifePath Portfolio's financial statements, is included in the LifePath Portfolios' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-441-7762 (toll-free) from 8:00 a.m. to 6:00 p.m. Eastern time on any business day.

LIFEPATH RETIREMENT PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                          INVESTOR A SHARES
                                             ---------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                             ---------------------------------------------------------------------------
                                                          2009            2008          2007          2006          2005
                                             ----------------- --------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            ---               -              -             -             -
 Net asset value, beginning of year             $    8.77        $    10.70      $   10.87     $   10.56    $   10.55
--------------------------------------------    -----------      ----------      ---------     ---------    ---------
Net investment income                               0.271              0.32          0.36          0.35          0.28
--------------------------------------------    -----------      ----------      ---------     ---------    ---------
 Net realized and unrealized gain (loss)            1.28              (1.92)         0.09          0.53          0.14
--------------------------------------------    -----------      ----------      ---------     ---------    ---------
Net increase (decrease) from investment
 operations                                         1.55           (   1.60)         0.45          0.88          0.42
--------------------------------------------    -----------      ----------      ---------     ---------    ---------
 Dividends and distributions from:
  Net investment income                             (0.29)            (0.29)         (0.35)        (0.36)        (0.31)
  Net realized gain                                 (0.00)/2/         (0.04)         (0.27)        (0.21)        (0.10)
--------------------------------------------    ------------     ----------      ---------     ---------    ----------
Total dividends and distributions                   (0.29)            (0.33)         (0.62)        (0.57)        (0.41)
--------------------------------------------    ------------     ----------      ---------     ---------    ----------
 Net asset value, end of year                  $   10.03         $     8.77      $   10.70     $   10.87    $   10.56
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
 Based on net asset value                         17.96   %          (15.24)%         4.17%         8.52%         4.05%
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
 Total expenses                                    1.34   %            1.36%          1.37%         1.38%         1.40%
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
Total expenses after expense reductions            1.00   %            1.01%          1.02%         1.03%         1.06%
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
 Net investment income                             2.83   %            3.11%          3.06%         3.18%         2.51%
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
SUPPLEMENTAL DATA
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
 Net assets, end of year (000)                 $  147,741        $   25,030      $  22,185     $  13,460    $    9,567
--------------------------------------------   -------------     ----------      ---------     ---------    ----------
Portfolio turnover of the Master Portfolio              6%               11%             6%           10%           11%
--------------------------------------------   -------------     ----------      ---------     ---------    ----------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

66

LIFEPATH 2020 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         INVESTOR A SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  11.75         $   16.24      $  16.77      $  15.22      $  14.60
--------------------------------------------    ----------       ---------      --------      --------      --------
Net investment income                              0.301              0.37          0.38          0.37         0.27
--------------------------------------------    ----------       ---------      --------      --------      --------
 Net realized and unrealized gain (loss)           2.28              (4.45)         0.13          1.56         0.64
--------------------------------------------    ----------       ---------      --------      --------      --------
Net increase (decrease) from investment
 operations                                        2.58            (  4.08)         0.51          1.93         0.91
--------------------------------------------    ----------       ---------      --------      --------      --------
 Dividends and distributions from:
  Net investment income                             (0.40)           (0.29)         (0.39)        (0.38)       (0.29)
  Net realized gain                                     -            (0.12)         (0.65)            -            -
  Return of capital                                 (0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    -- ------
Total dividends and distributions                   (0.40)           (0.41)         (1.04)        (0.38)       (0.29)
--------------------------------------------    ------------     ---------      ---------     ---------     --------
 Net asset value, end of year                   $  13.93         $   11.75      $  16.24      $  16.77      $  15.22
--------------------------------------------    ------------     ---------      ---------     ---------     --------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------     --------
 Based on net asset value                         22.42   %         (25.57)%         3.06%        12.77%        6.28%
--------------------------------------------    ------------     ---------      ---------     ---------     --------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------     --------
 Total expenses                                    1.33   %           1.32%          1.33%         1.33%        1.37%
--------------------------------------------    ------------     ---------      ---------     ---------     --------
Total expenses after expense reductions            0.97   %           0.98%          0.99%         1.00%        1.03%
--------------------------------------------    ------------     ---------      ---------     ---------     --------
 Net investment income                             2.42   %           2.51%          2.26%         2.31%        1.82%
--------------------------------------------    ------------     ---------      ---------     ---------     --------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------     --------
 Net assets, end of year (000)                  $ 268,514        $ 179,389      $ 180,740     $ 118,364     $ 57,525
--------------------------------------------    ------------     ---------      ---------     ---------     --------
Portfolio turnover of the Master Portfolio              6%              13%             7%           16%          17%
--------------------------------------------    ------------     ---------      ---------     ---------     --------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

67

LIFEPATH 2030 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                        INVESTOR A SHARES
                                             ------------------------------------------------------------------------
                                                                     YEAR ENDED DECEMBER 31,
                                             ------------------------------------------------------------------------
                                                          2009           2008          2007         2006         2005
                                             ----------------- -------------- ------------- ------------ ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -            -            -
 Net asset value, beginning of year             $  10.71         $   15.90      $  16.62      $  15.15     $  14.65
--------------------------------------------    ----------       ---------      --------      --------     --------
Net investment income                              0.261              0.29          0.31         0.28         0.22
--------------------------------------------    ----------       ---------      --------      --------     --------
 Net realized and unrealized gain (loss)           2.41              (5.17)         0.09         1.95         0.85
--------------------------------------------    ----------       ---------      --------      --------     --------
Net increase (decrease) from investment
 operations                                        2.67            (  4.88)         0.40         2.23         1.07
--------------------------------------------    ----------       ---------      --------      --------     --------
 Dividends and distributions from:
  Net investment income                             (0.33)           (0.23)         (0.31)       (0.32)       (0.23)
  Net realized gain                                     -            (0.08)         (0.81)       (0.44)       (0.34)
  Return of capital                                 (0.00)/2/            -              -            -            -
--------------------------------------------    ------------     ---------      ---------    -- ------     --------
Total dividends and distributions                   (0.33)           (0.31)         (1.12)       (0.76)       (0.57)
--------------------------------------------    ------------     ---------      ---------     --------     --------
 Net asset value, end of year                   $  13.05         $   10.71      $  15.90      $  16.62     $  15.15
--------------------------------------------    ------------     ---------      ---------     --------     --------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     --------     --------
 Based on net asset value                         25.51   %         (31.19)%         2.38%       14.83%        7.37%
--------------------------------------------    ------------     ---------      ---------     --------     --------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     --------     --------
 Total expenses                                    1.31   %           1.31%          1.32%        1.33%        1.35%
--------------------------------------------    ------------     ---------      ---------     --------     --------
Total expenses after expense reductions            0.95   %           0.97%          0.98%        0.99%        1.01%
--------------------------------------------    ------------     ---------      ---------     --------     --------
 Net investment income                             2.23   %           2.13%          1.85%        1.84%        1.52%
--------------------------------------------    ------------     ---------      ---------     --------     --------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     --------     --------
 Net assets, end of year (000)                  $ 210,372        $ 133,199      $ 135,684     $ 77,890     $ 39,134
--------------------------------------------    ------------     ---------      ---------     --------     --------
Portfolio turnover of the Master Portfolio              7%              13%             7%          22%          24%
--------------------------------------------    ------------     ---------      ---------     --------     --------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

68

LIFEPATH 2040 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         INVESTOR A SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                       2009            2008           2007          2006          2005
                                             -------------- --------------- -------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            -              -               -             -             -
 Net asset value, beginning of year            $   12.32      $    19.46      $   20.06      $   17.47     $   16.37
--------------------------------------------   ---------      ----------      ---------      ---------     ---------
Net investment income                               0.281           0.29           0.30          0.25          0.19
--------------------------------------------   ----------     ----------      ---------      ---------     ---------
 Net realized and unrealized gain (loss)            3.08           (7.13)          0.06          2.64          1.11
--------------------------------------------   ----------     ----------      ---------      ---------     ---------
Net increase (decrease) from investment
 operations                                         3.36        (   6.84)          0.36          2.89          1.30
--------------------------------------------   ----------     ----------      ---------      ---------     ---------
 Dividends and distributions from:
  Net investment income                             (0.35)         (0.22)          (0.31)        (0.30)        (0.20)
  Net realized gain                                     -          (0.08)          (0.65)            -             -
--------------------------------------------   ----------     ----------      ----------     ---------    --- ------
Total dividends and distributions                   (0.35)         (0.30)          (0.96)        (0.30)        (0.20)
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
 Net asset value, end of year                  $   15.33      $    12.32      $   19.46      $   20.06     $   17.47
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
TOTAL INVESTMENT RETURN/2/
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
 Based on net asset value                           27.85%        (35.56)%          1.78%        16.64%         8.01%
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/3/
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
 Total expenses                                      1.30%          1.29%           1.31%         1.32%         1.34%
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
Total expenses after expense reductions              0.94%          0.94%           0.97%         0.98%         1.01%
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
 Net investment income                               2.08%          1.80%           1.49%         1.46%         1.20%
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
SUPPLEMENTAL DATA
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
 Net assets, end of year (000)                 $  156,564     $   96,873      $  110,528     $  65,203     $  34,710
--------------------------------------------   ----------     ----------      ----------     ---------     ---------
Portfolio turnover of the Master Portfolio              6%            14%              8%           29%           38%
--------------------------------------------   ----------     ----------      ----------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Includes the reinvestment of dividends and distributions.

/3/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

69

LIFEPATH 2050 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                     INVESTOR A SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED              JUNE 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                 -                      -
 Net asset value, beginning of period                     $     13.47          $     20.00
----------------------------------------------------      -----------          -------------
Net investment income                                            0.412                0.14
----------------------------------------------------      ------------         -------------
 Net realized and unrealized gain (loss)                         3.63                   (6.59)
----------------------------------------------------      ------------         -------------
Net increase (decrease) from investment operations               4.04              (     6.45)
----------------------------------------------------      ------------         --------------
 Dividends and distributions from:
  Net investment income                                         ( 0.14)                 (0.06)
  Net realized gain                                             ( 0.55)                 (0.00)/3 /
  Return of capital                                                  -                  (0.02)
----------------------------------------------------      ------------         -----------------
Total dividends and distributions                               ( 0.69)                 (0.08)
----------------------------------------------------      ------------         -----------------
 Net asset value, end of period                           $     16.82          $     13.47
----------------------------------------------------      ------------         -----------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------      ------------         -----------------
 Based on net asset value                                        30.08%                (32.28)%/5/
----------------------------------------------------      ------------         ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------      ------------         ------------------
 Total expenses                                                   1.35%                 13.04%/7 /
----------------------------------------------------      ------------         ------------------
Total expenses after expense reductions                           0.84%                  0.91%/7 /
----------------------------------------------------      ------------         ------------------
 Net investment income                                            2.45%                  1.68%/7 /
----------------------------------------------------      ------------         ------------------
SUPPLEMENTAL DATA
----------------------------------------------------      ------------         ------------------
 Net assets, end of period (000)                          $      3,056         $           34
----------------------------------------------------      ------------         ------------------
Portfolio turnover of the Master Portfolio                          12%                     0%/8/
----------------------------------------------------      ------------         ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

/8/ Rounds to less than 1% .

70

DISCLAIMERS

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible

71

for and has not participated in the determination of the prices and amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

72

The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE Licensor Parties. None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/

NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of

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Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the LifePath Portfolios is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the LifePath Portfolio's investments. The annual report describes the LifePath Portfolio's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and LifePath Portfolio investment strategies that significantly affected the LifePath Portfolio's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION

A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each LifePath Portfolio, may be obtained free of charge, along with each LifePath Portfolio's annual and semi-annual reports, by calling (800) 441-7762, on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the LifePath Portfolios, please:

Call:       1-800-441-7762 (toll free)
            8:00 a.m. to 6:00 p.m. (Eastern time),
            on any business day

WORLD WIDE WEB

General LifePath Portfolio information and specific LifePath Portfolio performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com.

WRITTEN CORRESPONDENCE

BlackRock Funds III
PO Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

INTERNAL WHOLESALERS/BROKER DEALER SUPPORT
Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), on any business day. Call: (800) 882-0052.

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the LifePath Portfolios' policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about a LifePath Portfolio, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-LPA-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
LIFEPATH(Reg. TM) PORTFOLIOS

INVESTOR C SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

PORTFOLIO                                                        TICKER SYMBOL
------------------------------------------------------------     --------------
LifePath(Reg. TM) Retirement Portfolio - Investor C Shares                LPCRX
LifePath 2020 Portfolio(Reg. TM) - Investor C Shares                      LPCMX
LifePath 2030 Portfolio(Reg. TM) - Investor C Shares                      LPCNX
LifePath 2040 Portfolio(Reg. TM) - Investor C Shares                      LPCKX
LifePath(Reg. TM) 2050 Portfolio - Investor C Shares                      LPCPX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.


Table of Contents

LIFEPATH PORTFOLIO

  KEY FACTS AND DETAILS ABOUT THE LIFEPATH PORTFOLIOS, INCLUDING
OVERVIEW
  INVESTMENT OBJECTIVES, PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND
  EXPENSE INFORMATION, AND HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO.....................  1
  KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO...........................  7
  KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO........................... 14
  KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO........................... 21
  KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO........................... 28

DETAILS ABOUT THE LIFEPATH PORTFOLIOS

INVESTMENT TIME HORIZONS....................................... 35
A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES........ 36
A FURTHER DISCUSSION OF RISK FACTORS........................... 42

ACCOUNT INFORMATION

DETAILS ABOUT INVESTOR C SHARES......................... 48
HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES.......... 49
DISTRIBUTION AND SERVICE PAYMENTS....................... 56
ACCOUNT SERVICES AND PRIVILEGES......................... 57
LIFEPATH PORTFOLIOS' RIGHTS............................. 58
CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE........ 58
LIFEPATH PORTFOLIO DISTRIBUTIONS........................ 58
SHORT-TERM TRADING POLICY............................... 58
TAXES................................................... 59
MASTER/FEEDER AND FUND OF FUNDS STRUCTURES.............. 60

MANAGEMENT OF THE LIFEPATH PORTFOLIOS

INVESTMENT ADVISER............................. 62
PORTFOLIO MANAGERS............................. 62
ADMINISTRATIVE SERVICES........................ 63
CONFLICTS OF INTEREST.......................... 63
VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS.... 64
CERTAIN LIFEPATH PORTFOLIO POLICIES............ 64

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE LIFEPATH PORTFOLIOS........ 66
DISCLAIMERS............................................. 71

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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LifePath Retirement Portfolio Overview

KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO

INVESTMENT OBJECTIVE

LifePath Retirement Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors seeking income and moderate long-term growth of capital. LifePath Retirement Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH RETIREMENT PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor C Shares of LifePath Retirement Portfolio.

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Deferred Sales Charge (Load) (as                         1.00%(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     1.00%
 Other Expenses                                                                               0.52%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.02%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.33%
 Total Annual Class Operating Expenses(6)                                                     2.20%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.85%
  Reimbursements(2)(4)(6)


(1) There is no contingent deferred sales charge ("CDSC") on Investor C Shares after one year.

(2) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath Retirement Master Portfolio (the "Retirement Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Retirement Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the Retirement Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath Retirement Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath Retirement Portfolio and the Retirement Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath Retirement Portfolio and the Retirement Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath Retirement Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor C Shares of LifePath Retirement Portfolio and the Retirement Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the Retirement Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor C Shares of LifePath Retirement Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor C

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Shares of LifePath Retirement Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor C Shares of LifePath Retirement Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  288       $  619        $  1,114        $  2,477

You would pay the following expenses if you did not redeem your shares:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  188       $  619        $  1,114        $  2,477

PORTFOLIO TURNOVER

The Retirement Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath Retirement Portfolio's performance. During the most recent fiscal year, the Retirement Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH RETIREMENT PORTFOLIO


LifePath Retirement Portfolio invests all of its assets in the Retirement Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath Retirement Portfolio is designed for investors seeking current income and moderate long-term growth of capital. As of March 31, 2010, LifePath Retirement Portfolio held approximately 39% of its assets in Underlying Funds that invest primarily in equity securities, 61% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in real estate investment trusts ("REITs"), foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. Because LifePath Retirement Portfolio is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain LifePath Retirement Portfolio's risk profile.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH RETIREMENT PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath Retirement Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath Retirement Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath Retirement Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath Retirement Portfolio.

. ALLOCATION RISK - LifePath Retirement Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath Retirement Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath Retirement Portfolio's investment

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in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath Retirement Portfolio's use of derivatives may reduce LifePath Retirement Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath Retirement Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath Retirement Portfolio will lose money. These risks include:

. LifePath Retirement Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath Retirement Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath Retirement Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath Retirement Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath Retirement Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath Retirement Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath Retirement Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath Retirement Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath Retirement Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

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. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath Retirement Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath Retirement Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath Retirement Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath Retirement Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath Retirement Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath Retirement Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Investor C Shares offered in this Prospectus are expected to have substantially similar annual returns since Investor C and Institutional Shares are invested in the same Master Portfolio.
ANNUAL RETURNS FOR INVESTOR C SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE INVESTOR C SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES.

The bar chart shows the returns for Institutional Shares of LifePath Retirement Portfolio for each of the last ten calendar years. Investor C Shares have not, as of the date of this prospectus, commenced operations. The performance shown is that of Institutional Shares of LifePath Retirement Portfolio. The average annual total return table compares the performance of Institutional Shares of LifePath Retirement Portfolio to that of the LifePath Retirement Portfolio Custom Benchmark. The LifePath Retirement Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath Retirement Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for Institutional Shares of LifePath Retirement Portfolio reflect the Retirement Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath Retirement Portfolio reflect the direct investment by the Retirement Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath Retirement Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certian Life Path Retirement Portfolio expenses during these periods, Life Path Retirement Portfolio's returns would have been lower.

LIFEPATH RETIREMENT PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    4.73%
2001    3.60%
2002   -2.70%
2003   11.95%
2004    6.35%
2005    4.32%
2006    8.80%
2007    4.50%
2008  -15.04%
2009   18.25%

During the periods shown in the bar chart, the highest return for a quarter was 9.85% (quarter ended September 30, 2009) and the lowest return for a quarter was -7.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 2.79%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath Retirement Portfolio - Institutional Shares
  Return Before Taxes                                                                       18.25%       3.57%       4.12%
  Return After Taxes on Distributions                                                       17.09%       2.38%       2.79%
  Return After Taxes on Distributions and Sale of Fund Shares                               11.89%       2.49%       2.84%
 LifePath Retirement Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         16.75%       4.06%       5.09%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER


The Retirement Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                         THE
                      RETIREMENT
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath Retirement Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath Retirement Portfolio, you should contact LifePath Retirement Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath Retirement Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath Retirement Portfolio may reduce or waive these investment minimums in some cases:

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                                INVESTOR C SHARES
                                =====================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan

Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower
                                minimum

TAX INFORMATION

LifePath Retirement Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath Retirement Portfolio through a broker-dealer or other financial intermediary, LifePath Retirement Portfolio and BlackRock Investments, LLC, LifePath Retirement Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath Retirement Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath Retirement Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

6

LifePath 2020 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2020 Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020. LifePath 2020 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2020 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor C Shares of LifePath 2020 Portfolio.

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Deferred Sales Charge (Load) (as                         1.00%(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     1.00%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.33%
 Total Annual Class Operating Expenses(6)                                                     2.19%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                             (0.34)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.85%
  Reimbursements(2)(4)(6)


(1) There is no contingent deferred sales charge ("CDSC") on Investor C Shares after one year.

(2) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2020 Master Portfolio (the "2020 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2020 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2020 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2020 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2020 Portfolio and the 2020 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2020 Portfolio and the 2020 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2020 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor C Shares of LifePath 2020 Portfolio and the 2020 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2020 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor C Shares of LifePath 2020 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor C Shares

7

of LifePath 2020 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor C Shares of LifePath 2020 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  288       $  618        $  1,111        $  2,469

You would pay the following expenses if you did not redeem your shares:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  188       $  618        $  1,111        $  2,469

PORTFOLIO TURNOVER

The 2020 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2020 Portfolio's performance. During the most recent fiscal year, the 2020 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2020 PORTFOLIO


LifePath 2020 Portfolio invests all of its assets in the 2020 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2020 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2020. As of March 31, 2010, LifePath 2020 Portfolio held approximately 60% of its assets in Underlying Funds that invest primarily in equity securities, 40% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2020 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2020 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2020 Portfolio, which may be a primary source of income after retirement.

8

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2020 Portfolio, and determine whether any changes are required to enable LifePath 2020 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2020 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2020 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2020 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2020 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2020 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2020 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2020 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2020 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

9

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2020 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2020 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2020 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2020 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2020 Portfolio.

. ALLOCATION RISK - LifePath 2020 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2020 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2020 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2020 Portfolio's use of derivatives may reduce LifePath 2020 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2020 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2020 Portfolio will lose money. These risks include:

. LifePath 2020 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2020 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

10

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2020 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2020 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2020 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2020 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2020 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2020 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2020 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2020 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2020 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2020 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2020 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2020 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2020 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Investor C Shares offered in this Prospectus are expected to have substantially similar annual returns since Investor C and Institutional Shares are invested in the same Master Portfolio. ANNUAL RETURNS FOR INVESTOR C SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE INVESTOR C SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES.

The bar chart shows the returns for Institutional Shares of LifePath 2020 Portfolio for each of the last ten calendar years. Investor C Shares have not, as of the date of this prospectus, commenced operations. The performance shown is that of Institutional Shares of LifePath 2020 Portfolio. The average annual total return table compares the performance of Institutional Shares of LifePath 2020 Portfolio to that of the LifePath 2020 Portfolio Custom Benchmark. The LifePath 2020 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2020 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2020 Portfolio reflect the 2020 Master Portfolio's investment in Underlying Funds. For

11

all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2020 Portfolio reflect the direct investment by the 2020 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2020 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2020 Portfolio expenses during these periods, Life Path 2020 Portfolio's returns would have been lower.

LIFEPATH 2020 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -3.74%
2001    -6.42%
2002   -12.59%
2003    20.61%
2004     9.27%
2005     6.54%
2006    13.01%
2007     3.34%
2008   -25.42%
2009    22.71%

During the periods shown in the bar chart, the highest return for a quarter was 13.89% (quarter ended June 30, 2009) and the lowest return for a quarter was -14.21% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.30%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2020 Portfolio - Institutional Shares
  Return Before Taxes                                                                       22.71%       2.63%       1.68%
  Return After Taxes on Distributions                                                       21.50%       1.81%       0.89%
  Return After Taxes on Distributions and Sale of Fund Shares                               14.84%       1.94%       1.08%
 LifePath 2020 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         22.84%       3.27%       2.78%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

12

INVESTMENT ADVISER

The 2020 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2020
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2020 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2020 Portfolio, you should contact LifePath 2020 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2020 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2020 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR C SHARES
                                =====================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan

Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower
                                minimum

TAX INFORMATION

LifePath 2020 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2020 Portfolio through a broker-dealer or other financial intermediary, LifePath 2020 Portfolio and BlackRock Investments, LLC, LifePath 2020 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2020 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2020 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

13

LifePath 2030 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2030 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030. LifePath 2030 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2030 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor C Shares of LifePath 2030 Portfolio.

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Deferred Sales Charge (Load) (as                         1.00%(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     1.00%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.34%
 Total Annual Class Operating Expenses(6)                                                     2.20%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.85%
  Reimbursements(2)(4)(6)


(1) There is no contingent deferred sales charge ("CDSC") on Investor C Shares after one year.

(2) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2030 Master Portfolio (the "2030 Master Portfolio"), a series of Master Investment Portfolio ("MIP") has contractually agreed to waive its management fee at the 2030 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2030 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2030 Portfolio and the 2030 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2030 Portfolio and the 2030 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2030 Portfolio's PRO RATA share of the fees and expenses incurred by investing certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor C Shares of LifePath 2030 Portfolio and the 2030 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2030 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor C Shares of LifePath 2030 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor C Shares

14

of LifePath 2030 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor C Shares of LifePath 2030 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  288       $  619        $  1,114        $  2,477

You would pay the following expenses if you did not redeem your shares:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  188       $  619        $  1,114        $  2,477

PORTFOLIO TURNOVER

The 2030 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2030 Portfolio's performance. During the most recent fiscal year, the 2030 Master Portfolio's portfolio turnover rate was 7% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2030 PORTFOLIO


LifePath 2030 Portfolio invests all of its assets in the 2030 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2030 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2030. As of March 31, 2010, LifePath 2030 Portfolio held approximately 75% of its assets in Underlying Funds that invest primarily in equity securities, 25% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2030 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2030 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2030 Portfolio, which may be a primary source of income after retirement.

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The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2030 Portfolio, and determine whether any changes are required to enable LifePath 2030 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2030 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2030 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2030 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2030 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2030 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2030 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2030 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2030 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

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PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2030 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2030 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2030 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2030 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2030 Portfolio.

. ALLOCATION RISK - LifePath 2030 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2030 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2030 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2030 Portfolio's use of derivatives may reduce LifePath 2030 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2030 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2030 Portfolio will lose money. These risks include:

. LifePath 2030 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2030 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

17

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2030 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2030 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2030 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2030 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2030 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2030 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2030 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2030 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2030 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2030 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2030 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2030 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2030 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Investor C Shares offered in this Prospectus are expected to have substantially similar annual returns since Investor C and Institutional Shares are invested in the same Master Portfolio. ANNUAL RETURNS FOR INVESTOR C SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE INVESTOR C SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES.

The bar chart shows the returns for Institutional Shares of LifePath 2030 Portfolio for each of the last ten calendar years. Investor C Shares have not, as of the date of this prospectus, commenced operations. The performance shown is that of Institutional Shares of LifePath 2030 Portfolio. The average annual total return table compares the performance of Institutional Shares of LifePath 2030 Portfolio to that of the LifePath 2030 Portfolio Custom Benchmark. The LifePath 2030 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2030 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2030 Portfolio reflect the 2030 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2030 Portfolio reflect the direct investment by the 2030 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a

18

model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2030 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future.

If BFA and its affiliates had not waived or reimbursed certain Life Path 2030 Portfolio expenses during these periods, Life Path 2030 Portfolio's returns would have been lower.

LIFEPATH 2030 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -5.65%
2001    -9.94%
2002   -15.73%
2003    23.86%
2004    10.78%
2005     7.63%
2006    15.12%
2007     2.64%
2008   -31.03%
2009    25.77%

During the periods shown in the bar chart, the highest return for a quarter was 16.61% (quarter ended June 30, 2009) and the lowest return for a quarter was -17.90% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.62%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2030 Portfolio - Institutional Shares
  Return Before Taxes                                                                       25.77%       1.98%        0.81%
  Return After Taxes on Distributions                                                       24.68%       1.10%       -0.09%
  Return After Taxes on Distributions and Sale of Fund Shares                               16.88%       1.48%        0.39%
 LifePath 2030 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         27.05%       2.70%        1.82%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%       -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%        6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%        2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%        2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%        7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%        9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

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INVESTMENT ADVISER

The 2030 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2030
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2030 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2030 Portfolio, you should contact LifePath 2030 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2030 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2030 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR C SHARES
                                =====================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan

Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower
                                minimum

TAX INFORMATION

LifePath 2030 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2030 Portfolio through a broker-dealer or other financial intermediary, LifePath 2030 Portfolio and BlackRock Investments, LLC, LifePath 2030 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2030 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2030 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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LifePath 2040 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2040 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040. LifePath 2040 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2040 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor C Shares of LifePath 2040 Portfolio.

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Deferred Sales Charge (Load) (as                         1.00%(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     1.00%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.34%
 Total Annual Class Operating Expenses(6)                                                     2.20%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                            (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.85%
  Reimbursements(2)(4)(6)


(1) There is no contingent deferred sales charge ("CDSC") on Investor C Shares after one year.

(2) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2040 Master Portfolio (the "2040 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2040 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2040 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2040 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2040 Portfolio and the 2040 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2040 Portfolio and the 2040 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2040 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor C Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2040 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor C Shares of LifePath 2040 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor C Shares

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of LifePath 2040 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor C Shares of LifePath 2040 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  288       $  619        $  1,114        $  2,477

You would pay the following expenses if you did not redeem your shares:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  188       $  619        $  1,114        $  2,477

PORTFOLIO TURNOVER

The 2040 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2040 Portfolio's performance. During the most recent fiscal year, the 2040 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2040 PORTFOLIO


LifePath 2040 Portfolio invests all of its assets in the 2040 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of the equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2040 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2040. As of March 31, 2010, LifePath 2040 Portfolio held approximately 88% of its assets in Underlying Funds that invest primarily in equity securities, 12% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2040 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2040 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2040 Portfolio, which may be a primary source of income after retirement.

22

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2040 Portfolio, and determine whether any changes are required to enable LifePath 2040 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2040 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2040 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2040 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2040 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2040 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2040 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2040 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2040 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

23

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2040 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2040 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2040 Portfolio or your investment may not perform as well as other similar investments. The following is a summary description of certain risks of investing in LifePath 2040 Portfolio. An investment in LifePath 2040 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

. ALLOCATION RISK - LifePath 2040 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2040 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2040 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2040 Portfolio's use of derivatives may reduce LifePath 2040 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2040 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2040 Portfolio will lose money. These risks include:

. LifePath 2040 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2040 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

24

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2040 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2040 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2040 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2040 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2040 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2040 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2040 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2040 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2040 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2040 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2040 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2040 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2040 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Investor C Shares offered in this Prospectus are expected to have substantially similar annual returns since Investor C and Institutional Shares are invested in the same Master Portfolio. ANNUAL RETURNS FOR INVESTOR C SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE INVESTOR C SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES.

The bar chart shows the returns for Institutional Shares of LifePath 2040 Portfolio for each of the last ten calendar years. Investor C Shares have not, as of the date of this prospectus, commenced operations. The performance shown is that of Institutional Shares of LifePath 2040 Portfolio. The average annual total return table compares the performance of Institutional Shares of LifePath 2040 Portfolio to that of the LifePath 2040 Portfolio Custom Benchmark. The LifePath 2040 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2040 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2040 Portfolio reflect 2040 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2040 Portfolio reflect the direct investment by 2040 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a

25

model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2040 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future.

If BFA and its affiliates had not waived or reimbursed certain Life Path 2040 Portfolio expenses during these periods, Life Path 2040 Portfolio's returns would have been lower.

LIFEPATH 2040 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -9.71%
2001   -13.41%
2002   -18.73%
2003    27.64%
2004    11.43%
2005     8.24%
2006   16.97 %
2007     2.03%
2008   -35.40%
2009    28.08%

During the periods shown in the bar chart, the highest return for a quarter was 19.00% (quarter ended June 30, 2009) and the lowest return for a quarter was -20.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.88%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2040 Portfolio - Institutional Shares
  Return Before Taxes                                                                       28.08%       1.34%      -0.35%
  Return After Taxes on Distributions                                                       27.18%       0.87%      -0.88%
  Return After Taxes on Distributions and Sale of Fund Shares                               18.45%       1.08%      -0.43%
 LifePath 2040 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         30.52%       2.15%       0.87%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

26

INVESTMENT ADVISER

The 2040 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2040
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2040 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2040 Portfolio, you should contact LifePath 2040 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2040 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2040 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR C SHARES
                                =====================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan

Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2040 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2040 Portfolio through a broker-dealer or other financial intermediary, LifePath 2040 Portfolio and BlackRock Investments, LLC, LifePath 2040 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2040 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2040 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

27

LifePath 2050 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2050 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050. LifePath 2050 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2050 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Investor C Shares of LifePath 2050 Portfolio.

SHAREHOLDER FEES
(FEES PAID DIRECTLY FROM YOUR INVESTMENT)
 Maximum Deferred Sales Charge (Load) (as                         1.00%(1)
 percentage of offering price or redemption proceeds,
 whichever is lower)

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(2)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     1.00%
 Other Expenses                                                                               0.83%
  Administration Fees                                                                         0.50%
  Independent Expenses(3)(4)                                                                  0.33%
 Acquired Fund Fees and Expenses (Underlying Funds)(5)                                        0.34%
 Total Annual Class Operating Expenses(6)                                                     2.52%
 Fee Waivers and/or Expense Reimbursements(2)(4)                                            (0.67)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.85%
  Reimbursements(2)(4)(6)


(1) There is no contingent deferred sales charge ("CDSC") on Investor C Shares after one year.

(2) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2050 Master Portfolio (the "2050 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2050 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(3) Independent Expenses have been restated to reflect current fees.

(4) "Independent Expenses" consist of LifePath 2050 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services in connection with LifePath 2050 Portfolio and the 2050 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2050 Portfolio and the 2050 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(5) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2050 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(6) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Investor C Shares of LifePath 2050 Portfolio and the 2050 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2050 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Investor C Shares of LifePath 2050 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Investor C Shares

28

of LifePath 2050 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Investor C Shares of LifePath 2050 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  288       $  653        $  1,216        $  2,751

You would pay the following expenses if you did not redeem your shares:

1 YEAR       3 YEARS        5 YEARS         10 YEARS
$  188       $  653        $  1,216        $  2,751

PORTFOLIO TURNOVER

The 2050 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2050 Portfolio's performance. During the most recent fiscal year, the 2050 Master Portfolio's portfolio turnover rate was 12% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2050 PORTFOLIO


LifePath 2050 Portfolio invests all of its assets in the 2050 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2050 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2050. As of March 31, 2010, LifePath 2050 Portfolio held approximately 98% of its assets in Underlying Funds that invest primarily in equity securities, 1% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2050 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2050 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2050 Portfolio, which may be a primary source of income after retirement.

29

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2050 Portfolio, and determine whether any changes are required to enable LifePath 2050 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2050 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2050 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2050 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2050 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2050 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2050 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2050 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2050 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

30

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2050 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2050 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2050 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2050 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2050 Portfolio.

. ALLOCATION RISK - LifePath 2050 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2050 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2050 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2050 Portfolio's use of derivatives may reduce LifePath 2050 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2050 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2050 Portfolio will lose money. These risks include:

. LifePath 2050 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2050 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

31

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2050 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2050 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2050 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2050 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2050 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2050 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2050 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2050 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2050 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2050 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2050 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2050 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2050 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Investor C Shares offered in this Prospectus are expected to have substantially similar annual returns since Investor C and Institutional Shares are invested in the same Master Portfolio. ANNUAL RETURNS FOR INVESTOR C SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE INVESTOR C SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES.

The bar chart shows the returns for Institutional Shares of LifePath 2050 Portfolio for the last calendar year. Investor C Shares have not, as of the date of this prospectus, commenced operations. The performance shown is that of Institutional Shares of LifePath 2050 Portfolio. The average annual total return table compares the performance of Institutional Shares of LifePath 2050 Portfolio to that of the LifePath 2050 Portfolio Custom Benchmark. The LifePath 2050 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2050 Portfolio invests according to their weightings as of the most recent quarter-end. How LifePath 2050 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2050 Portfolio expenses during these periods, Life Path 2050 Portfolio's returns would have been lower.

32

LIFEPATH 2050 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   30.35%

During the period shown in the bar chart, the highest return for a quarter was 21.06% (quarter ended June 30, 2009) and the lowest return for a quarter was -12.76% (quarter ended March 31, 2009). The year-to-date return as of March 31, 2010 was 4.14%.

                                                                                                                 SINCE
AS OF 12/31/09                                                                                               INCEPTION JUNE
AVERAGE ANNUAL TOTAL RETURNS                                                                   1 YEAR           30, 2008
 LifePath 2050 Portfolio - Institutional Shares
  Return Before Taxes                                                                           30.35%          -7.86%
  Return After Taxes on Distributions                                                           28.59%          -8.77%
  Return After Taxes on Distributions and Sale of Fund Shares                                   19.85%          -7.12%
 LifePath 2050 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                             34.11%          -6.38%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                            27.25%            N/A
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                              5.93%             N/A
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             43.60%            N/A
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                          0.16%             N/A
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                           11.41%            N/A
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             38.25%             N/A

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

33

INVESTMENT ADVISER

The 2050 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2050
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2050 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2050 Portfolio, you should contact LifePath 2050 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2050 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2050 Portfolio may reduce or waive these investment minimums in some cases:

                                INVESTOR C SHARES
                                =====================================================

Minimum Initial Investment      $1,000 for all accounts except:
                                .  $250 for certain fee-based programs
                                .  $100 for retirement plans
                                .  $50, if establishing Automatic Investment Plan

Minimum Additional Investment   $50 for all accounts except certain retirement plans
                                and payroll deduction programs may have a lower minimum

TAX INFORMATION

LifePath 2050 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2050 Portfolio through a broker-dealer or other financial intermediary, LifePath 2050 Portfolio and BlackRock Investments, LLC, LifePath 2050 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2050 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2050 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the LifePath Portfolios

INVESTMENT TIME HORIZONS

Each LifePath Portfolio seeks to maximize return consistent with the quantitatively measured risk that investors on average may be willing to accept given a particular investment time horizon. An investor's time horizon marks the point when the investor plans to start making net withdrawals from his or her investments, in other words, the time when they will cease making new contributions to their investments. For many LifePath Portfolio investors, their time horizon is tied to the date that they plan to retire and begin gradually utilizing their investment to support themselves in retirement. For other LifePath Portfolio investors, their time horizon may represent the date when they plan to make substantial withdrawals for another purpose, such as a major purchase.

As a general rule, investors with a longer time horizon have a greater tolerance for risk than investors with a shorter time horizon. Long-term investors are more likely to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns. Each LifePath Portfolio has its own time horizon, as described in its investment objective in each LifePath Portfolio's "Key Facts" section in this Prospectus, which affects the targeted risk level of that LifePath Portfolio and, in turn, its asset allocation.

The allocations for LifePath Retirement Portfolio reflect the expectation that investors in or near retirement, or otherwise seeking current income, are willing to take some risk of loss of their investment in hopes of achieving moderate long term growth of capital. LifePath Retirement Portfolio is designed to help balance two risk factors that investors face during retirement: market risk (potential declines in market values) and longevity risk (living longer than expected). Specifically, the portfolio seeks to enable investors to maintain a steady withdrawal rate (about 3-5% per year) throughout their retirement without exhausting their investment. There is no guarantee that the performance of LifePath Retirement Portfolio will be sufficient to enable this withdrawal rate or that any one withdrawal rate is appropriate for all investors. Investors should work with a financial advisor or other expert to determine a sustainable withdrawal rate for their circumstances, and that withdrawal rate should be periodically reassessed throughout retirement as the value of the investor's portfolio changes.

Each LifePath Portfolio has a distinct investment objective tied to its time horizon:

. LifePath Retirement Portfolio is managed for investors seeking income and moderate long-term growth of capital.

. LifePath 2020 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020.

. LifePath 2030 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030.

. LifePath 2040 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040.

. LifePath 2050 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050.

You should carefully consider the asset allocation and risks of each LifePath Portfolio before deciding whether to invest.

The LifePath Portfolios are designed to offer individual investors comprehensive asset allocation strategies tailored to the time when they expect to begin withdrawing assets. Asset allocation is the distribution of investments among broad types of asset classes: equity securities, bonds and money market instruments. Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has the same objective and strategies as the applicable LifePath Portfolio. LifePath Retirement Portfolio invests all of its assets in Retirement Master Portfolio. LifePath 2020 Portfolio invests all of its assets in 2020 Master Portfolio. LifePath 2030 Portfolio invests all of its assets in 2030 Master Portfolio. LifePath 2040 Portfolio invests all of its assets in 2040 Master Portfolio. LifePath 2050 Portfolio invests all of its assets in 2050 Master Portfolio. To implement the asset allocation strategy, each Master Portfolio, in turn, invests in a combination of Underlying Funds in proportions based on its own comprehensive investment strategy that gradually becomes more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase. BFA is the investment adviser to the Master Portfolios. For simplicity's sake, all discussion of investment objective, strategies and risks of a particular LifePath Portfolio refers also to the

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investment objective, strategies and risks of the applicable Master Portfolio, unless otherwise indicated. A description of the relationship of the LifePath Portfolios to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder and Fund of Funds Structures."

WHICH LIFEPATH PORTFOLIO TO CONSIDER

The first step in choosing which LifePath Portfolio to consider is answering a key question: When will you need the money you are thinking of investing? Will it be in ten years, when your kids are ready for college? Or 30 years, when you retire?

The number in the name of most of the LifePath Portfolios is actually a year - a "target year" when you might expect to begin withdrawing your money. Selecting the LifePath Portfolio that may be most appropriate for your investment may be as simple as matching your target year with the closest LifePath Portfolio target year.

For example, let's say that you are investing for retirement purposes, and that you expect to retire at age 60. If you are 45 years old, you have 15 years before retirement. By adding 15 to the current year, you can define your "target year." If you expect to retire in the year 2025, as in this example, you may conclude that LifePath 2020 Portfolio is the most appropriate LifePath Portfolio for you.

The investment mix of the LifePath Portfolios gradually shifts from a greater concentration of higher-risk investments (namely, equity securities funds) to a greater concentration of lower-risk investments (namely, bond funds), thereby making the LifePath Portfolios increasingly conservative.

In making your investment decision, you should keep in mind:

. The LifePath Portfolios' investment strategies derive from the risk tolerance of average investors with a particular time horizon.

. The LifePath Portfolios' time horizons are based on the year in their name, except for LifePath Retirement Portfolio, which is designed for investors who are currently withdrawing, or plan in the near future to begin withdrawing, a substantial portion of their investment.

If you are willing to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns, you may invest some or all of your assets in a LifePath Portfolio with a longer time horizon. If you desire a more conservative investment and are willing to forego some potential returns, you may invest some or all of your assets in a LifePath Portfolio with a shorter time horizon. The final choice is yours.

A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES

Each LifePath Portfolio invests all of its assets in a corresponding Master Portfolio which allocates and reallocates its assets among the Underlying Funds. The Master Portfolios with longer time horizons invest a greater portion of their assets in Underlying Funds that invest in equity securities, which provide a greater opportunity for capital appreciation over the long-term but have a greater risk of loss. The Master Portfolios with shorter time horizons invest a greater portion of their assets in Underlying Funds that invest in bonds and money market instruments, which typically offer reduced risk and price volatility but forego some potential returns. Accordingly, under normal circumstances, the LifePath Portfolios with shorter time horizons have lower expected returns than the LifePath Portfolios with longer time horizons. In addition to investing in Underlying Funds, each Master Portfolio may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and invest the collateral in certain short-term instruments either directly or through one or more joint accounts or money market funds, as described in greater detail in the LifePath Portfolios' combined Statement of Additional Information ("SAI").

As each Master Portfolio approaches its designated time horizon, it systematically seeks to reduce the level of risk by allocating assets more conservatively among the Underlying Funds. This systematic shift toward more conservative investments is designed to reduce the risk of significant reductions in the value of an investment in a Master Portfolio as it approaches its time horizon.

For example, LifePath Retirement Portfolio has entered its "retirement phase" and seeks to maximize returns consistent with the risk that an average investor in retirement may be willing to accept. This does not mean, however, that it invests exclusively, or primarily, in Underlying Funds that are money market funds. Rather, because BFA believes that most investors are still willing to take some risks in pursuing returns even while drawing on their investments, almost all of LifePath Retirement Portfolio's assets will continue to be allocated to Underlying Funds that are equity and bond funds.

In determining the allocation of assets to the Underlying Funds, BFA uses a proprietary investment model that analyzes securities market data, including risk, asset class correlations, and expected returns, to provide portfolio

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allocations among the asset classes represented by the Underlying Funds. The allocations are periodically monitored and rebalanced in an effort to maximize expected return for a given level of risk. In managing the LifePath Portfolios, BFA focuses on long-term targets and objectives. The progression over time of a LifePath Portfolio's asset allocation to more conservative asset classes is a relatively steady process resulting in only gradual changes to the asset allocation from quarter to quarter. The Underlying Funds invest in a mix of equity securities, bonds and money market instruments. Certain Underlying Funds invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivatives, which are subject to additional risks, as described in the "Details About the LifePath Portfolios - A Further Discussion of Risk Factors" section of this Prospectus. The investment model adjusts each LifePath Portfolio's risk level by gradually making it more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase.

When a LifePath Portfolio reaches its stated time horizon and enters its most conservative phase, the allocation of its assets is expected to be similar to that of LifePath Retirement Portfolio. Such LifePath Portfolio and LifePath Retirement Portfolio may then continue to operate as separate funds or, subject to approval by the Trust's Board of Trustees, they may be merged into a single fund.

THE UNDERLYING FUNDS

Two of the Underlying Funds - Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio - are diversified portfolios of MIP. Active Stock Master Portfolio seeks to provide long-term appreciation of capital. BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors. CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return.

The remaining Underlying Funds, other than BlackRock Cash Funds: Institutional (the "Underlying Money Market Fund"), are ETFs that are part of the iShares family of funds ("Underlying iShares Funds"). Each of the Underlying iShares Funds seeks investment results that correspond generally to the performance, before fees and expenses, of its underlying index. As a result, adverse performance of a particular security in an Underlying iShares Fund's portfolio will ordinarily not result in the elimination of the security from the Underlying iShares Fund's portfolio. Each Underlying iShares Fund offers and issues iShares at their NAV per share only to certain institutional investors in aggregations of a specified number of iShares, generally in exchange for a basket of securities included in its underlying index, together with the deposit of a specified cash payment. The iShares for these Underlying iShares Funds are listed and traded on national securities exchanges and also may be listed on certain non-U.S. exchanges. BFA purchases iShares on behalf of the Master Portfolios in the secondary market.

The relative weightings for each Master Portfolio in the various Underlying Funds will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time.

Each Master Portfolio currently expects to invest in some or all of the Underlying Funds described below:

ACTIVE STOCK MASTER PORTFOLIO

Active Stock Master Portfolio seeks to provide long-term appreciation of capital. Active Stock Master Portfolio invests, under normal circumstances, at least 80% of its assets in common stocks. Active Stock Master Portfolio invests primarily in equity securities of U.S. companies with market capitalizations similar to the range of market capitalizations represented in the Standard & Poor's ("S&P") 500 Index(Reg. TM). BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors, such as relative values based on earnings and cash flows; earnings quality as measured by the company's financial condition and earnings reports; sentiment as expressed through management and market participant behavior; and industry classification. BFA considers risk parameters in deciding upon Active Stock Master Portfolio's aggregate holdings, and factors trading costs into its stock selection process.

COREALPHA BOND MASTER PORTFOLIO

CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return. BFA's models also allocate assets among bonds of different maturities based on yield characteristics and expectations. Specific investment selection decisions are made on the basis of evaluations of relative value, credit quality and other factors. CoreAlpha Bond Master Portfolio invests, under normal circumstances, at least 80% of its assets in bonds. For the purposes of this strategy, "bonds" include the following:
obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial

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mortgage-backed securities; debt obligations of U.S. corporations; U.S. dollar-denominated debt obligations of foreign issuers; municipal securities; and asset-backed securities. CoreAlpha Bond Master Portfolio invests a substantial portion of its assets in U.S.-registered, dollar-denominated bonds. CoreAlpha Bond Master Portfolio may invest in bonds of any maturity or duration.

BLACKROCK CASH FUNDS: INSTITUTIONAL

BlackRock Cash Funds: Institutional seeks a high level of income consistent with liquidity and the preservation of capital. BlackRock Cash Funds:
Institutional invests in high-quality, short-term money market instruments that include fixed-rate, floating-rate and variable-rate debt securities. BlackRock Cash Funds: Institutional also may invest in high-quality, short-term U.S. and foreign government debt, including the debt of agencies and instrumentalities, such as the Federal National Mortgage Association ("Fannie Mae"), U.S. and foreign bank obligations, corporate obligations, repurchase agreements and asset-backed securities.

UNDERLYING ISHARES FUNDS

In managing each of the Underlying iShares Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that has an investment profile similar to the underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the applicable underlying index. Underlying iShares Funds that use representative sampling may or may not hold all of the securities in the relevant underlying index.

ISHARES S&P 500 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P 500 Index(Reg. TM), which measures the performance of the large-capitalization sector of the U.S. equity market. The component stocks are weighted according to the float-adjusted market value of their outstanding shares.

ISHARES S&P MIDCAP 400 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P MidCap 400 IndexTM, which measures the performance of the mid-capitalization sector of the U.S. equity market. The stocks in the S&P MidCap 400 IndexTM have a market capitalization between $750 million and $3.3 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation. The S&P MidCap 400 IndexTM consists of stocks from a broad range of industries.

ISHARES S&P SMALLCAP 600 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P SmallCap 600 IndexTM, which measures the performance of the small-capitalization sector of the U.S. equity market. The stocks in the S&P SmallCap 600 IndexTM have a market capitalization between $200 million and $1 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation.

ISHARES S&P NATIONAL AMT-FREE MUNICIPAL BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P National AMT-Free Municipal Bond Index, which measures the performance of the investment-grade segment of the U.S. municipal bond market. As of May 31, 2009, there were 8,709 issues in the S&P National AMT-Free Municipal Bond Index.

ISHARES S&P NORTH AMERICAN NATURAL RESOURCES SECTOR INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P North American Natural Resources Sector IndexTM, which measures the performance of U.S.-traded stocks of natural resource-related companies in the U.S. and Canada, and includes companies in the following categories: producers of oil, gas and consumable fuels, energy equipment and services, metals and mining, manufacturers of paper and forest products, and producers of construction materials, containers and packaging.

ISHARES RUSSELL MIDCAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell Midcap Index, which measures the performance of the mid-capitalization sector of the U.S. equity market. The Russell Midcap Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000(Reg. TM) Index.

ISHARES RUSSELL 2000 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell 2000 Index, which measures the performance of the small capitalization sector of the U.S. equity market. The Russell 2000 Index is a float-adjusted, capitalization-weighted index of equity securities issued by the approximately 2,000 smallest issuers in the Russell 3000(Reg. TM) Index.

ISHARES COHEN & STEERS REALTY MAJORS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Cohen & Steers Realty Major Index (the "Cohen & Steers Index"),

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which consists of selected U.S. REITs. The objective of the Cohen & Steers Index is to represent relatively large and liquid REITs that may benefit from future consolidation and securitization of the U.S. real estate industry. REITs are selected for inclusion in the Cohen & Steers Index based on a rigorous review of several factors, including management, portfolio quality, and sector and geographic diversification. The REITs selected for inclusion in the Cohen & Steers Index must meet minimum market capitalization and liquidity requirements. The Cohen & Steers Index is weighted according to the total market value of each REIT's outstanding shares and is adjusted quarterly so that no REIT represents more than 8% of the Cohen & Steers Index. Within the REIT market, the Cohen & Steers Index is diversified across property sectors that represent the current market.

ISHARES FTSE EPRA/NAREIT DEVELOPED REAL ESTATE EX-U.S. INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which measures the stock performance of companies engaged in the ownership and development of the following real estate markets defined as developed by FTSE EPRA/NAREIT: Canada, Europe (including Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom (including the Channel Islands)), Middle East (Israel) and Asia (including Australia, Hong Kong, Japan, New Zealand and Singapore). As of May 29, 2009, the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index was comprised of stocks of companies in the following markets: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Italy, Japan, Netherlands, New Zealand, Norway, Poland, Singapore, Spain, Sweden, Switzerland and the United Kingdom.

ISHARES MSCI CANADA INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Canada Index developed by MSCI, Inc. ("MSCI"). The MSCI Canada Index consists of stocks traded primarily on the Toronto Stock Exchange.

ISHARES MSCI EAFE INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE(Reg. TM) Index, which has been developed by MSCI as an equity benchmark for its international stock performance. The MSCI EAFE Index includes stocks from Europe, Australasia and the Far East.

ISHARES MSCI EAFE SMALL CAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE Small Cap Index, which represents the small cap size segment of the MSCI EAFE Index. The MSCI EAFE(Reg. TM) Index includes securities from Europe, Australasia and the Far East. Under MSCI's Global Investable Market Index methodology, the small cap universe consists of the securities of those companies whose securities are not included in the large cap or mid cap segments of a particular market, which together comprise approximately 85% of each market's free float-adjusted market capitalization. The small cap segment covers the 85%-99% range of each market's free float-adjusted market capitalization.

ISHARES MSCI EMERGING MARKETS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Emerging Markets Index, which is designed to measure equity market performance in the global emerging markets. As of September 30, 2009, the MSCI Emerging Markets Index consisted of the following 22 emerging market country indexes: Brazil, Chile, China, Colombia, the Czech Republic, Egypt, Hungary, India, Indonesia, Israel, Malaysia, Mexico, Morocco, Peru, the Philippines, Poland, Russia, South Africa, South Korea, Taiwan, Thailand and Turkey. Emerging market country indexes may be added to or deleted from the MSCI Emerging Markets Index from time to time. The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares funds that invest in securities in the MSCI Emerging Markets Index. BFA waives a portion of its advisory fees otherwise due from the iShares MSCI Emerging Markets Index Fund in an amount equal to the portfolio management fees incurred by assets that are invested in shares of other iShares funds.

ISHARES BARCLAYS 1-3 YEAR CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 1-3 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 3-7 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 3-7 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to three years and less than seven years.

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ISHARES BARCLAYS 7-10 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 7-10 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years.

ISHARES BARCLAYS 10-20 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 10-20 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to ten years and less than 20 years.

ISHARES BARCLAYS 20+ YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 20+ Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of 20 years or more.

ISHARES BARCLAYS AGGREGATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Aggregate Bond Index, which measures the performance of the total U.S. investment-grade bond market, which includes investment-grade U.S. Treasury bonds, government-related bonds, investment-grade corporate bonds, mortgage pass-through securities, commercial mortgage-backed securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Barclays Capital U.S. Aggregate Bond Index have $250 million or more of outstanding face value and have at least one year remaining to maturity. In addition, the securities must be U.S. dollar-denominated, fixed-rate and non-convertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and Eurobonds are excluded from the Barclays Capital U.S. Aggregate Bond Index. The Barclays Capital U.S. Aggregate Bond Index is market capitalization weighted and the securities are updated on the last calendar day of each month.

ISHARES BARCLAYS CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Government/Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS INTERMEDIATE CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS INTERMEDIATE GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Government/

Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS MBS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. MBS Index, which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Government National Mortgage Association, Fannie Mae and the Federal Home Loan Mortgage Corporation.

ISHARES BARCLAYS SHORT TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Short Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of between one and 12 months.

ISHARES BARCLAYS TIPS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L), which measures the performance of the inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS."

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ISHARES JPMORGAN USD EMERGING MARKETS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the JPMorgan EMBI Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark which tracks the total return of actively traded external debt instruments in emerging market countries.

ISHARES IBOXX $ HIGH YIELD CORPORATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the iBoxx(Reg. TM) $ Liquid High Yield Index, which is a rules-based index consisting of liquid U.S. dollar-denominated, high yield corporate bonds for sale in the United States, as determined by the International Index Company Limited ("IIC"). The iBoxx(Reg. TM) $ Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated high yield liquid corporate bond market. The iBoxx(Reg. TM) $ Liquid High Yield Index is a modified market value weighted index. There is no limit to the number of issues in the iBoxx(Reg. TM) $ Liquid High Yield Index, but as of June 30, 2009, the iBoxx(Reg. TM) $ Liquid High Yield Index included approximately 281 constituents.

The following table lists the Underlying Funds and the asset allocation for each Master Portfolio as of March 31, 2010. BFA allocates each Master Portfolio's assets among the Underlying Funds based on the Master Portfolio's investment objective and policies. The asset allocation for each Master Portfolio will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time:

UNDERLYING FUNDS
(as of March 31, 2010)

                                                    LIFEPATH     LIFEPATH    LIFEPATH    LIFEPATH    LIFEPATH
                                                   RETIREMENT      2020        2030        2040        2050
                                                    PORTFOLIO   PORTFOLIO   PORTFOLIO   PORTFOLIO    PORTFOLIO
CAPITAL GROWTH
MIP-Active Stock Master Portfolio                     19.45%       30.45%      38.39%      44.64%       49.18%
iShares S&P MidCap 400 Index Fund                      4.93%        5.87%       6.54%       7.14%        8.10%
iShares S&P SmallCap 600 Index Fund                    2.18%        2.58%       2.89%       3.16%        3.54%
iShares MSCI EAFE Index Fund                           6.74%       10.08%      12.60%      14.73%       17.01%
iShares Cohen & Steers Realty Majors Index Fund        0.62%        1.87%       2.73%       3.50%        4.01%
iShares FTSE EPRA/NAREIT Developed Real Estate         0.99%        2.99%       4.43%       5.62%        6.40%
ex-U.S. Index Fund
iShares MSCI Emerging Markets Index Fund               2.40%        3.70%       4.66%       5.47%        6.09%
iShares MSCI Canada Index Fund                         0.82%        1.25%       1.54%       1.82%        2.02%
iShares MSCI EAFE Small Cap Index Fund                 0.81%        1.25%       1.47%       1.72%        2.00%
CAPITAL GROWTH AND INCOME
MIP-CoreAlpha Bond Master Portfolio                   51.96%       34.27%      21.48%      10.89%        0.99%
iShares Barclays TIPS Bond Fund                        8.87%        5.49%       3.08%       1.08%       N/A
INCOME
BlackRock Cash Funds: Institutional - SL Agency        0.23%        0.20%       0.19%       0.23%        0.66%
Shares


Note: The allocation percentages may not add to, or may appear to exceed, 100% due to rounding.

"Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," "S&P 500 Index(Reg. TM)," "S&P MidCap 400 IndexTM," "S&P SmallCap 600 IndexTM," "S&P National AMT-Free Municipal Bond IndexTM," and "S&P North American Natural Resources Sector IndexTM" are trademarks of Standard & Poor's Financial Services LLC (a subsidiary of The McGraw-Hill Companies) licensed for use for certain purposes by BTC. The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P SmallCap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and iShares S&P North American Natural Resources Sector Index Fund that are based on S&P Indexes are not sponsored, endorsed, sold or promoted by S&P or its affiliates, and S&P and its affiliates make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"FTSE," "EPRA," "NAREIT" and "FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index" are marks that have been licensed for use for certain purposes by BTC. The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together the "FTSE Licensor Parties"), and the FTSE Licensor Parties make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Cohen & Steers" and "Cohen & Steers Realty Majors Index" are trademarks of Cohen & Steers Capital Management, Inc. ("Cohen & Steers") licensed for use for certain purposes by BTC. The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers, and Cohen & Steers makes no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Barclays Capital Inc.," "Barclays Capital U.S. 1-3 Year Credit Bond Index," "Barclays Capital U.S. 1-3 Year Treasury Bond Index," "Barclays Capital U.S. 3-7 Year Treasury Bond Index," "Barclays Capital U.S. 7-10 Year Treasury Bond Index," "Barclays Capital U.S. 10-20 Year Treasury Bond Index," "Barclays Capital U.S. 20+ Year Treasury Bond Index," "Barclays Capital U.S. Aggregate Bond Index," "Barclays Capital U.S. Credit Bond Index," "Barclays Capital U.S. Government/Credit Bond Index," "Barclays Capital U.S. Intermediate Credit Bond Index," "Barclays Capital U.S. Intermediate Government/Credit Bond Index," "Barclays Capital U.S. MBS Index," "Barclays Capital U.S. Short Treasury Bond Index," and the "Barclays Capital

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U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)" (collectively referred to as the "iShares Bond Fund Indexes") are trademarks of Barclays Bank PLC licensed for use for certain purposes by BTC. The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund are not sponsored, endorsed, sold or promoted by Barclays Capital Inc. ("Barclays Capital"), and Barclays Capital makes no representation or warranty, express or implied, regarding the advisability of investing in iShares. The iShares Bond Fund Indexes are maintained by Barclays Capital. Neither BTC nor BFA has or will have a role in maintaining the iShares Bond Fund Indexes.

"MSCI Canada Index/SM/," "MSCI EAFE(Reg. TM) Index" and "MSCI Emerging Markets Index/SM/" are servicemarks and "MSCI EAFE Small Cap Index" is a trademark of MSCI, and such marks have been licensed for use for certain purposes by BTC. The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI, and neither MSCI nor any other party makes any representation or warranty, express or implied, regarding the advisability of investing in iShares.

A FURTHER DISCUSSION OF RISK FACTORS

This section contains a description of the general risks of investing in the LifePath Portfolios. "Description of the LifePath Portfolios and their Investments and Risks" in the SAI also includes more information about the LifePath Portfolios, their investments and the related risks. There can be no guarantee that a LifePath Portfolio will meet its objective or that a LifePath Portfolio's performance will be positive for any period of time. An investment in a LifePath Portfolio is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

GENERAL

The NAV of each LifePath Portfolio's shares is neither insured nor guaranteed, is not fixed and will fluctuate.

GENERAL RISKS APPLICABLE TO THE LIFEPATH PORTFOLIOS

ALLOCATION RISK - The LifePath Portfolios' ability to achieve their investment goals depends upon BFA's skill in determining the LifePath Portfolios' strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, there is no guarantee that the Underlying Funds will achieve their investment objectives, and the Underlying Funds' performance may be lower than the performance of the asset class which they were selected to represent. The Underlying Funds may change their investment objectives or policies without the approval of the LifePath Portfolios. If an Underlying Fund were to change its investment objective or policies, the LifePath Portfolios might be forced to withdraw their investment from the Underlying Fund at a disadvantageous time and price.

CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the LifePath Portfolios' investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The LifePath Portfolios' use of derivatives may reduce the LifePath Portfolios' returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the LifePath Portfolios' use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the LifePath Portfolios to sell or otherwise close a derivatives position could expose the LifePath Portfolios to losses and could make derivatives more difficult for the LifePath Portfolios to value accurately. The LifePath Portfolios could also suffer losses related to their derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally,

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BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the LifePath Portfolios' derivatives positions to lose value. When a derivative is used as a hedge against a position that the LifePath Portfolios hold, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the LifePath Portfolios' hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EMERGING MARKETS RISK - The risks of foreign investments are usually much greater for emerging markets. Investments in emerging markets may be considered speculative. Emerging markets include those in countries defined as emerging or developing by the World Bank, the International Finance Corporation or the United Nations. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain small markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards and requirements comparable to those to which U.S. companies are subject.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments are more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation, high rates of inflation or unfavorable diplomatic developments. In the past, governments of such nations have expropriated substantial amounts of private property, and most claims of the property owners have never been fully settled. There is no assurance that such expropriations will not reoccur. In such an event, it is possible that the LifePath Portfolio could lose the entire value of its investments in the affected market. Some countries have pervasiveness of corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth. National policies that may limit the LifePath Portfolio's investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other foreign or U.S. governmental laws or restrictions applicable to such investments. Sometimes, they may lack or be in the relatively early development of legal structures governing private and foreign investments and private property. In addition to withholding taxes on investment income, some countries with emerging markets may impose differential capital gains taxes on foreign investors.

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the LifePath Portfolios could decline if the financial condition of the companies the LifePath Portfolios invest in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

FOREIGN SECURITIES RISK - Securities traded in foreign markets have often (though not always) performed differently from securities traded in the United States. However, such investments often involve special risks not present in U.S. investments that can increase the chances that the LifePath Portfolio will lose money. In particular, the LifePath Portfolio is subject to the risk that because there may be fewer investors on foreign exchanges and a smaller number of securities traded each day, it may be more difficult for the LifePath Portfolio to buy and sell securities on those exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

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CERTAIN RISKS OF HOLDING FUND ASSETS OUTSIDE THE UNITED STATES - The LifePath Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories. Some foreign banks and securities depositories may be recently organized or new to the foreign custody business. In addition, there may be limited or no regulatory oversight of their operations. Also, the laws of certain countries limit the LifePath Portfolio's ability to recover its assets if a foreign bank, depository or issuer of a security, or any of their agents, goes bankrupt. In addition, it is often more expensive for the LifePath Portfolio to buy, sell and hold securities in certain foreign markets than in the United States. The increased expense of investing in foreign markets reduces the amount the LifePath Portfolio can earn on its investments and typically results in a higher operating expense ratio for the LifePath Portfolio than for investment companies invested only in the United States.

CURRENCY RISK - Securities and other instruments in which the LifePath Portfolio invests may be denominated or quoted in currencies other than the U.S. dollar. For this reason, changes in foreign currency exchange rates can affect the value of the LifePath Portfolio.

Generally, when the U.S. dollar rises in value against a foreign currency, a security denominated in that currency loses value because the currency is worth fewer U.S. dollars. Conversely, when the U.S. dollar decreases in value against a foreign currency, a security denominated in that currency gains value because the currency is worth more U.S. dollars. This risk, generally known as "currency risk," means that a strong U.S. dollar will reduce returns for U.S. investors while a weak U.S. dollar will increase those returns.

FOREIGN ECONOMY RISK - The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. Certain foreign economies may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. In addition, the governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Any of these actions could severely affect securities prices or impair the LifePath Portfolio's ability to purchase or sell foreign securities or transfer the LifePath Portfolio's assets or income back into the United States, or otherwise adversely affect the LifePath Portfolio's operations.

Other potential foreign market risks include foreign exchange controls, difficulties in pricing securities, defaults on foreign government securities, difficulties in enforcing legal judgments in foreign courts and political and social instability. Diplomatic and political developments, including rapid and adverse political changes, social instability, regional conflicts, terrorism and war, could affect the economies, industries and securities and currency markets, and the value of the LifePath Portfolio's investments, in non-U.S. countries. These factors are extremely difficult, if not impossible, to predict and take into account with respect to the LifePath Portfolio's investments.

GOVERNMENTAL SUPERVISION AND REGULATION/ACCOUNTING STANDARDS - Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as such regulations exist in the United States. They also may not have laws to protect investors that are comparable to U.S. securities laws. For example, some foreign countries may have no laws or rules against insider trading. Insider trading occurs when a person buys or sells a company's securities based on material non-public information about that company. In addition, some countries may have legal systems that may make it difficult for the LifePath Portfolio to vote proxies, exercise shareholder rights, and pursue legal remedies with respect to its foreign investments. Accounting standards in other countries are not necessarily the same as in the United States. If the accounting standards in another country do not require as much detail as U.S. accounting standards, it may be harder for LifePath Portfolio management to completely and accurately determine a company's financial condition.

SETTLEMENT RISK - Settlement and clearance procedures in certain foreign markets differ significantly from those in the United States. Foreign settlement and clearance procedures and trade regulations also may involve certain risks (such as delays in payment for or delivery of securities) not typically associated with the settlement of U.S. investments.

At times, settlements in certain foreign countries have not kept pace with the number of securities transactions. These problems may make it difficult for the LifePath Portfolio to carry out transactions. If the LifePath Portfolio cannot settle or is delayed in settling a purchase of securities, it may miss attractive investment opportunities and certain of its assets may be uninvested with no return earned thereon for some period. If the LifePath Portfolio cannot settle or is delayed in settling a sale of securities, it may lose money if the value of the security then declines or, if it has contracted to sell the security to another party; the LifePath Portfolio could be liable for any losses incurred.

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INVESTMENTS IN MUTUAL FUNDS AND ETFS RISK - Each LifePath Portfolio will invest substantially all of its assets in Underlying Funds, so the LifePath Portfolio's investment performance is directly related to the performance of the Underlying Funds. The LifePath Portfolios may also directly invest in ETFs. The LifePath Portfolio's net asset value will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in the LifePath Portfolios will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs. For example, the LifePath Portfolios indirectly pay a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds and ETFs.

One Underlying Fund may buy the same securities that another Underlying Fund sells. In addition, a LifePath Portfolio may buy the same securities that an Underlying Fund sells, or vice-versa. If this happens, an investor in the LifePath Portfolio would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in a LifePath Portfolio may receive taxable gains from portfolio transactions by an Underlying Fund, as well as taxable gains from transactions in shares of the Underlying Fund by the LifePath Portfolio. Certain of the Underlying Funds may hold common portfolio securities, thereby reducing the diversification benefits of the LifePath Portfolios.

In order to minimize expenses, the LifePath Portfolios intend to invest in the class of shares of each Underlying Fund with the lowest shareholder fees and net fund operating expenses. As the Underlying Funds or the LifePath Portfolios' allocations among the Underlying Funds change from time to time, or to the extent that the expense ratio of the Underlying Funds changes, the weighted average operating expenses borne by the LifePath Portfolios may increase or decrease.

Underlying iShares Funds are subject to additional risks due to their shares being listed and traded on securities exchanges. There can be no assurance that an active trading market for these particular ETFs will develop or be maintained. Trading in ETFs may be halted because of market conditions or for reasons that, in the view of the listing exchange, make trading in ETFs inadvisable. In addition, trading in ETFs is subject to trading halts caused by extraordinary market volatility pursuant to "circuit breaker" rules. There can be no assurance that the requirements necessary to maintain the listing of ETFs will continue to be met or will remain unchanged. An ETF may trade at, above or below its NAV. The NAV of an ETF will fluctuate with changes in the market value of its holdings. The trading price of an ETF will generally fluctuate in accordance with changes in its NAV, as well as market supply and demand.

JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the LifePath Portfolios. The major risks of junk bond investments include:

. Junk bonds may be issued by less creditworthy issuers. Issuers of junk bonds may have a larger amount of outstanding debt relative to their assets than issuers of investment grade bonds. In the event of an issuer's bankruptcy, claims of other creditors may have priority over the claims of junk bond holders, leaving few or no assets available to repay junk bond holders.

. Prices of junk bonds are subject to extreme price fluctuations. Adverse changes in an issuer's industry and general economic conditions may have a greater impact on the prices of junk bonds than on other higher rated fixed-income securities.

. Issuers of junk bonds may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.

. Junk bonds frequently have redemption features that permit an issuer to repurchase the security from the LifePath Portfolios before it matures. If the issuer redeems junk bonds, the LifePath Portfolios may have to invest the proceeds in bonds with lower yields and may lose income.

. Junk bonds may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the junk bond market, and there may be significant differences in the prices quoted for junk bonds by the dealers. Because they are less liquid, judgment may play a greater role in valuing certain of the LifePath Portfolios' securities than is the case with securities trading in a more liquid market.

. The LifePath Portfolios may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the LifePath Portfolios invest will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection

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risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. The characteristics of these mortgage-backed and asset-backed securities differ from traditional fixed-income securities. Like traditional fixed-income securities, the value of asset-backed securities typically increases when interest rates fall and decreases when interest rates rise. However, a main difference is that the principal on mortgage- or asset-backed securities may normally be prepaid at any time, which will reduce the yield and market value of these securities. Therefore, mortgage- and asset-backed backed securities are subject to "prepayment risk" and "extension risk." Because of prepayment risk and extension risk, mortgage-backed securities react differently to changes in interest rates than other fixed-income securities.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The LifePath Portfolios' investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The LifePath Portfolios' investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only (IOs), principal only (POs) or an amount that remains after other floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the LifePath Portfolios invest in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by BFA, it is possible that the LifePath Portfolios could lose all or substantially all of their investment.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the LifePath Portfolios' mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the LifePath Portfolios may invest may also provide a degree of investment leverage, which could cause the LifePath Portfolios to lose all or substantially all of their investment.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for the Underlying iShares Funds, those Underlying iShares Funds may hold stocks in companies that present risks that an investment adviser researching individual stocks might seek to avoid.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the LifePath Portfolios may have to invest their proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment

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proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

REIT INVESTMENT RISK - In addition to the risks facing real estate-related securities, such as a decline in property values due to increasing vacancies, a decline in rents resulting from unanticipated economic, legal or technological developments or a decline in the price of securities of real estate companies due to a failure of borrowers to pay their loans or poor management, investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the LifePath Portfolios may lose money and there may be a delay in recovering the loaned securities. The LifePath Portfolios could also lose money if they do not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the LifePath Portfolios.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

Each LifePath Portfolio must maintain cash balances to meet redemption requests, which may lower overall portfolio performance.

FOR A DESCRIPTION OF THE LIFEPATH PORTFOLIOS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THEIR MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A FURTHER DISCUSSION OF THE LIFEPATH PORTFOLIOS' INVESTMENTS AND RISKS, PLEASE REFER TO THE LIFEPATH PORTFOLIOS' SAI.

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Account Information

DETAILS ABOUT INVESTOR C SHARES

MINIMUM INVESTMENT

The initial and subsequent investment minimums for Investor C Shares of the LifePath Portfolios generally are as follows, although the LifePath Portfolios may reduce or waive these investment minimums in some cases:

MINIMUM INITIAL         $1,000(1) for all accounts except:
INVESTMENT
                        . $250 for certain fee-based programs
                        . $100 for retirement plans
                        . $50, if establishing Automatic Investment Plan
MINIMUM ADDITIONAL      $50 for all accounts except certain retirement plans and payroll deduction
INVESTMENT               programs may have a lower minimum


(1) The LifePath Portfolios will not accept a purchase order of $500,000 or more for Investor C Shares. Your financial intermediary may set a lower maximum for Investor C Shares.

DEFERRED SALES CHARGE

If you redeem Investor C Shares within one year after purchase, you may be charged a deferred sales charge of 1.00%. The charge will apply to the lesser of the original cost of the shares being redeemed or the proceeds of your redemption and will be calculated without regards to any redemption fee. When you redeem Investor C Shares, the redemption order is processed so that the lowest deferred sales charge is charged. Investor C Shares that are not subject to the deferred sales charge are redeemed first. In addition, you will not be charged a deferred sales charge when you redeem shares that you acquire through reinvestment of LifePath Portfolio dividends or capital gains. Any CDSC paid on the redemptions of Investor C Shares expressed as a percentage of the applicable redemption amount may be higher or lower than the charge described due to rounding.

Investor C Shares do not offer a conversion privilege.

LETTER OF INTENT

An investor may qualify for a reduced front-end sales charge immediately by signing a "Letter of Intent" stating the investor's intention to buy a specified amount of Investor A Shares, Investor C Shares or Institutional Shares in one or more funds sponsored and advised by BFA or its affiliates ("BlackRock Funds") within the next 13 months that would, if bought all at once, qualify the investor for a reduced sales charge. The initial investment must meet the minimum initial purchase requirement. The 13-month Letter of Intent period commences on the day that the Letter of Intent is received by the LifePath Portfolios, and the investor must tell the LifePath Portfolios that later purchases are subject to the Letter of Intent. Purchases submitted prior to the date the Letter of Intent is received by the LifePath Portfolios are not counted toward the sales charge reduction. During the term of the Letter of Intent, the LifePath Portfolios will hold Investor A Shares representing up to 5% of the indicated amount in an escrow account for payment of a higher sales load if the full amount indicated in the Letter of Intent is not purchased. If the full amount indicated is not purchased within the 13-month period, and the investor does not pay the higher sales load within 20 days, the LifePath Portfolios will redeem enough of Investor A Shares held in escrow to pay the difference.

RIGHT OF ACCUMULATION

Investors have a "right of accumulation" under which the current value of an investor's existing Investor A, Investor C and Institutional Shares in most BlackRock Funds and the investment in the BlackRock CollegeAdvantage 529 program by the investor or by or on behalf of the investor's spouse and minor children may be combined with the amount of the current purchase in determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge. Financial intermediaries may value current holdings of their customers differently for purposes of determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge, although customers of the same financial intermediary will be treated similarly. In order to use this right, the investor must alert BlackRock to the existence of any previously purchased shares.

CONTINGENT DEFERRED SALES CHARGE WAIVERS

The deferred sales charge relating to Investor C Shares may be reduced or waived in certain circumstances, such as:

48

. Redemptions of shares purchased through authorized qualified employee benefit plans or savings plans and rollovers of current investments in a LifePath Portfolio through such plans

. Exchanges pursuant to the exchange privilege

. Redemptions made in connection with minimum required distributions from IRA or 403(b)(7) accounts due to the shareholder reaching the age of 70 1/2

. Certain post-retirement withdrawals from an IRA or other retirement plan if you are over 59 1/2 years old

. Redemptions made with respect to certain retirement plans sponsored by a LifePath Portfolio, BFA or an affiliate

. Redemptions resulting from shareholder death as long as the waiver request is made within one year of death or, if later, reasonably promptly following completion of probate (including in connection with the distribution of account assets to a beneficiary of the decedent)

. Withdrawals resulting from shareholder disability (as defined in the U.S. Internal Revenue Code of 1986, as amended) (the "Internal Revenue Code"), as long as the disability arose subsequent to the purchase of the shares

. Involuntary redemptions made of shares in accounts with low balances

. Certain redemptions made through the Systematic Withdrawal Plan offered by a LifePath Portfolio, BFA or an affiliate

. Redemptions related to the payment of PNC Trust Company custodial IRA fees

. Redemptions when a shareholder can demonstrate hardship, in the absolute discretion of the LifePath Portfolio

Please contact your Financial Intermediary for more details on CDSCs.

HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES


The chart on the following pages summarizes how to buy, sell, exchange and transfer shares through your financial professional or other financial intermediary. You may also buy, sell, exchange and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling, transferring or exchanging shares through BlackRock, call
(800) 441-7762. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

Each LifePath Portfolio may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders and suspend and resume the sale of any share class of the LifePath Portfolio at any time for any reason.

In addition, the LifePath Portfolios may waive certain requirements regarding the purchase, sale, exchange or transfer of shares described below.

             HOW TO BUY SHARES
                   YOUR CHOICES               IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE    First, select the          The LifePath Portfolios offer other classes of shares (Investor A Shares,
                   share class appropriate    Class K Shares, Class R Shares and Institutional Shares) with different
                   for you                    features and expense levels, which you may be eligible to buy. Please see
                                              the LifePath Portfolios' Investor A Shares, Class K Shares, Class R Shares
                                              and Institutional Shares prospectuses for more information.
                                              When you place your initial order, you must indicate which share class you
                                              select (if you do not specify a class and do not qualify to purchase Investor
                                              C Shares, you will receive Investor A Shares).
                                              Certain factors, such as the amount of your investment, your time frame
                                              for investing, and your financial goals, may affect which share class you
                                              choose. Your financial representative can help you determine which share
                                              class is appropriate for you.

49

         HOW TO BUY SHARES
              YOUR CHOICES            IMPORTANT INFORMATION FOR YOU TO KNOW
               Next, determine         Refer to the minimum initial investment in the "Account Information -
              the amount of           Details About Investor C Shares" in this Prospectus. Be sure to note the
              your investment         maximum investment amounts in Investor C Shares.
                                      See "Account Information - Details About Investor C Shares" for
                                      information on lower initial investment requirements for certain LifePath
                                      Portfolio investors if their purchase, combined with purchases by other
                                      investors received together by a LifePath Portfolio, meets the minimum
                                      investment requirement.
               Have your               The price of your shares is based on the next calculation of a LifePath
              financial               Portfolio's NAV after your order is placed. Any purchase orders placed prior
              intermediary            to the close of business on the NYSE (generally 4:00 p.m. Eastern time)
              submit your             will be priced at the NAV determined that day. Certain financial
              purchase order          intermediaries, however, may require submission of orders prior to that
                                      time. A broker-dealer or financial institution maintaining the account in
                                      which you hold shares may charge a separate account, service or transaction
                                      fee on the purchase or sale of Fund shares that would be in addition to the
                                      fees and expenses shown in each LifePath Portfolio's "Fees and Expenses"
                                      table.
                                      Purchase orders placed after that time will be priced at the NAV
                                      determined on the next business day. The LifePath Portfolios may reject
                                      any order to buy shares and may suspend the sale of shares at any time.
                                      Financial intermediaries may charge a processing fee to confirm a
                                      purchase.
               Or contact              To purchase shares directly from BlackRock, call (800) 441-7762 and
              BlackRock (for          request a new account application. Mail the completed application along
              accounts held           with a check payable to "BlackRock Funds" to the Transfer Agent at the
              directly with           address on the application.
              BlackRock)
ADD TO YOUR    Purchase                The minimum investment for additional purchases is generally $50 for all
INVESTMENT    additional shares       accounts, except that certain retirement plans may have a lower minimum
                                      for additional purchases and certain payroll deduction programs, such as
                                      automatic investment plans, may have higher minimums. (The minimums for
                                      additional purchases may be waived under certain circumstances.)
               Have your               To purchase additional shares you may contact your financial professional
              financial               or financial intermediary. For more details on purchasing by Internet see
              professional            below.
              or financial
                                      PURCHASE BY TELEPHONE: Call (800) 441-7762 and speak with one of our
              intermediary
                                      representatives. The LifePath Portfolios have the right to reject any
              submit your
                                      telephone request for any reason.
              purchase order
              for additional shares
                                      PURCHASE IN WRITING: You may send a written request to BlackRock at the
                                      address on the back cover of this Prospectus.
                                      PURCHASE BY VRU: Investor C Shares may also be purchased by use of the
                                      LifePath Portfolio's automated voice response unit service ("VRU") at
                                      (800) 441-7762.

50

            HOW TO BUY SHARES
                 YOUR CHOICES               IMPORTANT INFORMATION FOR YOU TO KNOW
                  Or contact                 PURCHASE BY INTERNET: You may purchase your shares, and view activities
                 BlackRock                  in your account, by logging onto the BlackRock website at
                 (for accounts held         www.blackrock.com/funds. Purchases made on the Internet using the
                 directly with              Automated Clearing House Network ("ACH") will have a trade date that is
                 BlackRock)                 the day after the purchase is made. Certain institutional clients' purchase
                                            orders for Investor C Shares placed by wire prior to the close of business
                                            on the NYSE will be placed at the NAV determined that day. Contact your
                                            financial intermediary or BlackRock for further information. Each LifePath
                                            Portfolio limits Internet purchases in shares of the LifePath Portfolio to
                                            $25,000 per trade. Different maximums may apply to certain institutional
                                            investors. Please read the On-Line Services Disclosure Statement and User
                                            Agreement, the Terms and Conditions page and the Consent to Electronic
                                            Delivery Agreement (if you consent to electronic delivery), before
                                            attempting to transact online.
                                            The LifePath Portfolios employ reasonable procedures to confirm that
                                            transactions entered over the Internet are genuine. By entering into the
                                            User Agreement with a LifePath Portfolio in order to open an account
                                            through the website, the shareholder waives any right to reclaim any
                                            losses from a LifePath Portfolio or any of its affiliates, incurred through
                                            fraudulent activity.
                  Acquire additional         All dividends and capital gains distributions are automatically reinvested
                 shares by                  without a sales charge. To make any changes to your dividend and/or
                 reinvesting                capital gains distributions options, please call (800) 441-7762, or contact
                 dividends and              your financial professional (if your account is not held directly with
                 capital gains              BlackRock).
                  Participate                BlackRock's AIP allows you to invest a specific amount on a periodic basis
                 in the Automatic           from your checking or savings account into your investment account.
                 Investment Plan ("AIP")    Refer to the "Account Services and Privileges" section of this Prospectus
                                            for additional information.
HOW TO PAY FOR    Making payment             Payment for an order must be made in Federal funds or other immediately
SHARES           for purchases              available funds by the time specified by your financial professional or other
                                            financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                            on the first business day (in the case of Investor C Shares) following
                                            BlackRock's receipt of the order. If payment is not received by this time,
                                            the order will be canceled and you and your financial professional or other
                                            financial intermediary will be responsible for any loss to the LifePath
                                            Portfolios.
                                            For shares purchased directly from the LifePath Portfolio, a check payable
                                            to "BlackRock Funds," which bears the name of the LifePath Portfolio you
                                            are purchasing must accompany a completed purchase application. There
                                            is a $20 fee for each purchase check that is returned due to insufficient
                                            funds.
                                            The LifePath Portfolios do not accept third-party checks. You may also
                                            wire Federal funds to a LifePath Portfolio to purchase shares, but you must
                                            call (800) 441-7762 before doing so to confirm the wiring instructions.

51

       HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL    Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       Shareholders should indicate that they are redeeming Investor C Shares.
SHARES            intermediary    The price of your shares is based on the next calculation of a LifePath
                  submit your     Portfolio's NAV after your order is placed. For your redemption request to
                  sales order     be priced at the NAV on the day of your request, you must submit your
                                  request to your financial intermediary prior to that day's close of business
                                  on the NYSE (generally 4:00 p.m. Eastern time). Certain financial
                                  intermediaries, however, may require submission of orders prior to that
                                  time. Any redemption request placed after that time will be priced at the
                                  NAV at the close of business on the next business day.
                                  Financial intermediaries may charge a fee to process a redemption of
                                  shares.
                                  The LifePath Portfolios may reject an order to sell shares under certain
                                  circumstances.
                   Selling         METHODS OF REDEEMING
                  shares held
                                  REDEEM BY TELEPHONE: You may sell Investor C Shares held directly at
                  directly
                                  BlackRock by telephone request if certain conditions are met and if the
                  with
                                  amount being sold is less than (i) $100,000 for payments by check or (ii)
                  BlackRock
                                  $250,000 for payments through the ACH or wire transfer. Certain
                                  redemption requests such as those in excess of these amounts, must be
                                  in writing with a medallion signature guarantee. You can obtain a
                                  medallion signature guarantee stamp from a bank, securities dealer,
                                  securities broker, credit union, savings and loan association, national
                                  securities exchange or registered securities association. A notary public
                                  seal will not be acceptable.
                                   The LifePath Portfolios, the administrator and the distributor will employ
                                  reasonable procedures to confirm that instructions communicated by
                                  telephone are genuine. The LifePath Portfolios and their service providers
                                  will not be liable for any loss, liability, cost or expense for acting upon
                                  telephone instructions that are reasonably believed to be genuine in
                                  accordance with such procedures. The LifePath Portfolios may refuse a
                                  telephone redemption request if they believe it is advisable to do so.
                                  During periods of substantial economic or market change, telephone
                                  redemptions may be difficult to complete. Please find below alternative
                                  redemption methods.
                                   REDEEM BY VRU:Investor C Shares may also be redeemed by use of the
                                  LifePath Portfolios' VRU. Payment for Investor C Shares redeemed by VRU
                                  may be made for non-retirement accounts in amounts up to $25,000,
                                  either through check, ACH or wire.
                                   REDEEM BY INTERNET: You may redeem in your account by logging onto
                                  the BlackRock website at www.blackrock.com/funds. Proceeds from
                                  Internet redemptions may be sent via check, ACH or wire to the bank
                                  account of record. Payment for Investor C Shares redeemed by Internet
                                  may be made for non-retirement accounts in amounts up to $25,000,
                                  either through check, ACH or wire.

52

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                            BlackRock, P.O. Box 9819, Providence, RI 02940-8019 or, for overnight
                            delivery, 101 Sabin Street, Pawtucket, RI 02860-1427. All shareholders on
                            the account must sign the letter. A medallion signature guarantee will
                            generally be required but may be waived in certain limited circumstances.
                            You can obtain a medallion signature guarantee stamp from a bank,
                            securities dealer, securities broker, credit union, savings and loan
                            association, national securities exchange or registered securities
                            association. A notary public seal will not be acceptable. If you hold stock
                            certificates, return the certificates with the letter. Proceeds from
                            redemptions may be sent via check, ACH or wire to the bank account of
                            record.
                            PAYMENT OF REDEMPTION PROCEEDS
                            Redemption proceeds may be paid by check or, if a LifePath Portfolio has
                            verified banking information on file, through ACH or by wire transfer.
                             PAYMENT BY CHECK: BlackRock will normally mail redemption proceeds
                            within seven days following receipt of a properly completed request.
                            Shares can be redeemed by telephone and the proceeds sent by check to
                            the shareholder at the address on record. Shareholders will pay $15 for
                            redemption proceeds sent by check via overnight mail. You are responsible
                            for any additional charges imposed by your bank for this service.
                             PAYMENT BY WIRE TRANSFER: Payment for redeemed shares for which a
                            redemption order is received before 4:00 p.m. (Eastern time) on a
                            business day is normally made in Federal funds wired to the redeeming
                            shareholder on the next business day, provided that the LifePath
                            Portfolios' custodian is also open for business. Payment for redemption
                            orders received after 4:00 p.m. (Eastern time) or on a day when the
                            LifePath Portfolios' custodian is closed is normally wired in Federal funds
                            on the next business day following redemption on which the LifePath
                            Portfolio's custodian is open for business. The LifePath Portfolios reserve
                            the right to wire redemption proceeds within seven days after receiving a
                            redemption order if, in the judgment of the LifePath Portfolio, an earlier
                            payment could adversely affect a LifePath Portfolio.
                             If a shareholder has given authorization for expedited redemption, shares
                            can be redeemed by Federal wire transfer to a single previously designated
                            bank account. Shareholders will pay $7.50 for redemption proceeds sent
                            by Federal wire transfer. You are responsible for any additional charges
                            imposed by your bank for this service. No charge for wiring redemption
                            payments with respect to Investor C Shares is imposed by the LifePath
                            Portfolios.
                             The LifePath Portfolios are not responsible for the efficiency of the Federal
                            wire system or the shareholder's firm or bank. To change the name of the
                            single, designated bank account to receive wire redemption proceeds, it is
                            necessary to send a written request to the LifePath Portfolio at the
                            address on the back cover of this Prospectus.

53

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             PAYMENT BY ACH: Redemption proceeds may be sent to the shareholder's
                            bank account (checking or savings) via ACH. Payment for redeemed
                            shares for which a redemption order is received before 4:00 p.m. (Eastern
                            time) on a business day is normally sent to the redeeming shareholder the
                            next business day, with receipt at the receiving bank within the next two
                            business days (48-72 hours); provided that the LifePath Portfolios'
                            custodian is also open for business. Payment for redemption orders
                            received after 4:00 p.m. (Eastern time) or on a day when the LifePath
                            Portfolios' custodian is closed is normally sent on the next business day
                            following redemption on which the LifePath Portfolios' custodian is open
                            for business.
                            The LifePath Portfolios reserve the right to send redemption proceeds
                            within seven days after receiving a redemption order if, in the judgment of
                            a LifePath Portfolio, an earlier payment could adversely affect the LifePath
                            Portfolios. No charge for sending redemption payments via ACH is
                            imposed by the LifePath Portfolios. If you make a redemption request
                            before a LifePath Portfolio has collected payment for the purchase of
                            shares, the LifePath Portfolio may delay mailing your proceeds. This delay
                            will usually not exceed ten days.

54

       HOW TO EXCHANGE SHARES OR TRANSFER YOUR ACCOUNT
                     Your Choices
EXCHANGE PRIVILEGE    Selling shares
                     of one LifePath Portfolio to
                     purchase shares
                     of another
                     BlackRock Fund
                     ("exchanging")
TRANSFER SHARES TO    Transfer to a
ANOTHER SECURITIES   participating
DEALER OR OTHER      financial
FINANCIAL            professional or
INTERMEDIARY         other
                     financial
                     intermediary

                     Important Information for You to Know
EXCHANGE PRIVILEGE    Investor C Shares of the LifePath Portfolios are generally exchangeable for
                     shares of the same class of another BlackRock Fund.
                     You can exchange $1,000 or more of Investor C Shares from one LifePath
                     Portfolio into the same class of another BlackRock Fund which offers that
                     class of shares (you can exchange less than $1,000 of Investor C Shares if
                     you already have an account in the BlackRock Fund into which you are
                     exchanging). You may only exchange into a share class and BlackRock
                     Fund that are open to new investors or in which you have a current
                     account, if the BlackRock Fund is closed to new investors. If you held the
                     exchanged shares for 30 days or less, you may be charged a redemption
                     fee (please refer to the "Redemption Fee" section of this Prospectus for
                     additional information).
                     Some of the BlackRock Funds impose a different deferred sales charge
                     schedule. The CDSC will continue to be measured from the date of the
                     original purchase. The CDSC schedule applicable to your original purchase
                     will apply to the shares you receive in the exchange and any subsequent
                     exchange.
                     To exercise the exchange privilege, you may contact your financial
                     professional or financial intermediary. Alternatively, if your account is held
                     directly with BlackRock, you may: (i) call (800) 441-7762 and speak with
                     one of our representatives, (ii) make the exchange via the Internet by
                     accessing your account online at www.blackrock.com/funds, or (iii) send
                     a written request to the LifePath Portfolio at the address on the back cover
                     of this Prospectus. Please note, if you indicated on your New Account
                     Application that you did not want the Telephone Exchange Privilege, you
                     will not be able to place exchanges via the telephone until you update this
                     option either in writing or by calling (800) 441-7762. The LifePath
                     Portfolios have the right to reject any telephone request for any reason.
                     Although there is currently no express limit on the number of exchanges
                     that you can make, the exchange privilege may be modified or terminated
                     at any time in the future. The LifePath Portfolios may suspend or
                     terminate your exchange privilege at any time for any reason, including if a
                     LifePath Portfolio believes, in its sole discretion that you are engaging in
                     market timing activities. See "Frequent Trading in LifePath Portfolio
                     Shares" below. For U.S. federal income tax purposes, a share exchange is a
                     taxable event and a capital gain or loss may be realized. Please consult
                     your tax adviser or other financial professional before making an exchange
                     request.
TRANSFER SHARES TO    You may transfer your Investor C Shares of a LifePath Portfolio only to
ANOTHER SECURITIES   another financial professional or financial intermediary that has an
DEALER OR OTHER      agreement with the Distributor. Certain shareholder services may not be
FINANCIAL            available for the transferred shares. All future trading of these assets must
INTERMEDIARY         be coordinated by the receiving firm.
                     If your account is held directly with BlackRock, you may call (800) 441-
                     7762 with any questions; otherwise please contact your financial
                     intermediary to accomplish the transfer of shares.

55

HOW TO EXCHANGE SHARES OR TRANSFER YOUR ACCOUNT
                                    Your Choices
                                     Transfer to a
                                    non-participating
                                    financial professional
                                    or other
                                    financial intermediary

                                    Important Information for You to Know
                                     You must either:
                                    oTransfer your Investor C Shares to an account with a LifePath Portfolio; or
                                    oSell your shares, paying any applicable deferred sales charge.
                                    If your account is held directly with BlackRock, you may call (800) 441-7762
                                    with any questions; otherwise please contact your financial intermediary to
                                    accomplish the transfer of shares.

DISTRIBUTION AND SERVICE PAYMENTS


The LifePath Portfolios have adopted a shareholder servicing plan (the "Plan") with respect to Investor C Shares that allows each LifePath Portfolio to pay distribution and shareholder servicing fees for certain services provided to its Investor C shareholders under Rule 12b-1 of the Investment Company Act of 1940, as amended (the "1940 Act").

The distribution fees payable pursuant to the Plan to BlackRock Investments, LLC (the "Distributor") and/or its affiliates, including BlackRock, Inc. ("BlackRock"), The PNC Financial Services Group, Inc. ("PNC") and its affiliates, and to Merrill Lynch & Co., Inc. ("Merrill Lynch") and/or Bank of America Corporation ("BAC") and their affiliates and to Barclays Bank PLC ("Barclays") and its affiliates, are for distribution and sales support services. The distribution fees may be used to pay the Distributor for distribution services and to pay the Distributor and affiliates of BlackRock and PNC or Merrill Lynch and BAC or Barclays for sales support services provided in connection with the sale of Investor C Shares. The distribution fees may also be used to pay brokers, dealers, financial institutions and industry professionals (including BlackRock, PNC, Merrill Lynch, BAC, Barclays and their respective affiliates (each a "Financial Intermediary") for sales support services and related expenses. All Investor C Shares pay a maximum distribution fee per year that is a percentage of the average daily net asset value of the applicable LifePath Portfolio attributable to Investor C Shares.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and Financial Intermediaries for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a LifePath Portfolio's shares. Because the fees paid by a LifePath Portfolio under the Plan are paid out of LifePath Portfolio assets on an ongoing basis, over time these fees will increase the cost of your investment in the LifePath Portfolios and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a LifePath Portfolio may pay to a Financial Intermediary pursuant to the Plan and fees a LifePath Portfolio pays to PNC Global Investment Servicing (U.S.) Inc. (the "Transfer Agent"), BFA, on behalf of a LifePath Portfolio, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the LifePath Portfolio will pay the Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of LifePath Portfolio shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

The Plan permits BFA, the Distributor and their affiliates to make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to the LifePath Portfolios). From time to time, BFA, the Distributor or their affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA, the Distributor and their affiliates may compensate affiliated and unaffiliated Financial Intermediaries for the sale and distribution of shares of the LifePath Portfolios or for these other services to the LifePath Portfolios and shareholders. These payments would be in addition to the LifePath Portfolio payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, the Distributor and their affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a LifePath Portfolio to you. Please contact your Financial Intermediary for details about payments it may receive from a LifePath Portfolio or from BFA, the Distributor or their affiliates. For more information, see the LifePath Portfolios' SAI.

56

ACCOUNT SERVICES AND PRIVILEGES

The following table provides examples of account services and privileges available in your BlackRock account. Certain of these account services and privileges are only available to shareholders of Investor C Shares whose accounts are held directly with BlackRock. If your account is held directly with BlackRock, please call (800) 441-7762 for additional information as well as forms and applications. Otherwise, please contact your financial professional for assistance in requesting one or more of the following services and privileges.

AUTOMATIC          Allows systematic investments
INVESTMENT        on a periodic basis from
PLAN ("AIP")      checking or savings account.
DIVIDEND           Automatically invests your
ALLOCATION PLAN   distributions into another
                  BlackRock Fund of your
                  choice pursuant to your
                  instructions, without any
                  fees or sales charges.
EZ TRADER          Allows an investor to purchase
                  or sell Investor C Shares by
                  telephone or over the
                  Internet through ACH.
SYSTEMATIC         This feature can be used by
EXCHANGE          investors to systematically exchange
PLAN              money from one fund to up
                  to four other funds.
SYSTEMATIC         This feature can be used by
WITHDRAWAL        investors who want to receive
PLAN ("SWP")      regular distributions from their
                  accounts.

AUTOMATIC          BlackRock's AIP allows you to invest a specific amount on a periodic basis
INVESTMENT        from your checking or savings account into your investment account. You
PLAN ("AIP")      may apply for this option upon account opening or by completing the AIP
                  application. The minimum investment amount for an automatic
                  investment plan is $50 per portfolio.
DIVIDEND           Dividend and capital gains distributions may be reinvested in your account
ALLOCATION PLAN   to purchase additional shares or paid in cash. Using the Dividend
                  Allocation Plan, you can direct your distributions to your bank account
                  (checking or savings), to purchase shares of another fund at BlackRock
                  without any fees or sales charges, or by check to special payee. Please call
                  (800) 441-7762 for details. If investing into another fund at BlackRock, the
                  receiving fund must be open to new purchases.
EZ TRADER          (NOTE: This option is offered to shareholders whose accounts are held
                  directly with BlackRock. Please speak with your financial professional if your
                  account is held elsewhere).
                  Prior to establishing an EZ Trader account, please contact your bank to
                  confirm that it is a member of the ACH system. Once confirmed, complete
                  an application, making sure to include the appropriate bank information,
                  and return the application to the address listed on the form.
                  Prior to placing a telephone or internet purchase or sale order, please
                  contact (800) 441-7762 to confirm that your bank information has been
                  updated on your account. Once this is established, you may place your
                  request to sell shares with the LifePath Portfolios by telephone or Internet.
                  Proceeds will be sent to your pre-designated bank account.
SYSTEMATIC         A minimum of $10,000 in the initial BlackRock Fund is required and
EXCHANGE          investments in any additional funds must meet minimum initial
PLAN              investment requirements. For more information, please contact the
                  LifePath Portfolio at (800) 441-7762.
SYSTEMATIC         To start a Systematic Withdrawal Plan a shareholder must have a current
WITHDRAWAL        investment of $10,000 or more in a BlackRock Fund.
PLAN ("SWP")
                  Shareholders can elect to receive cash payments of $50 or more at any
                  interval they choose. Shareholders may sign up by completing the SWP
                  Application Form, which may be obtained from BlackRock.
                  Shareholders should realize that if withdrawals exceed income the invested
                  principal in their account will be depleted.
                  To participate in the SWP, shareholders must have their dividends
                  reinvested. Shareholders may change or cancel the SWP at any time, with
                  a minimum of 24 hours notice. No CDSC will be assessed on redemptions
                  of Investor C Shares made through the SWP that do not exceed 12% of
                  the account's NAV on an annualized basis. For example, monthly,
                  quarterly, and semi-annual SWP redemptions of Investor C Shares will
                  not be subject to the CDSC if they do not exceed 1% of an account's NAV
                  on the redemption date. SWP redemptions of Investor C Shares in excess
                  of this limit will still pay any applicable CDSC.
                  Ask your financial adviser or other financial intermediary for details.

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LIFEPATH PORTFOLIOS' RIGHTS

Each LifePath Portfolio may:

. Suspend the right of redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act,

. Postpone date of payment upon redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act or if a redemption request is made before a LifePath Portfolio has collected payment for the purchase of shares,

. Redeem shares for property other than cash if conditions exist which make cash payments undesirable in accordance with its rights under the 1940 Act, and

. Redeem shares involuntarily in certain cases, such as when the value of a shareholder account falls below a specified level.

NOTE ON LOW BALANCE ACCOUNTS. Because of the high cost of maintaining smaller shareholder accounts, a LifePath Portfolio may redeem the shares in your account (without charging any deferred sales charge) if the NAV of your account falls below $500 due to redemptions you have made. You will be notified that the value of your account is less than $500 before a LifePath Portfolio makes an involuntary redemption. You will then have 60 days to make an additional investment to bring the value of your account to at least $500 before a LifePath Portfolio takes any action. This involuntary redemption does not apply to accounts of authorized qualified employee benefit plans, selected fee-based programs or accounts established under the Uniform Gifts or Transfers to Minors Acts.

CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE

Each LifePath Portfolio's share price (also known as a LifePath Portfolio's NAV) is calculated by dividing the value of the net assets of the LifePath Portfolio (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the LifePath Portfolio, generally rounded to the nearest cent.

Each LifePath Portfolio's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern Time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating each LifePath Portfolio's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of each LifePath Portfolio is calculated based on the NAV of the Master Portfolio in which the LifePath Portfolio invests. The LifePath Portfolios' SAI includes a description of the methods for valuing the Master Portfolios' investments, including a description of the circumstances in which the Master Portfolios' investments would be valued using fair value pricing and the effects of using fair value pricing.

LIFEPATH PORTFOLIO DISTRIBUTIONS

The LifePath Portfolios distribute their net investment income to shareholders quarterly. The LifePath Portfolios distribute their net realized capital gains, if any, to shareholders at least annually. Distributions payable to you will be automatically reinvested in additional Investor C Shares of your LifePath Portfolio, unless you have elected to receive distribution payments in cash.

FREQUENT TRADING IN LIFEPATH PORTFOLIO SHARES

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and a LifePath Portfolio's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The LifePath Portfolios are not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. The exchange privilege is not intended as a vehicle for short-term trading. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of a LifePath Portfolio and its shareholders. For example, large flows of cash into and out of a LifePath Portfolio may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the LifePath Portfolio's investment goal. Frequent trading may cause a LifePath Portfolio to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the LifePath Portfolio's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. Each LifePath Portfolio will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of LifePath Portfolio Investments" below.

Each LifePath Portfolio discourages market timing and seeks to prevent frequent purchases and sales or exchanges of LifePath Portfolio shares that it determines may be detrimental to the LifePath Portfolio or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of LifePath Portfolio shares because certain legitimate strategies will not result in harm to a LifePath Portfolio or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, a LifePath Portfolio believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If a LifePath Portfolio rejects your purchase or exchange order, you will not be able to execute that transaction, and the LifePath Portfolio will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with a LifePath Portfolio, the LifePath Portfolio may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by a LifePath Portfolio. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide a LifePath Portfolio with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the LifePath Portfolio. While each LifePath Portfolio monitors for market timing activity, a LifePath Portfolio may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the LifePath Portfolio. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in a LifePath Portfolio's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by a LifePath Portfolio to be engaged in market timing or other improper trading activity, the LifePath Portfolio's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions. Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

A LifePath Portfolio may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

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TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the LifePath Portfolios and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the LifePath Portfolios' SAI for additional U.S. federal income tax information.

Distributions from your LifePath Portfolio's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional LifePath Portfolio shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the LifePath Portfolio's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the LifePath Portfolios generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the LifePath Portfolio's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S. and certain foreign corporations. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) A portion of distributions paid to corporate shareholders of the LifePath Portfolios may qualify for the dividends-received deduction available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

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In addition, if you sell your LifePath Portfolio shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

If you buy a LifePath Portfolio's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of a LifePath Portfolio that holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the LifePath Portfolio sells the appreciated securities and distributes the realized gain on the sale. The LifePath Portfolios have built up, or have the potential to build up, high levels of unrealized appreciation in their investments.

After the end of each year, the LifePath Portfolios will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the LifePath Portfolios if you fail to provide the LifePath Portfolios with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Sales proceeds are generally taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code, unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING LIFEPATH PORTFOLIO SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL

INCOME TAX ON LIFEPATH PORTFOLIO DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF LIFEPATH PORTFOLIO SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER AND FUND OF FUNDS STRUCTURES


The LifePath Portfolios do not have their own investment adviser. Instead, each LifePath Portfolio invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the LifePath Portfolio. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the LifePath Portfolios.

FEEDER FUND EXPENSES

Feeder funds, including the LifePath Portfolios, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund- specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a LifePath Portfolio's assets from its Master Portfolio if it believes doing so is in the best interests of the LifePath Portfolio's shareholders. If the Trust's Board of Trustees decides to withdraw a LifePath Portfolio's assets, it would then consider whether the LifePath Portfolio should hire its own investment adviser, invest in another master portfolio or take other action.

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FUND OF FUNDS

The Master Portfolios do not invest directly in a portfolio of securities. Instead, they invest in the Underlying Money Market Fund and other Underlying Funds that are also advised by BFA. Each Master Portfolio charges for its own direct expenses, in addition to bearing a PRO RATA share of the expenses charged by the Underlying Funds in which it invests.

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Management of the LifePath Portfolios

INVESTMENT ADVISER

Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the LifePath Portfolio. The Master Portfolios, in turn, invest in a combination of Underlying Funds. BFA, a registered investment adviser, serves as investment adviser to each Master Portfolio, and also serves as investment adviser to each Underlying Fund, with the exception of the Underlying Money Market Fund, which invests in a master portfolio advised by BFA. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive an annual management fee of 0.35% of each Master Portfolio's average daily net assets.

For its services to the Underlying Funds, BFA receives fees that differ from the fees described for the LifePath Portfolios in this Prospectus. BFA provides investment advisory services for the Underlying Funds that differ from the investment advisory services it provides for the Master Portfolios. For services provided to the Underlying Funds, BFA receives investment advisory fees from the Underlying Funds. In addition, BTC provides administration services to certain of the Underlying Funds and, for those services, may receive administration fees from those Underlying Funds. BFA has contractually agreed to waive its management fees at the Master Portfolio level in an amount equal to management and administration fees, if any, paid by the Underlying Funds to BFA and BTC, respectively, through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the LifePath Portfolios' annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS

Dagmar Nikles, Leslie Gambon, Alan Mason and Amy Whitelaw (the "Portfolio Management Team") are jointly and primarily responsible for the day-to-day management of the Master Portfolios and act collaboratively on all aspects concerning the Master Portfolios. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of their team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy, and overseeing members of his or her portfolio management team with more limited responsibilities.

Ms. Nikles has been employed as a Senior Investment Strategist in the defined contributions team at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A ("BGI")) since December 2009. From July 2003 to November 2009, Ms. Nikles was a member of the asset allocation portfolio management team at BGFA and BGI. Ms. Nikles has been a one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since June 2005.

Ms. Gambon has been employed as a member of the asset allocation portfolio management team at BFA and BTC since April 2007. From October 2004 to April 2007, Ms. Gambon was Head of Defined Contribution Portfolio Management at BGI. Ms. Gambon has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since May 2007.

Mr. Mason has been employed by BFA and BTC since December 2009. Mr. Mason is responsible for multi-asset class solutions for institutional clients. From 1991 to 2009, Mr. Mason served a variety of roles at BGFA and BGI, including eight years devoted to the development of transition management products. Mr. Mason has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since September 2009.

Ms. Whitelaw has been employed as Head of Defined Contributions Portfolio Management at BFA and BTC since December 2009. From October 2009 to November 2009, Ms. Whitelaw was Head of Defined Contributions Portfolio Management at BGFA and BGI. Ms. Whitelaw had been employed as a member of the portfolio management team at

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BGFA and BGI since July 2006. From April 2002 to April 2005, Ms. Whitelaw worked as a transition manager and strategist in the Transition Services group at BGFA and BGI.

The LifePath Portfolios' SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers' ownership of shares in the LifePath Portfolios.

ADMINISTRATIVE SERVICES

Pursuant to an Administration Agreement between the Trust, on behalf of the LifePath Portfolios, and BTC, BTC provides the following services, among others, as the LifePath Portfolios' administrator:

. Supervises the LifePath Portfolios' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the shareholder servicing agent ("Shareholder Servicing Agent") on behalf of the LifePath Portfolios.

BTC is entitled to receive fees for these services at the annual rate of 0.50% of the average daily net assets of Investor C Shares of each LifePath Portfolio. In addition to performing these services, BTC has agreed to bear all costs of operating the LifePath Portfolios, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the LifePath Portfolios or the Trust as defined in the 1940 Act and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

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Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolios have retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolios to the extent that the Master Portfolios participate in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolios, including a fee based on the returns earned on the Master Portfolios' investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolios may lend their portfolio securities under the securities lending program.

VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. Each LifePath Portfolio calculates the net asset value of each class of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00
p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

Each LifePath Portfolio's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. Each LifePath Portfolio values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If a LifePath Portfolio invests in foreign securities, these securities may trade on weekends or other days when the LifePath Portfolio does not price its shares. As a result, a LifePath Portfolio's net asset value may change on days when you will not be able to purchase or redeem the LifePath Portfolio's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a LifePath Portfolio's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, a LifePath Portfolio's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the LifePath Portfolio. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value.

A LifePath Portfolio may accept orders from certain authorized financial intermediaries or their designees. A LifePath Portfolio will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the LifePath Portfolio after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN LIFEPATH PORTFOLIO POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The LifePath Portfolios are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a LifePath Portfolio may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The LifePath Portfolios reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the LifePath Portfolios to verify their identity. The LifePath Portfolios also reserve the right to redeem any amounts in a LifePath Portfolio from persons whose identity it is unable to verify on a timely basis. It is the LifePath Portfolios' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

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BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

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Financial Highlights


The financial highlights tables in this section are intended to help investors understand the financial performance of Institutional Share of each LifePath Portfolio for the past five years, or if shorter, since inception. Certain information reflects financial results for a single Institutional Shares of each LifePath Portfolio. FINANCIAL PERFORMANCE FOR INVESTOR C SHARES WOULD DIFFER FROM THE FINANCIAL PERFORMANCE FOR INSTITUTIONAL SHARES BECAUSE THE CLASSES HAVE DIFFERENT EXPENSES. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Institutional Shares of a given LifePath Portfolio, assuming reinvestment of all distributions. The information has been audited by PricewaterhouseCoopers, LLP, whose report, along with the LifePath Portfolios' financial statements, is included in the LifePath Portfolios' annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-441-7762 (toll-free) Monday through Friday from 8:00 a.m. to 6:00 p.m. Eastern time on any business day.

LIFEPATH RETIREMENT PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         INSTITUTIONAL SHARES
                                             ----------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                             ----------------------------------------------------------------------------
                                                          2009            2008           2007          2006          2005
                                             ----------------- --------------- -------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            ---               -               -             -             -
 Net asset value, beginning of year             $    9.42        $    11.46      $   11.59      $   11.22     $   11.18
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net investment income                               0.321              0.37           0.39          0.39          0.30
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Net realized and unrealized gain (loss)            1.37              (2.06)          0.12          0.58          0.17
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net increase (decrease) from investment
 operations                                         1.69           (   1.69)          0.51          0.97          0.47
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Dividends and distributions from:
  Net investment income                             (0.31)         (   0.31)       (   0.37)     (   0.39)     (   0.33)
  Net realized gain                                 (0.00)/2/      (   0.04)       (   0.27)     (   0.21)     (   0.10)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
Total dividends and distributions                (   0.31)         (   0.35)       (   0.64)     (   0.60)     (   0.43)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
 Net asset value, end of year                  $   10.80         $     9.42      $   11.46      $   11.59     $   11.22
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Based on net asset value                         18.25   %          (15.04)%          4.50%         8.80%         4.32%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Total expenses                                    1.10   %            1.11%           1.12%         1.13%         1.15%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Total expenses after expense reductions            0.76   %            0.76%           0.77%         0.78%         0.81%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net investment income                             3.13   %            3.29%           3.43%         3.28%         2.72%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
SUPPLEMENTAL DATA
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net assets, end of year (000)                 $  438,987        $   92,717      $  136,923     $  91,518     $  99,349
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Portfolio turnover of the Master Portfolio              6%               11%              6%           10%           11%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

66

LIFEPATH 2020 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  12.32         $   16.98      $  17.48      $  15.85     $  15.19
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.351              0.44          0.45          0.40         0.30
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.38              (4.67)         0.14          1.64         0.68
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.73            (  4.23)         0.59          2.04         0.98
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.43)         (  0.31)       (  0.44)      (  0.41)     (  0.32)
  Net realized gain                                     -          (  0.12)       (  0.65)            -            -
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.43)         (  0.43)       (  1.09)      (  0.41)     (  0.32)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  14.62         $   12.32      $  16.98      $  17.48     $  15.85
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         22.71   %         (25.42)%         3.34%        13.01%        6.54%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.08   %           1.07%          1.08%         1.08%        1.12%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.72   %           0.73%          0.74%         0.75%        0.78%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.65   %           2.65%          2.52%         2.37%        2.01%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 663,890        $ 432,717      $ 781,519     $ 598,633    $ 578,497
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              6%              13%             7%           16%          17%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

67

LIFEPATH 2030 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  10.92         $   16.19      $  16.90      $  15.39     $  14.87
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.291              0.35          0.34          0.32         0.24
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.46              (5.29)         0.11          1.99         0.88
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.75            (  4.94)         0.45          2.31         1.12
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.36)         (  0.25)       (  0.35)      (  0.36)     (  0.26)
  Net realized gain                                     -          (  0.08)       (  0.81)      (  0.44)     (  0.34)
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.36)         (  0.33)       (  1.16)      (  0.80)     (  0.60)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  13.31         $   10.92      $  16.19      $  16.90     $  15.39
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         25.77   %         (31.03)%         2.64%        15.12%        7.63%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.06   %           1.06%          1.07%         1.08%        1.10%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.70   %           0.72%          0.73%         0.74%        0.76%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.47   %           2.29%          2.10%         1.95%        1.69%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 517,817        $ 315,028      $ 564,348     $ 408,564    $ 352,800
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              7%              13%             7%           22%          24%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

68

LIFEPATH 2040 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                     INSTITUTIONAL SHARES
                                             ---------------------------------------------------------------------
                                                                    YEAR ENDED DECEMBER 31,
                                             ---------------------------------------------------------------------
                                                      2009           2008          2007          2006         2005
                                             ------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------           -             -              -             -            -
 Net asset value, beginning of year            $  12.88      $   20.32      $  20.90      $  18.18     $  17.03
--------------------------------------------   --------      ---------      --------      --------     ---------
Net investment income                              0.321          0.35          0.34          0.31         0.21
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           3.22          (7.45)         0.08          2.76         1.18
--------------------------------------------   ---------     ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        3.54        (  7.10)         0.42          3.07         1.39
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                          (  0.38)      (  0.26)       (  0.35)      (  0.35)     (  0.24)
  Net realized gain                                    -       (  0.08)       (  0.65)            -            -
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total dividends and distributions                (  0.38)      (  0.34)       (  1.00)      (  0.35)     (  0.24)
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net asset value, end of year                  $  16.04      $   12.88      $  20.32      $  20.90     $  18.18
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/2/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Based on net asset value                          28.08%       (35.40)%         2.03%        16.97%        8.24%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/3/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Total expenses                                     1.05%         1.04%          1.06%         1.07%        1.09%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total expenses after expense reductions             0.69%         0.69%          0.72%         0.73%        0.76%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net investment income                              2.33%         2.02%          1.71%         1.62%        1.45%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                 $ 435,317     $ 248,491      $ 383,391     $ 278,716    $ 221,359
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio             6%           14%             8%           29%          38%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Includes the reinvestment of dividends and distributions.

/3/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

69

LIFEPATH 2050 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                    INSTITUTIONAL SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED              JUNE 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                -                       -
 Net asset value, beginning of period                      $    13.46          $     20.00
----------------------------------------------------       ----------          -------------
Net investment income                                           0.382                 0.10
----------------------------------------------------       ----------          -------------
 Net realized and unrealized gain (loss)                        3.68                    (6.52)
----------------------------------------------------       ----------          -------------
Net increase (decrease) from investment operations              4.06               (     6.42)
----------------------------------------------------       ----------          --------------
 Dividends and distributions from:
  Net investment income                                     (    0.16)             (     0.09)
  Net realized gain                                         (    0.55)             (     0.00)/3 /
  Return of capital                                                 -              (     0.03)
----------------------------------------------------       ----------          -----------------
Total dividends and distributions                           (    0.71)             (     0.12)
----------------------------------------------------       ----------          -----------------
 Net asset value, end of period                            $    16.81          $     13.46
----------------------------------------------------       ----------          -----------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------       ----------          -----------------
 Based on net asset value                                       30.35%                 (32.18)%/5/
----------------------------------------------------       ----------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------       ----------          ------------------
 Total expenses                                                  1.27%                  12.80%/7 /
----------------------------------------------------       ----------          ------------------
Total expenses after expense reductions                          0.67%                   0.68%/7 /
----------------------------------------------------       ----------          ------------------
 Net investment income                                           2.39%                   2.14%/7 /
----------------------------------------------------       ----------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------       ----------          ------------------
 Net assets, end of period (000)                           $   13,992          $          444
----------------------------------------------------       ----------          ------------------
Portfolio turnover of the Master Portfolio                         12%                      0%/8/
----------------------------------------------------       ----------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

/8/ Rounds to less than 1% .

70

DISCLAIMERS

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible

71

for and has not participated in the determination of the prices and amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

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The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE Licensor Parties. None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/

NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of

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Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the LifePath Portfolios is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the LifePath Portfolio's investments. The annual report describes the LifePath Portfolio's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and LifePath Portfolio investment strategies that significantly affected the LifePath Portfolio's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION

A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each LifePath Portfolio, may be obtained free of charge, along with each LifePath Portfolio's annual and semi-annual reports, by calling (800) 441-7762, on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the LifePath Portfolios, please:

Call:       1-800-441-7762 (toll free)
            8:00 a.m. to 6:00 p.m. (Eastern time),
            on any business day

WORLD WIDE WEB

General LifePath Portfolio information and specific LifePath Portfolio performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com.

WRITTEN CORRESPONDENCE

BlackRock Funds III
PO Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

INTERNAL WHOLESALERS/BROKER DEALER SUPPORT
Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), on any business day. Call: (800) 882-0052.

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the LifePath Portfolios' policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about a LifePath Portfolio, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-LPC-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
LIFEPATH(Reg. TM) PORTFOLIOS

INSTITUTIONAL SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

PORTFOLIO                                                     TICKER SYMBOL
---------------------------------------------------------     --------------
LifePath(Reg. TM) Retirement Portfolio - Institutional                 STLAX
Shares
LifePath 2020 Portfolio(Reg. TM) - Institutional Shares                STLCX
LifePath 2030 Portfolio(Reg. TM) - Institutional Shares                STLDX
LifePath 2040 Portfolio(Reg. TM) - Institutional Shares                STLEX
LifePath(Reg. TM) 2050 Portfolio - Institutional Shares                STLFX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

LIFEPATH PORTFOLIO

  KEY FACTS AND DETAILS ABOUT THE LIFEPATH PORTFOLIOS, INCLUDING
OVERVIEW
  INVESTMENT OBJECTIVES, PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND
  EXPENSE INFORMATION, AND HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO.....................  1
  KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO...........................  8
  KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO........................... 15
  KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO........................... 22
  KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO........................... 29

DETAILS ABOUT THE LIFEPATH PORTFOLIOS

INVESTMENT TIME HORIZONS....................................... 36
A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES........ 37
A FURTHER DISCUSSION OF RISK FACTORS........................... 43

ACCOUNT INFORMATION

DETAILS ABOUT INSTITUTIONAL SHARES...................... 49
HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES.......... 50
SHAREHOLDER SERVICING PAYMENTS.......................... 56
ACCOUNT SERVICES AND PRIVILEGES......................... 56
LIFEPATH PORTFOLIOS' RIGHTS............................. 58
CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE........ 58
LIFEPATH PORTFOLIO DISTRIBUTIONS........................ 58
SHORT-TERM TRADING POLICY............................... 58
TAXES................................................... 59
MASTER/FEEDER AND FUND OF FUNDS STRUCTURES.............. 60

MANAGEMENT OF THE LIFEPATH PORTFOLIOS

INVESTMENT ADVISER................................. 62
PORTFOLIO MANAGERS................................. 62
ADMINISTRATIVE SERVICES............................ 63
CONFLICTS OF INTEREST.............................. 63
VALUATIION OF THE LIFEPATH PORTFOLIO INVESTMENTS... 64
CERTAIN LIFEPATH PORTFOLIO POLICIES................ 64

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE LIFEPATH PORTFOLIOS........ 66
DISCLAIMERS............................................. 71

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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LifePath Retirement Portfolio Overview

KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO

INVESTMENT OBJECTIVE

LifePath Retirement Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors seeking income and moderate long-term growth of capital. LifePath Retirement Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH RETIREMENT PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of LifePath Retirement Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     None
 Other Expenses                                                                               0.52%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.02%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     1.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.85%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath Retirement Master Portfolio (the "Retirement Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Retirement Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the Retirement Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath Retirement Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath Retirement Portfolio and the Retirement Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath Retirement Portfolio and the Retirement Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effects to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath Retirement Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual class Operating Expenses in the table above and the following example reflect the expenses of Institutional Shares of LifePath Retirement Portfolio and the Retirement Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the Retirement Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Institutional Shares of LifePath Retirement Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of LifePath Retirement Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares of LifePath Retirement Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  87        $  310        $  590        $  1,391

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PORTFOLIO TURNOVER

The Retirement Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath Retirement Portfolio's performance. During the most recent fiscal year, the Retirement Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH RETIREMENT PORTFOLIO


LifePath Retirement Portfolio invests all of its assets in the Retirement Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath Retirement Portfolio is designed for investors seeking current income and moderate long-term growth of capital. As of March 31, 2010, LifePath Retirement Portfolio held approximately 39% of its assets in Underlying Funds that invest primarily in equity securities, 61% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in real estate investment trusts ("REITs"), foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. Because LifePath Retirement Portfolio is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain LifePath Retirement Portfolio's risk profile.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH RETIREMENT PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath Retirement Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath Retirement Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath Retirement Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath Retirement Portfolio.

. ALLOCATION RISK - LifePath Retirement Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath Retirement Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or groups of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath Retirement Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath Retirement Portfolio's use of derivatives may reduce LifePath Retirement Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath Retirement Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

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. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath Retirement Portfolio will lose money. These risks include:

. LifePath Retirement Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath Retirement Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath Retirement Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath Retirement Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath Retirement Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath Retirement Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath Retirement Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath Retirement Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath Retirement Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath Retirement Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath Retirement Portfolio may lose money and there may be a delay in

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recovering the loaned securities. LifePath Retirement Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath Retirement Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath Retirement Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath Retirement Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Institutional Shares of LifePath Retirement Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath Retirement Portfolio to that of the LifePath Retirement Portfolio Custom Benchmark. The LifePath Retirement Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath Retirement Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath Retirement Portfolio reflect the Retirement Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath Retirement Portfolio reflect the direct investment by the Retirement Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath Retirement Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path Retirement Portfolio expenses during these periods, Life Path Retirement Portfolio's returns would have been lower.

LIFEPATH RETIREMENT PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    4.73%
2001    3.60%
2002    -2.70%
2003   11.95%
2004    6.35%
2005    4.32%
2006    8.80%
2007    4.50%
2008   -15.04%
2009   18.25%

During the periods shown in the bar chart, the highest return for a quarter was 9.85% (quarter ended September 30, 2009) and the lowest return for a quarter was -7.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 2.79%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath Retirement Portfolio - Institutional Shares
  Return Before Taxes                                                                       18.25%       3.57%       4.12%
  Return After Taxes on Distributions                                                       17.09%       2.38%       2.79%
  Return After Taxes on Distributions and Sale of Fund Shares                               11.89%       2.49%       2.84%
 LifePath Retirement Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         16.75%       4.06%       5.09%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER


The Retirement Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                         THE
                      RETIREMENT
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

Institutional Shares of LifePath Retirement Portfolio are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or of its affiliates. The initial and subsequent investment minimums generally are as follows, although Institutional Shares of LifePath Retirement Portfolio may reduce or waive these investment minimums in some cases.

                             INSTITUTIONAL SHARES
                             ============================================
Minimum Initial Investment   $2 million for institutions and individuals

6

                                Institutional Shares are available to clients
                                of registered investment advisors
                                who have $250,000 invested in LifePath
                                Retirement Portfolio
Minimum Additional Investment   No subsequent minimum

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the New York Stock Exchange ("NYSE" or "Exchange") (generally 4:00 p.m. Eastern time) (or if regular trading on the NYSE closes early, at such closing time) on any day LifePath Retirement Portfolio is open (a "Business Day").

TAX INFORMATION

LifePath Retirement Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath Retirement Portfolio through a broker-dealer or other financial intermediary, LifePath Retirement Portfolio and BlackRock Investments, LLC, LifePath Retirement Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath Retirement Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath Retirement Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

7

LifePath 2020 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2020 Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020. LifePath 2020 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2020 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of LifePath 2020 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     None
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     1.19%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.34)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.85%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2020 Master Portfolio (the "2020 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2020 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2020 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist LifePath 2020 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2020 Portfolio and the 2020 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2020 Portfolio and the 2020 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effects to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2020 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Institutional Shares of LifePath 2020 Portfolio and the 2020 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2020 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Institutional Shares of LifePath 2020 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of LifePath 2020 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares of LifePath 2020 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  87        $  309        $  587        $  1,381

8

PORTFOLIO TURNOVER

The 2020 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2020 Portfolio's performance. During the most recent fiscal year, the 2020 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2020 PORTFOLIO


LifePath 2020 Portfolio invests all of its assets in the 2020 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2020 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2020. As of March 31, 2010, LifePath 2020 Portfolio held approximately 60% of its assets in Underlying Funds that invest primarily in equity securities, 40% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2020 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2020 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2020 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

9

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2020 Portfolio, and determine whether any changes are required to enable LifePath 2020 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2020 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2020 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2020 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2020 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2020 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2020 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2020 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2020 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2020 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2020 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2020 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2020 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2020 Portfolio.

. ALLOCATION RISK - LifePath 2020 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2020 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2020 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2020 Portfolio's use of derivatives may reduce LifePath 2020 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2020 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

10

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2020 Portfolio will lose money. These risks include:

. LifePath 2020 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2020 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2020 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2020 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2020 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2020 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2020 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2020 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2020 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2020 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

11

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2020 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2020 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2020 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2020 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2020 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Institutional Shares of LifePath 2020 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2020 Portfolio to that of the LifePath 2020 Portfolio Custom Benchmark. The LifePath 2020 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2020 Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for LifePath 2020 Portfolio reflect the 2020 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2020 Portfolio reflect the direct investment by the 2020 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2020 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2020 Portfolio expenses during these periods, Life Path 2020 Portfolio's returns would have been lower.

LIFEPATH 2020 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     -3.74%
2001     -6.42%
2002    -12.59%
2003    20.61%
2004     9.27%
2005     6.54%
2006    13.01%
2007     3.34%
2008   -25.42%
2009    22.71%

During the periods shown in the bar chart, the highest return for a quarter was 13.89% (quarter ended June 30, 2009) and the lowest return for a quarter was -14.21% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.30%.

12

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2020 Portfolio - Institutional Shares
  Return Before Taxes                                                                       22.71%       2.63%       1.68%
  Return After Taxes on Distributions                                                       21.50%       1.81%       0.89%
  Return After Taxes on Distributions and Sale of Fund Shares                               14.84%       1.94%       1.08%
 LifePath 2020 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         22.84%       3.27%       2.78%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2020 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2020
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

13

PURCHASE AND SALE OF SHARES

Institutional Shares of LifePath 2020 Portfolio are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or of its affiliates. The initial and subsequent investment minimums generally are as follows, although Institutional Shares of LifePath 2020 Portfolio may reduce or waive these investment minimums in some cases:

                                INSTITUTIONAL SHARES
                                ==================================================
Minimum Initial Investment      $2 million for institutions and individuals
                                Institutional Shares are available to clients of
                                registered investment advisors
                                who have $250,000 invested in LifePath 2020
                                Portfolio
Minimum Additional Investment   No subsequent minimum

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the New York Stock Exchange ("NYSE" or "Exchange") (generally 4:00 p.m. Eastern time) (or if regular trading on the NYSE closes early, at such closing time) on any day LifePath Retirement Portfolio is open (a "Business Day").

TAX INFORMATION

LifePath 2020 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2020 Portfolio through a broker-dealer or other financial intermediary, LifePath 2020 Portfolio and BlackRock Investments, LLC, LifePath 2020 Portfolio's distributor or its affiliates may pay the intermediary for the sale of LifePath 2020 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2020 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

14

LifePath 2030 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2030 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030. LifePath 2030 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2030 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of LifePath 2030 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     None
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.85%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2030 Master Portfolio (the "2030 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2030 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2030 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2030 Portfolio and the 2030 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2030 Portfolio and the 2030 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effects to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2030 Portfolio's PRO RATA share of the fees and expenses incurred by investing certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Institutional Shares of LifePath 2030 Portfolio and the 2030 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2030 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Institutional Shares of LifePath 2030 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of LifePath 2030 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares of LifePath 2030 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  87        $  310        $  590        $  1,391

15

PORTFOLIO TURNOVER

The 2030 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2030 Portfolio's performance. During the most recent fiscal year, the 2030 Master Portfolio's portfolio turnover rate was 7% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2030 PORTFOLIO


LifePath 2030 Portfolio invests all of its assets in the 2030 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2030 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2030. As of March 31, 2010, LifePath 2030 Portfolio held approximately 75% of its assets in Underlying Funds that invest primarily in equity securities, 25% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2030 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2030 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2030 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

16

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2030 Portfolio, and determine whether any changes are required to enable LifePath 2030 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2030 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2030 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2030 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2030 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2030 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2030 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2030 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2030 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2030 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2030 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2030 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2030 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2030 Portfolio.

. ALLOCATION RISK - LifePath 2030 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2030 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2030 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2030 Portfolio's use of derivatives may reduce LifePath 2030 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2030 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

17

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2030 Portfolio will lose money. These risks include:

. LifePath 2030 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2030 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2030 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2030 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2030 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2030 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2030 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2030 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2030 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2030 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

18

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2030 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2030 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2030 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2030 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2030 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Institutional Shares of LifePath 2030 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2030 Portfolio to that of the LifePath 2030 Portfolio Custom Benchmark. The LifePath 2030 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2030 Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for LifePath 2030 Portfolio reflect the 2030 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2030 Portfolio reflect the direct investment by the 2030 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2030 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2030 Portfolio expenses during these periods, Life Path 2030 Portfolio's returns would have been lower.

LIFEPATH 2030 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     -5.65%
2001     -9.94%
2002    -15.73%
2003    23.86%
2004    10.78%
2005     7.63%
2006    15.12%
2007     2.64%
2008    -31.03%
2009    25.77%

During the periods shown in the bar chart, the highest return for a quarter was 16.61% (quarter ended June 30, 2009) and the lowest return for a quarter was -17.90% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.62%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2030 Portfolio - Institutional Shares
  Return Before Taxes                                                                       25.77%       1.98%        0.81%
  Return After Taxes on Distributions                                                       24.68%       1.10%       -0.09%
  Return After Taxes on Distributions and Sale of Fund Shares                               16.88%       1.48%        0.39%
 LifePath 2030 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         27.05%       2.70%        1.82%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%       -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%        6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%        2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%        2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%        7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%        9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2030 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2030
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

Institutional Shares of LifePath 2030 Portfolio are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or of its affiliates. The initial and subsequent investment minimums generally are as follows, although Institutional Shares of LifePath 2030 Portfolio may reduce or waive these investment minimums in some cases:

                                INSTITUTIONAL SHARES
                                ==================================================
Minimum Initial Investment      $2 million for institutions and individuals
                                Institutional Shares are available to clients of
                                registered investment advisors
                                who have $250,000 invested in LifePath 2030
                                Portfolio
Minimum Additional Investment   No subsequent minimum

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the New York Stock Exchange ("NYSE" or "Exchange") (generally 4:00 p.m. Eastern time) (or if regular trading on the NYSE closes early, at such closing time) on any day LifePath Retirement Portfolio is open (a "Business Day").

TAX INFORMATION

LifePath 2030 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2030 Portfolio through a broker-dealer or other financial intermediary, LifePath 2030 Portfolio and BlackRock Investments, LLC, LifePath 2030 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2030 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2030 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

21

LifePath 2040 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2040 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040. LifePath 2040 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2040 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of LifePath 2040 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                         (    0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.85%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2040 Master Portfolio (the "2040 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2040 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2040 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2040 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2040 Portfolio and the 2040 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2040 Portfolio and the 2040 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effects to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2040 Portfolio's PRO RATA share of the fees and expenses incurred by investing certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Institutional Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2040 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Institutional Shares of LifePath 2040 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of LifePath 2040 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares of LifePath 2040 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  87        $  310        $  590        $  1,391

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PORTFOLIO TURNOVER

The 2040 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2040 Portfolio's performance. During the most recent fiscal year, the 2040 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2040 PORTFOLIO


LifePath 2040 Portfolio invests all of its assets in the 2040 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of the equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2040 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2040. As of March 31, 2010, LifePath 2040 Portfolio held approximately 88% of its assets in Underlying Funds that invest primarily in equity securities, 12% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2040 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2040 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2040 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

23

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2040 Portfolio, and determine whether any changes are required to enable LifePath 2040 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2040 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2040 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2040 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2040 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2040 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2040 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2040 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2040 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2040 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2040 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2040 Portfolio or your investment may not perform as well as other similar investments. The following is a summary description of certain risks of investing in LifePath 2040 Portfolio. An investment in LifePath 2040 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

. ALLOCATION RISK - LifePath 2040 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2040 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2040 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2040 Portfolio's use of derivatives may reduce LifePath 2040 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2040 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

24

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2040 Portfolio will lose money. These risks include:

. LifePath 2040 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2040 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2040 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2040 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2040 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2040 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2040 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2040 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2040 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2040 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

25

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2040 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2040 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2040 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2040 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2040 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Institutional Shares of LifePath 2040 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2040 Portfolio to that of the LifePath 2040 Portfolio Custom Benchmark. The LifePath 2040 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2040 Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for LifePath 2040 Portfolio reflect 2040 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2040 Portfolio reflect the direct investment by 2040 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2040 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2040 Portfolio expenses during these periods, Life Path 2040 Portfolio's returns would have been lower.

LIFEPATH 2040 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     -9.71%
2001    -13.41%
2002    -18.73%
2003    27.64%
2004    11.43%
2005     8.24%
2006   16.97 %
2007     2.03%
2008   -35.40%
2009    28.08%

During the periods shown in the bar chart, the highest return for a quarter was 19.00% (quarter ended June 30, 2009) and the lowest return for a quarter was -20.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.88%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2040 Portfolio - Institutional Shares
  Return Before Taxes                                                                       28.08%       1.34%      -0.35%
  Return After Taxes on Distributions                                                       27.18%       0.87%      -0.88%
  Return After Taxes on Distributions and Sale of Fund Shares                               18.45%       1.08%      -0.43%
 LifePath 2040 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         30.52%       2.15%       0.87%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2040 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2040
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

Institutional Shares of LifePath 2040 Portfolio are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or of its affiliates. The initial and subsequent investment minimums generally are as follows, although Institutional Shares of LifePath 2040 Portfolio may reduce or waive these investment minimums in some cases:

                                INSTITUTIONAL SHARES
                                ==================================================
Minimum Initial Investment      $2 million for institutions and individuals
                                Institutional Shares are available to clients of
                                registered investment advisors
                                who have $250,000 invested in LifePath 2040
                                Portfolio
Minimum Additional Investment   No subsequent minimum

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the New York Stock Exchange ("NYSE" or "Exchange") (generally 4:00 p.m. Eastern time) (or if regular trading on the NYSE closes early, at such closing time) on any day LifePath Retirement Portfolio is open (a "Business Day").

TAX INFORMATION

LifePath 2040 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2040 Portfolio through a broker-dealer or other financial intermediary, LifePath 2040 Portfolio and BlackRock Investments, LLC, LifePath 2040 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2040 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2040 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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LifePath 2050 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2050 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050. LifePath 2050 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2050 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of LifePath 2050 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.83%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.33%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.52%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                         (    0.67)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.85%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2050 Master Portfolio (the "2050 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2050 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2050 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2050 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services in connection with LifePath 2050 Portfolio and the 2050 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2050 Portfolio and the 2050 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effects to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2050 Portfolio's PRO RATA share of the fees and expenses incurred by investing certain other funds including the underlying funds.

(5) Total Annual Operating Expenses in the table above and the following example reflect the expenses of Institutional Shares of LifePath 2050 Portfolio and the 2050 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2050 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Institutional Shares of LifePath 2050 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of LifePath 2050 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares of LifePath 2050 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  87        $  345        $  698        $  1,694

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PORTFOLIO TURNOVER

The 2050 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2050 Portfolio's performance. During the most recent fiscal year, the 2050 Master Portfolio's portfolio turnover rate was 12% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2050 PORTFOLIO


LifePath 2050 Portfolio invests all of its assets in the 2050 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2050 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2050. As of March 31, 2010, LifePath 2050 Portfolio held approximately 98% of its assets in Underlying Funds that invest primarily in equity securities, 1% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2050 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2050 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2050 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach thier target dates:

[GRAPHIC APPEARS HERE]

30

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2050 Portfolio, and determine whether any changes are required to enable LifePath 2050 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2050 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2050 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2050 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2050 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2050 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2050 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2050 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2050 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2050 PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath 2050 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2050 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2050 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2050 Portfolio.

. ALLOCATION RISK - LifePath 2050 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2050 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2050 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2050 Portfolio's use of derivatives may reduce LifePath 2050 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2050 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

31

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2050 Portfolio will lose money. These risks include:

. LifePath 2050 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2050 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2050 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2050 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2050 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2050 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2050 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2050 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2050 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2050 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

32

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2050 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2050 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2050 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2050 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2050 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Institutional Shares of LifePath 2050 Portfolio for the last calendar year. The average annual total return table compares the performance of Institutional Shares of LifePath 2050 Portfolio to that of the LifePath 2050 Portfolio Custom Benchmark. The LifePath 2050 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2050 Portfolio invests according to their weightings as of the most recent quarter-end. How LifePath 2050 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2050 Portfolio expenses during these periods, Life Path 2050 Portfolio's returns would have been lower.

LIFEPATH 2050 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   30.35%

During the period shown in the bar chart, the highest return for a quarter was 21.06% (quarter ended June 30, 2009) and the lowest return for a quarter was -12.76% (quarter ended March 31, 2009). The year-to-date return as of March 31, 2010 was 4.14%.

33

                                                                                                                 SINCE
AS OF 12/31/09                                                                                               INCEPTION JUNE
AVERAGE ANNUAL TOTAL RETURNS                                                                   1 YEAR           30, 2008
 LifePath 2050 Portfolio - Institutional Shares
  Return Before Taxes                                                                           30.35%          -7.86%
  Return After Taxes on Distributions                                                           28.59%          -8.77%
  Return After Taxes on Distributions and Sale of Fund Shares                                   19.85%          -7.12%
 LifePath 2050 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                             34.11%          -6.38%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                            27.25%            N/A
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                              5.93%             N/A
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             43.60%            N/A
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                          0.16%             N/A
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                           11.41%            N/A
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             38.25%             N/A

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2050 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2050
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

34

PURCHASE AND SALE OF SHARES

Institutional Shares of LifePath 2050 Portfolio are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or of its affiliates. The initial and subsequent investment minimums generally are as follows, although Institutional Shares of LifePath 2050 Portfolio may reduce or waive these investment minimums in some cases:

                                INSTITUTIONAL SHARES
                                ==================================================
Minimum Initial Investment      $2 million for institutions and individuals
                                Institutional Shares are available to clients of
                                registered investment advisors
                                who have $250,000 invested in LifePath 2050
                                Portfolio
Minimum Additional Investment   No subsequent minimum

Your order to purchase or sell shares must be received in proper form by the close of regular trading on the New York Stock Exchange ("NYSE" or "Exchange") (generally 4:00 p.m. Eastern time) (or if regular trading on the NYSE closes early, at such closing time) on any day LifePath Retirement Portfolio is open (a "Business Day").

TAX INFORMATION

LifePath 2050 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2050 Portfolio through a broker-dealer or other financial intermediary, LifePath 2050 Portfolio and BlackRock Investments, LLC, LifePath 2050 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2050 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2050 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

35

Details About the LifePath Portfolios

INVESTMENT TIME HORIZONS

Each LifePath Portfolio seeks to maximize return consistent with the quantitatively measured risk that investors on average may be willing to accept given a particular investment time horizon. An investor's time horizon marks the point when the investor plans to start making net withdrawals from his or her investments, in other words, the time when they will cease making new contributions to their investments. For many LifePath Portfolio investors, their time horizon is tied to the date that they plan to retire and begin gradually utilizing their investment to support themselves in retirement. For other LifePath Portfolio investors, their time horizon may represent the date when they plan to make substantial withdrawals for another purpose, such as a major purchase.

As a general rule, investors with a longer time horizon have a greater tolerance for risk than investors with a shorter time horizon. Long-term investors are more likely to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns. Each LifePath Portfolio has its own time horizon, as described in its investment objective in each LifePath Portfolio's "Key Facts" section in this Prospectus, which affects the targeted risk level of that LifePath Portfolio and, in turn, its asset allocation.

The allocations for LifePath Retirement Portfolio reflect the expectation that investors in or near retirement, or otherwise seeking current income, are willing to take some risk of loss of their investment in hopes of achieving moderate long term growth of capital. LifePath Retirement Portfolio is designed to help balance two risk factors that investors face during retirement: market risk (potential declines in market values) and longevity risk (living longer than expected). Specifically, the portfolio seeks to enable investors to maintain a steady withdrawal rate (about 3-5% per year) throughout their retirement without exhausting their investment. There is no guarantee that the performance of LifePath Retirement Portfolio will be sufficient to enable this withdrawal rate or that any one withdrawal rate is appropriate for all investors. Investors should work with a financial advisor or other expert to determine a sustainable withdrawal rate for their circumstances, and that withdrawal rate should be periodically reassessed throughout retirement as the value of the investor's portfolio changes.

Each LifePath Portfolio has a distinct investment objective tied to its time horizon:

. LifePath Retirement Portfolio is managed for investors seeking income and moderate long-term growth of capital.

. LifePath 2020 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020.

. LifePath 2030 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030.

. LifePath 2040 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040.

. LifePath 2050 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050.

You should carefully consider the asset allocation and risks of each LifePath Portfolio before deciding whether to invest.

The LifePath Portfolios are designed to offer individual investors comprehensive asset allocation strategies tailored to the time when they expect to begin withdrawing assets. Asset allocation is the distribution of investments among broad types of asset classes: equity securities, bonds and money market instruments. Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has the same objective and strategies as the applicable LifePath Portfolio. LifePath Retirement Portfolio invests all of its assets in Retirement Master Portfolio. LifePath 2020 Portfolio invests all of its assets in 2020 Master Portfolio. LifePath 2030 Portfolio invests all of its assets in 2030 Master Portfolio. LifePath 2040 Portfolio invests all of its assets in 2040 Master Portfolio. LifePath 2050 Portfolio invests all of its assets in 2050 Master Portfolio. To implement the asset allocation strategy, each Master Portfolio, in turn, invests in a combination of Underlying Funds in proportions based on its own comprehensive investment strategy that gradually becomes more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase. BFA is the investment adviser to the Master Portfolios. For simplicity's sake, all discussion of investment objective, strategies and risks of a particular LifePath Portfolio refers also to the

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investment objective, strategies and risks of the applicable Master Portfolio, unless otherwise indicated. A description of the relationship of the LifePath Portfolios to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder and Fund of Funds Structures."

WHICH LIFEPATH PORTFOLIO TO CONSIDER

The first step in choosing which LifePath Portfolio to consider is answering a key question: When will you need the money you are thinking of investing? Will it be in ten years, when your kids are ready for college? Or 30 years, when you retire?

The number in the name of most of the LifePath Portfolios is actually a year - a "target year" when you might expect to begin withdrawing your money. Selecting the LifePath Portfolio that may be most appropriate for your investment may be as simple as matching your target year with the closest LifePath Portfolio target year.

For example, let's say that you are investing for retirement purposes, and that you expect to retire at age 60. If you are 45 years old, you have 15 years before retirement. By adding 15 to the current year, you can define your "target year." If you expect to retire in the year 2025, as in this example, you may conclude that LifePath 2020 Portfolio is the most appropriate LifePath Portfolio for you.

The investment mix of the LifePath Portfolios gradually shifts from a greater concentration of higher-risk investments (namely, equity securities funds) to a greater concentration of lower-risk investments (namely, bond funds), thereby making the LifePath Portfolios increasingly conservative.

In making your investment decision, you should keep in mind:

. The LifePath Portfolios' investment strategies derive from the risk tolerance of average investors with a particular time horizon.

. The LifePath Portfolios' time horizons are based on the year in their name, except for LifePath Retirement Portfolio, which is designed for investors who are currently withdrawing, or plan in the near future to begin withdrawing, a substantial portion of their investment.

If you are willing to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns, you may invest some or all of your assets in a LifePath Portfolio with a longer time horizon. If you desire a more conservative investment and are willing to forego some potential returns, you may invest some or all of your assets in a LifePath Portfolio with a shorter time horizon. The final choice is yours.

A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES

Each LifePath Portfolio invests all of its assets in a corresponding Master Portfolio which allocates and reallocates its assets among the Underlying Funds. The Master Portfolios with longer time horizons invest a greater portion of their assets in Underlying Funds that invest in equity securities, which provide a greater opportunity for capital appreciation over the long-term but have a greater risk of loss. The Master Portfolios with shorter time horizons invest a greater portion of their assets in Underlying Funds that invest in bonds and money market instruments, which typically offer reduced risk and price volatility but forego some potential returns. Accordingly, under normal circumstances, the LifePath Portfolios with shorter time horizons have lower expected returns than the LifePath Portfolios with longer time horizons. In addition to investing in Underlying Funds, each Master Portfolio may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and invest the collateral in certain short-term instruments either directly or through one or more joint accounts or money market funds, as described in greater detail in the LifePath Portfolios' combined Statement of Additional Information ("SAI").

As each Master Portfolio approaches its designated time horizon, it systematically seeks to reduce the level of risk by allocating assets more conservatively among the Underlying Funds. This systematic shift toward more conservative investments is designed to reduce the risk of significant reductions in the value of an investment in a Master Portfolio as it approaches its time horizon.

For example, LifePath Retirement Portfolio has entered its "retirement phase" and seeks to maximize returns consistent with the risk that an average investor in retirement may be willing to accept. This does not mean, however, that it invests exclusively, or primarily, in Underlying Funds that are money market funds. Rather, because BFA believes that most investors are still willing to take some risks in pursuing returns even while drawing on their investments, almost all of LifePath Retirement Portfolio's assets will continue to be allocated to Underlying Funds that are equity and bond funds.

In determining the allocation of assets to the Underlying Funds, BFA uses a proprietary investment model that analyzes securities market data, including risk, asset class correlations, and expected returns, to provide portfolio

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allocations among the asset classes represented by the Underlying Funds. The allocations are periodically monitored and rebalanced in an effort to maximize expected return for a given level of risk. In managing the LifePath Portfolios, BFA focuses on long-term targets and objectives. The progression over time of a LifePath Portfolio's asset allocation to more conservative asset classes is a relatively steady process resulting in only gradual changes to the asset allocation from quarter to quarter. The Underlying Funds invest in a mix of equity securities, bonds and money market instruments. Certain Underlying Funds invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivatives, which are subject to additional risks, as described in the "Details About the LifePath Portfolios - A Further Discussion of Risk Factors" section of this Prospectus. The investment model adjusts each LifePath Portfolio's risk level by gradually making it more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase.

When a LifePath Portfolio reaches its stated time horizon and enters its most conservative phase, the allocation of its assets is expected to be similar to that of LifePath Retirement Portfolio. Such LifePath Portfolio and LifePath Retirement Portfolio may then continue to operate as separate funds or, subject to approval by the Trust's Board of Trustees, they may be merged into a single fund.

THE UNDERLYING FUNDS

Two of the Underlying Funds - Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio - are diversified portfolios of MIP. Active Stock Master Portfolio seeks to provide long-term appreciation of capital. BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors. CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return.

The remaining Underlying Funds, other than BlackRock Cash Funds: Institutional (the "Underlying Money Market Fund"), are ETFs that are part of the iShares family of funds ("Underlying iShares Funds"). Each of the Underlying iShares Funds seeks investment results that correspond generally to the performance, before fees and expenses, of its underlying index. As a result, adverse performance of a particular security in an Underlying iShares Fund's portfolio will ordinarily not result in the elimination of the security from the Underlying iShares Fund's portfolio. Each Underlying iShares Fund offers and issues iShares at their NAV per share only to certain institutional investors in aggregations of a specified number of iShares, generally in exchange for a basket of securities included in its underlying index, together with the deposit of a specified cash payment. The iShares for these Underlying iShares Funds are listed and traded on national securities exchanges and also may be listed on certain non-U.S. exchanges. BFA purchases iShares on behalf of the Master Portfolios in the secondary market.

The relative weightings for each Master Portfolio in the various Underlying Funds will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time.

Each Master Portfolio currently expects to invest in some or all of the Underlying Funds described below:

ACTIVE STOCK MASTER PORTFOLIO

Active Stock Master Portfolio seeks to provide long-term appreciation of capital. Active Stock Master Portfolio invests, under normal circumstances, at least 80% of its assets in common stocks. Active Stock Master Portfolio invests primarily in equity securities of U.S. companies with market capitalizations similar to the range of market capitalizations represented in the Standard & Poor's ("S&P") 500 Index(Reg. TM). BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors, such as relative values based on earnings and cash flows; earnings quality as measured by the company's financial condition and earnings reports; sentiment as expressed through management and market participant behavior; and industry classification. BFA considers risk parameters in deciding upon Active Stock Master Portfolio's aggregate holdings, and factors trading costs into its stock selection process.

COREALPHA BOND MASTER PORTFOLIO

CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return. BFA's models also allocate assets among bonds of different maturities based on yield characteristics and expectations. Specific investment selection decisions are made on the basis of evaluations of relative value, credit quality and other factors. CoreAlpha Bond Master Portfolio invests, under normal circumstances, at least 80% of its assets in bonds. For the purposes of this strategy, "bonds" include the following:
obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial

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mortgage-backed securities; debt obligations of U.S. corporations; U.S. dollar-denominated debt obligations of foreign issuers; municipal securities; and asset-backed securities. CoreAlpha Bond Master Portfolio invests a substantial portion of its assets in U.S.-registered, dollar-denominated bonds. CoreAlpha Bond Master Portfolio may invest in bonds of any maturity or duration.

BLACKROCK CASH FUNDS: INSTITUTIONAL

BlackRock Cash Funds: Institutional seeks a high level of income consistent with liquidity and the preservation of capital. BlackRock Cash Funds:
Institutional invests in high-quality, short-term money market instruments that include fixed-rate, floating-rate and variable-rate debt securities. BlackRock Cash Funds: Institutional also may invest in high-quality, short-term U.S. and foreign government debt, including the debt of agencies and instrumentalities, such as the Federal National Mortgage Association ("Fannie Mae"), U.S. and foreign bank obligations, corporate obligations, repurchase agreements and asset-backed securities.

UNDERLYING ISHARES FUNDS

In managing each of the Underlying iShares Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that has an investment profile similar to the underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the applicable underlying index. Underlying iShares Funds that use representative sampling may or may not hold all of the securities in the relevant underlying index.

ISHARES S&P 500 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P 500 Index(Reg. TM), which measures the performance of the large-capitalization sector of the U.S. equity market. The component stocks are weighted according to the float-adjusted market value of their outstanding shares.

ISHARES S&P MIDCAP 400 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P MidCap 400 IndexTM, which measures the performance of the mid-capitalization sector of the U.S. equity market. The stocks in the S&P MidCap 400 IndexTM have a market capitalization between $750 million and $3.3 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation. The S&P MidCap 400 IndexTM consists of stocks from a broad range of industries.

ISHARES S&P SMALLCAP 600 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P SmallCap 600 IndexTM, which measures the performance of the small-capitalization sector of the U.S. equity market. The stocks in the S&P SmallCap 600 IndexTM have a market capitalization between $200 million and $1 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation.

ISHARES S&P NATIONAL AMT-FREE MUNICIPAL BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P National AMT-Free Municipal Bond Index, which measures the performance of the investment-grade segment of the U.S. municipal bond market. As of May 31, 2009, there were 8,709 issues in the S&P National AMT-Free Municipal Bond Index.

ISHARES S&P NORTH AMERICAN NATURAL RESOURCES SECTOR INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P North American Natural Resources Sector IndexTM, which measures the performance of U.S.-traded stocks of natural resource-related companies in the U.S. and Canada, and includes companies in the following categories: producers of oil, gas and consumable fuels, energy equipment and services, metals and mining, manufacturers of paper and forest products, and producers of construction materials, containers and packaging.

ISHARES RUSSELL MIDCAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell Midcap Index, which measures the performance of the mid-capitalization sector of the U.S. equity market. The Russell Midcap Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000(Reg. TM) Index.

ISHARES RUSSELL 2000 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell 2000 Index, which measures the performance of the small capitalization sector of the U.S. equity market. The Russell 2000 Index is a float-adjusted, capitalization-weighted index of equity securities issued by the approximately 2,000 smallest issuers in the Russell 3000(Reg. TM) Index.

ISHARES COHEN & STEERS REALTY MAJORS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Cohen & Steers Realty Major Index (the "Cohen & Steers Index"),

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which consists of selected U.S. REITs. The objective of the Cohen & Steers Index is to represent relatively large and liquid REITs that may benefit from future consolidation and securitization of the U.S. real estate industry. REITs are selected for inclusion in the Cohen & Steers Index based on a rigorous review of several factors, including management, portfolio quality, and sector and geographic diversification. The REITs selected for inclusion in the Cohen & Steers Index must meet minimum market capitalization and liquidity requirements. The Cohen & Steers Index is weighted according to the total market value of each REIT's outstanding shares and is adjusted quarterly so that no REIT represents more than 8% of the Cohen & Steers Index. Within the REIT market, the Cohen & Steers Index is diversified across property sectors that represent the current market.

ISHARES FTSE EPRA/NAREIT DEVELOPED REAL ESTATE EX-U.S. INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which measures the stock performance of companies engaged in the ownership and development of the following real estate markets defined as developed by FTSE EPRA/NAREIT: Canada, Europe (including Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom (including the Channel Islands)), Middle East (Israel) and Asia (including Australia, Hong Kong, Japan, New Zealand and Singapore). As of May 29, 2009, the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index was comprised of stocks of companies in the following markets: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Italy, Japan, Netherlands, New Zealand, Norway, Poland, Singapore, Spain, Sweden, Switzerland and the United Kingdom.

ISHARES MSCI CANADA INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Canada Index developed by MSCI, Inc. ("MSCI"). The MSCI Canada Index consists of stocks traded primarily on the Toronto Stock Exchange.

ISHARES MSCI EAFE INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE(Reg. TM) Index, which has been developed by MSCI as an equity benchmark for its international stock performance. The MSCI EAFE Index includes stocks from Europe, Australasia and the Far East.

ISHARES MSCI EAFE SMALL CAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE Small Cap Index, which represents the small cap size segment of the MSCI EAFE Index. The MSCI EAFE(Reg. TM) Index includes securities from Europe, Australasia and the Far East. Under MSCI's Global Investable Market Index methodology, the small cap universe consists of the securities of those companies whose securities are not included in the large cap or mid cap segments of a particular market, which together comprise approximately 85% of each market's free float-adjusted market capitalization. The small cap segment covers the 85%-99% range of each market's free float-adjusted market capitalization.

ISHARES MSCI EMERGING MARKETS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Emerging Markets Index, which is designed to measure equity market performance in the global emerging markets. As of September 30, 2009, the MSCI Emerging Markets Index consisted of the following 22 emerging market country indexes: Brazil, Chile, China, Colombia, the Czech Republic, Egypt, Hungary, India, Indonesia, Israel, Malaysia, Mexico, Morocco, Peru, the Philippines, Poland, Russia, South Africa, South Korea, Taiwan, Thailand and Turkey. Emerging market country indexes may be added to or deleted from the MSCI Emerging Markets Index from time to time. The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares funds that invest in securities in the MSCI Emerging Markets Index. BFA waives a portion of its advisory fees otherwise due from the iShares MSCI Emerging Markets Index Fund in an amount equal to the portfolio management fees incurred by assets that are invested in shares of other iShares funds.

ISHARES BARCLAYS 1-3 YEAR CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 1-3 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 3-7 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 3-7 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to three years and less than seven years.

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ISHARES BARCLAYS 7-10 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 7-10 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years.

ISHARES BARCLAYS 10-20 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 10-20 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to ten years and less than 20 years.

ISHARES BARCLAYS 20+ YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 20+ Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of 20 years or more.

ISHARES BARCLAYS AGGREGATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Aggregate Bond Index, which measures the performance of the total U.S. investment-grade bond market, which includes investment-grade U.S. Treasury bonds, government-related bonds, investment-grade corporate bonds, mortgage pass-through securities, commercial mortgage-backed securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Barclays Capital U.S. Aggregate Bond Index have $250 million or more of outstanding face value and have at least one year remaining to maturity. In addition, the securities must be U.S. dollar-denominated, fixed-rate and non-convertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and Eurobonds are excluded from the Barclays Capital U.S. Aggregate Bond Index. The Barclays Capital U.S. Aggregate Bond Index is market capitalization weighted and the securities are updated on the last calendar day of each month.

ISHARES BARCLAYS CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Government/Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS INTERMEDIATE CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS INTERMEDIATE GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Government/

Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS MBS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. MBS Index, which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Government National Mortgage Association, Fannie Mae and the Federal Home Loan Mortgage Corporation.

ISHARES BARCLAYS SHORT TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Short Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of between one and 12 months.

ISHARES BARCLAYS TIPS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L), which measures the performance of the inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS."

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ISHARES JPMORGAN USD EMERGING MARKETS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the JPMorgan EMBI Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark which tracks the total return of actively traded external debt instruments in emerging market countries.

ISHARES IBOXX $ HIGH YIELD CORPORATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the iBoxx(Reg. TM) $ Liquid High Yield Index, which is a rules-based index consisting of liquid U.S. dollar-denominated, high yield corporate bonds for sale in the United States, as determined by the International Index Company Limited ("IIC"). The iBoxx(Reg. TM) $ Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated high yield liquid corporate bond market. The iBoxx(Reg. TM) $ Liquid High Yield Index is a modified market value weighted index. There is no limit to the number of issues in the iBoxx(Reg. TM) $ Liquid High Yield Index, but as of June 30, 2009, the iBoxx(Reg. TM) $ Liquid High Yield Index included approximately 281 constituents.

The following table lists the Underlying Funds and the asset allocation for each Master Portfolio as of March 31, 2010. BFA allocates each Master Portfolio's assets among the Underlying Funds based on the Master Portfolio's investment objective and policies. The asset allocation for each Master Portfolio will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time:

UNDERLYING FUNDS
(as of March 31, 2010)

                                                    LIFEPATH     LIFEPATH    LIFEPATH    LIFEPATH    LIFEPATH
                                                   RETIREMENT      2020        2030        2040        2050
                                                    PORTFOLIO   PORTFOLIO   PORTFOLIO   PORTFOLIO    PORTFOLIO
CAPITAL GROWTH
MIP-Active Stock Master Portfolio                     19.45%       30.45%      38.39%      44.64%       49.18%
iShares S&P MidCap 400 Index Fund                      4.93%        5.87%       6.54%       7.14%        8.10%
iShares S&P SmallCap 600 Index Fund                    2.18%        2.58%       2.89%       3.16%        3.54%
iShares MSCI EAFE Index Fund                           6.74%       10.08%      12.60%      14.73%       17.01%
iShares Cohen & Steers Realty Majors Index Fund        0.62%        1.87%       2.73%       3.50%        4.01%
iShares FTSE EPRA/NAREIT Developed Real Estate         0.99%        2.99%       4.43%       5.62%        6.40%
ex-U.S. Index Fund
iShares MSCI Emerging Markets Index Fund               2.40%        3.70%       4.66%       5.47%        6.09%
iShares MSCI Canada Index Fund                         0.82%        1.25%       1.54%       1.82%        2.02%
iShares MSCI EAFE Small Cap Index Fund                 0.81%        1.25%       1.47%       1.72%        2.00%
CAPITAL GROWTH AND INCOME
MIP-CoreAlpha Bond Master Portfolio                   51.96%       34.27%      21.48%      10.89%        0.99%
iShares Barclays TIPS Bond Fund                        8.87%        5.49%       3.08%       1.08%       N/A
INCOME
BlackRock Cash Funds: Institutional - SL Agency        0.23%        0.20%       0.19%       0.23%        0.66%
Shares


Note: The allocation percentages may not add to, or may appear to exceed, 100% due to rounding.

"Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," "S&P 500 Index(Reg. TM)," "S&P MidCap 400 IndexTM," "S&P SmallCap 600 IndexTM," "S&P National AMT-Free Municipal Bond IndexTM," and "S&P North American Natural Resources Sector IndexTM" are trademarks of Standard & Poor's Financial Services LLC (a subsidiary of The McGraw-Hill Companies) licensed for use for certain purposes by BTC. The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P SmallCap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and iShares S&P North American Natural Resources Sector Index Fund that are based on S&P Indexes are not sponsored, endorsed, sold or promoted by S&P or its affiliates, and S&P and its affiliates make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"FTSE," "EPRA," "NAREIT" and "FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index" are marks that have been licensed for use for certain purposes by BTC. The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together the "FTSE Licensor Parties"), and the FTSE Licensor Parties make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Cohen & Steers" and "Cohen & Steers Realty Majors Index" are trademarks of Cohen & Steers Capital Management, Inc. ("Cohen & Steers") licensed for use for certain purposes by BTC. The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers, and Cohen & Steers makes no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Barclays Capital Inc.," "Barclays Capital U.S. 1-3 Year Credit Bond Index," "Barclays Capital U.S. 1-3 Year Treasury Bond Index," "Barclays Capital U.S. 3-7 Year Treasury Bond Index," "Barclays Capital U.S. 7-10 Year Treasury Bond Index," "Barclays Capital U.S. 10-20 Year Treasury Bond Index," "Barclays Capital U.S. 20+ Year Treasury Bond Index," "Barclays Capital U.S. Aggregate Bond Index," "Barclays Capital U.S. Credit Bond Index," "Barclays Capital U.S. Government/Credit Bond Index," "Barclays Capital U.S. Intermediate Credit Bond Index," "Barclays Capital U.S. Intermediate Government/Credit Bond Index," "Barclays Capital U.S. MBS Index," "Barclays Capital U.S. Short Treasury Bond Index," and the "Barclays Capital

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U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)" (collectively referred to as the "iShares Bond Fund Indexes") are trademarks of Barclays Bank PLC licensed for use for certain purposes by BTC. The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund are not sponsored, endorsed, sold or promoted by Barclays Capital Inc. ("Barclays Capital"), and Barclays Capital makes no representation or warranty, express or implied, regarding the advisability of investing in iShares. The iShares Bond Fund Indexes are maintained by Barclays Capital. Neither BTC nor BFA has or will have a role in maintaining the iShares Bond Fund Indexes.

"MSCI Canada Index/SM/," "MSCI EAFE(Reg. TM) Index" and "MSCI Emerging Markets Index/SM/" are servicemarks and "MSCI EAFE Small Cap Index" is a trademark of MSCI, and such marks have been licensed for use for certain purposes by BTC. The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI, and neither MSCI nor any other party makes any representation or warranty, express or implied, regarding the advisability of investing in iShares.

A FURTHER DISCUSSION OF RISK FACTORS

This section contains a description of the general risks of investing in the LifePath Portfolios. "Description of the LifePath Portfolios and their Investments and Risks" in the SAI also includes more information about the LifePath Portfolios, their investments and the related risks. There can be no guarantee that a LifePath Portfolio will meet its objective or that a LifePath Portfolio's performance will be positive for any period of time. An investment in a LifePath Portfolio is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

GENERAL

The NAV of each LifePath Portfolio's shares is neither insured nor guaranteed, is not fixed and will fluctuate.

GENERAL RISKS APPLICABLE TO THE LIFEPATH PORTFOLIOS

ALLOCATION RISK - The LifePath Portfolios' ability to achieve their investment goals depends upon BFA's skill in determining the LifePath Portfolios' strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, there is no guarantee that the Underlying Funds will achieve their investment objectives, and the Underlying Funds' performance may be lower than the performance of the asset class which they were selected to represent. The Underlying Funds may change their investment objectives or policies without the approval of the LifePath Portfolios. If an Underlying Fund were to change its investment objective or policies, the LifePath Portfolios might be forced to withdraw their investment from the Underlying Fund at a disadvantageous time and price.

CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the LifePath Portfolios' investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The LifePath Portfolios' use of derivatives may reduce the LifePath Portfolios' returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the LifePath Portfolios' use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the LifePath Portfolios to sell or otherwise close a derivatives position could expose the LifePath Portfolios to losses and could make derivatives more difficult for the LifePath Portfolios to value accurately. The LifePath Portfolios could also suffer losses related to their derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally,

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BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the LifePath Portfolios' derivatives positions to lose value. When a derivative is used as a hedge against a position that the LifePath Portfolios hold, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the LifePath Portfolios' hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EMERGING MARKETS RISK - The risks of foreign investments are usually much greater for emerging markets. Investments in emerging markets may be considered speculative. Emerging markets include those in countries defined as emerging or developing by the World Bank, the International Finance Corporation or the United Nations. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain small markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards and requirements comparable to those to which U.S. companies are subject.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments are more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation, high rates of inflation or unfavorable diplomatic developments. In the past, governments of such nations have expropriated substantial amounts of private property, and most claims of the property owners have never been fully settled. There is no assurance that such expropriations will not reoccur. In such an event, it is possible that the LifePath Portfolio could lose the entire value of its investments in the affected market. Some countries have pervasiveness of corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth. National policies that may limit the LifePath Portfolio's investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other foreign or U.S. governmental laws or restrictions applicable to such investments. Sometimes, they may lack or be in the relatively early development of legal structures governing private and foreign investments and private property. In addition to withholding taxes on investment income, some countries with emerging markets may impose differential capital gains taxes on foreign investors.

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the LifePath Portfolios could decline if the financial condition of the companies the LifePath Portfolios invest in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

FOREIGN SECURITIES RISK - Securities traded in foreign markets have often (though not always) performed differently from securities traded in the United States. However, such investments often involve special risks not present in U.S. investments that can increase the chances that the LifePath Portfolio will lose money. In particular, the LifePath Portfolio is subject to the risk that because there may be fewer investors on foreign exchanges and a smaller number of securities traded each day, it may be more difficult for the LifePath Portfolio to buy and sell securities on those exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

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CERTAIN RISKS OF HOLDING FUND ASSETS OUTSIDE THE UNITED STATES - The LifePath Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories. Some foreign banks and securities depositories may be recently organized or new to the foreign custody business. In addition, there may be limited or no regulatory oversight of their operations. Also, the laws of certain countries limit the LifePath Portfolio's ability to recover its assets if a foreign bank, depository or issuer of a security, or any of their agents, goes bankrupt. In addition, it is often more expensive for the LifePath Portfolio to buy, sell and hold securities in certain foreign markets than in the United States. The increased expense of investing in foreign markets reduces the amount the LifePath Portfolio can earn on its investments and typically results in a higher operating expense ratio for the LifePath Portfolio than for investment companies invested only in the United States.

CURRENCY RISK - Securities and other instruments in which the LifePath Portfolio invests may be denominated or quoted in currencies other than the U.S. dollar. For this reason, changes in foreign currency exchange rates can affect the value of the LifePath Portfolio.

Generally, when the U.S. dollar rises in value against a foreign currency, a security denominated in that currency loses value because the currency is worth fewer U.S. dollars. Conversely, when the U.S. dollar decreases in value against a foreign currency, a security denominated in that currency gains value because the currency is worth more U.S. dollars. This risk, generally known as "currency risk," means that a strong U.S. dollar will reduce returns for U.S. investors while a weak U.S. dollar will increase those returns.

FOREIGN ECONOMY RISK - The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. Certain foreign economies may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. In addition, the governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Any of these actions could severely affect securities prices or impair the LifePath Portfolio's ability to purchase or sell foreign securities or transfer the LifePath Portfolio's assets or income back into the United States, or otherwise adversely affect the LifePath Portfolio's operations.

Other potential foreign market risks include foreign exchange controls, difficulties in pricing securities, defaults on foreign government securities, difficulties in enforcing legal judgments in foreign courts and political and social instability. Diplomatic and political developments, including rapid and adverse political changes, social instability, regional conflicts, terrorism and war, could affect the economies, industries and securities and currency markets, and the value of the LifePath Portfolio's investments, in non-U.S. countries. These factors are extremely difficult, if not impossible, to predict and take into account with respect to the LifePath Portfolio's investments.

GOVERNMENTAL SUPERVISION AND REGULATION/ACCOUNTING STANDARDS - Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as such regulations exist in the United States. They also may not have laws to protect investors that are comparable to U.S. securities laws. For example, some foreign countries may have no laws or rules against insider trading. Insider trading occurs when a person buys or sells a company's securities based on material non-public information about that company. In addition, some countries may have legal systems that may make it difficult for the LifePath Portfolio to vote proxies, exercise shareholder rights, and pursue legal remedies with respect to its foreign investments. Accounting standards in other countries are not necessarily the same as in the United States. If the accounting standards in another country do not require as much detail as U.S. accounting standards, it may be harder for LifePath Portfolio management to completely and accurately determine a company's financial condition.

SETTLEMENT RISK - Settlement and clearance procedures in certain foreign markets differ significantly from those in the United States. Foreign settlement and clearance procedures and trade regulations also may involve certain risks (such as delays in payment for or delivery of securities) not typically associated with the settlement of U.S. investments.

At times, settlements in certain foreign countries have not kept pace with the number of securities transactions. These problems may make it difficult for the LifePath Portfolio to carry out transactions. If the LifePath Portfolio cannot settle or is delayed in settling a purchase of securities, it may miss attractive investment opportunities and certain of its assets may be uninvested with no return earned thereon for some period. If the LifePath Portfolio cannot settle or is delayed in settling a sale of securities, it may lose money if the value of the security then declines or, if it has contracted to sell the security to another party; the LifePath Portfolio could be liable for any losses incurred.

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INVESTMENTS IN MUTUAL FUNDS AND ETFS RISK - Each LifePath Portfolio will invest substantially all of its assets in Underlying Funds, so the LifePath Portfolio's investment performance is directly related to the performance of the Underlying Funds. The LifePath Portfolios may also directly invest in ETFs. The LifePath Portfolio's net asset value will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in the LifePath Portfolios will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs. For example, the LifePath Portfolios indirectly pay a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds and ETFs.

One Underlying Fund may buy the same securities that another Underlying Fund sells. In addition, a LifePath Portfolio may buy the same securities that an Underlying Fund sells, or vice-versa. If this happens, an investor in the LifePath Portfolio would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in a LifePath Portfolio may receive taxable gains from portfolio transactions by an Underlying Fund, as well as taxable gains from transactions in shares of the Underlying Fund by the LifePath Portfolio. Certain of the Underlying Funds may hold common portfolio securities, thereby reducing the diversification benefits of the LifePath Portfolios.

In order to minimize expenses, the LifePath Portfolios intend to invest in the class of shares of each Underlying Fund with the lowest shareholder fees and net fund operating expenses. As the Underlying Funds or the LifePath Portfolios' allocations among the Underlying Funds change from time to time, or to the extent that the expense ratio of the Underlying Funds changes, the weighted average operating expenses borne by the LifePath Portfolios may increase or decrease.

Underlying iShares Funds are subject to additional risks due to their shares being listed and traded on securities exchanges. There can be no assurance that an active trading market for these particular ETFs will develop or be maintained. Trading in ETFs may be halted because of market conditions or for reasons that, in the view of the listing exchange, make trading in ETFs inadvisable. In addition, trading in ETFs is subject to trading halts caused by extraordinary market volatility pursuant to "circuit breaker" rules. There can be no assurance that the requirements necessary to maintain the listing of ETFs will continue to be met or will remain unchanged. An ETF may trade at, above or below its NAV. The NAV of an ETF will fluctuate with changes in the market value of its holdings. The trading price of an ETF will generally fluctuate in accordance with changes in its NAV, as well as market supply and demand.

JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the LifePath Portfolios. The major risks of junk bond investments include:

. Junk bonds may be issued by less creditworthy issuers. Issuers of junk bonds may have a larger amount of outstanding debt relative to their assets than issuers of investment grade bonds. In the event of an issuer's bankruptcy, claims of other creditors may have priority over the claims of junk bond holders, leaving few or no assets available to repay junk bond holders.

. Prices of junk bonds are subject to extreme price fluctuations. Adverse changes in an issuer's industry and general economic conditions may have a greater impact on the prices of junk bonds than on other higher rated fixed-income securities.

. Issuers of junk bonds may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.

. Junk bonds frequently have redemption features that permit an issuer to repurchase the security from the LifePath Portfolios before it matures. If the issuer redeems junk bonds, the LifePath Portfolios may have to invest the proceeds in bonds with lower yields and may lose income.

. Junk bonds may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the junk bond market, and there may be significant differences in the prices quoted for junk bonds by the dealers. Because they are less liquid, judgment may play a greater role in valuing certain of the LifePath Portfolios' securities than is the case with securities trading in a more liquid market.

. The LifePath Portfolios may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the LifePath Portfolios invest will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection

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risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. The characteristics of these mortgage-backed and asset-backed securities differ from traditional fixed-income securities. Like traditional fixed-income securities, the value of asset-backed securities typically increases when interest rates fall and decreases when interest rates rise. However, a main difference is that the principal on mortgage- or asset-backed securities may normally be prepaid at any time, which will reduce the yield and market value of these securities. Therefore, mortgage- and asset-backed backed securities are subject to "prepayment risk" and "extension risk." Because of prepayment risk and extension risk, mortgage-backed securities react differently to changes in interest rates than other fixed-income securities.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The LifePath Portfolios' investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The LifePath Portfolios' investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only (IOs), principal only (POs) or an amount that remains after other floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the LifePath Portfolios invest in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by BFA, it is possible that the LifePath Portfolios could lose all or substantially all of their investment.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the LifePath Portfolios' mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the LifePath Portfolios may invest may also provide a degree of investment leverage, which could cause the LifePath Portfolios to lose all or substantially all of their investment.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for the Underlying iShares Funds, those Underlying iShares Funds may hold stocks in companies that present risks that an investment adviser researching individual stocks might seek to avoid.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the LifePath Portfolios may have to invest their proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment

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proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

REIT INVESTMENT RISK - In addition to the risks facing real estate-related securities, such as a decline in property values due to increasing vacancies, a decline in rents resulting from unanticipated economic, legal or technological developments or a decline in the price of securities of real estate companies due to a failure of borrowers to pay their loans or poor management, investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the LifePath Portfolios may lose money and there may be a delay in recovering the loaned securities. The LifePath Portfolios could also lose money if they do not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the LifePath Portfolios.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

Each LifePath Portfolio must maintain cash balances to meet redemption requests, which may lower overall portfolio performance.

FOR A DESCRIPTION OF THE LIFEPATH PORTFOLIOS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THEIR MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A FURTHER DISCUSSION OF THE LIFEPATH PORTFOLIOS' INVESTMENTS AND RISKS, PLEASE REFER TO THE LIFEPATH PORTFOLIOS' SAI.

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Account Information

DETAILS ABOUT INSTITUTIONAL SHARES

MINIMUM INVESTMENT

Institutional Shares of the LifePath Portfolios are limited to certain investors, including current institutional shareholders that meet certain requirements, certain retirement plans, participants in certain programs sponsored by BlackRock or its affiliates or financial intermediaries and certain employees and affiliates of BlackRock or its affiliates. Institutional Shares of the LifePath Portfolio's initial and subsequent investment minimums generally are as follows, although Institutional Shares of the LifePath Portfolios may reduce or waive these investment minimums in some cases:

MINIMUM INITIAL         $2 million for institutions and individuals
INVESTMENT
                        Institutional Shares are available to clients of registered investment advisors
                       who have $250,000 invested in the LifePath Portfolios
MINIMUM ADDITIONAL      No subsequent minimum
INVESTMENT

Institutional Shares are not subject to any sales charge. Only certain investors are eligible to buy Institutional Shares. Your financial professional or other financial intermediary can help you determine whether you are eligible to buy Institutional Shares. A LifePath Portfolio may permit a lower initial investment for certain investors if their purchase, combined with purchases by other investors received together by the LifePath Portfolios, meets the minimum investment requirement.

Eligible institutional investors include the following:

. Investors who currently own Institutional Shares of a LifePath Portfolio may make additional purchases of Institutional Shares of that LifePath Portfolio from the Portfolio

. Institutional and individual retail investors with a minimum investment of $2 million who purchase through certain broker-dealers or directly from a LifePath Portfolio

. Certain qualified retirement plans

. Investors in selected fee based programs

. Clients of registered investment advisers who have $250,000 invested in a LifePath Portfolio

. Trust department clients of PNC Bank and Merrill Lynch Bank & Trust Company, FSB and their affiliates for whom they (i) act in a fiduciary capacity (excluding participant directed employee benefit plans); (ii) otherwise have investment discretion; or (iii) act as custodian for at least $2 million in assets

. Unaffiliated banks, thrifts or trust companies that have agreements with the Distributor

. Holders of certain Merrill Lynch sponsored unit investment trusts ("UITs") who reinvest dividends received from such UITs in shares of a LifePath Portfolio

. Employees, officers and directors/trustees of BlackRock, Inc., funds sponsored and advised by BFA or its affiliates ("BlackRock Funds"), The PNC Financial Services Group, Inc., Merrill Lynch & Co., Inc. or their respective affiliates

LETTER OF INTENT

An investor may qualify for a reduced front-end sales charge immediately by signing a "Letter of Intent" stating the investor's intention to buy a specified amount of Investor A Shares, Investor C Shares or Institutional Shares in one or more BlackRock Funds within the next 13 months that would, if bought all at once, qualify the investor for a reduced sales charge. The initial investment must meet the minimum initial purchase requirement. The 13-month Letter of Intent period commences on the day that the Letter of Intent is received by the LifePath Portfolios, and the investor must tell the LifePath Portfolios that later purchases are subject to the Letter of Intent. Purchases submitted prior to the date the Letter of Intent is received by the LifePath Portfolios are not counted toward the sales charge reduction.

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During the term of the Letter of Intent, the LifePath Portfolios will hold Investor A Shares representing up to 5% of the indicated amount in an escrow account for payment of a higher sales load if the full amount indicated in the Letter of Intent is not purchased. If the full amount indicated is not purchased within the 13-month period, and the investor does not pay the higher sales load within 20 days, the LifePath Portfolios will redeem enough of Investor A Shares held in escrow to pay the difference.

RIGHT OF ACCUMULATION

Investors have a "right of accumulation" under which the current value of an investor's existing Investor A, Investor C and Institutional Shares in most BlackRock Funds and the investment in the BlackRock CollegeAdvantage 529 program by the investor or by or on behalf of the investor's spouse and minor children may be combined with the amount of the current purchase in determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge. Financial intermediaries may value current holdings of their customers differently for purposes of determining whether an investor qualifies for a breakpoint and a reduced front-end sales charge, although customers of the same financial intermediary will be treated similarly. In order to use this right, the investor must alert BlackRock to the existence of any previously purchased shares.

HOW TO BUY, SELL, EXCHANGE AND TRANSFER SHARES


The chart on the following pages summarizes how to buy, sell, exchange and transfer shares through your financial professional or other financial intermediary. You may also buy, sell, exchange and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling, transferring or exchanging shares through BlackRock, call
(800) 441-7762. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

Each LifePath Portfolio may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders and suspend and resume the sale of any share class of the LifePath Portfolio at any time for any reason.

In addition, the LifePath Portfolios may waive certain requirements regarding the purchase, sale, exchange or transfer of shares described below.

             HOW TO BUY SHARES
                   YOUR CHOICES               IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE    First, select the          The LifePath Portfolios offer other classes of shares (Investor A Shares,
                   share class appropriate    Investor C Shares, Class K Shares and Class R Shares) with different
                   for you                    features and expense levels, which you may be eligible to buy. Please see
                                              the LifePath Portfolios' Investor A Shares, Investor C Shares, Class K Shares
                                              and Class R Shares prospectuses for more information.
                                              When you place your initial order, you must indicate which share class you
                                              select (if you do not specify a class and do not qualify to purchase
                                              Institutional Shares, you will receive Investor A Shares).
                                              Certain factors, such as the amount of your investment, your time frame
                                              for investing, and your financial goals, may affect which share class you
                                              choose. Your financial representative can help you determine which share
                                              class is appropriate for you.
                    Next, determine            Refer to the minimum initial investment in the "Account Information -
                   the amount of              Details About Institutional Shares" in this Prospectus.
                   your investment
                                              See "Account Information - Details About Institutional Shares" for
                                              information on lower initial investment requirements for certain LifePath
                                              Portfolio investors if their purchase, combined with purchases by other
                                              investors received together by a LifePath Portfolio, meets the minimum
                                              investment requirement.

50

         HOW TO BUY SHARES
              YOUR CHOICES            IMPORTANT INFORMATION FOR YOU TO KNOW
               Have your               The price of your shares is based on the next calculation of a LifePath
              financial               Portfolio's NAV after your order is placed. Any purchase orders placed prior
              intermediary            to the close of business on the NYSE (generally 4:00 p.m. Eastern time)
              submit your             will be priced at the NAV determined that day. Certain financial
              purchase order          intermediaries, however, may require submission of orders prior to that
                                      time. A broker-dealer or financial institution maintaining the account in
                                      which you hold shares may charge a separate account, service or
                                      transaction fee on the purchase or sale of Fund shares that would be in
                                      addition to the fees and expenses shown in each LifePath Portfolio's "Fees
                                      and Expenses" table.
                                      Purchase orders placed after that time will be priced at the NAV
                                      determined on the next business day. The LifePath Portfolios may reject
                                      any order to buy shares and may suspend the sale of shares at any
                                      time. Financial intermediaries may charge a processing fee to confirm a
                                      purchase.
               Or contact              To purchase shares directly from BlackRock, call (800) 441-7762 and
              BlackRock (for          request a new account application. Mail the completed application along
              accounts held           with a check payable to "BlackRock Funds" to PNC Global Investment
              directly with           Servicing (U.S.) Inc. (the "Transfer Agent") at the address on the
              BlackRock)              application.
ADD TO YOUR    Have your               To purchase additional shares you may contact your financial professional
INVESTMENT    financial               or financial intermediary. For more details on purchasing by Internet see
              professional            below.
              or financial
              intermediary
              submit your
              purchase order
              for additional shares

              Or contact              PURCHASE BY TELEPHONE: Call (800) 441-7762 and speak with one of our
              BlackRock               representatives. The LifePath Portfolios have the right to reject any
              (for accounts held      telephone request for any reason.
              directly with           PURCHASE IN WRITING: You may send a written request to BlackRock at the
              BlackRock)              address on the back cover of this Prospectus.
                                      PURCHASE BY VRU: Institutional Shares may also be purchased by use of
                                      the LifePath Portfolio's automated voice response unit service ("VRU") at
                                      (800) 441-7762.

                                       PURCHASE BY INTERNET: You may purchase your shares, and view activities
                                      in your account, by logging onto the BlackRock website at
                                      www.blackrock.com/funds. Purchases made on the Internet using the
                                      Automated Clearing House Network ("ACH") will have a trade date that is
                                      the day after the purchase is made. Certain institutional clients' purchase
                                      orders for Institutional Shares placed by wire prior to the close of business
                                      on the NYSE will be placed at the NAV determined that day. Contact your
                                      financial intermediary or BlackRock for further information. Each LifePath
                                      Portfolio limits Internet purchases in shares of the LifePath Portfolio to
                                      $25,000 per trade. Different maximums may apply to certain institutional
                                      investors. Please read the On-Line Services Disclosure Statement and User
                                      Agreement, the Terms and Conditions page and the Consent to Electronic
                                      Delivery Agreement (if you consent to electronic delivery), before
                                      attempting to transact online.
                                       The LifePath Portfolios employ reasonable procedures to confirm that
                                      transactions entered over the Internet are genuine. By entering into the
                                      User Agreement with a LifePath Portfolio in order to open an account
                                      through the website, the shareholder waives any right to reclaim any
                                      losses from a LifePath Portfolio or any of its affiliates, incurred through
                                      fraudulent activity.

51

            HOW TO BUY SHARES
                 YOUR CHOICES               IMPORTANT INFORMATION FOR YOU TO KNOW
                  Acquire additional         All dividends and capital gains distributions are automatically reinvested
                 shares by                  without a sales charge. To make any changes to your dividend and/or
                 reinvesting                capital gains distributions options, please call (800) 441-7762, or contact
                 dividends and              your financial professional (if your account is not held directly with
                 capital gains              BlackRock).
                  Participate                BlackRock's AIP allows you to invest a specific amount on a periodic basis
                 in the Automatic           from your checking or savings account into your investment account.
                 Investment Plan ("AIP")    Refer to the "Account Services and Privileges" section of this Prospectus
                                            for additional information.
HOW TO PAY FOR    Making payment             Payment for an order must be made in Federal funds or other immediately
SHARES           for                        available funds by the time specified by your financial professional or other
                 purchases                  financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                            on the first business day following BlackRock's receipt of the order. If
                                            payment is not received by this time, the order will be canceled and you
                                            and your financial professional or other financial intermediary will be
                                            responsible for any loss to the LifePath Portfolios.
                                             For shares purchased directly from the LifePath Portfolio, a check payable
                                            to "BlackRock Funds," which bears the name of the LifePath Portfolio you
                                            are purchasing must accompany a completed purchase application. There
                                            is a $20 fee for each purchase check that is returned due to insufficient
                                            funds.
                                             The LifePath Portfolios do not accept third-party checks. You may also
                                            wire Federal funds to a LifePath Portfolio to purchase shares, but you must
                                            call (800) 441-7762 before doing so to confirm the wiring instructions.

       HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL    Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       Shareholders should indicate that they are redeeming Institutional Shares.
SHARES            intermediary    The price of your shares is based on the next calculation of a LifePath
                  submit your     Portfolio's NAV after your order is placed. For your redemption request to
                  sales order     be priced at the NAV on the day of your request, you must submit your
                                  request to your financial intermediary prior to that day's close of business
                                  on the NYSE (generally 4:00 p.m. Eastern time). Certain financial
                                  intermediaries, however, may require submission of orders prior to that
                                  time. Any redemption request placed after that time will be priced at the
                                  NAV at the close of business on the next business day.
                                   Financial intermediaries may charge a fee to process a redemption of
                                  shares. Shareholders should indicate which class of shares they are
                                  redeeming.
                                   The LifePath Portfolios may reject an order to sell shares under certain
                                  circumstances.
                   Selling         METHODS OF REDEEMING
                  shares held
                                  REDEEM BY TELEPHONE: For Institutional Shares, certain redemption
                  directly
                                  requests may require written instructions with a medallion signature
                  with
                                  guarantee. Call (800) 441-7762 for details.
                  BlackRock
                                   You can obtain a medallion signature guarantee stamp from a bank,
                                  securities dealer, securities broker, credit union, savings and loan
                                  association, national securities exchange or registered securities
                                  association. A notary public seal will not be acceptable.

52

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             The LifePath Portfolios, their administrator and the distributor will employ
                            reasonable procedures to confirm that instructions communicated by
                            telephone are genuine. The LifePath Portfolios and their service providers
                            will not be liable for any loss, liability, cost or expense for acting upon
                            telephone instructions that are reasonably believed to be genuine in
                            accordance with such procedures. The LifePath Portfolios may refuse a
                            telephone redemption request if they believe it is advisable to do so.
                             During periods of substantial economic or market change, telephone
                            redemptions may be difficult to complete. Please find below alternative
                            redemption methods.
                             REDEEM BY VRU: Institutional Shares may also be redeemed by use of the
                            LifePath Portfolios' automated VRU. Payment for Institutional Shares
                            redeemed by VRU may be made for non-retirement accounts in amounts
                            up to $25,000, either through check, ACH or wire.
                             REDEEM BY INTERNET: You may redeem in your account by logging onto
                            the BlackRock website at www.blackrock.com/funds. Proceeds from
                            Internet redemptions may be sent via check, ACH or wire to the bank
                            account of record. Different maximums may apply to investors in
                            Institutional Shares.
                             REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                            BlackRock, P.O. Box 9819, Providence, RI 02940-8019 or, for overnight
                            delivery, 101 Sabin Street, Pawtucket, RI 02860-1427. All shareholders on
                            the account must sign the letter. A medallion signature guarantee will
                            generally be required but may be waived in certain limited circumstances.
                            You can obtain a medallion signature guarantee stamp from a bank,
                            securities dealer, securities broker, credit union, savings and loan
                            association, national securities exchange or registered securities
                            association. A notary public seal will not be acceptable. If you hold stock
                            certificates, return the certificates with the letter. Proceeds from
                            redemptions may be sent via check, ACH or wire to the bank account of
                            record.
                             PAYMENT OF REDEMPTION PROCEEDS: Redemption proceeds may be paid by
                            check or, if a LifePath Portfolio has verified banking information on file,
                            through ACH or by wire transfer.
                             PAYMENT BY CHECK: BlackRock will normally mail redemption proceeds
                            within seven days following receipt of a properly completed request.
                            Shares can be redeemed by telephone and the proceeds sent by check to
                            the shareholder at the address on record. Shareholders will pay $15 for
                            redemption proceeds sent by check via overnight mail. You are responsible
                            for any additional charges imposed by your bank for this service.
                             PAYMENT BY WIRE TRANSFER: Payment for redeemed shares for which a
                            redemption order is received before 4:00 p.m. (Eastern time) on a
                            business day is normally made in Federal funds wired to the redeeming
                            shareholder on the next business day, provided that the LifePath
                            Portfolios' custodian is also open for business. Payment for redemption
                            orders received after 4:00 p.m. (Eastern time) or on a day when the
                            LifePath Portfolios' custodian is closed is normally wired in Federal funds
                            on the next business day following redemption on which the LifePath
                            Portfolios' custodian is open for business. The LifePath Portfolios reserve
                            the right to wire redemption proceeds within seven days after receiving a
                            redemption order if, in the judgment of the LifePath Portfolio, an earlier
                            payment could adversely affect a LifePath Portfolio.

53

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             If a shareholder has given authorization for expedited redemption, shares
                            can be redeemed by Federal wire transfer to a single previously designated
                            bank account. Shareholders will pay $7.50 for redemption proceeds sent
                            by Federal wire transfer. You are responsible for any additional charges
                            imposed by your bank for this service. No charge for wiring redemption
                            payments with respect to Institutional Shares is imposed by the LifePath
                            Portfolios.
                            The LifePath Portfolios are not responsible for the efficiency of the Federal
                            wire system or the shareholder's firm or bank. To change the name of the
                            single, designated bank account to receive wire redemption proceeds, it is
                            necessary to send a written request to the LifePath Portfolio at the
                            address on the back cover of this Prospectus.
                             PAYMENT BY ACH: Redemption proceeds may be sent to the shareholder's
                            bank account (checking or savings) via ACH. Payment for redeemed
                            shares for which a redemption order is received before 4:00 p.m. (Eastern
                            time) on a business day is normally sent to the redeeming shareholder the
                            next business day, with receipt at the receiving bank within the next two
                            business days (48-72 hours); provided that the LifePath Portfolios'
                            custodian is also open for business. Payment for redemption orders
                            received after 4:00 p.m. (Eastern time) or on a day when the LifePath
                            Portfolios' custodian is closed is normally sent on the next business day
                            following redemption on which the LifePath Portfolios' custodian is open
                            for business.
                            The LifePath Portfolios reserve the right to send redemption proceeds
                            within seven days after receiving a redemption order if, in the judgment of
                            a LifePath Portfolio, an earlier payment could adversely affect the LifePath
                            Portfolio. No charge for sending redemption payments via ACH is imposed
                            by the LifePath Portfolio. If you make a redemption request before a
                            LifePath Portfolio has collected payment for the purchase of shares, the
                            LifePath Portfolio may delay mailing your proceeds. This delay will usually
                            not exceed ten days.

54

       HOW TO EXCHANGE SHARES OR TRANSFER YOUR ACCOUNT
                     YOUR CHOICES
EXCHANGE PRIVILEGE    Selling shares
                     of one LifePath Portfolio to
                     purchase shares
                     of another
                     BlackRock Fund
                     ("exchanging")
TRANSFER SHARES TO    Transfer to a
ANOTHER SECURITIES   participating
DEALER OR OTHER      financial
FINANCIAL            professional or
INTERMEDIARY         other
                     financial
                     intermediary
                      Transfer to a
                     non-participating
                     financial professional
                     or other
                     financial intermediary

                     IMPORTANT INFORMATION FOR YOU TO KNOW
EXCHANGE PRIVILEGE    Institutional Shares of the LifePath Portfolios are generally exchangeable
                     for shares of the same class of another BlackRock Fund.
                     Investors who own Institutional Shares of the LifePath Portfolios may
                     make exchanges into Institutional Shares of other BlackRock Funds except,
                     for investors holdings shares through certain client accounts at financial
                     professionals that are omnibus with the fund or do not meet applicable
                     minimums. There is no required minimum amount with respect to
                     exchanges of Institutional Shares. You may only exchange into a share
                     class and BlackRock Fund that are open to new investors or in which you
                     have a current account, if the fund is closed to new investors. If you held
                     the exchanged shares for 30 days or less, you may be charged a
                     redemption fee (please refer to the "Redemption Fee" section of this
                     Prospectus for additional information).
                     To exercise the exchange privilege, you may contact your financial
                     professional or financial intermediary. Alternatively, if your account is held
                     directly with BlackRock, you may: (i) call (800) 441-7762 and speak with
                     one of our representatives, (ii) make the exchange via the Internet by
                     accessing your account online at www.blackrock.com/funds, or (iii) send
                     a written request to the LifePath Portfolio at the address on the back cover
                     of this Prospectus. Please note, if you indicated on your New Account
                     Application that you did not want the Telephone Exchange Privilege, you
                     will not be able to place exchanges via the telephone until you update this
                     option either in writing or by calling (800) 441-7762. The LifePath
                     Portfolios have the right to reject any telephone request for any reason.
                     Although there is currently no express limit on the number of exchanges
                     that you can make, the exchange privilege may be modified or terminated
                     at any time in the future. The LifePath Portfolios may suspend or
                     terminate your exchange privilege at any time for any reason, including if a
                     LifePath Portfolio believes, in its sole discretion that you are engaging in
                     market timing activities. See "Frequent Trading in LifePath Portfolio
                     Shares" below. For U.S. federal income tax purposes, a share exchange is a
                     taxable event and a capital gain or loss may be realized. Please consult
                     your tax adviser or other financial professional before making an exchange
                     request.
TRANSFER SHARES TO    You may transfer your Institutional Shares of a LifePath Portfolio only to
ANOTHER SECURITIES   another financial professional or financial intermediary that has an
DEALER OR OTHER      agreement with the Distributor. Certain shareholder services may not be
FINANCIAL            available for the transferred shares. All future trading of these assets must
INTERMEDIARY         be coordinated by the receiving firm.
                     If your account is held directly with BlackRock, you may call (800) 441-
                     7762 with any questions; otherwise please contact your financial
                     intermediary to accomplish the transfer of shares.
                      You must either:
                     oTransfer your Institutional Shares to an account with a LifePath Portfolio;
                     or
                     oSell your shares, paying any applicable deferred sales charge.
                     If your account is held directly with BlackRock, you may call (800) 441-7762
                     with any questions; otherwise please contact your financial intermediary to
                     accomplish the transfer of shares.

55

SHAREHOLDER SERVICING PAYMENTS


The LifePath Portfolios have adopted a shareholder servicing plan (the "Plan") that allows each LifePath Portfolio to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a LifePath Portfolio's shares. Because the fees paid by a LifePath Portfolio under the Plan are paid out of the LifePath Portfolio's assets on an ongoing basis, over time these fees will increase the cost of your investment in the LifePath Portfolios and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a LifePath Portfolio may pay to a Financial Intermediary pursuant to the Plan and fees a LifePath Portfolio pays to the Transfer Agent, BFA, on behalf of a LifePath Portfolio, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the LifePath Portfolio will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either
(1) a percentage of the average daily net assets of LifePath Portfolio shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the LifePath Portfolios and shareholders. These payments would be in addition to the LifePath Portfolio payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a LifePath Portfolio to you. Please contact your Financial Intermediary for details about payments it may receive from a LifePath Portfolio or from BFA or its affiliates. For more information, see the LifePath Portfolios' SAI.

ACCOUNT SERVICES AND PRIVILEGES


The following table provides examples of account services and privileges available in your BlackRock account. Certain of these account services and privileges are only available to shareholders of Institutional Shares whose accounts are held directly with BlackRock. If your account is held directly with BlackRock, please call (800) 441-7762 for additional information as well as forms and applications. Otherwise, please contact your financial professional for assistance in requesting one or more of the following services and privileges.

AUTOMATIC          Allows systematic investments     BlackRock's AIP allows you to invest a specific amount on a periodic basis
INVESTMENT        on a periodic basis from          from your checking or savings account into your investment account. You
PLAN ("AIP")      checking or savings account.      may apply for this option upon account opening or by completing the AIP
                                                    application. The minimum investment amount for an automatic
                                                    investment plan is $50 per portfolio.
DIVIDEND           Automatically invests your        Dividend and capital gains distributions may be reinvested in your account
ALLOCATION PLAN   distributions into another        to purchase additional shares or paid in cash. Using the Dividend
                  BlackRock Fund of your            Allocation Plan, you can direct your distributions to your bank account
                  choice pursuant to your           (checking or savings), to purchase shares of another fund at BlackRock
                  instructions, without any         without any fees or sales charges, or by check to special payee. Please call
                  fees or sales charges.            (800) 441-7762 for details. If investing into another fund at BlackRock, the
                                                    receiving fund must be open to new purchases.

56

EZ TRADER        Allows an investor to purchase
                or sell Institutional Shares by
                telephone or over the
                Internet through ACH.
SYSTEMATIC       This feature can be used by
EXCHANGE        investors to systematically exchange
PLAN            money from one fund to up
                to four other funds.
SYSTEMATIC       This feature can be used by
WITHDRAWAL      investors who want to receive
PLAN ("SWP")    regular distributions from their
                accounts.
REINSTATEMENT
PRIVILEGE

EZ TRADER        (NOTE: This option is offered to shareholders whose accounts are held
                directly with BlackRock. Please speak with your financial professional if
                your account is held elsewhere).
                Prior to establishing an EZ Trader account, please contact your bank to
                confirm that it is a member of the ACH system. Once confirmed, complete
                an application, making sure to include the appropriate bank information,
                and return the application to the address listed on the form.
                Prior to placing a telephone or internet purchase or sale order, please
                contact (800) 441-7762 to confirm that your bank information has been
                updated on your account. Once this is established, you may place your
                request to sell shares with the LifePath Portfolios by telephone or Internet.
                Proceeds will be sent to your pre-designated bank account.
SYSTEMATIC       A minimum of $10,000 in the initial BlackRock Fund is required and
EXCHANGE        investments in any additional funds must meet minimum initial
PLAN            investment requirements. For more information, please contact the
                LifePath Portfolio at (800) 441-7762.
SYSTEMATIC       To start a Systematic Withdrawal Plan a shareholder must have a current
WITHDRAWAL      investment of $10,000 or more in a BlackRock Fund.
PLAN ("SWP")
                Shareholders can elect to receive cash payments of $50 or more at any
                interval they choose. Shareholders may sign up by completing the SWP
                Application Form, which may be obtained from BlackRock.
                Shareholders should realize that if withdrawals exceed income the
                invested principal in their account will be depleted.
                To participate in the SWP, shareholders must have their dividends
                reinvested. Shareholders may change or cancel the SWP at any time, with
                a minimum of 24 hours notice. If a shareholder purchases additional
                Investor A Shares of a fund at the same time he or she redeems shares
                through the SWP, that investor may lose money because of the sales
                charge involved. No contingent deferred sales charge ("CDSC") will be
                assessed on redemptions of Investor Shares made through the SWP that
                do not exceed 12% of the account's net asset value on an annualized
                basis. For example, monthly, quarterly, and semi-annual SWP redemptions
                of Investor Shares will not be subject to the CDSC if they do not exceed
                1%, 3% and 6%, respectively, of an account's net asset value on the
                redemption date. SWP redemptions of Investor A or Investor C Shares in
                excess of this limit will still pay any applicable CDSC.
                Ask your financial adviser or other financial intermediary for details.
REINSTATEMENT    If you redeem Investor A or Institutional Shares, and within 60 days buy
PRIVILEGE       new Investor A Shares of the SAME fund, you will not pay a sales charge
                on the new purchase amount. This right may be exercised once a year and
                within 60 days of the redemption, provided that Investor A Share class of
                that fund is currently open to new investors or the shareholder has a
                current account in that closed fund. Shares will be purchased at the net
                asset value calculated at the close of trading on the day the request is
                received. To exercise this privilege, the LifePath Portfolios must receive
                written notification from the shareholder of record or the financial
                professional of record, at the time of purchase. Investors should consult a
                tax adviser concerning the tax consequences of exercising this
                reinstatement privilege.

57

LIFEPATH PORTFOLIOS' RIGHTS


Each LifePath Portfolio may:

. Suspend the right of redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the Investment Company Act of 1940, as amended (the "1940 Act),

. Postpone date of payment upon redemption if trading is halted or restricted on the Exchange or under other emergency conditions described in the 1940 Act or if a redemption request is made before a LifePath Portfolio has collected payment for the purchase of shares,

. Redeem shares for property other than cash if conditions exist which make cash payments undesirable in accordance with its rights under the 1940 Act, and

. Redeem shares involuntarily in certain cases, such as when the value of a shareholder account falls below a specified level.

NOTE ON LOW BALANCE ACCOUNTS. Because of the high cost of maintaining smaller shareholder accounts, a LifePath Portfolio may redeem the shares in your account (without charging any deferred sales charge) if the NAV of your account falls below $500 due to redemptions you have made. You will be notified that the value of your account is less than $500 before a LifePath Portfolio makes an involuntary redemption. You will then have 60 days to make an additional investment to bring the value of your account to at least $500 before a LifePath Portfolio takes any action. This involuntary redemption does not apply to accounts of authorized qualified employee benefit plans, selected fee-based programs or accounts established under the Uniform Gifts or Transfers to Minors Acts.

CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE

Each LifePath Portfolio's share price (also known as a LifePath Portfolio's NAV) is calculated by dividing the value of the net assets of the LifePath Portfolio (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the LifePath Portfolio, generally rounded to the nearest cent.

Each LifePath Portfolio's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern Time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating each LifePath Portfolio's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of each LifePath Portfolio is calculated based on the NAV of the Master Portfolio in which the LifePath Portfolio invests. The LifePath Portfolios' SAI includes a description of the methods for valuing the Master Portfolios' investments, including a description of the circumstances in which the Master Portfolios' investments would be valued using fair value pricing and the effects of using fair value pricing.

LIFEPATH PORTFOLIO DISTRIBUTIONS

The LifePath Portfolios distribute their net investment income to shareholders quarterly. The LifePath Portfolios distribute their net realized capital gains, if any, to shareholders at least annually. Distributions payable to you will be automatically reinvested in additional Institutional Shares of your LifePath Portfolio, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and a Master Portfolio's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The Master Portfolios are not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. The exchange privilege is not intended as a vehicle for short-term trading. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of a Master Portfolio and its shareholders. For example, large flows of cash into and out of a Master Portfolio may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the Master Portfolio's investment goal. Frequent trading may cause a Master Portfolio to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the Master Portfolio's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. Each Master Portfolio will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of Master Portfolio Investments" below.

Each Master Portfolio discourages market timing and seeks to prevent frequent purchases and sales or exchanges of Master Portfolio shares that it determines may be detrimental to the Master Portfolio or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of Master Portfolio shares because certain legitimate strategies will not result in harm to a Master Portfolio or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, a Master Portfolio believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If a Master Portfolio rejects your purchase or exchange order, you will not be able to execute that transaction, and the Master Portfolio will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with a Master Portfolio, the Master Portfolio may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by a Master Portfolio. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide a Master Portfolio with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the Master Portfolio. While each Master Portfolio monitors for market timing activity, a Master Portfolio may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the Master Portfolio. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in a Master Portfolio's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by a Master Portfolio to be engaged in market timing or other improper trading activity, the Master Portfolio's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

A Master Portfolio may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

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TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the LifePath Portfolios and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the LifePath Portfolios' SAI for additional U.S. federal income tax information.

Distributions from your LifePath Portfolio's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional LifePath Portfolio shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the LifePath Portfolio's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the LifePath Portfolios generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the LifePath Portfolio's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S. and certain foreign corporations. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) A portion of distributions paid to corporate shareholders of the LifePath Portfolios may qualify for the dividends-received deduction available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

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In addition, if you sell your LifePath Portfolio shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

If you buy a LifePath Portfolio's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of a LifePath Portfolio that holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the LifePath Portfolio sells the appreciated securities and distributes the realized gain on the sale. The LifePath Portfolios have built up, or have the potential to build up, high levels of unrealized appreciation in their investments.

After the end of each year, the LifePath Portfolios will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the LifePath Portfolios if you fail to provide the LifePath Portfolios with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Sales proceeds generally are taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code, unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING LIFEPATH PORTFOLIO SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL

INCOME TAX ON LIFEPATH PORTFOLIO DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF LIFEPATH PORTFOLIO SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER AND FUND OF FUNDS STRUCTURES


The LifePath Portfolios do not have their own investment adviser. Instead, each LifePath Portfolio invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the LifePath Portfolio. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the LifePath Portfolios.

FEEDER FUND EXPENSES

Feeder funds, including the LifePath Portfolios, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund- specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a LifePath Portfolio's assets from its Master Portfolio if it believes doing so is in the best interests of the LifePath Portfolio's shareholders. If the Trust's Board of Trustees decides to withdraw a LifePath Portfolio's assets, it would then consider whether the LifePath Portfolio should hire its own investment adviser, invest in another master portfolio or take other action.

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FUND OF FUNDS

The Master Portfolios do not invest directly in a portfolio of securities. Instead, they invest in the Underlying Money Market Fund and other Underlying Funds that are also advised by BFA. Each Master Portfolio charges for its own direct expenses, in addition to bearing a PRO RATA share of the expenses charged by the Underlying Funds in which it invests.

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Management of the LifePath Portfolios

INVESTMENT ADVISER

Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the LifePath Portfolio. The Master Portfolios, in turn, invest in a combination of Underlying Funds. BFA, a registered investment adviser, serves as investment adviser to each Master Portfolio, and also serves as investment adviser to each Underlying Fund, with the exception of the Underlying Money Market Fund, which invests in a master portfolio advised by BFA. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive an annual management fee of 0.35% of each Master Portfolio's average daily net assets.

For its services to the Underlying Funds, BFA receives fees that differ from the fees described for the LifePath Portfolios in this Prospectus. BFA provides investment advisory services for the Underlying Funds that differ from the investment advisory services it provides for the Master Portfolios. For services provided to the Underlying Funds, BFA receives investment advisory fees from the Underlying Funds. In addition, BTC provides administration services to certain of the Underlying Funds and, for those services, may receive administration fees from those Underlying Funds. BFA has contractually agreed to waive its management fees at the Master Portfolio level in an amount equal to management and administration fees, if any, paid by the Underlying Funds to BFA and BTC, respectively, through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc. ("BlackRock"). As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the LifePath Portfolios' annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS

Dagmar Nikles, Leslie Gambon, Alan Mason and Amy Whitelaw (the "Portfolio Managers") are jointly and primarily responsible for the day-to-day management of the Master Portfolios and act collaboratively on all aspects concerning the Master Portfolios. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of their team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy, and overseeing members of his or her portfolio management team with more limited responsibilities.

Ms. Nikles has been employed as a Senior Investment Strategist in the defined contributions team at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A ("BGI")) since December 2009. From July 2003 to November 2009, Ms. Nikles was a member of the asset allocation portfolio management team at BGFA and BGI. Ms. Nikles has been a one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since June 2005.

Ms. Gambon has been employed as a member of the asset allocation portfolio management team at BFA and BTC since April 2007. From October 2004 to April 2007, Ms. Gambon was Head of Defined Contribution Portfolio Management at BGI. Ms. Gambon has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since May 2007.

Mr. Mason has been employed by BFA and BTC since December 2009. Mr. Mason is responsible for multi-asset class solutions for institutional clients. From 1991 to 2009, Mr. Mason served a variety of roles at BGFA and BGI, including eight years devoted to the development of transition management products. Mr. Mason has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since September 2009.

Ms. Whitelaw has been employed as Head of Defined Contributions Portfolio Management at BFA and BTC since December 2009. From October 2009 to November 2009, Ms. Whitelaw was Head of Defined Contributions Portfolio Management at BGFA and BGI. Ms. Whitelaw had been employed as a member of the portfolio management team at

62

BGFA and BGI since July 2006. From April 2002 to April 2005, Ms. Whitelaw worked as a transition manager and strategist in the Transition Services group at BGFA and BGI.

The LifePath Portfolios' SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers' ownership of shares in the LifePath Portfolios.

ADMINISTRATIVE SERVICES

Pursuant to an Administration Agreement between the Trust, on behalf of the LifePath Portfolios, and BTC, BTC provides the following services, among others, as the LifePath Portfolios' administrator:

. Supervises the LifePath Portfolios' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the shareholder servicing agent ("Shareholder Servicing Agent") on behalf of the LifePath Portfolios.

BTC is entitled to receive fees for these services at the annual rate of 0.50% of the average daily net assets of Institutional Shares of each LifePath Portfolio. In addition to performing these services, BTC has agreed to bear all costs of operating the LifePath Portfolios, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the LifePath Portfolios or the Trust as defined in the 1940 Act and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

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Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolios have retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolios to the extent that the Master Portfolios participate in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolios, including a fee based on the returns earned on the Master Portfolios' investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolios may lend their portfolio securities under the securities lending program.

VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. Each LifePath Portfolio calculates the net asset value of each class of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00
p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

Each LifePath Portfolio's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. Each LifePath Portfolio values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If a LifePath Portfolio invests in foreign securities, these securities may trade on weekends or other days when the LifePath Portfolio does not price its shares. As a result, a LifePath Portfolio's net asset value may change on days when you will not be able to purchase or redeem the LifePath Portfolio's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open- end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a LifePath Portfolio's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, a LifePath Portfolio's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio,s assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the LifePath Portfolio. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value.

A LifePath Portfolio may accept orders from certain authorized financial intermediaries or their designees. A LifePath Portfolio will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the LifePath Portfolio after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN LIFEPATH PORTFOLIO POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The LifePath Portfolios are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a LifePath Portfolio may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The LifePath Portfolios reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the LifePath Portfolios to verify their identity. The LifePath Portfolios also reserve the right to redeem any amounts in a LifePath Portfolio from persons whose identity it is unable to verify on a timely basis. It is the LifePath Portfolios' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

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BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

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Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Institutional Shares of each LifePath Portfolio for the past five years or, if shorter, since inception. Certain information reflects financial results for a single Institutional Share of each LifePath Portfolio. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Institutional Shares of a given LifePath Portfolio, assuming reinvestment of all distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each LifePath Portfolio's financial statements, is included in the LifePath Portfolios' combined annual report. You may obtain copies of annual report, at no cost, by calling 1-800-441-7762 (toll-free) from 8:00 a.m. to 6:00 p.m. Eastern time on any business day.

LIFEPATH RETIREMENT PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         INSTITUTIONAL SHARES
                                             ----------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                             ----------------------------------------------------------------------------
                                                          2009            2008           2007          2006          2005
                                             ----------------- --------------- -------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            ---               -               -             -             -
 Net asset value, beginning of year             $    9.42        $    11.46      $   11.59      $   11.22     $   11.18
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net investment income                               0.321              0.37           0.39          0.39          0.30
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Net realized and unrealized gain (loss)            1.37              (2.06)          0.12          0.58          0.17
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net increase (decrease) from investment
 operations                                         1.69           (   1.69)          0.51          0.97          0.47
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Dividends and distributions from:
  Net investment income                          (   0.31)         (   0.31)       (   0.37)     (   0.39)     (   0.33)
  Net realized gain                              (   0.00)/2/      (   0.04)       (   0.27)     (   0.21)     (   0.10)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
Total dividends and distributions                (   0.31)         (   0.35)       (   0.64)     (   0.60)     (   0.43)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
 Net asset value, end of year                  $   10.80         $     9.42      $   11.46      $   11.59     $   11.22
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Based on net asset value                         18.25   %          (15.04)%          4.50%         8.80%         4.32%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Total expenses                                    1.10   %            1.11%           1.12%         1.13%         1.15%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Total expenses after expense reductions            0.76   %            0.76%           0.77%         0.78%         0.81%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net investment income                             3.13   %            3.29%           3.43%         3.28%         2.72%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
SUPPLEMENTAL DATA
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net assets, end of year (000)                 $  438,987        $   92,717      $  136,923     $  91,518     $  99,349
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Portfolio turnover of the Master Portfolio              6%               11%              6%           10%           11%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

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LIFEPATH 2020 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  12.32         $   16.98      $  17.48      $  15.85     $  15.19
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.351              0.44          0.45          0.40         0.30
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.38              (4.67)         0.14          1.64         0.68
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.73            (  4.23)         0.59          2.04         0.98
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.43)         (  0.31)       (  0.44)      (  0.41)     (  0.32)
  Net realized gain                                     -          (  0.12)       (  0.65)            -            -
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.43)         (  0.43)       (  1.09)      (  0.41)     (  0.32)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  14.62         $   12.32      $  16.98      $  17.48     $  15.85
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         22.71   %         (25.42)%         3.34%        13.01%        6.54%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.08   %           1.07%          1.08%         1.08%        1.12%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.72   %           0.73%          0.74%         0.75%        0.78%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.65   %           2.65%          2.52%         2.37%        2.01%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 663,890        $ 432,717      $ 781,519     $ 598,633    $ 578,497
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              6%              13%             7%           16%          17%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

67

LIFEPATH 2030 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  10.92         $   16.19      $  16.90      $  15.39     $  14.87
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.291              0.35          0.34          0.32         0.24
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.46              (5.29)         0.11          1.99         0.88
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.75            (  4.94)         0.45          2.31         1.12
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.36)         (  0.25)       (  0.35)      (  0.36)     (  0.26)
  Net realized gain                                     -          (  0.08)       (  0.81)      (  0.44)     (  0.34)
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.36)         (  0.33)       (  1.16)      (  0.80)     (  0.60)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  13.31         $   10.92      $  16.19      $  16.90     $  15.39
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         25.77   %         (31.03)%         2.64%        15.12%        7.63%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.06   %           1.06%          1.07%         1.08%        1.10%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.70   %           0.72%          0.73%         0.74%        0.76%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.47   %           2.29%          2.10%         1.95%        1.69%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 517,817        $ 315,028      $ 564,348     $ 408,564    $ 352,800
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              7%              13%             7%           22%          24%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

68

LIFEPATH 2040 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                     INSTITUTIONAL SHARES
                                             ---------------------------------------------------------------------
                                                                    YEAR ENDED DECEMBER 31,
                                             ---------------------------------------------------------------------
                                                      2009           2008          2007          2006         2005
                                             ------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------           -             -              -             -            -
 Net asset value, beginning of year            $  12.88      $   20.32      $  20.90      $  18.18     $  17.03
--------------------------------------------   --------      ---------      --------      --------     ---------
Net investment income                              0.321          0.35          0.34          0.31         0.21
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           3.22          (7.45)         0.08          2.76         1.18
--------------------------------------------   ---------     ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        3.54        (  7.10)         0.42          3.07         1.39
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                          (  0.38)      (  0.26)       (  0.35)      (  0.35)     (  0.24)
  Net realized gain                                    -       (  0.08)       (  0.65)            -            -
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total dividends and distributions                (  0.38)      (  0.34)       (  1.00)      (  0.35)     (  0.24)
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net asset value, end of year                  $  16.04      $   12.88      $  20.32      $  20.90     $  18.18
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/2/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Based on net asset value                          28.08%       (35.40)%         2.03%        16.97%        8.24%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/3/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Total expenses                                     1.05%         1.04%          1.06%         1.07%        1.09%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total expenses after expense reductions             0.69%         0.69%          0.72%         0.73%        0.76%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net investment income                              2.33%         2.02%          1.71%         1.62%        1.45%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                 $ 435,317     $ 248,491      $ 383,391     $ 278,716    $ 221,359
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio             6%           14%             8%           29%          38%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Includes the reinvestment of dividends and distributions.

/3/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

69

LIFEPATH 2050 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                    INSTITUTIONAL SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED              JUNE 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                -                       -
 Net asset value, beginning of period                      $    13.46          $     20.00
----------------------------------------------------       ----------          -------------
Net investment income                                           0.382                 0.10
----------------------------------------------------       ----------          -------------
 Net realized and unrealized gain (loss)                        3.68                    (6.52)
----------------------------------------------------       ----------          -------------
Net increase (decrease) from investment operations              4.06               (     6.42)
----------------------------------------------------       ----------          --------------
 Dividends and distributions from:
  Net investment income                                     (    0.16)             (     0.09)
  Net realized gain                                         (    0.55)             (     0.00)/3 /
  Return of capital                                                 -              (     0.03)
----------------------------------------------------       ----------          -----------------
Total dividends and distributions                           (    0.71)             (     0.12)
----------------------------------------------------       ----------          -----------------
 Net asset value, end of period                            $    16.81          $     13.46
----------------------------------------------------       ----------          -----------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------       ----------          -----------------
 Based on net asset value                                       30.35%                 (32.18)%/5/
----------------------------------------------------       ----------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------       ----------          ------------------
 Total expenses                                                  1.27%                  12.80%/7 /
----------------------------------------------------       ----------          ------------------
Total expenses after expense reductions                          0.67%                   0.68%/7 /
----------------------------------------------------       ----------          ------------------
 Net investment income                                           2.39%                   2.14%/7 /
----------------------------------------------------       ----------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------       ----------          ------------------
 Net assets, end of period (000)                           $   13,992          $          444
----------------------------------------------------       ----------          ------------------
Portfolio turnover of the Master Portfolio                         12%                      0%/8/
----------------------------------------------------       ----------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

/8/ Rounds to less than 1% .

70

DISCLAIMERS

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible

71

for and has not participated in the determination of the prices and amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

72

The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE Licensor Parties. None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/

NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of

73

Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the LifePath Portfolios is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the LifePath Portfolio's investments. The annual report describes the LifePath Portfolio's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and LifePath Portfolio investment strategies that significantly affected the LifePath Portfolio's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION

A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each LifePath Portfolio, may be obtained free of charge, along with each LifePath Portfolio's annual and semi-annual reports, by calling (800) 441-7762, on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the LifePath Portfolios, please:

Call:       1-800-441-7762 (toll free)
            8:00 a.m. to 6:00 p.m. (Eastern time),
            on any business day

WORLD WIDE WEB

General LifePath Portfolio information and specific LifePath Portfolio performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com.

WRITTEN CORRESPONDENCE

BlackRock Funds III
PO Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

INTERNAL WHOLESALERS/BROKER DEALER SUPPORT
Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), on any business day. Call: (800) 882-0052.

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the LifePath Portfolios' policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about a LifePath Portfolio, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-LPI-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVES BLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
LIFEPATH(Reg. TM) PORTFOLIOS

CLASS K SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

PORTFOLIO                                                     TICKER SYMBOL
---------------------------------------------------------     --------------
LifePath(Reg. TM) Retirement Portfolio - Class K Shares                LPSAX
LifePath 2020 Portfolio(Reg. TM) - Class K Shares                      LPSCX
LifePath 2030 Portfolio(Reg. TM) - Class K Shares                      LPSDX
LifePath 2040 Portfolio(Reg. TM) - Class K Shares                      LPSFX
LifePath(Reg. TM) 2050 Portfolio - Class K Shares                      LPSGX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

LIFEPATH PORTFOLIO

  KEY FACTS AND DETAILS ABOUT THE LIFEPATH PORTFOLIOS, INCLUDING
OVERVIEW
  INVESTMENT OBJECTIVES, PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND
  EXPENSE INFORMATION, AND HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO.....................  1
  KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO...........................  7
  KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO........................... 14
  KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO........................... 21
  KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO........................... 28

DETAILS ABOUT THE LIFEPATH PORTFOLIOS

INVESTMENT TIME HORIZONS....................................... 35
A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES........ 36
A FURTHER DISCUSSION OF RISK FACTORS........................... 42

ACCOUNT INFORMATION

DETAILS ABOUT CLASS K SHARES............................ 48
HOW TO BUY, SELL AND TRANSFER SHARES.................... 48
LIFEPATH PORTFOLIOS' RIGHTS............................. 51
CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE........ 51
LIFEPATH PORTFOLIO DISTRIBUTIONS........................ 51
Short Term Trading Policy............................... 51
TAXES................................................... 52
MASTER/FEEDER AND FUND OF FUNDS STRUCTURES.............. 52

MANAGEMENT OF THE LIFEPATH PORTFOLIOS

INVESTMENT ADVISER......................... 54
PORTFOLIO MANAGERS......................... 54
ADMINISTRATIVE SERVICES.................... 55
CONFLICTS OF INTEREST...................... 55
Valuation of Fund Investments.............. 55
CERTAIN LIFEPATH PORTFOLIO POLICIES........ 56

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE LIFEPATH PORTFOLIOS........ 58
DISCLAIMERS............................................. 63

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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LifePath Retirement Portfolio Overview

KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO

INVESTMENT OBJECTIVE

LifePath Retirement Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors seeking income and moderate long-term growth of capital. LifePath Retirement Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH RETIREMENT PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class K Shares (formerly, Class S Shares) of LifePath Retirement Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.17%
  Administration Fees                                                                         0.15%
  Independent Expenses(2)(3)                                                                  0.02%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     0.85%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.50%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath Retirement Master Portfolio (the "Retirement Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Retirement Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the Retirement Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath Retirement Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services in connection with LifePath Retirement Portfolio and the Retirement Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath Retirement Portfolio and the Retirement Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath Retirement Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the Underlying Funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class K Shares of LifePath Retirement Portfolio and the Retirement Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the Retirement Master Portfolio invests.

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EXAMPLE

This Example is intended to help you compare the cost of investing in Class K Shares of LifePath Retirement Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class K Shares of LifePath Retirement Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class K Shares of LifePath Retirement Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  51        $  199        $  401        $  982

PORTFOLIO TURNOVER

The Retirement Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath Retirement Portfolio's performance. During the most recent fiscal year, the Retirement Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH RETIREMENT PORTFOLIO


LifePath Retirement Portfolio invests all of its assets in the Retirement Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath Retirement Portfolio is designed for investors seeking current income and moderate long-term growth of capital. As of March 31, 2010, LifePath Retirement Portfolio held approximately 39% of its assets in Underlying Funds that invest primarily in equity securities, 61% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in real estate investment trusts ("REITs"), foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. Because LifePath Retirement Portfolio is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain LifePath Retirement Portfolio's risk profile.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH RETIREMENT PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath Retirement Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath Retirement Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath Retirement Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath Retirement Portfolio.

. ALLOCATION RISK - LifePath Retirement Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath Retirement Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath Retirement Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the

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securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath Retirement Portfolio's use of derivatives may reduce LifePath Retirement Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath Retirement Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath Retirement Portfolio will lose money. These risks include:

. LifePath Retirement Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath Retirement Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath Retirement Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath Retirement Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath Retirement Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath Retirement Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath Retirement Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath Retirement Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath Retirement Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

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. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath Retirement Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath Retirement Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath Retirement Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath Retirement Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath Retirement Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Class K Shares of LifePath Retirement Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Class K Shares of LifePath Retirement Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Class K Shares were designated Class S Shares and were subject to different sales charges and service and distribution fees. The performance information for the periods from January 1, 1999 through May 30, 2008 (the date Class K Shares commenced operations) shows the performance of Institutional Shares of LifePath Retirement Portfolio adjusted to reflect the fees and expenses of Class K Shares. Performance from May 30, 2008 through December 31, 2009 reflects the actual performance of Class K Shares. The average annual total return table compares the performance of Class K Shares of LifePath Retirement Portfolio to that of the LifePath Retirement Portfolio Custom Benchmark. The LifePath Retirement Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath Retirement Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for LifePath Retirement Portfolio reflect Retirement Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath Retirement Portfolio reflect the direct investment by Retirement Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath Retirement Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path Retirement Portfolio expenses during these periods, LifePath Retirement Portfolio's returns would have been lower.

LIFEPATH RETIREMENT PORTFOLIO - CLASS K SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     5.08%
2001     3.95%
2002    -2.35%
2003    12.30%
2004     6.70%
2005     4.67%
2006     9.15%
2007     4.85%
2008   -15.04%
2009    18.53%

During the periods shown in the bar chart, the highest return for a quarter was 9.84% (quarter ended September 30, 2009) and the lowest return for a quarter was -7.85% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 2.87%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath Retirement Portfolio - Class K Shares
  Return Before Taxes                                                                       18.53%       3.79%       4.33%
  Return After Taxes on Distributions                                                       17.25%       2.58%       3.00%
  Return After Taxes on Distributions and Sale of Fund Shares                               12.08%       2.70%       3.07%
 LifePath Retirement Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         16.75%       4.06%       5.09%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER


The Retirement Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                         THE
                      RETIREMENT
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

Class K Shares of LifePath Retirement Portfolio are available only to (i) qualified recordkeepers with a distribution and/

or fund servicing agreement (establishing an omnibus trading relationship) maintained with LifePath Retirement Portfolio's distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (collectively, "Institutions"). You may purchase or redeem shares of LifePath Retirement Portfolio each day the New York Stock Exchange ("NYSE" or "Exchange") is open (a "Business Day"). Class K Shares are normally purchased through a customer's account at an Institution through procedures established by such Institution. Purchase orders may also be placed by calling (800) 441-7762 or by mail

5

(c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019). LifePath Retirement Portfolio's initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

TAX INFORMATION

LifePath Retirement Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath Retirement Portfolio through a broker-dealer or other financial intermediary, LifePath Retirement Portfolio and BlackRock Investments, LLC, LifePath Retirement Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath Retirement Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath Retirement Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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LifePath 2020 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2020 Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020. LifePath 2020 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2020 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class K Shares of LifePath 2020 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.16%
  Administration Fees                                                                         0.15%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     0.84%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.34)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.50%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2020 Master Portfolio (the "2020 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2020 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2020 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP. (2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2020 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2020 Portfolio and the 2020 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2020 Portfolio and the 2020 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2020 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the Underlying Funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class K Shares of LifePath 2020 Portfolio and the 2020 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2020 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class K Shares of LifePath 2020 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class K Shares of LifePath 2020 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class K Shares of LifePath 2020 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  51        $  198        $  397        $  972

7

PORTFOLIO TURNOVER

The 2020 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2020 Portfolio's performance. During the most recent fiscal year, the 2020 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2020 PORTFOLIO


LifePath 2020 Portfolio invests all of its assets in the 2020 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2020 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2020. As of March 31, 2010, LifePath 2020 Portfolio held approximately 60% of its assets in Underlying Funds that invest primarily in equity securities, 40% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2020 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2020 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2020 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

8

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2020 Portfolio, and determine whether any changes are required to enable LifePath 2020 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2020 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2020 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2020 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2020 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2020 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2020 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2020 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2020 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2020 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2020 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2020 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2020 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2020 Portfolio.

. ALLOCATION RISK - LifePath 2020 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2020 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2020 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2020 Portfolio's use of derivatives may reduce LifePath 2020 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2020 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

9

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2020 Portfolio will lose money. These risks include:

. LifePath 2020 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2020 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2020 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2020 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2020 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2020 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2020 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2020 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2020 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2020 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

10

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2020 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2020 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2020 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2020 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Class K Shares of LifePath 2020 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Class K Shares of LifePath 2020 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Class K Shares were designated Class S Shares and were subject to different sales charges and service and distribution fees. The performance information for the periods from January 1, 1999 through May 30, 2008 (the date Class K Shares commenced operations) shows the performance of Institutional Shares of LifePath 2020 Portfolio adjusted to reflect the fees and expenses of Class K Shares. Performance from May 30, 2008 through December 31, 2009 reflects the actual performance of Class K Shares. The average annual total return table compares the performance (before and after taxes) of Class K Shares of LifePath 2020 Portfolio to that of the LifePath 2020 Portfolio Custom Benchmark. The LifePath 2020 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2020 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2020 Portfolio reflect 2020 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2020 Portfolio reflect the direct investment by 2020 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2020 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain LifePath 2020 Portfolio expenses during these periods, Life Path 2020 Portfolio's returns would have been lower.

LIFEPATH 2020 PORTFOLIO - CLASS K SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -3.39%
2001    -6.07%
2002   -12.24%
2003    20.96%
2004     9.62%
2005     6.89%
2006    13.36%
2007     3.69%
2008   -25.38%
2009    23.15%

During the periods shown in the bar chart, the highest return for a quarter was 13.99% (quarter ended June 30, 2009) and the lowest return for a quarter was -14.10% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.39%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2020 Portfolio - Class K Shares
  Return Before Taxes                                                                       23.15%       2.88%       1.94%
  Return After Taxes on Distributions                                                       21.81%       2.03%       1.14%
  Return After Taxes on Distributions and Sale of Fund Shares                               15.14%       2.20%       1.34%
 LifePath 2020 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         22.84%       3.27%       2.78%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2020 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2020
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

Class K Shares of LifePath 2020 Portfolio are available only to (i) qualified recordkeepers with a distribution and/or fund servicing agreement (establishing an omnibus trading relationship) maintained with LifePath 2020 Portfolio's distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (collectively, "Institutions"). You may purchase or redeem shares of LifePath 2020 Portfolio each Business Day. Class K Shares are normally purchased through a customer's account at an Institution through procedures established by such Institution. Purchase orders may also be placed by calling (800) 441-7762 or by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019). LifePath 2020 Portfolio's initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

TAX INFORMATION

LifePath 2020 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2020 Portfolio through a broker-dealer or other financial intermediary, LifePath 2020 Portfolio and BlackRock Investments, LLC, LifePath 2020 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2020 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2020 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

13

LifePath 2030 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2030 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030. LifePath 2030 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2030 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class K Shares of LifePath 2030 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.16%
  Administration Fees                                                                         0.15%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     0.85%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.50%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2030 Master Portfolio (the "2030 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at 2030 Master Portfolio level in an amount equal to the advisory fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2030 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2030 Portfolio and the 2030 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2030 Portfolio and the 2030 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2030 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class K Shares of LifePath 2030 Portfolio and the 2030 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2030 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class K Shares of LifePath 2030 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class K Shares of LifePath 2030 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class K Shares of LifePath 2030 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  51        $  199        $  401        $  982

14

PORTFOLIO TURNOVER

The 2030 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2030 Portfolio's performance. During the most recent fiscal year, the 2030 Master Portfolio's portfolio turnover rate was 7% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2030 PORTFOLIO


LifePath 2030 Portfolio invests all of its assets in the 2030 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2030 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2030. As of March 31, 2010, LifePath 2030 Portfolio held approximately 75% of its assets in Underlying Funds that invest primarily in equity securities, 25% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2030 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2030 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2030 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

15

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2030 Portfolio, and determine whether any changes are required to enable LifePath 2030 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2030 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2030 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2030 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2030 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2030 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2030 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2030 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2030 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2030 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2030 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2030 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2030 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2030 Portfolio.

. ALLOCATION RISK - LifePath 2030 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2030 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2030 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2030 Portfolio's use of derivatives may reduce LifePath 2030 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2030 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

16

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2030 Portfolio will lose money. These risks include:

. LifePath 2030 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2030 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2030 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2030 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2030 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2030 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2030 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2030 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2030 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2030 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

17

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2030 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2030 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2030 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2030 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Class K Shares of LifePath 2030 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Class K Shares of LifePath 2030 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Class K Shares were designated Class S Shares and were subject to different sales charges and service and distribution fees. The performance information for the periods from January 1, 1999 through May 30, 2008 (the date Class K Shares commenced operations) shows the performance of Institutional Shares of LifePath 2030 Portfolio adjusted to reflect the fees and expenses of Class K Shares. Performance from May 30, 2008 through December 31, 2009 reflects the actual performance of Class K Shares. The average annual total return table compares the performance (before and after taxes) of Class K Shares of LifePath 2030 Portfolio to that of the LifePath 2030 Portfolio Custom Benchmark. The LifePath 2030 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2030 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2030 Portfolio reflect 2030 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2030 Portfolio reflect the direct investment by 2030 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2030 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain LifePath 2030 Portfolio expenses during these periods, Life Path 2030 Portfolio's returns would have been lower.

LIFEPATH 2030 PORTFOLIO - CLASS K SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -5.30%
2001    -9.59%
2002   -15.38%
2003    24.21%
2004    11.13%
2005     7.98%
2006    15.47%
2007     2.99%
2008   -31.06%
2009    26.23%

During the periods shown in the bar chart, the highest return for a quarter was 16.83% (quarter ended June 30, 2009) and the lowest return for a quarter was -17.85% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.71%.

18

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2030 Portfolio - Class K Shares
  Return Before Taxes                                                                       26.23%       2.21%       1.06%
  Return After Taxes on Distributions                                                       25.02%       1.31%       0.17%
  Return After Taxes on Distributions and Sale of Fund Shares                               17.19%       1.72%       0.63%
 LifePath 2030 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         27.05%       2.70%       1.82%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2030 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2030
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

19

PURCHASE AND SALE OF SHARES

Class K Shares of LifePath 2030 Portfolio are available only to (i) qualified recordkeepers with a distribution and/or fund servicing agreement (establishing an omnibus trading relationship) maintained with LifePath 2030 Portfolio's distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (collectively, "Institutions"). You may purchase or redeem shares of LifePath 2030 Portfolio each Business Day. Class K Shares are normally purchased through a customer's account at an Institution through procedures established by such Institution. Purchase orders may also be placed by calling (800) 441-7762 or by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019). LifePath 2030 Portfolio's initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

TAX INFORMATION

LifePath 2030 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2030 Portfolio through a broker-dealer or other financial intermediary, LifePath 2030 Portfolio and BlackRock Investments, LLC, LifePath 2030 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2030 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2030 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

20

LifePath 2040 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2040 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040. LifePath 2040 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2040 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class K Shares of LifePath 2040 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.16%
  Administration Fees                                                                         0.15%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     0.85%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.50%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2040 Master Portfolio (the "2040 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at 2040 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which 2040 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2040 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2040 Portfolio and the 2040 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2040 Portfolio and the 2040 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2040 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class K Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2040 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class K Shares of LifePath 2040 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class K Shares of LifePath 2040 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class K Shares of LifePath 2040 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  51        $  199        $  401        $  982

21

PORTFOLIO TURNOVER

The 2040 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2040 Portfolio's performance. During the most recent fiscal year, the 2040 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2040 PORTFOLIO


LifePath 2040 Portfolio invests all of its assets in the 2040 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of the equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2040 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2040. As of March 31, 2010, LifePath 2040 Portfolio held approximately 88% of its assets in Underlying Funds that invest primarily in equity securities, 12% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2040 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2040 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2040 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

22

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2040 Portfolio, and determine whether any changes are required to enable LifePath 2040 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2040 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2040 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2040 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2040 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2040 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2040 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2040 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2040 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2040 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2040 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2040 Portfolio or your investment may not perform as well as other similar investments. The following is a summary description of certain risks of investing in LifePath 2040 Portfolio. An investment in LifePath 2040 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

. ALLOCATION RISK - LifePath 2040 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2040 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2040 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2040 Portfolio's use of derivatives may reduce LifePath 2040 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2040 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

23

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2040 Portfolio will lose money. These risks include:

. LifePath 2040 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2040 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2040 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2040 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2040 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2040 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2040 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2040 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2040 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2040 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

24

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2040 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2040 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2040 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2040 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Class K Shares of LifePath 2040 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Class K Shares of LifePath 2040 Portfolio for each of the last ten calendar years. Prior to May 1, 2010, Class K Shares were designated Class S Shares and were subject to different sales charges and service and distribution fees. The performance information for the periods from January 1, 1999 through May 30, 2008 (the date Class K Shares commenced operations) shows the performance of Institutional Shares of LifePath 2040 Portfolio adjusted to reflect the fees and expenses of Class K Shares. Performance from May 30, 2008 through December 31, 2009 reflects the actual performance of Class K Shares. The average annual total return table compares the performance (before and after taxes) of Class K Shares of LifePath 2040 Portfolio to that of the LifePath 2040 Portfolio Custom Benchmark. The LifePath 2040 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2040 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2040 Portfolio reflect 2040 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2040 Portfolio reflect the direct investment by 2040 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2040 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2040 Portfolio expenses during these periods, LifePath 2040 Portfolio's returns would have been lower.

LIFEPATH 2040 PORTFOLIO - CLASS K SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     -9.36%
2001    -13.06%
2002    -18.38%
2003     27.99%
2004     11.78%
2005      8.59%
2006     17.32%
2007      2.38%
2008    -35.41%
2009     28.52%

During the periods shown in the bar chart, the highest return for a quarter was 19.11% (quarter ended June 30, 2009) and the lowest return for a quarter was -20.70% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.98%.

25

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2040 Portfolio - Class K Shares
  Return Before Taxes                                                                       28.52%       1.56%      -0.08%
  Return After Taxes on Distributions                                                       27.52%       1.07%      -0.61%
  Return After Taxes on Distributions and Sale of Fund Shares                               18.77%       1.37%      -0.17%
 LifePath 2040 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         30.52%       2.15%       0.87%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2040 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2040
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

26

PURCHASE AND SALE OF SHARES

Class K Shares of LifePath 2040 Portfolio are available only to (i) qualified recordkeepers with a distribution and/or fund servicing agreement (establishing an omnibus trading relationship) maintained with LifePath 2040 Portfolio's distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (collectively, "Institutions"). You may purchase or redeem shares of LifePath 2040 Portfolio each Business Day. Class K Shares are normally purchased through a customer's account at an Institution through procedures established by such Institution. Purchase orders may also be placed by calling (800) 441-7762 or by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019). LifePath 2040 Portfolio's initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

TAX INFORMATION

LifePath 2040 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2040 Portfolio through a broker-dealer or other financial intermediary, LifePath 2040 Portfolio and BlackRock Investments, LLC, LifePath 2040 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2040 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker- dealer or other financial intermediary and your individual financial professional to recommend LifePath 2040 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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LifePath 2050 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2050 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050. LifePath 2050 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2050 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class K Shares of LifePath 2050 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                               0.48%
  Administration Fees                                                                         0.15%
  Independent Expenses(2)(3)                                                                  0.33%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.17%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                            (0.67)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       0.50%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2050 Master Portfolio (the "2050 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2050 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2050 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2050 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2050 Portfolio and the 2050 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2050 Portfolio and the 2050 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2050 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class K Shares of LifePath 2050 Portfolio and the 2050 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2050 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class K Shares of LifePath 2050 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class K Shares of LifePath 2050 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class K Shares of LifePath 2050 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  51        $  235        $  510        $  1,297

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PORTFOLIO TURNOVER

The 2050 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2050 Portfolio's performance. During the most recent fiscal year, the 2050 Master Portfolio's portfolio turnover rate was 12% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2050 PORTFOLIO


LifePath 2050 Portfolio invests all of its assets in the 2050 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2050 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2050. As of March 31, 2010, LifePath 2050 Portfolio held approximately 98% of its assets in Underlying Funds that invest primarily in equity securities, 1% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2050 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2050 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2050 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as the LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

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The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2050 Portfolio, and determine whether any changes are required to enable LifePath 2050 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2050 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2050 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2050 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2050 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2050 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2050 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2050 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2050 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2050 PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath 2050 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2050 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2050 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2050 Portfolio.

. ALLOCATION RISK - LifePath 2050 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2050 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2050 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2050 Portfolio's use of derivatives may reduce LifePath 2050 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2050 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

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. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2050 Portfolio will lose money. These risks include:

. LifePath 2050 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2050 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2050 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2050 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2050 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2050 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2050 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2050 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2050 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2050 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

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. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2050 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2050 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2050 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2050 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Class K Shares of LifePath 2050 Portfolio by showing the changes in their performance from year to year. The bar chart shows the returns for Class K Shares of LifePath 2050 Portfolio for the last calendar year. Prior to May 1, 2010, Class K Shares were designated Class S Shares and were subject to different sales charges and service and distribution fees. The average annual total return table compares the performance (before and after taxes) of Class K Shares of LifePath 2050 Portfolio to that of the LifePath 2050 Portfolio Custom Benchmark. The LifePath 2050 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath 2050 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for LifePath 2050 Portfolio reflect 2050 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for LifePath 2050 Portfolio reflect the direct investment by 2050 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2050 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2050 Portfolio expenses during these periods, LifePath 2050 Portfolio's returns would have been lower.

LIFEPATH 2050 PORTFOLIO - CLASS K SHARES

ANNUAL TOTAL RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   30.89%

During the period shown in the bar chart, the highest return for a quarter was 21.13% (quarter ended June 30, 2009) and the lowest return for a quarter was -12.65% (quarter ended March 31, 2009). The year-to-date return as of March 31, 2010 was 4.19%.

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                                                                                                                 SINCE
AS OF 12/31/09                                                                                               INCEPTION JUNE
AVERAGE ANNUAL TOTAL RETURNS                                                                   1 YEAR           30, 2008
 LifePath 2050 Portfolio - Class K Shares
  Return Before Taxes                                                                           30.89%          -7.53%
  Return After Taxes on Distributions                                                           29.05%          -8.49%
  Return After Taxes on Distributions and Sale of Fund Shares                                   20.20%          -6.87%
 LifePath 2050 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                             34.11%          -6.38%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                            27.25%            N/A
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                              5.93%             N/A
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             43.60%            N/A
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                          0.16%             N/A
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                           11.41%            N/A
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             38.25%             N/A

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2050 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2050
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

Class K Shares of LifePath 2050 Portfolio are available only to (i) qualified recordkeepers with a distribution and/or fund servicing agreement (establishing an omnibus trading relationship) maintained with LifePath 2050 Portfolio's distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (collectively, "Institutions"). You may purchase or redeem shares of LifePath 2050 Portfolio each Business Day. Class K Shares are normally purchased through a customer's account at an Institution through procedures established by such Institution. Purchase orders may also be placed by calling (800) 441-7762 or by mail (c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019). LifePath 2050 Portfolio's initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

TAX INFORMATION

LifePath 2050 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2050 Portfolio through a broker-dealer or other financial intermediary, LifePath 2050 Portfolio and BlackRock Investments, LLC, LifePath 2050 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2050 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker- dealer or other financial intermediary and your individual financial professional to recommend LifePath 2050 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the LifePath Portfolios

INVESTMENT TIME HORIZONS

Each LifePath Portfolio seeks to maximize return consistent with the quantitatively measured risk that investors on average may be willing to accept given a particular investment time horizon. An investor's time horizon marks the point when the investor plans to start making net withdrawals from his or her investments, in other words, the time when they will cease making new contributions to their investments. For many LifePath Portfolio investors, their time horizon is tied to the date that they plan to retire and begin gradually utilizing their investment to support themselves in retirement. For other LifePath Portfolio investors, their time horizon may represent the date when they plan to make substantial withdrawals for another purpose, such as a major purchase.

As a general rule, investors with a longer time horizon have a greater tolerance for risk than investors with a shorter time horizon. Long-term investors are more likely to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns. Each LifePath Portfolio has its own time horizon, as described in its investment objective in each LifePath Portfolio's "Key Facts" section in this Prospectus, which affects the targeted risk level of that LifePath Portfolio and, in turn, its asset allocation.

The allocations for LifePath Retirement Portfolio reflect the expectation that investors in or near retirement, or otherwise seeking current income, are willing to take some risk of loss of their investment in hopes of achieving moderate long term growth of capital. LifePath Retirement Portfolio is designed to help balance two risk factors that investors face during retirement: market risk (potential declines in market values) and longevity risk (living longer than expected). Specifically, the portfolio seeks to enable investors to maintain a steady withdrawal rate (about 3-5% per year) throughout their retirement without exhausting their investment. There is no guarantee that the performance of LifePath Retirement Portfolio will be sufficient to enable this withdrawal rate or that any one withdrawal rate is appropriate for all investors. Investors should work with a financial advisor or other expert to determine a sustainable withdrawal rate for their circumstances, and that withdrawal rate should be periodically reassessed throughout retirement as the value of the investor's portfolio changes.

Each LifePath Portfolio has a distinct investment objective tied to its time horizon:

. LifePath Retirement Portfolio is managed for investors seeking income and moderate long-term growth of capital.

. LifePath 2020 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020.

. LifePath 2030 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030.

. LifePath 2040 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040.

. LifePath 2050 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050.

You should carefully consider the asset allocation and risks of each LifePath Portfolio before deciding whether to invest.

The LifePath Portfolios are designed to offer individual investors comprehensive asset allocation strategies tailored to the time when they expect to begin withdrawing assets. Asset allocation is the distribution of investments among broad types of asset classes: equity securities, bonds and money market instruments. Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has the same objective and strategies as the applicable LifePath Portfolio. LifePath Retirement Portfolio invests all of its assets in Retirement Master Portfolio. LifePath 2020 Portfolio invests all of its assets in 2020 Master Portfolio. LifePath 2030 Portfolio invests all of its assets in 2030 Master Portfolio. LifePath 2040 Portfolio invests all of its assets in 2040 Master Portfolio. LifePath 2050 Portfolio invests all of its assets in 2050 Master Portfolio. To implement the asset allocation strategy, each Master Portfolio, in turn, invests in a combination of Underlying Funds in proportions based on its own comprehensive investment strategy that gradually becomes more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase. BFA is the investment adviser to the Master Portfolios. For simplicity's sake, all discussion of investment objective, strategies and risks of a particular LifePath Portfolio refers also to the

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investment objective, strategies and risks of the applicable Master Portfolio, unless otherwise indicated. A description of the relationship of the LifePath Portfolios to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder and Fund of Funds Structures."

WHICH LIFEPATH PORTFOLIO TO CONSIDER

The first step in choosing which LifePath Portfolio to consider is answering a key question: When will you need the money you are thinking of investing? Will it be in ten years, when your kids are ready for college? Or 30 years, when you retire?

The number in the name of most of the LifePath Portfolios is actually a year - a "target year" when you might expect to begin withdrawing your money. Selecting the LifePath Portfolio that may be most appropriate for your investment may be as simple as matching your target year with the closest LifePath Portfolio target year.

For example, let's say that you are investing for retirement purposes, and that you expect to retire at age 60. If you are 45 years old, you have 15 years before retirement. By adding 15 to the current year, you can define your "target year." If you expect to retire in the year 2025, as in this example, you may conclude that LifePath 2020 Portfolio is the most appropriate LifePath Portfolio for you.

The investment mix of the LifePath Portfolios gradually shifts from a greater concentration of higher-risk investments (namely, equity securities funds) to a greater concentration of lower-risk investments (namely, bond funds), thereby making the LifePath Portfolios increasingly conservative.

In making your investment decision, you should keep in mind:

. The LifePath Portfolios' investment strategies derive from the risk tolerance of average investors with a particular time horizon.

. The LifePath Portfolios' time horizons are based on the year in their name, except for LifePath Retirement Portfolio, which is designed for investors who are currently withdrawing, or plan in the near future to begin withdrawing, a substantial portion of their investment.

If you are willing to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns, you may invest some or all of your assets in a LifePath Portfolio with a longer time horizon. If you desire a more conservative investment and are willing to forego some potential returns, you may invest some or all of your assets in a LifePath Portfolio with a shorter time horizon. The final choice is yours.

A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES

Each LifePath Portfolio invests all of its assets in a corresponding Master Portfolio which allocates and reallocates its assets among the Underlying Funds. The Master Portfolios with longer time horizons invest a greater portion of their assets in Underlying Funds that invest in equity securities, which provide a greater opportunity for capital appreciation over the long-term but have a greater risk of loss. The Master Portfolios with shorter time horizons invest a greater portion of their assets in Underlying Funds that invest in bonds and money market instruments, which typically offer reduced risk and price volatility but forego some potential returns. Accordingly, under normal circumstances, the LifePath Portfolios with shorter time horizons have lower expected returns than the LifePath Portfolios with longer time horizons. In addition to investing in Underlying Funds, each Master Portfolio may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and invest the collateral in certain short-term instruments either directly or through one or more joint accounts or money market funds, as described in greater detail in the LifePath Portfolios' combined Statement of Additional Information ("SAI").

As each Master Portfolio approaches its designated time horizon, it systematically seeks to reduce the level of risk by allocating assets more conservatively among the Underlying Funds. This systematic shift toward more conservative investments is designed to reduce the risk of significant reductions in the value of an investment in a Master Portfolio as it approaches its time horizon.

For example, LifePath Retirement Portfolio has entered its "retirement phase" and seeks to maximize returns consistent with the risk that an average investor in retirement may be willing to accept. This does not mean, however, that it invests exclusively, or primarily, in Underlying Funds that are money market funds. Rather, because BFA believes that most investors are still willing to take some risks in pursuing returns even while drawing on their investments, almost all of LifePath Retirement Portfolio's assets will continue to be allocated to Underlying Funds that are equity and bond funds.

In determining the allocation of assets to the Underlying Funds, BFA uses a proprietary investment model that analyzes securities market data, including risk, asset class correlations, and expected returns, to provide portfolio

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allocations among the asset classes represented by the Underlying Funds. The allocations are periodically monitored and rebalanced in an effort to maximize expected return for a given level of risk. In managing the LifePath Portfolios, BFA focuses on long-term targets and objectives. The progression over time of a LifePath Portfolio's asset allocation to more conservative asset classes is a relatively steady process resulting in only gradual changes to the asset allocation from quarter to quarter. The Underlying Funds invest in a mix of equity securities, bonds and money market instruments. Certain Underlying Funds invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivatives, which are subject to additional risks, as described in the "Details About the LifePath Portfolios - A Further Discussion of Risk Factors" section of this Prospectus. The investment model adjusts each LifePath Portfolio's risk level by gradually making it more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase.

When a LifePath Portfolio reaches its stated time horizon and enters its most conservative phase, the allocation of its assets is expected to be similar to that of LifePath Retirement Portfolio. Such LifePath Portfolio and LifePath Retirement Portfolio may then continue to operate as separate funds or, subject to approval by the Trust's Board of Trustees, they may be merged into a single fund.

THE UNDERLYING FUNDS

Two of the Underlying Funds - Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio - are diversified portfolios of MIP. Active Stock Master Portfolio seeks to provide long-term appreciation of capital. BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors. CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return.

The remaining Underlying Funds, other than BlackRock Cash Funds: Institutional (the "Underlying Money Market Fund"), are ETFs that are part of the iShares family of funds ("Underlying iShares Funds"). Each of the Underlying iShares Funds seeks investment results that correspond generally to the performance, before fees and expenses, of its underlying index. As a result, adverse performance of a particular security in an Underlying iShares Fund's portfolio will ordinarily not result in the elimination of the security from the Underlying iShares Fund's portfolio. Each Underlying iShares Fund offers and issues iShares at their NAV per share only to certain institutional investors in aggregations of a specified number of iShares, generally in exchange for a basket of securities included in its underlying index, together with the deposit of a specified cash payment. The iShares for these Underlying iShares Funds are listed and traded on national securities exchanges and also may be listed on certain non-U.S. exchanges. BFA purchases iShares on behalf of the Master Portfolios in the secondary market.

The relative weightings for each Master Portfolio in the various Underlying Funds will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time.

Each Master Portfolio currently expects to invest in some or all of the Underlying Funds described below:

ACTIVE STOCK MASTER PORTFOLIO

Active Stock Master Portfolio seeks to provide long-term appreciation of capital. Active Stock Master Portfolio invests, under normal circumstances, at least 80% of its assets in common stocks. Active Stock Master Portfolio invests primarily in equity securities of U.S. companies with market capitalizations similar to the range of market capitalizations represented in the Standard & Poor's ("S&P") 500 Index(Reg. TM). BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors, such as relative values based on earnings and cash flows; earnings quality as measured by the company's financial condition and earnings reports; sentiment as expressed through management and market participant behavior; and industry classification. BFA considers risk parameters in deciding upon Active Stock Master Portfolio's aggregate holdings, and factors trading costs into its stock selection process.

COREALPHA BOND MASTER PORTFOLIO

CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return. BFA's models also allocate assets among bonds of different maturities based on yield characteristics and expectations. Specific investment selection decisions are made on the basis of evaluations of relative value, credit quality and other factors. CoreAlpha Bond Master Portfolio invests, under normal circumstances, at least 80% of its assets in bonds. For the purposes of this strategy, "bonds" include the following:
obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial

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mortgage-backed securities; debt obligations of U.S. corporations; U.S. dollar-denominated debt obligations of foreign issuers; municipal securities; and asset-backed securities. CoreAlpha Bond Master Portfolio invests a substantial portion of its assets in U.S.-registered, dollar-denominated bonds. CoreAlpha Bond Master Portfolio may invest in bonds of any maturity or duration.

BLACKROCK CASH FUNDS: INSTITUTIONAL

BlackRock Cash Funds: Institutional seeks a high level of income consistent with liquidity and the preservation of capital. BlackRock Cash Funds:
Institutional invests in high-quality, short-term money market instruments that include fixed-rate, floating-rate and variable-rate debt securities. BlackRock Cash Funds: Institutional also may invest in high-quality, short-term U.S. and foreign government debt, including the debt of agencies and instrumentalities, such as the Federal National Mortgage Association ("Fannie Mae"), U.S. and foreign bank obligations, corporate obligations, repurchase agreements and asset-backed securities.

UNDERLYING ISHARES FUNDS

In managing each of the Underlying iShares Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that has an investment profile similar to the underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the applicable underlying index. Underlying iShares Funds that use representative sampling may or may not hold all of the securities in the relevant underlying index.

ISHARES S&P 500 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P 500 Index(Reg. TM), which measures the performance of the large-capitalization sector of the U.S. equity market. The component stocks are weighted according to the float-adjusted market value of their outstanding shares.

ISHARES S&P MIDCAP 400 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P MidCap 400 IndexTM, which measures the performance of the mid-capitalization sector of the U.S. equity market. The stocks in the S&P MidCap 400 IndexTM have a market capitalization between $750 million and $3.3 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation. The S&P MidCap 400 IndexTM consists of stocks from a broad range of industries.

ISHARES S&P SMALLCAP 600 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P SmallCap 600 IndexTM, which measures the performance of the small-capitalization sector of the U.S. equity market. The stocks in the S&P SmallCap 600 IndexTM have a market capitalization between $200 million and $1 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation.

ISHARES S&P NATIONAL AMT-FREE MUNICIPAL BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P National AMT-Free Municipal Bond Index, which measures the performance of the investment-grade segment of the U.S. municipal bond market. As of May 31, 2009, there were 8,709 issues in the S&P National AMT-Free Municipal Bond Index.

ISHARES S&P NORTH AMERICAN NATURAL RESOURCES SECTOR INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P North American Natural Resources Sector IndexTM, which measures the performance of U.S.-traded stocks of natural resource-related companies in the U.S. and Canada, and includes companies in the following categories: producers of oil, gas and consumable fuels, energy equipment and services, metals and mining, manufacturers of paper and forest products, and producers of construction materials, containers and packaging.

ISHARES RUSSELL MIDCAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell Midcap Index, which measures the performance of the mid-capitalization sector of the U.S. equity market. The Russell Midcap Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000(Reg. TM) Index.

ISHARES RUSSELL 2000 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell 2000 Index, which measures the performance of the small capitalization sector of the U.S. equity market. The Russell 2000 Index is a float-adjusted, capitalization-weighted index of equity securities issued by the approximately 2,000 smallest issuers in the Russell 3000(Reg. TM) Index.

ISHARES COHEN & STEERS REALTY MAJORS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Cohen & Steers Realty Major Index (the "Cohen & Steers Index"),

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which consists of selected U.S. REITs. The objective of the Cohen & Steers Index is to represent relatively large and liquid REITs that may benefit from future consolidation and securitization of the U.S. real estate industry. REITs are selected for inclusion in the Cohen & Steers Index based on a rigorous review of several factors, including management, portfolio quality, and sector and geographic diversification. The REITs selected for inclusion in the Cohen & Steers Index must meet minimum market capitalization and liquidity requirements. The Cohen & Steers Index is weighted according to the total market value of each REIT's outstanding shares and is adjusted quarterly so that no REIT represents more than 8% of the Cohen & Steers Index. Within the REIT market, the Cohen & Steers Index is diversified across property sectors that represent the current market.

ISHARES FTSE EPRA/NAREIT DEVELOPED REAL ESTATE EX-U.S. INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which measures the stock performance of companies engaged in the ownership and development of the following real estate markets defined as developed by FTSE EPRA/NAREIT: Canada, Europe (including Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom (including the Channel Islands)), Middle East (Israel) and Asia (including Australia, Hong Kong, Japan, New Zealand and Singapore). As of May 29, 2009, the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index was comprised of stocks of companies in the following markets: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Italy, Japan, Netherlands, New Zealand, Norway, Poland, Singapore, Spain, Sweden, Switzerland and the United Kingdom.

ISHARES MSCI CANADA INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Canada Index developed by MSCI, Inc. ("MSCI"). The MSCI Canada Index consists of stocks traded primarily on the Toronto Stock Exchange.

ISHARES MSCI EAFE INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE(Reg. TM) Index, which has been developed by MSCI as an equity benchmark for its international stock performance. The MSCI EAFE Index includes stocks from Europe, Australasia and the Far East.

ISHARES MSCI EAFE SMALL CAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE Small Cap Index, which represents the small cap size segment of the MSCI EAFE Index. The MSCI EAFE(Reg. TM) Index includes securities from Europe, Australasia and the Far East. Under MSCI's Global Investable Market Index methodology, the small cap universe consists of the securities of those companies whose securities are not included in the large cap or mid cap segments of a particular market, which together comprise approximately 85% of each market's free float-adjusted market capitalization. The small cap segment covers the 85%-99% range of each market's free float-adjusted market capitalization.

ISHARES MSCI EMERGING MARKETS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Emerging Markets Index, which is designed to measure equity market performance in the global emerging markets. As of September 30, 2009, the MSCI Emerging Markets Index consisted of the following 22 emerging market country indexes: Brazil, Chile, China, Colombia, the Czech Republic, Egypt, Hungary, India, Indonesia, Israel, Malaysia, Mexico, Morocco, Peru, the Philippines, Poland, Russia, South Africa, South Korea, Taiwan, Thailand and Turkey. Emerging market country indexes may be added to or deleted from the MSCI Emerging Markets Index from time to time. The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares funds that invest in securities in the MSCI Emerging Markets Index. BFA waives a portion of its advisory fees otherwise due from the iShares MSCI Emerging Markets Index Fund in an amount equal to the portfolio management fees incurred by assets that are invested in shares of other iShares funds.

ISHARES BARCLAYS 1-3 YEAR CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 1-3 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 3-7 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 3-7 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to three years and less than seven years.

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ISHARES BARCLAYS 7-10 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 7-10 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years.

ISHARES BARCLAYS 10-20 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 10-20 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to ten years and less than 20 years.

ISHARES BARCLAYS 20+ YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 20+ Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of 20 years or more.

ISHARES BARCLAYS AGGREGATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Aggregate Bond Index, which measures the performance of the total U.S. investment-grade bond market, which includes investment-grade U.S. Treasury bonds, government-related bonds, investment-grade corporate bonds, mortgage pass-through securities, commercial mortgage-backed securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Barclays Capital U.S. Aggregate Bond Index have $250 million or more of outstanding face value and have at least one year remaining to maturity. In addition, the securities must be U.S. dollar-denominated, fixed-rate and non-convertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and Eurobonds are excluded from the Barclays Capital U.S. Aggregate Bond Index. The Barclays Capital U.S. Aggregate Bond Index is market capitalization weighted and the securities are updated on the last calendar day of each month.

ISHARES BARCLAYS CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Government/Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS INTERMEDIATE CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS INTERMEDIATE GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Government/

Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS MBS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. MBS Index, which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Government National Mortgage Association, Fannie Mae and the Federal Home Loan Mortgage Corporation.

ISHARES BARCLAYS SHORT TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Short Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of between one and 12 months.

ISHARES BARCLAYS TIPS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L), which measures the performance of the inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS."

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ISHARES JPMORGAN USD EMERGING MARKETS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the JPMorgan EMBI Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark which tracks the total return of actively traded external debt instruments in emerging market countries.

ISHARES IBOXX $ HIGH YIELD CORPORATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the iBoxx(Reg. TM) $ Liquid High Yield Index, which is a rules-based index consisting of liquid U.S. dollar-denominated, high yield corporate bonds for sale in the United States, as determined by the International Index Company Limited ("IIC"). The iBoxx(Reg. TM) $ Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated high yield liquid corporate bond market. The iBoxx(Reg. TM) $ Liquid High Yield Index is a modified market value weighted index. There is no limit to the number of issues in the iBoxx(Reg. TM) $ Liquid High Yield Index, but as of June 30, 2009, the iBoxx(Reg. TM) $ Liquid High Yield Index included approximately 281 constituents.

The following table lists the Underlying Funds and the asset allocation for each Master Portfolio as of March 31, 2010. BFA allocates each Master Portfolio's assets among the Underlying Funds based on the Master Portfolio's investment objective and policies. The asset allocation for each Master Portfolio will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time:

UNDERLYING FUNDS
(as of March 31, 2010)

                                                    LIFEPATH     LIFEPATH    LIFEPATH    LIFEPATH    LIFEPATH
                                                   RETIREMENT      2020        2030        2040        2050
                                                    PORTFOLIO   PORTFOLIO   PORTFOLIO   PORTFOLIO    PORTFOLIO
CAPITAL GROWTH
MIP-Active Stock Master Portfolio                     19.45%       30.45%      38.39%      44.64%       49.18%
iShares S&P MidCap 400 Index Fund                      4.93%        5.87%       6.54%       7.14%        8.10%
iShares S&P SmallCap 600 Index Fund                    2.18%        2.58%       2.89%       3.16%        3.54%
iShares MSCI EAFE Index Fund                           6.74%       10.08%      12.60%      14.73%       17.01%
iShares Cohen & Steers Realty Majors Index Fund        0.62%        1.87%       2.73%       3.50%        4.01%
iShares FTSE EPRA/NAREIT Developed Real Estate         0.99%        2.99%       4.43%       5.62%        6.40%
ex-U.S. Index Fund
iShares MSCI Emerging Markets Index Fund               2.40%        3.70%       4.66%       5.47%        6.09%
iShares MSCI Canada Index Fund                         0.82%        1.25%       1.54%       1.82%        2.02%
iShares MSCI EAFE Small Cap Index Fund                 0.81%        1.25%       1.47%       1.72%        2.00%
CAPITAL GROWTH AND INCOME
MIP-CoreAlpha Bond Master Portfolio                   51.96%       34.27%      21.48%      10.89%        0.99%
iShares Barclays TIPS Bond Fund                        8.87%        5.49%       3.08%       1.08%       N/A
INCOME
BlackRock Cash Funds: Institutional - SL Agency        0.23%        0.20%       0.19%       0.23%        0.66%
Shares


Note: The allocation percentages may not add to, or may appear to exceed, 100% due to rounding.

"Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," "S&P 500 Index(Reg. TM)," "S&P MidCap 400 IndexTM," "S&P SmallCap 600 IndexTM," "S&P National AMT-Free Municipal Bond IndexTM," and "S&P North American Natural Resources Sector IndexTM" are trademarks of Standard & Poor's Financial Services LLC (a subsidiary of The McGraw-Hill Companies) licensed for use for certain purposes by BTC. The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P SmallCap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and iShares S&P North American Natural Resources Sector Index Fund that are based on S&P Indexes are not sponsored, endorsed, sold or promoted by S&P or its affiliates, and S&P and its affiliates make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"FTSE," "EPRA," "NAREIT" and "FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index" are marks that have been licensed for use for certain purposes by BTC. The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together the "FTSE Licensor Parties"), and the FTSE Licensor Parties make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Cohen & Steers" and "Cohen & Steers Realty Majors Index" are trademarks of Cohen & Steers Capital Management, Inc. ("Cohen & Steers") licensed for use for certain purposes by BTC. The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers, and Cohen & Steers makes no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Barclays Capital Inc.," "Barclays Capital U.S. 1-3 Year Credit Bond Index," "Barclays Capital U.S. 1-3 Year Treasury Bond Index," "Barclays Capital U.S. 3-7 Year Treasury Bond Index," "Barclays Capital U.S. 7-10 Year Treasury Bond Index," "Barclays Capital U.S. 10-20 Year Treasury Bond Index," "Barclays Capital U.S. 20+ Year Treasury Bond Index," "Barclays Capital U.S. Aggregate Bond Index," "Barclays Capital U.S. Credit Bond Index," "Barclays Capital U.S. Government/Credit Bond Index," "Barclays Capital U.S. Intermediate Credit Bond Index," "Barclays Capital U.S. Intermediate Government/Credit Bond Index," "Barclays Capital U.S. MBS Index," "Barclays Capital U.S. Short Treasury Bond Index," and the "Barclays Capital

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U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)" (collectively referred to as the "iShares Bond Fund Indexes") are trademarks of Barclays Bank PLC licensed for use for certain purposes by BTC. The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund are not sponsored, endorsed, sold or promoted by Barclays Capital Inc. ("Barclays Capital"), and Barclays Capital makes no representation or warranty, express or implied, regarding the advisability of investing in iShares. The iShares Bond Fund Indexes are maintained by Barclays Capital. Neither BTC nor BFA has or will have a role in maintaining the iShares Bond Fund Indexes.

"MSCI Canada Index/SM/," "MSCI EAFE(Reg. TM) Index" and "MSCI Emerging Markets Index/SM/" are servicemarks and "MSCI EAFE Small Cap Index" is a trademark of MSCI, and such marks have been licensed for use for certain purposes by BTC. The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI, and neither MSCI nor any other party makes any representation or warranty, express or implied, regarding the advisability of investing in iShares.

A FURTHER DISCUSSION OF RISK FACTORS

This section contains a description of the general risks of investing in the LifePath Portfolios. "Description of the LifePath Portfolios and their Investments and Risks" in the SAI also includes more information about the LifePath Portfolios, their investments and the related risks. There can be no guarantee that a LifePath Portfolio will meet its objective or that a LifePath Portfolio's performance will be positive for any period of time. An investment in a LifePath Portfolio is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

GENERAL

The NAV of each LifePath Portfolio's shares is neither insured nor guaranteed, is not fixed and will fluctuate.

GENERAL RISKS APPLICABLE TO THE LIFEPATH PORTFOLIOS

ALLOCATION RISK - The LifePath Portfolios' ability to achieve their investment goals depends upon BFA's skill in determining the LifePath Portfolios' strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, there is no guarantee that the Underlying Funds will achieve their investment objectives, and the Underlying Funds' performance may be lower than the performance of the asset class which they were selected to represent. The Underlying Funds may change their investment objectives or policies without the approval of the LifePath Portfolios. If an Underlying Fund were to change its investment objective or policies, the LifePath Portfolios might be forced to withdraw their investment from the Underlying Fund at a disadvantageous time and price.

CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the LifePath Portfolios' investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The LifePath Portfolios' use of derivatives may reduce the LifePath Portfolios' returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the LifePath Portfolios' use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the LifePath Portfolios to sell or otherwise close a derivatives position could expose the LifePath Portfolios to losses and could make derivatives more difficult for the LifePath Portfolios to value accurately. The LifePath Portfolios could also suffer losses related to their derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally,

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BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the LifePath Portfolios' derivatives positions to lose value. When a derivative is used as a hedge against a position that the LifePath Portfolios hold, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the LifePath Portfolios' hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EMERGING MARKETS RISK - The risks of foreign investments are usually much greater for emerging markets. Investments in emerging markets may be considered speculative. Emerging markets include those in countries defined as emerging or developing by the World Bank, the International Finance Corporation or the United Nations. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain small markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards and requirements comparable to those to which U.S. companies are subject.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments are more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation, high rates of inflation or unfavorable diplomatic developments. In the past, governments of such nations have expropriated substantial amounts of private property, and most claims of the property owners have never been fully settled. There is no assurance that such expropriations will not reoccur. In such an event, it is possible that the LifePath Portfolio could lose the entire value of its investments in the affected market. Some countries have pervasiveness of corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth. National policies that may limit the LifePath Portfolio's investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other foreign or U.S. governmental laws or restrictions applicable to such investments. Sometimes, they may lack or be in the relatively early development of legal structures governing private and foreign investments and private property. In addition to withholding taxes on investment income, some countries with emerging markets may impose differential capital gains taxes on foreign investors.

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the LifePath Portfolios could decline if the financial condition of the companies the LifePath Portfolios invest in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

FOREIGN SECURITIES RISK - Securities traded in foreign markets have often (though not always) performed differently from securities traded in the United States. However, such investments often involve special risks not present in U.S. investments that can increase the chances that the LifePath Portfolio will lose money. In particular, the LifePath Portfolio is subject to the risk that because there may be fewer investors on foreign exchanges and a smaller number of securities traded each day, it may be more difficult for the LifePath Portfolio to buy and sell securities on those exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

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CERTAIN RISKS OF HOLDING FUND ASSETS OUTSIDE THE UNITED STATES - The LifePath Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories. Some foreign banks and securities depositories may be recently organized or new to the foreign custody business. In addition, there may be limited or no regulatory oversight of their operations. Also, the laws of certain countries limit the LifePath Portfolio's ability to recover its assets if a foreign bank, depository or issuer of a security, or any of their agents, goes bankrupt. In addition, it is often more expensive for the LifePath Portfolio to buy, sell and hold securities in certain foreign markets than in the United States. The increased expense of investing in foreign markets reduces the amount the LifePath Portfolio can earn on its investments and typically results in a higher operating expense ratio for the LifePath Portfolio than for investment companies invested only in the United States.

CURRENCY RISK - Securities and other instruments in which the LifePath Portfolio invests may be denominated or quoted in currencies other than the U.S. dollar. For this reason, changes in foreign currency exchange rates can affect the value of the LifePath Portfolio.

Generally, when the U.S. dollar rises in value against a foreign currency, a security denominated in that currency loses value because the currency is worth fewer U.S. dollars. Conversely, when the U.S. dollar decreases in value against a foreign currency, a security denominated in that currency gains value because the currency is worth more U.S. dollars. This risk, generally known as "currency risk," means that a strong U.S. dollar will reduce returns for U.S. investors while a weak U.S. dollar will increase those returns.

FOREIGN ECONOMY RISK - The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. Certain foreign economies may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. In addition, the governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Any of these actions could severely affect securities prices or impair the LifePath Portfolio's ability to purchase or sell foreign securities or transfer the LifePath Portfolio's assets or income back into the United States, or otherwise adversely affect the LifePath Portfolio's operations.

Other potential foreign market risks include foreign exchange controls, difficulties in pricing securities, defaults on foreign government securities, difficulties in enforcing legal judgments in foreign courts and political and social instability. Diplomatic and political developments, including rapid and adverse political changes, social instability, regional conflicts, terrorism and war, could affect the economies, industries and securities and currency markets, and the value of the LifePath Portfolio's investments, in non-U.S. countries. These factors are extremely difficult, if not impossible, to predict and take into account with respect to the LifePath Portfolio's investments.

GOVERNMENTAL SUPERVISION AND REGULATION/ACCOUNTING STANDARDS - Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as such regulations exist in the United States. They also may not have laws to protect investors that are comparable to U.S. securities laws. For example, some foreign countries may have no laws or rules against insider trading. Insider trading occurs when a person buys or sells a company's securities based on material non-public information about that company. In addition, some countries may have legal systems that may make it difficult for the LifePath Portfolio to vote proxies, exercise shareholder rights, and pursue legal remedies with respect to its foreign investments. Accounting standards in other countries are not necessarily the same as in the United States. If the accounting standards in another country do not require as much detail as U.S. accounting standards, it may be harder for LifePath Portfolio management to completely and accurately determine a company's financial condition.

SETTLEMENT RISK - Settlement and clearance procedures in certain foreign markets differ significantly from those in the United States. Foreign settlement and clearance procedures and trade regulations also may involve certain risks (such as delays in payment for or delivery of securities) not typically associated with the settlement of U.S. investments.

At times, settlements in certain foreign countries have not kept pace with the number of securities transactions. These problems may make it difficult for the LifePath Portfolio to carry out transactions. If the LifePath Portfolio cannot settle or is delayed in settling a purchase of securities, it may miss attractive investment opportunities and certain of its assets may be uninvested with no return earned thereon for some period. If the LifePath Portfolio cannot settle or is delayed in settling a sale of securities, it may lose money if the value of the security then declines or, if it has contracted to sell the security to another party; the LifePath Portfolio could be liable for any losses incurred.

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INVESTMENTS IN MUTUAL FUNDS AND ETFS RISK - Each LifePath Portfolio will invest substantially all of its assets in Underlying Funds, so the LifePath Portfolio's investment performance is directly related to the performance of the Underlying Funds. The LifePath Portfolios may also directly invest in ETFs. The LifePath Portfolio's net asset value will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in the LifePath Portfolios will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs. For example, the LifePath Portfolios indirectly pay a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds and ETFs.

One Underlying Fund may buy the same securities that another Underlying Fund sells. In addition, a LifePath Portfolio may buy the same securities that an Underlying Fund sells, or vice-versa. If this happens, an investor in the LifePath Portfolio would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in a LifePath Portfolio may receive taxable gains from portfolio transactions by an Underlying Fund, as well as taxable gains from transactions in shares of the Underlying Fund by the LifePath Portfolio. Certain of the Underlying Funds may hold common portfolio securities, thereby reducing the diversification benefits of the LifePath Portfolios.

In order to minimize expenses, the LifePath Portfolios intend to invest in the class of shares of each Underlying Fund with the lowest shareholder fees and net fund operating expenses. As the Underlying Funds or the LifePath Portfolios' allocations among the Underlying Funds change from time to time, or to the extent that the expense ratio of the Underlying Funds changes, the weighted average operating expenses borne by the LifePath Portfolios may increase or decrease.

Underlying iShares Funds are subject to additional risks due to their shares being listed and traded on securities exchanges. There can be no assurance that an active trading market for these particular ETFs will develop or be maintained. Trading in ETFs may be halted because of market conditions or for reasons that, in the view of the listing exchange, make trading in ETFs inadvisable. In addition, trading in ETFs is subject to trading halts caused by extraordinary market volatility pursuant to "circuit breaker" rules. There can be no assurance that the requirements necessary to maintain the listing of ETFs will continue to be met or will remain unchanged. An ETF may trade at, above or below its NAV. The NAV of an ETF will fluctuate with changes in the market value of its holdings. The trading price of an ETF will generally fluctuate in accordance with changes in its NAV, as well as market supply and demand.

JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the LifePath Portfolios. The major risks of junk bond investments include:

. Junk bonds may be issued by less creditworthy issuers. Issuers of junk bonds may have a larger amount of outstanding debt relative to their assets than issuers of investment grade bonds. In the event of an issuer's bankruptcy, claims of other creditors may have priority over the claims of junk bond holders, leaving few or no assets available to repay junk bond holders.

. Prices of junk bonds are subject to extreme price fluctuations. Adverse changes in an issuer's industry and general economic conditions may have a greater impact on the prices of junk bonds than on other higher rated fixed-income securities.

. Issuers of junk bonds may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.

. Junk bonds frequently have redemption features that permit an issuer to repurchase the security from the LifePath Portfolios before it matures. If the issuer redeems junk bonds, the LifePath Portfolios may have to invest the proceeds in bonds with lower yields and may lose income.

. Junk bonds may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the junk bond market, and there may be significant differences in the prices quoted for junk bonds by the dealers. Because they are less liquid, judgment may play a greater role in valuing certain of the LifePath Portfolios' securities than is the case with securities trading in a more liquid market.

. The LifePath Portfolios may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the LifePath Portfolios invest will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection

45

risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. The characteristics of these mortgage-backed and asset-backed securities differ from traditional fixed-income securities. Like traditional fixed-income securities, the value of asset-backed securities typically increases when interest rates fall and decreases when interest rates rise. However, a main difference is that the principal on mortgage- or asset-backed securities may normally be prepaid at any time, which will reduce the yield and market value of these securities. Therefore, mortgage- and asset-backed backed securities are subject to "prepayment risk" and "extension risk." Because of prepayment risk and extension risk, mortgage-backed securities react differently to changes in interest rates than other fixed-income securities.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The LifePath Portfolios' investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The LifePath Portfolios' investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only (IOs), principal only (POs) or an amount that remains after other floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the LifePath Portfolios invest in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by BFA, it is possible that the LifePath Portfolios could lose all or substantially all of their investment.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the LifePath Portfolios' mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the LifePath Portfolios may invest may also provide a degree of investment leverage, which could cause the LifePath Portfolios to lose all or substantially all of their investment.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for the Underlying iShares Funds, those Underlying iShares Funds may hold stocks in companies that present risks that an investment adviser researching individual stocks might seek to avoid.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the LifePath Portfolios may have to invest their proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment

46

proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

REIT INVESTMENT RISK - In addition to the risks facing real estate-related securities, such as a decline in property values due to increasing vacancies, a decline in rents resulting from unanticipated economic, legal or technological developments or a decline in the price of securities of real estate companies due to a failure of borrowers to pay their loans or poor management, investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the LifePath Portfolios may lose money and there may be a delay in recovering the loaned securities. The LifePath Portfolios could also lose money if they do not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the LifePath Portfolios.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

Each LifePath Portfolio must maintain cash balances to meet redemption requests, which may lower overall portfolio performance.

FOR A DESCRIPTION OF THE LIFEPATH PORTFOLIOS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THEIR MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A FURTHER DISCUSSION OF THE LIFEPATH PORTFOLIOS' INVESTMENTS AND RISKS, PLEASE REFER TO THE LIFEPATH PORTFOLIOS' SAI.

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Account Information

DETAILS ABOUT CLASS K SHARES

Class K Shares of the LifePath Portfolios are available only to (i) qualified recordkeepers with a distribution and/ or fund servicing agreement (establishing an omnibus trading relationship) maintained with the LifePath Portfolios' distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non-qualified plans that they sponsor (previously defined collectively as "Institutions"). The LifePath Portfolios' initial minimum investment for Class K Shares is $1. The minimum investment for additional purchases is $1.

Class K Shares of the LifePath Portfolios are distributed by BlackRock Investments, LLC (the "Distributor").

HOW TO BUY, SELL AND TRANSFER SHARES


The chart on the following pages summarizes how to buy, sell and transfer shares through your financial professional or other financial intermediary. You may also buy, sell and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling or transferring shares through BlackRock, call (800) 441-7762. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

Each LifePath Portfolio may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders and suspend and resume the sale of any share class of the LifePath Portfolio at any time for any reason.

In addition, the LifePath Portfolios may waive certain requirements regarding the purchase, sale or transfer of shares described below.

                                                 HOW TO BUY SHARES
                   YOUR CHOICES        IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE    Determine           There is a $1 minimum investment for all accounts.
                   the amount of
                   your investment
                    Have your           The price of your shares is based on the next calculation of a LifePath
                   financial           Portfolio's NAV after your order is placed. Any purchase orders placed prior
                   intermediary        to the close of business on the NYSE (generally 4:00 p.m. Eastern time)
                   submit your         will be priced at the NAV determined that day. Certain financial
                   purchase order      intermediaries, however, may require submission of orders prior to that
                                       time. A broker-dealer or financial institution maintaining the account in
                                       which you hold shares may charge a separate account, service or
                                       transaction fee on the purchase or sale of Fund shares that would be in
                                       addition to the fees and expenses shown in each LifePath Portfolio's "Fees
                                       and Expenses" table.
                                       Purchase orders placed after that time will be priced at the NAV
                                       determined on the next business day. The LifePath Portfolios may reject
                                       any order to buy shares and may suspend the sale of shares at any time.
                                       Financial intermediaries may charge a processing fee to confirm a
                                       purchase.
                    Or contact          To purchase shares directly from BlackRock, call (800) 441-7762 and
                   BlackRock (for      request a new account application. Mail the completed application along
                   accounts held       with a check payable to "BlackRock Funds" to PNC Global Investment
                   directly with       Servicing (U.S.) Inc. (the "Transfer Agent") at the address on the
                   BlackRock)          application.
ADD TO YOUR         Purchase            The minimum investment for additional purchases is $1.
INVESTMENT         additional shares

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                                                   HOW TO BUY SHARES
                 YOUR CHOICES            IMPORTANT INFORMATION FOR YOU TO KNOW
                  Have your               To purchase additional shares you may contact your financial professional
                 financial               or financial intermediary.
                 professional
                 or financial
                 intermediary
                 submit your
                 purchase order
                 for additional shares
                  Or contact              PURCHASE BY TELEPHONE: Call (800) 441-7762 and speak with one of our
                 BlackRock               representatives. The LifePath Portfolios have the right to reject any
                 (for accounts held      telephone request for any reason.
                 directly with
                                         PURCHASE IN WRITING: You may send a written request to BlackRock at the
                 BlackRock)
                                         address on the back cover of this Prospectus.
                  Acquire additional      All dividends and capital gains distributions are automatically reinvested
                 shares by               without a sales charge. To make any changes to your dividend and/or
                 reinvesting             capital gains distributions options, please call (800) 441-7762, or contact
                 dividends and           your financial professional (if your account is not held directly with
                 capital gains           BlackRock).
HOW TO PAY FOR    Making payment          Payment for an order must be made in Federal funds or other immediately
SHARES           for                     available funds by the time specified by your financial professional or other
                 purchases               financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                         on the first business day (in the case of Class K Shares) following
                                         BlackRock's receipt of the order. If payment is not received by this time,
                                         the order will be canceled and you and your financial professional or other
                                         financial intermediary will be responsible for any loss to the LifePath
                                         Portfolios.
                                          For shares purchased directly from the LifePath Portfolio, a check payable
                                         to "BlackRock Funds," which bears the name of the LifePath Portfolio you
                                         are purchasing must accompany a completed purchase application.

       HOW TO SELL SHARES
                  YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL    Have your       You can make redemption requests through your financial professional.
REDEMPTION OF     financial       Shareholders should indicate that they are redeeming Class K Shares. The
SHARES            intermediary    price of your shares is based on the next calculation of a LifePath
                  submit your     Portfolio's NAV after your order is placed. For your redemption request to
                  sales order     be priced at the NAV on the day of your request, you must submit your
                                  request to your financial intermediary prior to that day's close of business
                                  on the NYSE (generally 4:00 p.m. Eastern time). Certain financial
                                  intermediaries, however, may require submission of orders prior to that
                                  time. Any redemption request placed after that time will be priced at the
                                  NAV at the close of business on the next business day.
                                   Financial intermediaries may charge a fee to process a redemption of
                                  shares.
                                   The LifePath Portfolios may reject an order to sell shares under certain
                                  circumstances.
                   Selling         METHODS OF REDEEMING
                  shares held
                                  REDEEM BY TELEPHONE: You may sell shares held at BlackRock via
                  directly
                                  telephone request by telephoning (800) 441-7762.
                  with
                  BlackRock

49

HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             The LifePath Portfolios, their administrator and the Distributor will employ
                            reasonable procedures to confirm that instructions communicated by
                            telephone are genuine. The LifePath Portfolios and their service providers
                            will not be liable for any loss, liability, cost or expense for acting upon
                            telephone instructions that are reasonably believed to be genuine in
                            accordance with such procedures. The LifePath Portfolios may refuse a
                            telephone redemption request if they believe it is advisable to do so.
                             During periods of substantial economic or market change, telephone
                            redemptions may be difficult to complete. Please find below alternative
                            redemption methods.
                             REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                            BlackRock. All shareholders on the account must sign the letter. A
                            medallion signature guarantee will generally be required but may be
                            waived in certain limited circumstances. You can obtain a medallion
                            signature guarantee stamp from a bank, securities dealer, securities
                            broker, credit union, savings and loan association, national securities
                            exchange or registered securities association. A notary public seal will not
                            be acceptable. If you hold stock certificates, return the certificates with
                            the letter. Proceeds from redemptions may be sent via check, ACH or wire
                            to the bank account of record.
                             PAYMENT OF REDEMPTION PROCEEDS BY WIRE TRANSFER: Payment for
                            redeemed shares for which a redemption order is received before 4:00
                            p.m. (Eastern time) on a business day is normally made in Federal funds
                            wired to the redeeming shareholder on the next business day, provided
                            that the LifePath Portfolios' custodian is also open for business. Payment
                            for redemption orders received after 4:00 p.m. (Eastern time) or on a day
                            when the LifePath Portfolios' custodian is closed is normally wired in
                            Federal funds on the next business day following redemption on which
                            the LifePath Portfolio's custodian is open for business. The LifePath
                            Portfolios reserve the right to wire redemption proceeds within seven days
                            after receiving a redemption order if, in the judgment of the LifePath
                            Portfolio, an earlier payment could adversely affect a LifePath Portfolio. No
                            charge for wiring redemption payments with respect to Class K Shares is
                            imposed by the LifePath Portfolios, although plans may charge their
                            customer accounts for redemption services. Information relating to such
                            redemption services and charges, if any, should be obtained by customers
                            from their plans.
                             The LifePath Portfolios are not responsible for the efficiency of the Federal
                            wire system or the shareholder's firm or bank. To change the name of the
                            single, designated bank account to receive wire redemption proceeds, it is
                            necessary to send a written request to the LifePath Portfolio at the
                            address on the back cover of this Prospectus.

                                             HOW TO TRANSFER YOUR ACCOUNT
                     Your Choices       Important Information for You to Know
TRANSFER SHARES TO    Transfer to a      You may transfer your Class K Shares of a LifePath Portfolio only to
ANOTHER SECURITIES   participating      another financial professional or financial intermediary that has an
DEALER OR OTHER      financial          agreement with the Distributor. Certain shareholder services may not be
FINANCIAL            professional or    available for the transferred shares. All future trading of these assets must
INTERMEDIARY         other              be coordinated by the receiving firm.
                     financial
                                        If your account is held directly with BlackRock, you may call (800) 441-
                     intermediary
                                        7762 with any questions; otherwise please contact your financial
                                        intermediary to accomplish the transfer of shares.

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                              HOW TO TRANSFER YOUR ACCOUNT
Your Choices             Important Information for You to Know
 Transfer to a            You must either:
non-participating
                         oTransfer your Class K Shares to an account with a LifePath Portfolio; or
financial professional
                         oSell your shares, paying any applicable deferred sales charge.
or other
financial intermediary
                         If your account is held directly with BlackRock, you may call (800) 441-
                         7762 with any questions; otherwise please contact your financial
                         intermediary to accomplish the transfer of shares.

LIFEPATH PORTFOLIOS' RIGHTS


Each LifePath Portfolio may:

. Suspend the right of redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the Investment Company Act of 1940 Act, as amended (the "1940 Act"),

. Postpone date of payment upon redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act or if a redemption request is made before a LifePath Portfolio has collected payment for the purchase of shares,

. Redeem shares for property other than cash if conditions exist which make cash payments undesirable in accordance with its rights under the 1940 Act, and

. Redeem shares involuntarily in certain cases, such as when the value of a shareholder account falls below a specified level.

CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE


Each LifePath Portfolio's share price (also known as a LifePath Portfolio's NAV) is calculated by dividing the value of the net assets of the LifePath Portfolio (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the LifePath Portfolio, generally rounded to the nearest cent.

Each LifePath Portfolio's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern Time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating each LifePath Portfolio's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of each LifePath Portfolio is calculated based on the NAV of the Master Portfolio in which the LifePath Portfolio invests. The LifePath Portfolios' SAI includes a description of the methods for valuing the Master Portfolios' investments, including a description of the circumstances in which the Master Portfolios' investments would be valued using fair value pricing and the effects of using fair value pricing.

LIFEPATH PORTFOLIO DISTRIBUTIONS


The LifePath Portfolios distribute their net investment income to shareholders quarterly. The LifePath Portfolios distribute their net realized capital gains, if any, to shareholders at least annually. Distributions payable to you will be automatically reinvested in additional Class K Shares of your LifePath Portfolio, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and a LifePath Portfolio's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The LifePath Portfolios are not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. The exchange privilege is not intended as a vehicle for short-term trading. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of a LifePath Portfolio and its shareholders. For example, large flows of cash into and out of a LifePath Portfolio may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the LifePath Portfolio's investment goal. Frequent trading may cause a LifePath Portfolio to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the LifePath Portfolio's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. Each LifePath Portfolio will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of LifePath Portfolio Investments" below.

Each LifePath Portfolio discourages market timing and seeks to prevent frequent purchases and sales or exchanges of LifePath Portfolio shares that it determines may be detrimental to the LifePath Portfolio or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of LifePath Portfolio shares because certain legitimate strategies will not result in harm to a LifePath Portfolio or shareholders.

51

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, a LifePath Portfolio believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If a LifePath Portfolio rejects your purchase or exchange order, you will not be able to execute that transaction, and the LifePath Portfolio will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with a LifePath Portfolio, the LifePath Portfolio may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by a LifePath Portfolio. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide a LifePath Portfolio with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the LifePath Portfolio. While each LifePath Portfolio monitors for market timing activity, a LifePath Portfolio may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the LifePath Portfolio. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in a LifePath Portfolio's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by a LifePath Portfolio to be engaged in market timing or other improper trading activity, the LifePath Portfolio's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

A LifePath Portfolio may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

TAXES


The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the LifePath Portfolios and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the LifePath Portfolios' SAI for additional U.S. federal income tax information.

Shareholders that are exempt from U.S. federal income tax, such as retirement plans that are qualified under Section 401 of the U.S. Internal Revenue Code of 1986, as amended generally are not subject to U.S. federal income tax on fund dividends or distributions or on sales of LifePath Portfolio shares. However, in the case of LifePath Portfolio shares held through a non-qualified deferred compensation plan, fund dividends and distributions received by the plan and sales of LifePath Portfolio shares by the plan generally will be taxable to the employer sponsoring such plan in accordance with U.S. federal income tax laws governing deferred compensation plans.

A plan participant whose retirement plan invests in LifePath Portfolio shares generally is not taxed on LifePath Portfolio dividends or distributions received by the plan or on sales of LifePath Portfolio shares by the plan for U.S. federal income tax purposes. However, distributions to plan participants from a retirement plan generally are taxable to plan participants as ordinary income. Special rules may also apply to such distributions. Plan participants should contact their own tax advisers for more information.

You must provide your correct social security number or other taxpayer identification number to the LifePath Portfolio along with any certifications required by the U.S. Internal Revenue Service when you open an account.

MASTER/FEEDER AND FUND OF FUNDS STRUCTURES


The LifePath Portfolios do not have their own investment adviser. Instead, each LifePath Portfolio invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the LifePath Portfolio. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the LifePath Portfolios.

52

FEEDER FUND EXPENSES

Feeder funds, including the LifePath Portfolios, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund- specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a LifePath Portfolio's assets from its Master Portfolio if it believes doing so is in the best interests of the LifePath Portfolio's shareholders. If the Trust's Board of Trustees decides to withdraw a LifePath Portfolio's assets, it would then consider whether the LifePath Portfolio should hire its own investment adviser, invest in another master portfolio or take other action.

FUND OF FUNDS

The Master Portfolios do not invest directly in a portfolio of securities. Instead, they invest in the Underlying Money Market Fund and other Underlying Funds that are also advised by BFA. Each Master Portfolio charges for its own direct expenses, in addition to bearing a PRO RATA share of the expenses charged by the Underlying Funds in which it invests.

53

Management of the LifePath Portfolios

INVESTMENT ADVISER


Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the LifePath Portfolio. The Master Portfolios, in turn, invest in a combination of Underlying Funds. BFA, a registered investment adviser, serves as investment adviser to each Master Portfolio, and also serves as investment adviser to each Underlying Fund, with the exception of the Underlying Money Market Fund, which invests in a master portfolio advised by BFA. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive an annual management fee of 0.35% of each Master Portfolio's average daily net assets.

For its services to the Underlying Funds, BFA receives fees that differ from the fees described for the LifePath Portfolios in this Prospectus. BFA provides investment advisory services for the Underlying Funds that differ from the investment advisory services it provides for the Master Portfolios. For services provided to the Underlying Funds, BFA receives investment advisory fees from the Underlying Funds. In addition, BTC provides administration services to certain of the Underlying Funds and, for those services, may receive administration fees from those Underlying Funds. BFA has contractually agreed to waive its management fees at the Master Portfolio level in an amount equal to management and administration fees, if any, paid by the Underlying Funds to BFA and BTC, respectively, through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc. ("BlackRock"). As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the LifePath Portfolios' annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS


Dagmar Nikles, Leslie Gambon, Alan Mason and Amy Whitelaw (the "Portfolio Management Team") are jointly and primarily responsible for the day-to-day management of the Master Portfolios and act collaboratively on all aspects concerning the Master Portfolios. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of their team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy, and overseeing members of his or her portfolio management team with more limited responsibilities.

Ms. Nikles has been employed as a Senior Investment Strategist in the defined contributions team at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A ("BGI")) since December 2009. From July 2003 to November 2009, Ms. Nikles was a member of the asset allocation portfolio management team at BGFA and BGI. Ms. Nikles has been a one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since June 2005.

Ms. Gambon has been employed as a member of the asset allocation portfolio management team at BFA and BTC since April 2007. From October 2004 to April 2007, Ms. Gambon was Head of Defined Contribution Portfolio Management at BGI. Ms. Gambon has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since May 2007.

Mr. Mason has been employed by BFA and BTC since December 2009. Mr. Mason is responsible for multi-asset class solutions for institutional clients. From 1991 to 2009, Mr. Mason served a variety of roles at BGFA and BGI, including eight years devoted to the development of transition management products. Mr. Mason has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since September 2009.

Ms. Whitelaw has been employed as Head of Defined Contributions Portfolio Management at BFA and BTC since December 2009. From October 2009 to November 2009, Ms. Whitelaw was Head of Defined Contributions Portfolio Management at BGFA and BGI. Ms. Whitelaw had been employed as a member of the portfolio management team at

54

BGFA and BGI since July 2006. From April 2002 to April 2005, Ms. Whitelaw worked as a transition manager and strategist in the Transition Services group at BGFA and BGI.

The LifePath Portfolios' SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers' ownership of shares in the LifePath Portfolios.

ADMINISTRATIVE SERVICES


Pursuant to an Administration Agreement between the Trust, on behalf of the LifePath Portfolios, and BTC, BTC provides the following services, among others, as the LifePath Portfolios' administrator:

. Supervises the LifePath Portfolios' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. With respect to the other Classes of the LifePath Portfolios, engaging and supervising the shareholder servicing agent (the "Shareholder Servicing Agent") on behalf of the LifePath Portfolios.

BTC is entitled to receive fees for these services at the annual rate of 0.15% of the average daily net assets of Class K Shares of each LifePath Portfolio. In addition to performing these services, BTC has agreed to bear all costs of operating the LifePath Portfolios, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the LifePath Portfolios or the Trust as defined in the 1940 Act and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and the PNC Financial Services Group, Inc. and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch & Co, Inc. and its affiliates, including Bank of America ("BAC") (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the LifePath Portfolios. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the LifePath Portfolios. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the LifePath Portfolios. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the LifePath Portfolios.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the LifePath Portfolios for appropriate investment opportunities. The results of the LifePath Portfolios investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the LifePath Portfolios could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the LifePath Portfolios may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the LifePath Portfolios. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the LifePath Portfolios.

55

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolios have retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolios to the extent that the Master Portfolios participate in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolios, including a fee based on the returns earned on the Master Portfolios' investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolios may lend their portfolio securities under the securities lending program.

VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. Each LifePath Portfolio calculates the net asset value of each class of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00
p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

Each LifePath Portfolio's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. Each LifePath Portfolio values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If a LifePath Portfolio invests in foreign securities, these securities may trade on weekends or other days when the LifePath Portfolio does not price its shares. As a result, a LifePath Portfolio's net asset value may change on days when you will not be able to purchase or redeem the LifePath Portfolio's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a LifePath Portfolio's shares are determined as of such times. When market quotations are not readily available or are not believed by BFA to be reliable, a LifePath Portfolio's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the LifePath Portfolio. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value.

A LifePath Portfolio may accept orders from certain authorized financial intermediaries or their designees. A LifePath Portfolio will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the LifePath Portfolio after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN LIFEPATH PORTFOLIO POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The LifePath Portfolios are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a LifePath Portfolio may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The LifePath Portfolios reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the LifePath Portfolios to verify their identity. The LifePath Portfolios also reserve the right to redeem any amounts in a LifePath Portfolio from persons whose identity it is unable to verify on a timely basis. It is the LifePath Portfolios' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

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BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

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Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Class K Shares of each LifePath Portfolio for the past five years or, if shorter, since inception. Certain information reflects financial results for a single Class K Share of each LifePath Portfolio. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Class K Shares of a given LifePath Portfolio, assuming reinvestment of all distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each LifePath Portfolio's financial statements, is included in the LifePath Portfolios' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-441-7762 (toll-free) from 8:00 a.m. to 6:00 p.m. Eastern time on any business day.

LIFEPATH RETIREMENT PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         CLASS K SHARES
                                                         -----------------------------------------------
                                                                                                  PERIOD
                                                                  YEAR ENDED               MAY 30, 20081
                                                                DECEMBER 31,             TO DECEMBER 31,
                                                                        2009                        2008
                                                         -------------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                  --                         -
 Net asset value, beginning of period                       $      9.44             $     11.46
----------------------------------------------------        ------------            ------------
Net investment income                                             0.352                    0.25
----------------------------------------------------        ------------            ------------
 Net realized and unrealized gain (loss)                          1.33                       (1.97)
----------------------------------------------------        ------------            ------------
Net increase (decrease) from investment operations                1.68                       (1.72)
----------------------------------------------------        ------------            --------------
 Dividends and distributions from:
  Net investment income                                           (0.34)                     (0.26)
  Net realized gain                                               (0.00)/3/                  (0.04)
----------------------------------------------------       ----- ---------          --------------
Total dividends and distributions                                 (0.34)                     (0.30)
----------------------------------------------------        --------------          --------------
 Net asset value, end of period                            $     10.78              $      9.44
----------------------------------------------------       ---------------          --------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------       ---------------          --------------
 Based on net asset value                                       18.53   %                   (15.53)%/5/
----------------------------------------------------       ---------------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------       ---------------          ------------------
 Total expenses                                                  0.74   %                     0.79%/7 /
----------------------------------------------------       ---------------          ------------------
Total expenses after expense reductions                          0.40   %                     0.44%/7 /
----------------------------------------------------       ---------------          ------------------
 Net investment income                                           3.43   %                     4.08%/7 /
----------------------------------------------------       ---------------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------       ---------------          ------------------
 Net assets, end of period (000)                           $        292             $           35
----------------------------------------------------       ---------------          ------------------
Portfolio turnover of the Master Portfolio                            6%                        11%
----------------------------------------------------       ---------------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

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LIFEPATH 2020 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                          CLASS K SHARES
                                                         ------------------------------------------------
                                                                                                   PERIOD
                                                                   YEAR ENDED               MAY 30, 20081
                                                                 DECEMBER 31,             TO DECEMBER 31,
                                                                         2009                        2008
                                                         --------------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                   --                         -
 Net asset value, beginning of period                       $     12.33              $     16.90
----------------------------------------------------        -------------            ------------
Net investment income                                             0.402                     0.30
----------------------------------------------------        -------------            ------------
 Net realized and unrealized gain (loss)                          2.35                        (4.48)
----------------------------------------------------        -------------            ------------
Net increase (decrease) from investment operations                2.75                   (     4.18)
----------------------------------------------------        -------------            --------------
 Dividends and distributions from:
  Net investment income                                       (     0.47)                (     0.27)
  Net realized gain                                                    -                 (     0.12)
  Return of capital                                           (     0.00)/3/                      -
----------------------------------------------------        ---------------          --------------
Total dividends and distributions                             (     0.47)                (     0.39)
----------------------------------------------------        ---------------          --------------
 Net asset value, end of period                             $     14.61              $     12.33
----------------------------------------------------        ---------------          --------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------        ---------------          --------------
 Based on net asset value                                        23.15   %                   (25.28)%/5/
----------------------------------------------------        ---------------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------        ---------------          ------------------
 Total expenses                                                   0.73   %                     0.76%/7 /
----------------------------------------------------        ---------------          ------------------
Total expenses after expense reductions                           0.37   %                     0.42%/7 /
----------------------------------------------------        ---------------          ------------------
 Net investment income                                            3.05   %                     4.27%/7 /
----------------------------------------------------        ---------------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------        ---------------          ------------------
 Net assets, end of period (000)                            $        967             $          416
----------------------------------------------------        ---------------          ------------------
Portfolio turnover of the Master Portfolio                             6%                        13%
----------------------------------------------------        ---------------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

59

LIFEPATH 2030 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                          CLASS K SHARES
                                                         ------------------------------------------------
                                                                                                   PERIOD
                                                                   YEAR ENDED               MAY 30, 20081
                                                                 DECEMBER 31,             TO DECEMBER 31,
                                                                         2009                        2008
                                                         --------------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                   --                         -
 Net asset value, beginning of period                       $     10.92              $     16.07
----------------------------------------------------        -------------            ------------
Net investment income                                             0.382                     0.25
----------------------------------------------------        -------------            ------------
 Net realized and unrealized gain (loss)                          2.40                        (5.09)
----------------------------------------------------        -------------            ------------
Net increase (decrease) from investment operations                2.78                   (     4.84)
----------------------------------------------------        -------------            --------------
 Dividends and distributions from:
  Net investment income                                       (     0.40)                (     0.23)
  Net realized gain                                                    -                 (     0.08)
  Return of capital                                           (     0.00)/3/                      -
----------------------------------------------------        ---------------          --------------
Total dividends and distributions                             (     0.40)                (     0.31)
----------------------------------------------------        ---------------          --------------
 Net asset value, end of period                             $     13.30              $     10.92
----------------------------------------------------        ---------------          --------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------        ---------------          --------------
 Based on net asset value                                        26.23   %                   (30.65)%/5/
----------------------------------------------------        ---------------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------        ---------------          ------------------
 Total expenses                                                   0.71   %                     0.73%/7 /
----------------------------------------------------        ---------------          ------------------
Total expenses after expense reductions                           0.35   %                     0.39%/7 /
----------------------------------------------------        ---------------          ------------------
 Net investment income                                            3.19   %                     3.44%/7 /
----------------------------------------------------        ---------------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------        ---------------          ------------------
 Net assets, end of period (000)                            $        396             $           95
----------------------------------------------------        ---------------          ------------------
Portfolio turnover of the Master Portfolio                             7%                        13%
----------------------------------------------------        ---------------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

60

LIFEPATH 2040 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       CLASS K SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED               MAY 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                 -                      -
 Net asset value, beginning of period                     $     12.87          $     20.11
----------------------------------------------------      -----------          ------------
Net investment income                                            0.382                0.31
----------------------------------------------------      ------------         ------------
 Net realized and unrealized gain (loss)                         3.21                   (7.21)
----------------------------------------------------      ------------         ------------
Net increase (decrease) from investment operations               3.59              (     6.90)
----------------------------------------------------      ------------         --------------
 Dividends and distributions from:
  Net investment income                                     (     0.43)            (     0.26)
  Net realized gain                                                  -             (     0.08)
----------------------------------------------------      ------------         --------------
Total dividends and distributions                           (     0.43)            (     0.34)
----------------------------------------------------      ------------         --------------
 Net asset value, end of period                           $     16.03          $     12.87
----------------------------------------------------      ------------         --------------
TOTAL INVESTMENT RETURN/3/
----------------------------------------------------      ------------         --------------
 Based on net asset value                                        28.52%                (34.75)%/4/
----------------------------------------------------      ------------         ------------------
RATIOS TO AVERAGE NET ASSETS/5/
----------------------------------------------------      ------------         ------------------
 Total expenses                                                   0.70%                  0.69%/6 /
----------------------------------------------------      ------------         ------------------
Total expenses after expense reductions                           0.34%                  0.36%/6 /
----------------------------------------------------      ------------         ------------------
 Net investment income                                            2.73%                  3.31%/6 /
----------------------------------------------------      ------------         ------------------
SUPPLEMENTAL DATA
----------------------------------------------------      ------------         ------------------
 Net assets, end of period (000)                          $         11         $            6
----------------------------------------------------      ------------         ------------------
Portfolio turnover of the Master Portfolio                           6%                    14%
----------------------------------------------------      ------------         ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Not annualized.

/5/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/6/ Annualized.

61

LIFEPATH 2050 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       CLASS K SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED              JUNE 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                 -                      -
 Net asset value, beginning of period                     $     13.46          $     20.00
----------------------------------------------------      -----------          -------------
Net investment income                                            0.642                0.17
----------------------------------------------------      ------------         -------------
 Net realized and unrealized gain (loss)                         3.49                   (6.57)
----------------------------------------------------      ------------         -------------
Net increase (decrease) from investment operations               4.13              (     6.40)
----------------------------------------------------      ------------         --------------
 Dividends and distributions from:
  Net investment income                                     (     0.19)            (     0.11)
  Net realized gain                                         (     0.55)            (     0.00)/3 /
  Return of capital                                                  -             (     0.03)
----------------------------------------------------      ------------         -----------------
Total dividends and distributions                           (     0.74)            (     0.14)
----------------------------------------------------      ------------         -----------------
 Net asset value, end of period                           $     16.85          $     13.46
----------------------------------------------------      ------------         -----------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------      ------------         -----------------
 Based on net asset value                                        30.89%                (32.10)%/5/
----------------------------------------------------      ------------         ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------      ------------         ------------------
 Total expenses                                                   1.37%                 12.41%/7 /
----------------------------------------------------      ------------         ------------------
Total expenses after expense reductions                           0.58%                  0.29%/7 /
----------------------------------------------------      ------------         ------------------
 Net investment income                                            4.34%                  3.94%/7 /
----------------------------------------------------      ------------         ------------------
SUPPLEMENTAL DATA
----------------------------------------------------      ------------         ------------------
 Net assets, end of period (000)                          $         55         $           24
----------------------------------------------------      ------------         ------------------
Portfolio turnover of the Master Portfolio                          12%                     0%/8/
----------------------------------------------------      ------------         ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

/8/ Rounds to less than 1% .

62

DISCLAIMERS

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible

63

for and has not participated in the determination of the prices and amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

64

The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE Licensor Parties. None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/

NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of

65

Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

66

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the LifePath Portfolios is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the LifePath Portfolio's investments. The annual report describes the LifePath Portfolio's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and LifePath Portfolio investment strategies that significantly affected the LifePath Portfolio's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION

A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each LifePath Portfolio, may be obtained free of charge, along with each LifePath Portfolio's annual and semi-annual reports, by calling (800) 441-7762, on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the LifePath Portfolios, please:

Call:       1-800-441-7762 (toll free)
            8:00 a.m. to 6:00 p.m. (Eastern time),
            on any business day

WORLD WIDE WEB

General LifePath Portfolio information and specific LifePath Portfolio performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com.

WRITTEN CORRESPONDENCE

BlackRock Funds III
PO Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

INTERNAL WHOLESALERS/BROKER DEALER SUPPORT
Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), on any business day. Call: (800) 882-0052.

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the LifePath Portfolios' policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about a LifePath Portfolio, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-LCK-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
LIFEPATH(Reg. TM) PORTFOLIOS

CLASS R SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

PORTFOLIO                                                     TICKER SYMBOL
---------------------------------------------------------     --------------
LifePath(Reg. TM) Retirement Portfolio - Class R Shares                LPRRX
LifePath 2020 Portfolio(Reg. TM) - Class R Shares                      LPRMX
LifePath 2030 Portfolio(Reg. TM) - Class R Shares                      LPRNX
LifePath 2040 Portfolio(Reg. TM) - Class R Shares                      LPRKX
LifePath(Reg. TM) 2050 Portfolio - Class R Shares                      LPRPX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

LIFEPATH PORTFOLIO

  KEY FACTS AND DETAILS ABOUT THE LIFEPATH PORTFOLIOS, INCLUDING
OVERVIEW
  INVESTMENT OBJECTIVES, PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND
  EXPENSE INFORMATION, AND HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO.....................  1
  KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO...........................  7
  KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO........................... 14
  KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO........................... 21
  KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO........................... 28

DETAILS ABOUT THE LIFEPATH PORTFOLIOS

INVESTMENT TIME HORIZONS....................................... 35
A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES........ 36
A FURTHER DISCUSSION OF RISK FACTORS........................... 42

ACCOUNT INFORMATION

DETAILS ABOUT CLASS R SHARES............................ 48
DISTRIBUTION AND SERVICE PAYMENTS....................... 48
HOW TO BUY, SELL AND TRANSFER SHARES.................... 49
ACCOUNT SERVICES AND PRIVILEGES......................... 52
LIFEPATH PORTFOLIOS' RIGHTS............................. 52
CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE........ 53
LIFEPATH PORTFOLIO DISTRIBUTIONS........................ 53
SHORT TERM TRADING POLICY............................... 53
TAXES................................................... 54
MASTER/FEEDER AND FUND OF FUNDS STRUCTURES.............. 55

MANAGEMENT OF THE LIFEPATH PORTFOLIOS

INVESTMENT ADVISER...................................... 56
PORTFOLIO MANAGERS...................................... 56
ADMINISTRATIVE SERVICES................................. 57
CONFLICTS OF INTEREST................................... 57
VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS............. 58
CERTAIN LIFEPATH PORTFOLIO POLICIES..................... 58

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE LIFEPATH PORTFOLIOS........ 60
DISCLAIMERS............................................. 65

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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LifePath Retirement Portfolio Overview

KEY FACTS ABOUT LIFEPATH RETIREMENT PORTFOLIO

INVESTMENT OBJECTIVE

LifePath Retirement Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors seeking income and moderate long-term growth of capital. LifePath Retirement Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH RETIREMENT PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class R Shares (formerly, Class R-1 Shares) of LifePath Retirement Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.50%
 Other Expenses                                                                               0.52%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.02%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     1.70%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.35%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath Retirement Master Portfolio (the "Retirement Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the Retirement Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the Retirement Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath Retirement Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath Retirement Portfolio and the Retirement Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath Retirement Portfolio and the Retirement Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath Retirement Portfolio's PRO RATA share of the fees and expenses incurred by investing certain other funds including the underlying fees.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class R Shares of LifePath Retirement Portfolio and the Retirement Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the Retirement Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class R Shares of LifePath Retirement Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class R Shares of LifePath Retirement Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class R Shares of LifePath Retirement Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  137       $  466        $  855        $  1,948

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PORTFOLIO TURNOVER

The Retirement Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath Retirement Portfolio's performance. During the most recent fiscal year, the Retirement Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH RETIREMENT PORTFOLIO


LifePath Retirement Portfolio invests all of its assets in the Retirement Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath Retirement Portfolio is designed for investors seeking current income and moderate long-term growth of capital. As of March 31, 2010, LifePath Retirement Portfolio held approximately 39% of its assets in Underlying Funds that invest primarily in equity securities, 61% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in real estate investment trusts ("REITs"), foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. Because LifePath Retirement Portfolio is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain LifePath Retirement Portfolio's risk profile.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH RETIREMENT PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath Retirement Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath Retirement Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath Retirement Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath Retirement Portfolio.

. ALLOCATION RISK - LifePath Retirement Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath Retirement Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath Retirement Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath Retirement Portfolio's use of derivatives may reduce LifePath Retirement Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath Retirement Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative.

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Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath Retirement Portfolio will lose money. These risks include:

. LifePath Retirement Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath Retirement Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath Retirement Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath Retirement Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath Retirement Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath Retirement Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath Retirement Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath Retirement Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath Retirement Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath Retirement Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

3

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath Retirement Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath Retirement Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath Retirement Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath Retirement Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath Retirement Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Class R Shares offered in this Prospectus are expected to have substantially similar annual returns since Institutional and Class R Shares are invested in the same Master Portfolios.
ANNUAL RETURNS FOR CLASS R SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE CLASS R SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES. The bar chart shows the returns for Institutional Shares of LifePath Retirement Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath Retirement Portfolio to that of the LifePath Retirement Portfolio Custom Benchmark. The LifePath Retirement Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of the asset classes in which LifePath Retirement Portfolio invests according to their weightings as of the most recent quarter- end. Effective March 15, 2004, the returns for Institutional Shares of LifePath Retirement Portfolio reflect the Retirement Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath Retirement Portfolio reflect the direct investment by the Retirement Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath Retirement Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path Retirement Portfolio expenses during these periods, Life Path Retirement Portfolio's returns would have been lower.

LIFEPATH RETIREMENT PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    4.73%
2001    3.60%
2002   -2.70%
2003   11.95%
2004    6.35%
2005    4.32%
2006    8.80%
2007    4.50%
2008  -15.04%
2009   18.25%

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During the periods shown in the bar chart, the highest return for a quarter was 9.85% (quarter ended September 30, 2009) and the lowest return for a quarter was -7.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 2.79%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath Retirement Portfolio - Institutional Shares
  Return Before Taxes                                                                       18.25%       3.57%       4.12%
  Return After Taxes on Distributions                                                       17.09%       2.38%       2.79%
  Return After Taxes on Distributions and Sale of Fund Shares                               11.89%       2.49%       2.84%
 LifePath Retirement Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         16.75%       4.06%       5.09%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER


The Retirement Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                         THE
                      RETIREMENT
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath Retirement Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath Retirement Portfolio, you should contact LifePath Retirement Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath Retirement Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath

5

Retirement Portfolio may reduce or waive these investment minimums in some cases:

                                CLASS R SHARES
                                ===================================================

Minimum Initial Investment      $100 for certain retirement accounts and qualified
                                employee benefit plans

Minimum Additional Investment   No subsequent minimum

TAX INFORMATION

LifePath Retirement Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath Retirement Portfolio through a broker-dealer or other financial intermediary, LifePath Retirement Portfolio and BlackRock Investments, LLC, LifePath Retirement Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath Retirement Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath Retirement Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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LifePath 2020 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2020 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2020 Portfolio, a series of BlackRock Funds III (the "Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020. LifePath 2020 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2020 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class R Shares of LifePath 2020 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.50%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.33%
 Total Annual Class Operating Expenses(5)                                                     1.69%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.34)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.35%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2020 Master Portfolio (the "2020 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2020 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2020 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2020 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services in connection with LifePath 2020 Portfolio and the 2020 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2020 Portfolio and the 2020 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2020 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class R Shares of LifePath 2020 Portfolio and the 2020 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2020 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class R Shares of LifePath 2020 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class R Shares of LifePath 2020 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class R Shares of LifePath 2020 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  137       $  465        $  852        $  1,939

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PORTFOLIO TURNOVER

The 2020 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2020 Portfolio's performance. During the most recent fiscal year, the 2020 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2020 PORTFOLIO


LifePath 2020 Portfolio invests all of its assets in the 2020 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds (the "Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2020 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2020. As of March 31, 2010, LifePath 2020 Portfolio held approximately 60% of its assets in Underlying Funds that invest primarily in equity securities, 40% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. As the stated time horizon approaches, the allocation will become more conservative and have lower expected returns.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2020 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2020 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2020 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

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The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2020 Portfolio, and determine whether any changes are required to enable LifePath 2020 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2020 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2020 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2020 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2020 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2020 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2020 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2020 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2020 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2020 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2020 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2020 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2020 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2020 Portfolio.

. ALLOCATION RISK - LifePath 2020 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2020 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or groups of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2020 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2020 Portfolio's use of derivatives may reduce LifePath 2020 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2020 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

9

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2020 Portfolio will lose money. These risks include:

. LifePath 2020 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2020 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2020 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2020 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2020 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2020 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2020 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2020 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2020 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2020 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

10

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2020 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2020 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2020 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2020 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2020 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Class R Shares offered in this Prospectus are expected to have substantially similar annual returns since Institutional and Class R Shares are invested in the same Master Portfolios. ANNUAL RETURNS FOR CLASS R SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE CLASS R SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES. The bar chart shows the returns for Institutional Shares of LifePath 2020 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2020 Portfolio to that of the LifePath 2020 Portfolio Custom Benchmark. The LifePath 2020 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2020 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2020 Portfolio reflect the 2020 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2020 Portfolio reflect the direct investment by the 2020 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2020 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2020 Portfolio expenses during these periods, Life Path 2020 Portfolio's returns would have been lower.

LIFEPATH 2020 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -3.74%
2001    -6.42%
2002   -12.59%
2003    20.61%
2004     9.27%
2005     6.54%
2006    13.01%
2007     3.34%
2008   -25.42%
2009    22.71%

During the periods shown in the bar chart, the highest return for a quarter was 13.89% (quarter ended June 30, 2009) and the lowest return for a quarter was -14.21% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.30%.

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AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2020 Portfolio - Institutional Shares
  Return Before Taxes                                                                       22.71%       2.63%       1.68%
  Return After Taxes on Distributions                                                       21.50%       1.81%       0.89%
  Return After Taxes on Distributions and Sale of Fund Shares                               14.84%       1.94%       1.08%
 LifePath 2020 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         22.84%       3.27%       2.78%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2020 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2020
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2020 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2020 Portfolio, you should contact LifePath 2020 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2020 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2020 Portfolio may reduce or waive these investment minimums in some cases:

                                CLASS R SHARES
                                ===================================================

Minimum Initial Investment      $100 for certain retirement accounts and qualified
                                employee benefit plans

Minimum Additional Investment   No subsequent minimum

TAX INFORMATION

LifePath 2020 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2020 Portfolio through a broker-dealer or other financial intermediary, LifePath 2020 Portfolio and BlackRock Investments, LLC, LifePath 2020 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2020 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2020 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

13

LifePath 2030 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2030 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2030 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030. LifePath 2030 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2030 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class R Shares of LifePath 2030 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.50%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.70%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.35%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2030 Master Portfolio (the "2030 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2030 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2030 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2030 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2030 Portfolio and the 2030 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2030 Portfolio and the 2030 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2030 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class R Shares of LifePath 2030 Portfolio and the 2030 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2030 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class R Shares of LifePath 2030 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class R Shares of LifePath 2030 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class R Shares of LifePath 2030 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  137       $  466        $  855        $  1,948

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PORTFOLIO TURNOVER

The 2030 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2030 Portfolio's performance. During the most recent fiscal year, the 2030 Master Portfolio's portfolio turnover rate was 7% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2030 PORTFOLIO


LifePath 2030 Portfolio invests all of its assets in the 2030 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2030 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2030. As of March 31, 2010, LifePath 2030 Portfolio held approximately 75% of its assets in Underlying Funds that invest primarily in equity securities, 25% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2030 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2030 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2030 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

15

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2030 Portfolio, and determine whether any changes are required to enable LifePath 2030 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2030 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2030 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2030 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2030 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2030 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2030 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2030 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2030 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2030 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2030 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2030 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2030 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2030 Portfolio.

. ALLOCATION RISK - LifePath 2030 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2030 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2030 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2030 Portfolio's use of derivatives may reduce LifePath 2030 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2030 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

16

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2030 Portfolio will lose money. These risks include:

. LifePath 2030 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2030 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2030 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2030 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2030 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2030 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2030 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2030 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2030 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2030 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

17

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2030 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2030 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2030 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2030 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2030 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Class R Shares offered in this Prospectus are expected to have substantially similar annual returns since Institutional and Class R Shares are invested in the same Master Portfolios. ANNUAL RETURNS FOR CLASS R SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE CLASS R SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES. The bar chart shows the returns for Institutional Shares of LifePath 2030 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2030 Portfolio to that of the LifePath 2030 Portfolio Custom Benchmark. The LifePath 2030 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2030 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2030 Portfolio reflect the 2030 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2030 Portfolio reflect the direct investment by the 2030 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2030 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2030 Portfolio expenses during these periods, Life Path 2030 Portfolio's returns would have been lower.

LIFEPATH 2030 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -5.65%
2001    -9.94%
2002   -15.73%
2003    23.86%
2004    10.78%
2005     7.63%
2006    15.12%
2007     2.64%
2008   -31.03%
2009    25.77%

During the periods shown in the bar chart, the highest return for a quarter was 16.61% (quarter ended June 30, 2009) and the lowest return for a quarter was -17.90% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.62%.

18

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2030 Portfolio - Institutional Shares
  Return Before Taxes                                                                       25.77%       1.98%        0.81%
  Return After Taxes on Distributions                                                       24.68%       1.10%       -0.09%
  Return After Taxes on Distributions and Sale of Fund Shares                               16.88%       1.48%        0.39%
 LifePath 2030 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         27.05%       2.70%        1.82%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%       -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%        6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%        2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%        2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%        7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%        9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2030 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2030
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles       2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason          2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

19

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2030 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2030 Portfolio, you should contact LifePath 2030 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2030 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2030 Portfolio may reduce or waive these investment minimums in some cases:

                                CLASS R SHARES
                                ===================================================

Minimum Initial Investment      $100 for certain retirement accounts and qualified
                                employee benefit plans

Minimum Additional Investment   No subsequent minimum

TAX INFORMATION

LifePath 2030 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2030 Portfolio through a broker-dealer or other financial intermediary, LifePath 2030 Portfolio and BlackRock Investments, LLC, LifePath 2030 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2030 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2030 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

20

LifePath 2040 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2040 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2040 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040. LifePath 2040 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2040 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class R Shares of LifePath 2040 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.50%
 Other Expenses                                                                               0.51%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.01%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     1.70%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.35)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.35%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2040 Master Portfolio (the "2040 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2040 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2040 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2040 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to LifePath 2040 Portfolio and the 2040 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, Class R Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2040 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class R Shares of LifePath 2040 Portfolio and the 2040 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2040 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class R Shares of LifePath 2040 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class R Shares of LifePath 2040 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class R Shares of LifePath 2040 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  137       $  466        $  855        $  1,948

21

PORTFOLIO TURNOVER

The 2040 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2040 Portfolio's performance. During the most recent fiscal year, the 2040 Master Portfolio's portfolio turnover rate was 6% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2040 PORTFOLIO


LifePath 2040 Portfolio invests all of its assets in the 2040 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of the equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2040 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2040. As of March 31, 2010, LifePath 2040 Portfolio held approximately 88% of its assets in Underlying Funds that invest primarily in equity securities, 12% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index. As the stated time horizon approaches, the allocation will become more conservative and have lower expected returns.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2040 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2040 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2040 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

22

The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2040 Portfolio, and determine whether any changes are required to enable LifePath 2040 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2040 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2040 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2040 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2040 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2040 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2040 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2040 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2040 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2040 PORTFOLIO

Risk is inherent in all investing. The value of your investment in LifePath 2040 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2040 Portfolio or your investment may not perform as well as other similar investments. The following is a summary description of certain risks of investing in LifePath 2040 Portfolio. An investment in LifePath 2040 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

. ALLOCATION RISK - LifePath 2040 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2040 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or groups of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2040 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2040 Portfolio's use of derivatives may reduce LifePath 2040 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2040 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

23

. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2040 Portfolio will lose money. These risks include:

. LifePath 2040 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2040 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2040 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2040 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2040 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2040 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2040 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2040 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2040 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2040 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

24

. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2040 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2040 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2040 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2040 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2040 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Class R Shares offered in this Prospectus are expected to have substantially similar annual returns since Institutional and Class R Shares are invested in the same Master Portfolios. ANNUAL RETURNS FOR CLASS R SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE CLASS R SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES. The bar chart shows the returns for Institutional Shares of LifePath 2040 Portfolio for each of the last ten calendar years. The average annual total return table compares the performance of Institutional Shares of LifePath 2040 Portfolio to that of the LifePath 2040 Portfolio Custom Benchmark. The LifePath 2040 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2040 Portfolio invests according to their weightings as of the most recent quarter-end. Effective March 15, 2004, the returns for Institutional Shares of LifePath 2040 Portfolio reflect 2040 Master Portfolio's investment in Underlying Funds. For all periods prior to March 15, 2004, the returns for Institutional Shares of LifePath 2040 Portfolio reflect the direct investment by 2040 Master Portfolio in a portfolio of securities and also reflect investment in accordance with a model that included "tactical," or short-term, shifts in allocation between stocks and bonds. How LifePath 2040 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2040 Portfolio expenses during these periods, Life Path 2040 Portfolio's returns would have been lower.

LIFEPATH 2040 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    -9.71%
2001   -13.41%
2002   -18.73%
2003    27.64%
2004    11.43%
2005     8.24%
2006    16.97%
2007     2.03%
2008   -35.40%
2009    28.08%

During the periods shown in the bar chart, the highest return for a quarter was 19.00% (quarter ended June 30, 2009) and the lowest return for a quarter was -20.80% (quarter ended December 31, 2008). The year-to-date return as of March 31, 2010 was 3.88%.

25

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                                               1 YEAR     5 YEARS     10 YEARS
 LifePath 2040 Portfolio - Institutional Shares
  Return Before Taxes                                                                       28.08%       1.34%      -0.35%
  Return After Taxes on Distributions                                                       27.18%       0.87%      -0.88%
  Return After Taxes on Distributions and Sale of Fund Shares                               18.45%       1.08%      -0.43%
 LifePath 2040 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                         30.52%       2.15%       0.87%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                        27.25%       0.69%      -0.20%
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                          5.93%       4.97%       6.33%
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         43.60%       6.04%       2.69%
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                      0.16%       2.88%       2.84%
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                       11.41%       4.63%       7.69%
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                         38.25%       2.00%       9.21%

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2040 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2040
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

26

PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2040 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2040 Portfolio, you should contact LifePath 2040 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2040 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2040 Portfolio may reduce or waive these investment minimums in some cases:

                                CLASS R SHARES
                                ===================================================

Minimum Initial Investment      $100 for certain retirement accounts and qualified
                                employee benefit plans

Minimum Additional Investment   No subsequent minimum

TAX INFORMATION

LifePath 2040 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2040 Portfolio through a broker-dealer or other financial intermediary, LifePath 2040 Portfolio and BlackRock Investments, LLC, LifePath 2040 Portfolio's distributor, or its affiliates may pay the intermediary for the sale of LifePath 2040 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2040 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

27

LifePath 2050 Portfolio Overview

KEY FACTS ABOUT LIFEPATH 2050 PORTFOLIO

INVESTMENT OBJECTIVE

LifePath 2050 Portfolio, a series of BlackRock Funds III ("the Trust"), is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050. LifePath 2050 Portfolio's investment objective may be changed by the Trust's Board of Trustees without shareholder approval.

FEES AND EXPENSES OF LIFEPATH 2050 PORTFOLIO


The table below describes the fees and expenses that you may pay if you buy and hold Class R Shares of LifePath 2050 Portfolio.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                            0.35%
 Distribution and/or Service (12b-1) Fees                                                     0.50%
 Other Expenses                                                                               0.83%
  Administration Fees                                                                         0.50%
  Independent Expenses(2)(3)                                                                  0.33%
 Acquired Fund Fees and Expenses (Underlying Funds)(4)                                        0.34%
 Total Annual Class Operating Expenses(5)                                                     2.02%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                             (0.67)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                       1.35%
  Reimbursements(1)(3)(5)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to LifePath 2050 Master Portfolio (the "2050 Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive its management fee at the 2050 Master Portfolio level in an amount equal to the management fees and administration fees, if any, received by BFA or BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), from each investment company in which the 2050 Master Portfolio invests through the close of business on November 30, 2011 (the "contractual waiver"). The contractual waiver may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of LifePath 2050 Portfolio's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services in connection with LifePath 2050 Portfolio and the 2050 Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, LifePath 2050 Portfolio and the 2050 Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) "Acquired Fund Fees and Expenses (Underlying Funds)" reflect LifePath 2050 Portfolio's PRO RATA share of the fees and expenses incurred by investing in certain other funds including the underlying funds.

(5) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of Class R Shares of LifePath 2050 Portfolio and the 2050 Master Portfolio and also reflect a weighted average of the total operating expense ratios of the underlying funds in which the 2050 Master Portfolio invests.

EXAMPLE

This Example is intended to help you compare the cost of investing in Class R Shares of LifePath 2050 Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Class R Shares of LifePath 2050 Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Class R Shares of LifePath 2050 Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS        10 YEARS
$  137       $  500        $  961        $  2,237

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PORTFOLIO TURNOVER

The 2050 Master Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These costs, which are not reflected in annual class operating expenses or in the example, affect LifePath 2050 Portfolio's performance. During the most recent fiscal year, the 2050 Master Portfolio's portfolio turnover rate was 12% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES OF LIFEPATH 2050 PORTFOLIO


LifePath 2050 Portfolio invests all of its assets in the 2050 Master Portfolio, a separate mutual fund with a substantially identical investment objective, which allocates and reallocates its assets among a combination of equity, bond and money market funds ("the Underlying Funds") in proportions based on its own comprehensive investment strategy.

LifePath 2050 Portfolio is designed for investors expecting to retire or to begin withdrawing assets around the year 2050. As of March 31, 2010, LifePath 2050 Portfolio held approximately 98% of its assets in Underlying Funds that invest primarily in equity securities, 1% of its assets in Underlying Funds that invest primarily in bonds and the remainder of its assets in Underlying Funds that invest primarily in money market instruments. Certain Underlying Funds may invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a commodity, a currency or an index.

Under normal circumstances, the asset allocation will change over time according to a predetermined "glide path" as LifePath 2050 Portfolio approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, LifePath 2050 Portfolio's asset mix becomes more conservative - both prior to and after retirement - as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of LifePath 2050 Portfolio, which may be a primary source of income after retirement.

The following chart illustrates the glide path - the target allocation among asset classes as LifePath Portfolios approach their target dates:

[GRAPHIC APPEARS HERE]

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The asset allocation targets are established by the portfolio managers working with oversight from a committee of BFA investment professionals. The investment team, including the portfolio managers and this investment committee, meets regularly to assess market conditions, review the asset allocation targets of LifePath 2050 Portfolio, and determine whether any changes are required to enable LifePath 2050 Portfolio to achieve its investment objective.

Although the asset allocation targets listed for the "glide path" are general, long term targets, BFA may periodically adjust the proportion of equity funds and fixed-income funds in LifePath 2050 Portfolio, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of LifePath 2050 Portfolio. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect LifePath 2050 Portfolio or achieve its investment objective.

BFA's second step in the structuring of LifePath 2050 Portfolio is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in LifePath 2050 Portfolio are considered when selecting Underlying Funds. The specific Underlying Funds selected for LifePath 2050 Portfolio are determined at BFA's discretion and may change as deemed appropriate to allow LifePath 2050 Portfolio to meet its investment objective. See "A Further Discussion of Principal Investment Strategies" section of the Prospectus for a complete list of the Underlying Funds, their classification into equity or fixed-income funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income funds, BFA seeks to diversify LifePath 2050 Portfolio. The equity allocation may be further diversified by style (including both value and growth funds), market capitalization (including both large cap and small cap funds), globally (including domestic and international (including emerging market) funds), or other factors. The fixed-income allocation may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non-investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. The percentage allocation to the various styles of equity and fixed-income are determined at the discretion of the investment team and can be changed to reflect the current market environment.

PRINCIPAL RISKS OF INVESTING IN LIFEPATH 2050 PORTFOLIO


Risk is inherent in all investing. The value of your investment in LifePath 2050 Portfolio, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in LifePath 2050 Portfolio or your investment may not perform as well as other similar investments. An investment in LifePath 2050 Portfolio is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a summary description of certain risks of investing in LifePath 2050 Portfolio.

. ALLOCATION RISK - LifePath 2050 Portfolio's ability to achieve its investment goal depends upon BFA's skill in determining LifePath 2050 Portfolio's strategic asset class allocation and in selecting the best mix of Underlying Funds. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions.

. CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

. DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of LifePath 2050 Portfolio's investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

. DERIVATIVES RISK - LifePath 2050 Portfolio's use of derivatives may reduce LifePath 2050 Portfolio's returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of LifePath 2050 Portfolio's use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets.

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. EMERGING MARKETS RISK - Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

. EQUITY SECURITIES RISK - Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

. EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall.

. FOREIGN SECURITIES RISK - Foreign investments often involve special risks not present in U.S. investments that can increase the chances that LifePath 2050 Portfolio will lose money. These risks include:

. LifePath 2050 Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

. Changes in foreign currency exchange rates can affect the value of LifePath 2050 Portfolio's portfolio.

. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries.

. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

. INVESTMENTS IN MUTUAL FUNDS AND EXCHANGE TRADED FUNDS RISK - LifePath 2050 Portfolio will invest substantially all of its assets in underlying BlackRock funds, so LifePath 2050 Portfolio's investment performance is directly related to the performance of the Underlying Funds. LifePath 2050 Portfolio may also directly invest in exchange traded funds ("ETFs"). LifePath 2050 Portfolio's net asset value ("NAV") will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in LifePath 2050 Portfolio will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs.

. JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for LifePath 2050 Portfolio.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which LifePath 2050 Portfolio invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage- and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. Mortgage- and asset- backed securities are subject to credit, interest rate, prepayment and extension risks. These securities also are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

. PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for certain Underlying Funds, those Underlying Funds may hold stocks in companies that present risks that an adviser researching individual stocks might seek to avoid.

. PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and LifePath 2050 Portfolio may have to invest the proceeds in securities with lower yields.

. REIT INVESTMENT RISK - Investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

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. SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, LifePath 2050 Portfolio may lose money and there may be a delay in recovering the loaned securities. LifePath 2050 Portfolio could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for LifePath 2050 Portfolio.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which LifePath 2050 Portfolio may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of LifePath 2050 Portfolio by showing the changes in their performance from year to year. Although Institutional Shares are not offered in this prospectus ("Prospectus"), the returns for Institutional Shares are provided herein because Class R Shares offered in this Prospectus are expected to have substantially similar annual returns since Institutional and Class R Shares are invested in the same Master Portfolios. ANNUAL RETURNS FOR CLASS R SHARES WOULD DIFFER FROM ANNUAL RETURNS FOR INSTITUTIONAL SHARES BECAUSE CLASS R SHARES ARE EXPECTED TO HAVE HIGHER EXPENSES THAN INSTITUTIONAL SHARES. The bar chart shows the returns for Institutional Shares of LifePath 2050 Portfolio for the last calendar year. The average annual total return table compares the performance of Institutional Shares of LifePath 2050 Portfolio to that of the LifePath 2050 Portfolio Custom Benchmark. The LifePath 2050 Portfolio Custom Benchmark, a customized weighted index comprised of the different indexes set forth in the table below, is representative of of the asset classes in which LifePath 2050 Portfolio invests according to their weightings as of the most recent quarter-end. How LifePath 2050 Portfolio performed in the past (before and after taxes) is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Life Path 2050 Portfolio expenses during these periods, Life Path 2050 Portfolio's returns would have been lower.

LIFEPATH 2050 PORTFOLIO - INSTITUTIONAL SHARES

ANNUAL TOTAL RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   30.35%

During the period shown in the bar chart, the highest return for a quarter was 21.06% (quarter ended June 30, 2009) and the lowest return for a quarter was -12.76% (quarter ended March 31, 2009). The year-to-date return as of March 31, 2010 was 4.14%.

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                                                                                                                 SINCE
AS OF 12/31/09                                                                                               INCEPTION JUNE
AVERAGE ANNUAL TOTAL RETURNS                                                                   1 YEAR           30, 2008
 LifePath 2050 Portfolio - Institutional Shares
  Return Before Taxes                                                                           30.35%          -7.86%
  Return After Taxes on Distributions                                                           28.59%          -8.77%
  Return After Taxes on Distributions and Sale of Fund Shares                                   19.85%          -7.12%
 LifePath 2050 Portfolio Custom Benchmark (Reflects no deductions for fees,
 expenses or taxes)                                                                             34.11%          -6.38%
 S&P 1500 Index (Reflects no deductions for fees, expenses or taxes)                            27.25%            N/A
 Barclays Capital U.S. Aggregate Bond Index (Reflects no deductions for fees,
 expenses or taxes)                                                                              5.93%             N/A
 MSCI All Country World Index ex US IMI Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             43.60%            N/A
 Citigroup 3-Month Treasury Bill Index (Reflects no deductions for fees, expenses or
 taxes)                                                                                          0.16%             N/A
 Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)
 (Reflects no deductions for fees, expenses or taxes)                                           11.41%            N/A
 FTSE EPRA/NAREIT Global Real Estate Index (Reflects no deductions for fees,
 expenses or taxes)                                                                             38.25%             N/A

After-tax returns in the table above are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax- deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

INVESTMENT ADVISER

The 2050 Master Portfolio's investment manager is BFA.

PORTFOLIO MANAGERS

                      PORTFOLIO
                      MANAGER OF
                       THE 2050
                        MASTER
                      PORTFOLIO
NAME                    SINCE        TITLE
 Dagmar Nikles          2005            Director of BTC
 Leslie Gambon       2007            Director of BTC
 Alan Mason             2009            Managing Director of BTC
 Amy Whitelaw        2010            Director of BTC

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PURCHASE AND SALE OF SHARES

You may purchase or redeem shares of LifePath 2050 Portfolio on each day the New York Stock Exchange ("NYSE") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold shares through LifePath 2050 Portfolio, you should contact LifePath 2050 Portfolio by phone at (800) 441-7762 or by mail c/o BlackRock Funds III, P.O. Box 9819, Providence, RI 02940-8019. LifePath 2050 Portfolio's initial and subsequent investment minimums generally are as follows, although LifePath 2050 Portfolio may reduce or waive these investment minimums in some cases:

                                CLASS R SHARES
                                ===================================================

Minimum Initial Investment      $100 for certain retirement accounts and qualified
                                employee benefit plans

Minimum Additional Investment   No subsequent minimum

TAX INFORMATION

LifePath 2050 Portfolio's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of LifePath 2050 Portfolio through a broker-dealer or other financial intermediary, LifePath 2050 Portfolio and BlackRock Investments, LLC, LifePath 2050 Portfolio's distributor or its affiliates may pay the intermediary for the sale of LifePath 2050 Portfolio shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend LifePath 2050 Portfolio over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the LifePath Portfolios

INVESTMENT TIME HORIZONS

Each LifePath Portfolio seeks to maximize return consistent with the quantitatively measured risk that investors on average may be willing to accept given a particular investment time horizon. An investor's time horizon marks the point when the investor plans to start making net withdrawals from his or her investments, in other words, the time when they will cease making new contributions to their investments. For many LifePath Portfolio investors, their time horizon is tied to the date that they plan to retire and begin gradually utilizing their investment to support themselves in retirement. For other LifePath Portfolio investors, their time horizon may represent the date when they plan to make substantial withdrawals for another purpose, such as a major purchase.

As a general rule, investors with a longer time horizon have a greater tolerance for risk than investors with a shorter time horizon. Long-term investors are more likely to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns. Each LifePath Portfolio has its own time horizon, as described in its investment objective in each LifePath Portfolio's "Key Facts" section in this Prospectus, which affects the targeted risk level of that LifePath Portfolio and, in turn, its asset allocation.

The allocations for LifePath Retirement Portfolio reflect the expectation that investors in or near retirement, or otherwise seeking current income, are willing to take some risk of loss of their investment in hopes of achieving moderate long term growth of capital. LifePath Retirement Portfolio is designed to help balance two risk factors that investors face during retirement: market risk (potential declines in market values) and longevity risk (living longer than expected). Specifically, the portfolio seeks to enable investors to maintain a steady withdrawal rate (about 3-5% per year) throughout their retirement without exhausting their investment. There is no guarantee that the performance of LifePath Retirement Portfolio will be sufficient to enable this withdrawal rate or that any one withdrawal rate is appropriate for all investors. Investors should work with a financial advisor or other expert to determine a sustainable withdrawal rate for their circumstances, and that withdrawal rate should be periodically reassessed throughout retirement as the value of the investor's portfolio changes.

Each LifePath Portfolio has a distinct investment objective tied to its time horizon:

. LifePath Retirement Portfolio is managed for investors seeking income and moderate long-term growth of capital.

. LifePath 2020 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2020.

. LifePath 2030 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2030.

. LifePath 2040 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2040.

. LifePath 2050 Portfolio is managed for investors planning to retire (or begin to withdraw substantial portions of their investment) approximately in the year 2050.

You should carefully consider the asset allocation and risks of each LifePath Portfolio before deciding whether to invest.

The LifePath Portfolios are designed to offer individual investors comprehensive asset allocation strategies tailored to the time when they expect to begin withdrawing assets. Asset allocation is the distribution of investments among broad types of asset classes: equity securities, bonds and money market instruments. Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has the same objective and strategies as the applicable LifePath Portfolio. LifePath Retirement Portfolio invests all of its assets in Retirement Master Portfolio. LifePath 2020 Portfolio invests all of its assets in 2020 Master Portfolio. LifePath 2030 Portfolio invests all of its assets in 2030 Master Portfolio. LifePath 2040 Portfolio invests all of its assets in 2040 Master Portfolio. LifePath 2050 Portfolio invests all of its assets in 2050 Master Portfolio. To implement the asset allocation strategy, each Master Portfolio, in turn, invests in a combination of Underlying Funds in proportions based on its own comprehensive investment strategy that gradually becomes more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase. BFA is the investment adviser to the Master Portfolios. For simplicity's sake, all discussion of investment objective, strategies and risks of a particular LifePath Portfolio refers also to the

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investment objective, strategies and risks of the applicable Master Portfolio, unless otherwise indicated. A description of the relationship of the LifePath Portfolios to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder and Fund of Funds Structures."

WHICH LIFEPATH PORTFOLIO TO CONSIDER

The first step in choosing which LifePath Portfolio to consider is answering a key question: When will you need the money you are thinking of investing? Will it be in ten years, when your kids are ready for college? Or 30 years, when you retire?

The number in the name of most of the LifePath Portfolios is actually a year - a "target year" when you might expect to begin withdrawing your money. Selecting the LifePath Portfolio that may be most appropriate for your investment may be as simple as matching your target year with the closest LifePath Portfolio target year.

For example, let's say that you are investing for retirement purposes, and that you expect to retire at age 60. If you are 45 years old, you have 15 years before retirement. By adding 15 to the current year, you can define your "target year." If you expect to retire in the year 2025, as in this example, you may conclude that LifePath 2020 Portfolio is the most appropriate LifePath Portfolio for you.

The investment mix of the LifePath Portfolios gradually shifts from a greater concentration of higher-risk investments (namely, equity securities funds) to a greater concentration of lower-risk investments (namely, bond funds), thereby making the LifePath Portfolios increasingly conservative.

In making your investment decision, you should keep in mind:

. The LifePath Portfolios' investment strategies derive from the risk tolerance of average investors with a particular time horizon.

. The LifePath Portfolios' time horizons are based on the year in their name, except for LifePath Retirement Portfolio, which is designed for investors who are currently withdrawing, or plan in the near future to begin withdrawing, a substantial portion of their investment.

If you are willing to accept a greater risk of loss in exchange for the potential to achieve higher long-term returns, you may invest some or all of your assets in a LifePath Portfolio with a longer time horizon. If you desire a more conservative investment and are willing to forego some potential returns, you may invest some or all of your assets in a LifePath Portfolio with a shorter time horizon. The final choice is yours.

A FURTHER DISCUSSION OF PRINCIPAL INVESTMENT STRATEGIES

Each LifePath Portfolio invests all of its assets in a corresponding Master Portfolio which allocates and reallocates its assets among the Underlying Funds. The Master Portfolios with longer time horizons invest a greater portion of their assets in Underlying Funds that invest in equity securities, which provide a greater opportunity for capital appreciation over the long-term but have a greater risk of loss. The Master Portfolios with shorter time horizons invest a greater portion of their assets in Underlying Funds that invest in bonds and money market instruments, which typically offer reduced risk and price volatility but forego some potential returns. Accordingly, under normal circumstances, the LifePath Portfolios with shorter time horizons have lower expected returns than the LifePath Portfolios with longer time horizons. In addition to investing in Underlying Funds, each Master Portfolio may borrow, lend its portfolio securities to brokers, dealers and financial institutions, and invest the collateral in certain short-term instruments either directly or through one or more joint accounts or money market funds, as described in greater detail in the LifePath Portfolios' combined Statement of Additional Information ("SAI").

As each Master Portfolio approaches its designated time horizon, it systematically seeks to reduce the level of risk by allocating assets more conservatively among the Underlying Funds. This systematic shift toward more conservative investments is designed to reduce the risk of significant reductions in the value of an investment in a Master Portfolio as it approaches its time horizon.

For example, LifePath Retirement Portfolio has entered its "retirement phase" and seeks to maximize returns consistent with the risk that an average investor in retirement may be willing to accept. This does not mean, however, that it invests exclusively, or primarily, in Underlying Funds that are money market funds. Rather, because BFA believes that most investors are still willing to take some risks in pursuing returns even while drawing on their investments, almost all of LifePath Retirement Portfolio's assets will continue to be allocated to Underlying Funds that are equity and bond funds.

In determining the allocation of assets to the Underlying Funds, BFA uses a proprietary investment model that analyzes securities market data, including risk, asset class correlations, and expected returns, to provide portfolio

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allocations among the asset classes represented by the Underlying Funds. The allocations are periodically monitored and rebalanced in an effort to maximize expected return for a given level of risk. In managing the LifePath Portfolios, BFA focuses on long-term targets and objectives. The progression over time of a LifePath Portfolio's asset allocation to more conservative asset classes is a relatively steady process resulting in only gradual changes to the asset allocation from quarter to quarter. The Underlying Funds invest in a mix of equity securities, bonds and money market instruments. Certain Underlying Funds invest in REITs, foreign securities, emerging markets, below investment-grade bonds and derivatives, which are subject to additional risks, as described in the "Details About the LifePath Portfolios - A Further Discussion of Risk Factors" section of this Prospectus. The investment model adjusts each LifePath Portfolio's risk level by gradually making it more conservative as the year in the LifePath Portfolio's name approaches, except for LifePath Retirement Portfolio, which is already in its most conservative phase.

When a LifePath Portfolio reaches its stated time horizon and enters its most conservative phase, the allocation of its assets is expected to be similar to that of LifePath Retirement Portfolio. Such LifePath Portfolio and LifePath Retirement Portfolio may then continue to operate as separate funds or, subject to approval by the Trust's Board of Trustees, they may be merged into a single fund.

THE UNDERLYING FUNDS

Two of the Underlying Funds - Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio - are diversified portfolios of MIP. Active Stock Master Portfolio seeks to provide long-term appreciation of capital. BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors. CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return.

The remaining Underlying Funds, other than BlackRock Cash Funds: Institutional (the "Underlying Money Market Fund"), are ETFs that are part of the iShares family of funds ("Underlying iShares Funds"). Each of the Underlying iShares Funds seeks investment results that correspond generally to the performance, before fees and expenses, of its underlying index. As a result, adverse performance of a particular security in an Underlying iShares Fund's portfolio will ordinarily not result in the elimination of the security from the Underlying iShares Fund's portfolio. Each Underlying iShares Fund offers and issues iShares at their NAV per share only to certain institutional investors in aggregations of a specified number of iShares, generally in exchange for a basket of securities included in its underlying index, together with the deposit of a specified cash payment. The iShares for these Underlying iShares Funds are listed and traded on national securities exchanges and also may be listed on certain non-U.S. exchanges. BFA purchases iShares on behalf of the Master Portfolios in the secondary market.

The relative weightings for each Master Portfolio in the various Underlying Funds will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time.

Each Master Portfolio currently expects to invest in some or all of the Underlying Funds described below:

ACTIVE STOCK MASTER PORTFOLIO

Active Stock Master Portfolio seeks to provide long-term appreciation of capital. Active Stock Master Portfolio invests, under normal circumstances, at least 80% of its assets in common stocks. Active Stock Master Portfolio invests primarily in equity securities of U.S. companies with market capitalizations similar to the range of market capitalizations represented in the Standard & Poor's ("S&P") 500 Index(Reg. TM). BFA invests Active Stock Master Portfolio's assets using a proprietary quantitative model that is designed to select stocks based on an analysis of a wide range of company-specific factors, such as relative values based on earnings and cash flows; earnings quality as measured by the company's financial condition and earnings reports; sentiment as expressed through management and market participant behavior; and industry classification. BFA considers risk parameters in deciding upon Active Stock Master Portfolio's aggregate holdings, and factors trading costs into its stock selection process.

COREALPHA BOND MASTER PORTFOLIO

CoreAlpha Bond Master Portfolio seeks to provide a combination of income and capital growth. BFA invests CoreAlpha Bond Master Portfolio's assets pursuant to a systematic method that relies on proprietary quantitative models to allocate assets among various bond sectors by evaluating each sector's relative value and risk-adjusted return. BFA's models also allocate assets among bonds of different maturities based on yield characteristics and expectations. Specific investment selection decisions are made on the basis of evaluations of relative value, credit quality and other factors. CoreAlpha Bond Master Portfolio invests, under normal circumstances, at least 80% of its assets in bonds. For the purposes of this strategy, "bonds" include the following:
obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial

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mortgage-backed securities; debt obligations of U.S. corporations; U.S. dollar-denominated debt obligations of foreign issuers; municipal securities; and asset-backed securities. CoreAlpha Bond Master Portfolio invests a substantial portion of its assets in U.S.-registered, dollar-denominated bonds. CoreAlpha Bond Master Portfolio may invest in bonds of any maturity or duration.

BLACKROCK CASH FUNDS: INSTITUTIONAL

BlackRock Cash Funds: Institutional seeks a high level of income consistent with liquidity and the preservation of capital. BlackRock Cash Funds:
Institutional invests in high-quality, short-term money market instruments that include fixed-rate, floating-rate and variable-rate debt securities. BlackRock Cash Funds: Institutional also may invest in high-quality, short-term U.S. and foreign government debt, including the debt of agencies and instrumentalities, such as the Federal National Mortgage Association ("Fannie Mae"), U.S. and foreign bank obligations, corporate obligations, repurchase agreements and asset-backed securities.

UNDERLYING ISHARES FUNDS

In managing each of the Underlying iShares Funds, BFA uses a representative sampling index strategy. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that has an investment profile similar to the underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the applicable underlying index. Underlying iShares Funds that use representative sampling may or may not hold all of the securities in the relevant underlying index.

ISHARES S&P 500 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P 500 Index(Reg. TM), which measures the performance of the large-capitalization sector of the U.S. equity market. The component stocks are weighted according to the float-adjusted market value of their outstanding shares.

ISHARES S&P MIDCAP 400 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P MidCap 400 IndexTM, which measures the performance of the mid-capitalization sector of the U.S. equity market. The stocks in the S&P MidCap 400 IndexTM have a market capitalization between $750 million and $3.3 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation. The S&P MidCap 400 IndexTM consists of stocks from a broad range of industries.

ISHARES S&P SMALLCAP 600 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P SmallCap 600 IndexTM, which measures the performance of the small-capitalization sector of the U.S. equity market. The stocks in the S&P SmallCap 600 IndexTM have a market capitalization between $200 million and $1 billion (which may fluctuate depending on the overall level of the equity markets) as of May 29, 2009 and are selected for liquidity and industry group representation.

ISHARES S&P NATIONAL AMT-FREE MUNICIPAL BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P National AMT-Free Municipal Bond Index, which measures the performance of the investment-grade segment of the U.S. municipal bond market. As of May 31, 2009, there were 8,709 issues in the S&P National AMT-Free Municipal Bond Index.

ISHARES S&P NORTH AMERICAN NATURAL RESOURCES SECTOR INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the S&P North American Natural Resources Sector IndexTM, which measures the performance of U.S.-traded stocks of natural resource-related companies in the U.S. and Canada, and includes companies in the following categories: producers of oil, gas and consumable fuels, energy equipment and services, metals and mining, manufacturers of paper and forest products, and producers of construction materials, containers and packaging.

ISHARES RUSSELL MIDCAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell Midcap Index, which measures the performance of the mid-capitalization sector of the U.S. equity market. The Russell Midcap Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000(Reg. TM) Index.

ISHARES RUSSELL 2000 INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Russell 2000 Index, which measures the performance of the small capitalization sector of the U.S. equity market. The Russell 2000 Index is a float-adjusted, capitalization-weighted index of equity securities issued by the approximately 2,000 smallest issuers in the Russell 3000(Reg. TM) Index.

ISHARES COHEN & STEERS REALTY MAJORS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Cohen & Steers Realty Major Index (the "Cohen & Steers Index"),

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which consists of selected U.S. REITs. The objective of the Cohen & Steers Index is to represent relatively large and liquid REITs that may benefit from future consolidation and securitization of the U.S. real estate industry. REITs are selected for inclusion in the Cohen & Steers Index based on a rigorous review of several factors, including management, portfolio quality, and sector and geographic diversification. The REITs selected for inclusion in the Cohen & Steers Index must meet minimum market capitalization and liquidity requirements. The Cohen & Steers Index is weighted according to the total market value of each REIT's outstanding shares and is adjusted quarterly so that no REIT represents more than 8% of the Cohen & Steers Index. Within the REIT market, the Cohen & Steers Index is diversified across property sectors that represent the current market.

ISHARES FTSE EPRA/NAREIT DEVELOPED REAL ESTATE EX-U.S. INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which measures the stock performance of companies engaged in the ownership and development of the following real estate markets defined as developed by FTSE EPRA/NAREIT: Canada, Europe (including Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom (including the Channel Islands)), Middle East (Israel) and Asia (including Australia, Hong Kong, Japan, New Zealand and Singapore). As of May 29, 2009, the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index was comprised of stocks of companies in the following markets: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong, Italy, Japan, Netherlands, New Zealand, Norway, Poland, Singapore, Spain, Sweden, Switzerland and the United Kingdom.

ISHARES MSCI CANADA INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Canada Index developed by MSCI, Inc. ("MSCI"). The MSCI Canada Index consists of stocks traded primarily on the Toronto Stock Exchange.

ISHARES MSCI EAFE INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE(Reg. TM) Index, which has been developed by MSCI as an equity benchmark for its international stock performance. The MSCI EAFE Index includes stocks from Europe, Australasia and the Far East.

ISHARES MSCI EAFE SMALL CAP INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI EAFE Small Cap Index, which represents the small cap size segment of the MSCI EAFE Index. The MSCI EAFE(Reg. TM) Index includes securities from Europe, Australasia and the Far East. Under MSCI's Global Investable Market Index methodology, the small cap universe consists of the securities of those companies whose securities are not included in the large cap or mid cap segments of a particular market, which together comprise approximately 85% of each market's free float-adjusted market capitalization. The small cap segment covers the 85%-99% range of each market's free float-adjusted market capitalization.

ISHARES MSCI EMERGING MARKETS INDEX FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the MSCI Emerging Markets Index, which is designed to measure equity market performance in the global emerging markets. As of September 30, 2009, the MSCI Emerging Markets Index consisted of the following 22 emerging market country indexes: Brazil, Chile, China, Colombia, the Czech Republic, Egypt, Hungary, India, Indonesia, Israel, Malaysia, Mexico, Morocco, Peru, the Philippines, Poland, Russia, South Africa, South Korea, Taiwan, Thailand and Turkey. Emerging market country indexes may be added to or deleted from the MSCI Emerging Markets Index from time to time. The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares funds that invest in securities in the MSCI Emerging Markets Index. BFA waives a portion of its advisory fees otherwise due from the iShares MSCI Emerging Markets Index Fund in an amount equal to the portfolio management fees incurred by assets that are invested in shares of other iShares funds.

ISHARES BARCLAYS 1-3 YEAR CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 1-3 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 1-3 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to one year and less than three years.

ISHARES BARCLAYS 3-7 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 3-7 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to three years and less than seven years.

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ISHARES BARCLAYS 7-10 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 7-10 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to seven years and less than ten years.

ISHARES BARCLAYS 10-20 YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 10-20 Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than or equal to ten years and less than 20 years.

ISHARES BARCLAYS 20+ YEAR TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. 20+ Year Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of 20 years or more.

ISHARES BARCLAYS AGGREGATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Aggregate Bond Index, which measures the performance of the total U.S. investment-grade bond market, which includes investment-grade U.S. Treasury bonds, government-related bonds, investment-grade corporate bonds, mortgage pass-through securities, commercial mortgage-backed securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Barclays Capital U.S. Aggregate Bond Index have $250 million or more of outstanding face value and have at least one year remaining to maturity. In addition, the securities must be U.S. dollar-denominated, fixed-rate and non-convertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and Eurobonds are excluded from the Barclays Capital U.S. Aggregate Bond Index. The Barclays Capital U.S. Aggregate Bond Index is market capitalization weighted and the securities are updated on the last calendar day of each month.

ISHARES BARCLAYS CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Government/Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year.

ISHARES BARCLAYS INTERMEDIATE CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Credit Bond Index, which measures the performance of investment-grade corporate debt and sovereign, supranational, local authority and non-U.S. agency bonds that are U.S. dollar-denominated and have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS INTERMEDIATE GOVERNMENT/CREDIT BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Intermediate Government/

Credit Bond Index, which measures the performance of U.S. dollar-denominated U.S. Treasuries, government-related (I.E., U.S. and foreign agencies, sovereign, supranational and local authority debt), and investment-grade credit securities that have a remaining maturity of greater than or equal to one year and less than ten years.

ISHARES BARCLAYS MBS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. MBS Index, which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Government National Mortgage Association, Fannie Mae and the Federal Home Loan Mortgage Corporation.

ISHARES BARCLAYS SHORT TREASURY BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Short Treasury Bond Index, which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of between one and 12 months.

ISHARES BARCLAYS TIPS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays Capital U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L), which measures the performance of the inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS."

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ISHARES JPMORGAN USD EMERGING MARKETS BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the JPMorgan EMBI Global Core Index, which is a broad, diverse U.S. dollar-denominated emerging markets debt benchmark which tracks the total return of actively traded external debt instruments in emerging market countries.

ISHARES IBOXX $ HIGH YIELD CORPORATE BOND FUND seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the iBoxx(Reg. TM) $ Liquid High Yield Index, which is a rules-based index consisting of liquid U.S. dollar-denominated, high yield corporate bonds for sale in the United States, as determined by the International Index Company Limited ("IIC"). The iBoxx(Reg. TM) $ Liquid High Yield Index is designed to provide a broad representation of the U.S. dollar-denominated high yield liquid corporate bond market. The iBoxx(Reg. TM) $ Liquid High Yield Index is a modified market value weighted index. There is no limit to the number of issues in the iBoxx(Reg. TM) $ Liquid High Yield Index, but as of June 30, 2009, the iBoxx(Reg. TM) $ Liquid High Yield Index included approximately 281 constituents.

The following table lists the Underlying Funds and the asset allocation for each Master Portfolio as of March 31, 2010. BFA allocates each Master Portfolio's assets among the Underlying Funds based on the Master Portfolio's investment objective and policies. The asset allocation for each Master Portfolio will vary over time, and BFA is not required to invest any Master Portfolio's assets in each of the Underlying Funds or in any particular percentage in any given Underlying Fund. BFA may add, eliminate or replace Underlying Funds at any time:

UNDERLYING FUNDS
(as of March 31, 2010)

                                                    LIFEPATH     LIFEPATH    LIFEPATH    LIFEPATH    LIFEPATH
                                                   RETIREMENT      2020        2030        2040        2050
                                                    PORTFOLIO   PORTFOLIO   PORTFOLIO   PORTFOLIO    PORTFOLIO
CAPITAL GROWTH
MIP-Active Stock Master Portfolio                     19.45%       30.45%      38.39%      44.64%       49.18%
iShares S&P MidCap 400 Index Fund                      4.93%        5.87%       6.54%       7.14%        8.10%
iShares S&P SmallCap 600 Index Fund                    2.18%        2.58%       2.89%       3.16%        3.54%
iShares MSCI EAFE Index Fund                           6.74%       10.08%      12.60%      14.73%       17.01%
iShares Cohen & Steers Realty Majors Index Fund        0.62%        1.87%       2.73%       3.50%        4.01%
iShares FTSE EPRA/NAREIT Developed Real Estate         0.99%        2.99%       4.43%       5.62%        6.40%
ex-U.S. Index Fund
iShares MSCI Emerging Markets Index Fund               2.40%        3.70%       4.66%       5.47%        6.09%
iShares MSCI Canada Index Fund                         0.82%        1.25%       1.54%       1.82%        2.02%
iShares MSCI EAFE Small Cap Index Fund                 0.81%        1.25%       1.47%       1.72%        2.00%
CAPITAL GROWTH AND INCOME
MIP-CoreAlpha Bond Master Portfolio                   51.96%       34.27%      21.48%      10.89%        0.99%
iShares Barclays TIPS Bond Fund                        8.87%        5.49%       3.08%       1.08%       N/A
INCOME
BlackRock Cash Funds: Institutional - SL Agency        0.23%        0.20%       0.19%       0.23%        0.66%
Shares


Note: The allocation percentages may not add to, or may appear to exceed, 100% due to rounding.

"Standard & Poor's(Reg. TM)," "S&P(Reg. TM)," "S&P 500 Index(Reg. TM)," "S&P MidCap 400 IndexTM," "S&P SmallCap 600 IndexTM," "S&P National AMT-Free Municipal Bond IndexTM," and "S&P North American Natural Resources Sector IndexTM" are trademarks of Standard & Poor's Financial Services LLC (a subsidiary of The McGraw-Hill Companies) licensed for use for certain purposes by BTC. The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P SmallCap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and iShares S&P North American Natural Resources Sector Index Fund that are based on S&P Indexes are not sponsored, endorsed, sold or promoted by S&P or its affiliates, and S&P and its affiliates make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"FTSE," "EPRA," "NAREIT" and "FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index" are marks that have been licensed for use for certain purposes by BTC. The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together the "FTSE Licensor Parties"), and the FTSE Licensor Parties make no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Cohen & Steers" and "Cohen & Steers Realty Majors Index" are trademarks of Cohen & Steers Capital Management, Inc. ("Cohen & Steers") licensed for use for certain purposes by BTC. The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers, and Cohen & Steers makes no representation or warranty, express or implied, regarding the advisability of investing in iShares.

"Barclays Capital Inc.," "Barclays Capital U.S. 1-3 Year Credit Bond Index," "Barclays Capital U.S. 1-3 Year Treasury Bond Index," "Barclays Capital U.S. 3-7 Year Treasury Bond Index," "Barclays Capital U.S. 7-10 Year Treasury Bond Index," "Barclays Capital U.S. 10-20 Year Treasury Bond Index," "Barclays Capital U.S. 20+ Year Treasury Bond Index," "Barclays Capital U.S. Aggregate Bond Index," "Barclays Capital U.S. Credit Bond Index," "Barclays Capital U.S. Government/Credit Bond Index," "Barclays Capital U.S. Intermediate Credit Bond Index," "Barclays Capital U.S. Intermediate Government/Credit Bond Index," "Barclays Capital U.S. MBS Index," "Barclays Capital U.S. Short Treasury Bond Index," and the "Barclays Capital

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U.S. Treasury Inflation Protected Securities (TIPS) Index (Series-L)" (collectively referred to as the "iShares Bond Fund Indexes") are trademarks of Barclays Bank PLC licensed for use for certain purposes by BTC. The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund are not sponsored, endorsed, sold or promoted by Barclays Capital Inc. ("Barclays Capital"), and Barclays Capital makes no representation or warranty, express or implied, regarding the advisability of investing in iShares. The iShares Bond Fund Indexes are maintained by Barclays Capital. Neither BTC nor BFA has or will have a role in maintaining the iShares Bond Fund Indexes.

"MSCI Canada Index/SM/," "MSCI EAFE(Reg. TM) Index" and "MSCI Emerging Markets Index/SM/" are servicemarks and "MSCI EAFE Small Cap Index" is a trademark of MSCI, and such marks have been licensed for use for certain purposes by BTC. The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI, and neither MSCI nor any other party makes any representation or warranty, express or implied, regarding the advisability of investing in iShares.

A FURTHER DISCUSSION OF RISK FACTORS

This section contains a description of the general risks of investing in the LifePath Portfolios. "Description of the LifePath Portfolios and their Investments and Risks" in the SAI also includes more information about the LifePath Portfolios, their investments and the related risks. There can be no guarantee that a LifePath Portfolio will meet its objective or that a LifePath Portfolio's performance will be positive for any period of time. An investment in a LifePath Portfolio is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or by any bank or government agency.

GENERAL

The NAV of each LifePath Portfolio's shares is neither insured nor guaranteed, is not fixed and will fluctuate.

GENERAL RISKS APPLICABLE TO THE LIFEPATH PORTFOLIOS

ALLOCATION RISK - The LifePath Portfolios' ability to achieve their investment goals depends upon BFA's skill in determining the LifePath Portfolios' strategic asset class allocation and in selecting the best mix of Underlying Funds and direct investments. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds may be incorrect in view of actual market conditions. In addition, there is no guarantee that the Underlying Funds will achieve their investment objectives, and the Underlying Funds' performance may be lower than the performance of the asset class which they were selected to represent. The Underlying Funds may change their investment objectives or policies without the approval of the LifePath Portfolios. If an Underlying Fund were to change its investment objective or policies, the LifePath Portfolios might be forced to withdraw their investment from the Underlying Fund at a disadvantageous time and price.

CONCENTRATION RISK - To the extent that an underlying index of an Underlying Fund is concentrated in the securities of companies, a particular market, industry, group of industries, sector or asset class, country, region or group of countries, that Underlying Fund may be adversely affected by the performance of those securities, may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that market, industry, group of industries, sector or asset class, country, region or group of countries.

DEBT SECURITIES RISK - Debt securities, such as bonds, involve credit risk. Credit risk is the risk that the borrower will not make timely payments of principal and interest. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the LifePath Portfolios' investment in that issuer. The degree of credit risk depends on the issuer's financial condition and on the terms of the securities. Debt securities are also subject to interest rate risk. Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

DERIVATIVES RISK - The LifePath Portfolios' use of derivatives may reduce the LifePath Portfolios' returns and/or increase volatility. Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the LifePath Portfolios' use of derivatives is that the fluctuations in their values may not correlate perfectly with the overall securities markets. Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. In addition, some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The possible lack of a liquid secondary market for derivatives and the resulting inability of the LifePath Portfolios to sell or otherwise close a derivatives position could expose the LifePath Portfolios to losses and could make derivatives more difficult for the LifePath Portfolios to value accurately. The LifePath Portfolios could also suffer losses related to their derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally,

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BFA may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the LifePath Portfolios' derivatives positions to lose value. When a derivative is used as a hedge against a position that the LifePath Portfolios hold, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the LifePath Portfolios' hedging transactions will be effective. The income from certain derivatives may be subject to U.S. federal income tax.

EMERGING MARKETS RISK - The risks of foreign investments are usually much greater for emerging markets. Investments in emerging markets may be considered speculative. Emerging markets include those in countries defined as emerging or developing by the World Bank, the International Finance Corporation or the United Nations. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience hyper-inflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain small markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing and financial reporting standards and requirements comparable to those to which U.S. companies are subject.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments are more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation, high rates of inflation or unfavorable diplomatic developments. In the past, governments of such nations have expropriated substantial amounts of private property, and most claims of the property owners have never been fully settled. There is no assurance that such expropriations will not reoccur. In such an event, it is possible that the LifePath Portfolio could lose the entire value of its investments in the affected market. Some countries have pervasiveness of corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets, which may impair investment and economic growth. National policies that may limit the LifePath Portfolio's investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other foreign or U.S. governmental laws or restrictions applicable to such investments. Sometimes, they may lack or be in the relatively early development of legal structures governing private and foreign investments and private property. In addition to withholding taxes on investment income, some countries with emerging markets may impose differential capital gains taxes on foreign investors.

EQUITY SECURITIES RISK - Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate and can decline and reduce the value of a portfolio investing in equities. The value of equity securities purchased by the LifePath Portfolios could decline if the financial condition of the companies the LifePath Portfolios invest in decline or if overall market and economic conditions deteriorate. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or an increase in production costs and competitive conditions within an industry. In addition, they may decline due to general market conditions that are not specifically related to a company or industry, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or generally adverse investor sentiment.

EXTENSION RISK - When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these securities to fall. Rising interest rates tend to extend the duration of securities, making them more sensitive to changes in interest rates. The value of longer-term securities generally changes more in response to changes in interest rates than shorter-term securities. As a result, in a period of rising interest rates, securities may exhibit additional volatility and may lose value.

FOREIGN SECURITIES RISK - Securities traded in foreign markets have often (though not always) performed differently from securities traded in the United States. However, such investments often involve special risks not present in U.S. investments that can increase the chances that the LifePath Portfolio will lose money. In particular, the LifePath Portfolio is subject to the risk that because there may be fewer investors on foreign exchanges and a smaller number of securities traded each day, it may be more difficult for the LifePath Portfolio to buy and sell securities on those exchanges. In addition, prices of foreign securities may go up and down more than prices of securities traded in the United States.

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CERTAIN RISKS OF HOLDING FUND ASSETS OUTSIDE THE UNITED STATES - The LifePath Portfolio generally holds its foreign securities and cash in foreign banks and securities depositories. Some foreign banks and securities depositories may be recently organized or new to the foreign custody business. In addition, there may be limited or no regulatory oversight of their operations. Also, the laws of certain countries limit the LifePath Portfolio's ability to recover its assets if a foreign bank, depository or issuer of a security, or any of their agents, goes bankrupt. In addition, it is often more expensive for the LifePath Portfolio to buy, sell and hold securities in certain foreign markets than in the United States. The increased expense of investing in foreign markets reduces the amount the LifePath Portfolio can earn on its investments and typically results in a higher operating expense ratio for the LifePath Portfolio than for investment companies invested only in the United States.

CURRENCY RISK - Securities and other instruments in which the LifePath Portfolio invests may be denominated or quoted in currencies other than the U.S. dollar. For this reason, changes in foreign currency exchange rates can affect the value of the LifePath Portfolio.

Generally, when the U.S. dollar rises in value against a foreign currency, a security denominated in that currency loses value because the currency is worth fewer U.S. dollars. Conversely, when the U.S. dollar decreases in value against a foreign currency, a security denominated in that currency gains value because the currency is worth more U.S. dollars. This risk, generally known as "currency risk," means that a strong U.S. dollar will reduce returns for U.S. investors while a weak U.S. dollar will increase those returns.

FOREIGN ECONOMY RISK - The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. Certain foreign economies may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. In addition, the governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Any of these actions could severely affect securities prices or impair the LifePath Portfolio's ability to purchase or sell foreign securities or transfer the LifePath Portfolio's assets or income back into the United States, or otherwise adversely affect the LifePath Portfolio's operations.

Other potential foreign market risks include foreign exchange controls, difficulties in pricing securities, defaults on foreign government securities, difficulties in enforcing legal judgments in foreign courts and political and social instability. Diplomatic and political developments, including rapid and adverse political changes, social instability, regional conflicts, terrorism and war, could affect the economies, industries and securities and currency markets, and the value of the LifePath Portfolio's investments, in non-U.S. countries. These factors are extremely difficult, if not impossible, to predict and take into account with respect to the LifePath Portfolio's investments.

GOVERNMENTAL SUPERVISION AND REGULATION/ACCOUNTING STANDARDS - Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as such regulations exist in the United States. They also may not have laws to protect investors that are comparable to U.S. securities laws. For example, some foreign countries may have no laws or rules against insider trading. Insider trading occurs when a person buys or sells a company's securities based on material non-public information about that company. In addition, some countries may have legal systems that may make it difficult for the LifePath Portfolio to vote proxies, exercise shareholder rights, and pursue legal remedies with respect to its foreign investments. Accounting standards in other countries are not necessarily the same as in the United States. If the accounting standards in another country do not require as much detail as U.S. accounting standards, it may be harder for LifePath Portfolio management to completely and accurately determine a company's financial condition.

SETTLEMENT RISK - Settlement and clearance procedures in certain foreign markets differ significantly from those in the United States. Foreign settlement and clearance procedures and trade regulations also may involve certain risks (such as delays in payment for or delivery of securities) not typically associated with the settlement of U.S. investments.

At times, settlements in certain foreign countries have not kept pace with the number of securities transactions. These problems may make it difficult for the LifePath Portfolio to carry out transactions. If the LifePath Portfolio cannot settle or is delayed in settling a purchase of securities, it may miss attractive investment opportunities and certain of its assets may be uninvested with no return earned thereon for some period. If the LifePath Portfolio cannot settle or is delayed in settling a sale of securities, it may lose money if the value of the security then declines or, if it has contracted to sell the security to another party; the LifePath Portfolio could be liable for any losses incurred.

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INVESTMENTS IN MUTUAL FUNDS AND ETFS RISK - Each LifePath Portfolio will invest substantially all of its assets in Underlying Funds, so the LifePath Portfolio's investment performance is directly related to the performance of the Underlying Funds. The LifePath Portfolios may also directly invest in ETFs. The LifePath Portfolio's net asset value will change with changes in the value of the mutual funds, ETFs and other securities in which it invests. An investment in the LifePath Portfolios will entail more direct and indirect costs and expenses than a direct investment in the Underlying Funds and ETFs. For example, the LifePath Portfolios indirectly pay a portion of the expenses (including operating expenses and management fees) incurred by the Underlying Funds and ETFs.

One Underlying Fund may buy the same securities that another Underlying Fund sells. In addition, a LifePath Portfolio may buy the same securities that an Underlying Fund sells, or vice-versa. If this happens, an investor in the LifePath Portfolio would indirectly bear the costs of these transactions without accomplishing the intended investment purpose. Also, an investor in a LifePath Portfolio may receive taxable gains from portfolio transactions by an Underlying Fund, as well as taxable gains from transactions in shares of the Underlying Fund by the LifePath Portfolio. Certain of the Underlying Funds may hold common portfolio securities, thereby reducing the diversification benefits of the LifePath Portfolios.

In order to minimize expenses, the LifePath Portfolios intend to invest in the class of shares of each Underlying Fund with the lowest shareholder fees and net fund operating expenses. As the Underlying Funds or the LifePath Portfolios' allocations among the Underlying Funds change from time to time, or to the extent that the expense ratio of the Underlying Funds changes, the weighted average operating expenses borne by the LifePath Portfolios may increase or decrease.

Underlying iShares Funds are subject to additional risks due to their shares being listed and traded on securities exchanges. There can be no assurance that an active trading market for these particular ETFs will develop or be maintained. Trading in ETFs may be halted because of market conditions or for reasons that, in the view of the listing exchange, make trading in ETFs inadvisable. In addition, trading in ETFs is subject to trading halts caused by extraordinary market volatility pursuant to "circuit breaker" rules. There can be no assurance that the requirements necessary to maintain the listing of ETFs will continue to be met or will remain unchanged. An ETF may trade at, above or below its NAV. The NAV of an ETF will fluctuate with changes in the market value of its holdings. The trading price of an ETF will generally fluctuate in accordance with changes in its NAV, as well as market supply and demand.

JUNK BONDS RISK - Although junk bonds generally pay higher rates of interest than investment grade bonds, junk bonds are high risk investments that may cause income and principal losses for the LifePath Portfolios. The major risks of junk bond investments include:

. Junk bonds may be issued by less creditworthy issuers. Issuers of junk bonds may have a larger amount of outstanding debt relative to their assets than issuers of investment grade bonds. In the event of an issuer's bankruptcy, claims of other creditors may have priority over the claims of junk bond holders, leaving few or no assets available to repay junk bond holders.

. Prices of junk bonds are subject to extreme price fluctuations. Adverse changes in an issuer's industry and general economic conditions may have a greater impact on the prices of junk bonds than on other higher rated fixed-income securities.

. Issuers of junk bonds may be unable to meet their interest or principal payment obligations because of an economic downturn, specific issuer developments, or the unavailability of additional financing.

. Junk bonds frequently have redemption features that permit an issuer to repurchase the security from the LifePath Portfolios before it matures. If the issuer redeems junk bonds, the LifePath Portfolios may have to invest the proceeds in bonds with lower yields and may lose income.

. Junk bonds may be less liquid than higher rated fixed-income securities, even under normal economic conditions. There are fewer dealers in the junk bond market, and there may be significant differences in the prices quoted for junk bonds by the dealers. Because they are less liquid, judgment may play a greater role in valuing certain of the LifePath Portfolios' securities than is the case with securities trading in a more liquid market.

. The LifePath Portfolios may incur expenses to the extent necessary to seek recovery upon default or to negotiate new terms with a defaulting issuer.

. The credit rating of a high yield security does not necessarily address its market value risk. Ratings and market value may change from time to time, positively or negatively, to reflect new developments regarding the issuer.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the LifePath Portfolios invest will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection

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risk is the risk that the securities selected by fund management will underperform the markets, the relevant indexes or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

MORTGAGE- AND ASSET-BACKED SECURITIES RISK - Mortgage-backed securities (residential and commercial) and asset-backed securities represent interests in "pools" of mortgages or other assets, including consumer loans or receivables held in trust. The characteristics of these mortgage-backed and asset-backed securities differ from traditional fixed-income securities. Like traditional fixed-income securities, the value of asset-backed securities typically increases when interest rates fall and decreases when interest rates rise. However, a main difference is that the principal on mortgage- or asset-backed securities may normally be prepaid at any time, which will reduce the yield and market value of these securities. Therefore, mortgage- and asset-backed backed securities are subject to "prepayment risk" and "extension risk." Because of prepayment risk and extension risk, mortgage-backed securities react differently to changes in interest rates than other fixed-income securities.

Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. The LifePath Portfolios' investments in asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. These securities also are subject to the risk of default on the underlying mortgage or assets, particularly during periods of economic downturn. Certain CMBS are issued in several classes with different levels of yield and credit protection. The LifePath Portfolios' investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit and prepayment risks.

Mortgage-backed securities may be either pass-through securities or collateralized mortgage obligations ("CMOs"). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only (IOs), principal only (POs) or an amount that remains after other floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as "mortgage derivatives" and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the LifePath Portfolios invest in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by BFA, it is possible that the LifePath Portfolios could lose all or substantially all of their investment.

The residential mortgage market in the United States recently has experienced difficulties that may adversely affect the performance and market value of certain of the LifePath Portfolios' mortgage-related investments. Delinquencies and losses on residential mortgage loans (especially subprime and second-lien mortgage loans) generally have increased recently and may continue to increase, and a decline in or flattening of housing values (as has recently been experienced and may continue to be experienced in many housing markets) may exacerbate such delinquencies and losses. Also, a number of residential mortgage loan originators have recently experienced serious financial difficulties or bankruptcy. Reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen.

Asset-backed securities entail certain risks not presented by mortgage-backed securities, including the risk that in certain states it may be difficult to perfect the liens securing the collateral backing certain asset-backed securities. In addition, certain asset-backed securities are based on loans that are unsecured, which means that there is no collateral to seize if the underlying borrower defaults. Certain mortgage-backed securities in which the LifePath Portfolios may invest may also provide a degree of investment leverage, which could cause the LifePath Portfolios to lose all or substantially all of their investment.

PASSIVE INVESTMENT RISK - Because BFA does not select individual companies in the underlying indexes for the Underlying iShares Funds, those Underlying iShares Funds may hold stocks in companies that present risks that an investment adviser researching individual stocks might seek to avoid.

PREPAYMENT RISK - When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the LifePath Portfolios may have to invest their proceeds in securities with lower yields. In periods of falling interest rates, the rate of prepayments tends to increase (as does price fluctuation) as borrowers are motivated to pay off debt and refinance at new lower rates. During such periods, reinvestment of the prepayment

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proceeds by the management team will generally be at lower rates of return than the return on the assets that were prepaid. Prepayment reduces the yield to maturity and the average life of the security.

REIT INVESTMENT RISK - In addition to the risks facing real estate-related securities, such as a decline in property values due to increasing vacancies, a decline in rents resulting from unanticipated economic, legal or technological developments or a decline in the price of securities of real estate companies due to a failure of borrowers to pay their loans or poor management, investments in REITs involve unique risks. REITs may have limited financial resources, may trade less frequently and in limited volume and may be more volatile than other securities.

SECURITIES LENDING RISK - Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, the LifePath Portfolios may lose money and there may be a delay in recovering the loaned securities. The LifePath Portfolios could also lose money if they do not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could trigger adverse tax consequences for the LifePath Portfolios.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

Each LifePath Portfolio must maintain cash balances to meet redemption requests, which may lower overall portfolio performance.

FOR A DESCRIPTION OF THE LIFEPATH PORTFOLIOS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THEIR MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A FURTHER DISCUSSION OF THE LIFEPATH PORTFOLIOS' INVESTMENTS AND RISKS, PLEASE REFER TO THE LIFEPATH PORTFOLIOS' SAI.

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Account Information

DETAILS ABOUT CLASS R SHARES

MINIMUM INVESTMENT

The initial and subsequent investment minimums for Class R Shares of the LifePath Portfolios generally are as follows, although the LifePath Portfolios may reduce or waive these investment minimums in some cases:

MINIMUM INITIAL         $100 for certain retirement accounts and qualified employee benefit plans
INVESTMENT
MINIMUM ADDITIONAL      No subsequent minimum
INVESTMENT

Class R Shares are available only to certain retirement and qualified employee benefit plans. If you buy Class R Shares, you will pay neither an initial sales charge nor a contingent deferred sales charge. However, Class R Shares are subject to a distribution fee of 0.25% per year and a service fee of 0.25% per year. Because these fees are paid out of a LifePath Portfolio's assets on an ongoing basis, over time these fees increase the cost of your investment and may cost you more than paying other types of sales charges.

Class R Shares do not offer a conversion privilege.

BlackRock Investments, LLC (the "Distributor") currently pays the annual Class R Shares distribution fee and annual Class R Shares service fee to dealers as an ongoing concession and as a shareholder servicing fee, respectively, on a monthly basis.

DISTRIBUTION AND SERVICE PAYMENTS


The LifePath Portfolios have adopted a shareholder servicing plan (the "Plan") with respect to Class R Shares that allow each LifePath Portfolio to pay shareholder servicing fees for certain services provided to its Class R shareholders under Rule 12b-1 of the Investment Company Act of 1940, as amended (the "1940 Act").

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (including BlackRock, Inc., The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co., Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a LifePath Portfolio's shares. Because the fees paid by a LifePath Portfolio under the Plan are paid out of LifePath Portfolio assets on an ongoing basis, over time these fees will increase the cost of your investment in the LifePath Portfolios and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a LifePath Portfolio may pay to a Financial Intermediary pursuant to the Plan and fees a LifePath Portfolio pays to PNC Global Investment Servicing (U.S.) Inc. (the "Transfer Agent"), BFA, on behalf of a LifePath Portfolio, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the LifePath Portfolio will pay the Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of LifePath Portfolio shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

The Plan permits BFA, the Distributor and their affiliates to make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to the LifePath Portfolios). From time to time, BFA, the Distributor or their affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA, the Distributor and their affiliates may compensate affiliated and unaffiliated Financial Intermediaries for the sale and distribution of shares of the LifePath Portfolios or for these other services to the LifePath Portfolios and shareholders. These payments would be in addition to the LifePath Portfolio payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by

48

BFA, the Distributor and their affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a LifePath Portfolio to you. Please contact your Financial Intermediary for details about payments it may receive from a LifePath Portfolio or from BFA, the Distributor or their affiliates. For more information, see the LifePath Portfolios' SAI.

HOW TO BUY, SELL AND TRANSFER SHARES


The chart on the following pages summarizes how to buy, sell and transfer shares through your financial professional or other financial intermediary. You may also buy, sell and transfer shares through BlackRock, if your account is held directly with BlackRock. To learn more about buying, selling or transferring shares through BlackRock, call (800) 441-7762. Because the selection of a mutual fund involves many considerations, your financial professional or other financial intermediary may help you with this decision.

Each LifePath Portfolio may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholders and suspend and resume the sale of any share class of the LifePath Portfolio at any time for any reason.

In addition, the LifePath Portfolios may waive certain requirements regarding the purchase, sale, exchange or transfer of shares described below.

                    HOW TO BUY SHARES
                   YOUR CHOICES
INITIAL PURCHASE    Determine the amount of your
                   investment
                    Have your financial intermediary
                   submit your purchase order
                    Or contact BlackRock (for
                   accounts held directly with
                   BlackRock)
ADD TO YOUR         Purchase additional shares
INVESTMENT
                    Have your financial professional or
                   financial intermediary submit your
                   purchase order for additional shares
                    Or contact BlackRock (for accounts
                   held directly with BlackRock)

                   IMPORTANT INFORMATION FOR YOU TO KNOW
INITIAL PURCHASE    There is a $100 minimum for certain retirement accounts and qualified
                   employee benefit plans.
                    The price of your shares is based on the next calculation of a LifePath
                   Portfolio's NAV after your order is placed. Any purchase orders placed prior
                   to the close of business on the NYSE (generally 4:00 p.m. Eastern time)
                   will be priced at the NAV determined that day. Certain financial
                   intermediaries, however, may require submission of orders prior to that
                   time. A broker-dealer or financial institution maintaining the account in
                   which you hold shares may charge a separate account, service or
                   transaction fee on the purchase or sale of Fund shares that would be in
                   addition to the fees and expenses shown in each LifePath Portfolio's "Fees
                   and Expenses" table. Purchase orders placed after that time will be priced
                   at the NAV determined on the next business day. The LifePath Portfolios
                   may reject any order to buy shares and may suspend the sale of shares at
                   any time. Financial intermediaries may charge a processing fee to confirm
                   a purchase.
                    To purchase shares directly from BlackRock, call (800) 441-7762 and
                   request a new account application. Mail the completed application along
                   with a check payable to "BlackRock Funds" to the Transfer Agent at the
                   address on the application.
ADD TO YOUR         There is no minimum investment for additional purchases.
INVESTMENT
                    To purchase additional shares you may contact your financial professional
                   or financial intermediary.
                    PURCHASE BY TELEPHONE: Call (800) 441-7762 and speak with one of our
                   representatives. The LifePath Portfolios have the right to reject any
                   telephone request for any reason.
                   PURCHASE IN WRITING: You may send a written request to BlackRock at the
                   address on the back cover of this Prospectus.

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                                                       HOW TO BUY SHARES
                 YOUR CHOICES                     IMPORTANT INFORMATION FOR YOU TO KNOW
                  Acquire additional shares by     All dividends and capital gains distributions are automatically reinvested
                 reinvesting dividends and        without a sales charge. To make any changes to your dividend and/or
                 capital gains                    capital gains distributions options, please call (800) 441-7762, or contact
                                                  your financial professional (if your account is not held directly with
                                                  BlackRock).
HOW TO PAY FOR    Making payment for               Payment for an order must be made in Federal funds or other immediately
SHARES           purchases                        available funds by the time specified by your financial professional or other
                                                  financial intermediary, but in no event later than 4:00 p.m. (Eastern time)
                                                  on the first business day (in the case of Class R Shares) following
                                                  BlackRock's receipt of the order. If payment is not received by this time,
                                                  the order will be canceled and you and your financial professional or other
                                                  financial intermediary will be responsible for any loss to the LifePath
                                                  Portfolios.
                                                  For shares purchased directly from the LifePath Portfolio, a check payable
                                                  to "BlackRock Funds," which bears the name of the LifePath Portfolio you
                                                  are purchasing must accompany a completed purchase application.

               HOW TO SELL SHARES
                  YOUR CHOICES                     IMPORTANT INFORMATION FOR YOU TO KNOW
FULL OR PARTIAL    Have your financial              You can make redemption requests through your financial professional.
REDEMPTION OF     intermediary submit your         Shareholders should indicate that they are redeeming Class R Shares. The
SHARES            sales order                      price of your shares is based on the next calculation of a LifePath
                                                   Portfolio's NAV after your order is placed. For your redemption request to
                                                   be priced at the NAV on the day of your request, you must submit your
                                                   request to your financial intermediary prior to that day's close of business
                                                   on the NYSE (generally 4:00 p.m. Eastern time). Certain financial
                                                   intermediaries, however, may require submission of orders prior to that
                                                   time. Any redemption request placed after that time will be priced at the
                                                   NAV at the close of business on the next business day.
                                                   Financial intermediaries may charge a fee to process a redemption of
                                                   shares.
                                                   The LifePath Portfolios may reject an order to sell shares under certain
                                                   circumstances.
                   Selling shares held directly     METHODS OF REDEEMING
                  with BlackRock
                                                   REDEEM BY TELEPHONE: You may sell shares held at BlackRock via
                                                   telephone request by telephoning (800) 441-7762.
                                                    The LifePath Portfolios, their administrator and the Distributor will employ
                                                   reasonable procedures to confirm that instructions communicated by
                                                   telephone are genuine. The LifePath Portfolios and their service providers
                                                   will not be liable for any loss, liability, cost or expense for acting upon
                                                   telephone instructions that are reasonably believed to be genuine in
                                                   accordance with such procedures. The LifePath Portfolios may refuse a
                                                   telephone redemption request if they believe it is advisable to do so.
                                                   During periods of substantial economic or market change, telephone
                                                   redemptions may be difficult to complete. Please find below alternative
                                                   redemption methods.

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HOW TO SELL SHARES
            YOUR CHOICES    IMPORTANT INFORMATION FOR YOU TO KNOW
                             REDEEM IN WRITING: You may sell shares held at BlackRock by writing to
                            BlackRock. All shareholders on the account must sign the letter. A
                            medallion signature guarantee will generally be required but may be
                            waived in certain limited circumstances. You can obtain a medallion
                            signature guarantee stamp from a bank, securities dealer, securities
                            broker, credit union, savings and loan association, national securities
                            exchange or registered securities association. A notary public seal will not
                            be acceptable. If you hold stock certificates, return the certificates with
                            the letter. Proceeds from redemptions may be sent via check, ACH or wire
                            to the bank account of record.
                             PAYMENT OF REDEMPTION PROCEEDS BY WIRE TRANSFER: Payment for
                            redeemed shares for which a redemption order is received before 4:00
                            p.m. (Eastern time) on a business day is normally made in Federal funds
                            wired to the redeeming shareholder on the next business day, provided
                            that the LifePath Portfolios' custodian is also open for business. Payment
                            for redemption orders received after 4:00 p.m. (Eastern time) or on a day
                            when the LifePath Portfolios' custodian is closed is normally wired in
                            Federal funds on the next business day following redemption on which
                            the LifePath Portfolios' custodian is open for business. The LifePath
                            Portfolios reserve the right to wire redemption proceeds within seven days
                            after receiving a redemption order if, in the judgment of the LifePath
                            Portfolio, an earlier payment could adversely affect a LifePath Portfolio.
                             No charge for wiring redemption payments with respect to Class R Shares
                            is imposed by the LifePath Portfolios, although plans may charge their
                            customer accounts for redemption services. Information relating to such
                            redemption services and charges, if any, should be obtained by customers
                            from their plans.
                            The LifePath Portfolios are not responsible for the efficiency of the Federal
                            wire system or the shareholder's firm or bank. To change the name of the
                            single, designated bank account to receive wire redemption proceeds, it is
                            necessary to send a written request to the LifePath Portfolio at the
                            address on the back cover of this Prospectus.

                                                HOW TO TRANSFER YOUR ACCOUNT
                     YOUR CHOICES              IMPORTANT INFORMATION FOR YOU TO KNOW
TRANSFER SHARES TO    Transfer to a             You may transfer your Class R Shares of a LifePath Portfolio only to
ANOTHER SECURITIES   participating             another financial professional or financial intermediary that has an
DEALER OR OTHER      financial                 agreement with the Distributor. Certain shareholder services may not be
FINANCIAL            professional or           available for the transferred shares. All future trading of these assets must
INTERMEDIARY         other                     be coordinated by the receiving firm.
                     financial
                                               If your account is held directly with BlackRock, you may call (800) 441-
                     intermediary
                                               7762 with any questions; otherwise please contact your financial
                                               intermediary to accomplish the transfer of shares.
                      Transfer to a             You must either:
                     non-participating         oTransfer your Class R Shares to an account with a LifePath Portfolio; or
                     financial professional    oSell your shares, paying any applicable deferred sales charge.
                     or other
                                               If your account is held directly with BlackRock, you may call (800) 441-
                     financial intermediary
                                               7762 with any questions; otherwise please contact your financial
                                               intermediary to accomplish the transfer of shares.

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LIFEPATH PORTFOLIOS' RIGHTS

Each LifePath Portfolio may:

. Suspend the right of redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act,

. Postpone date of payment upon redemption if trading is halted or restricted on the NYSE or under other emergency conditions described in the 1940 Act or if a redemption request is made before a LifePath Portfolio has collected payment for the purchase of shares,

. Redeem shares for property other than cash if conditions exist which make cash payments undesirable in accordance with its rights under the 1940 Act, and

. Redeem shares involuntarily in certain cases, such as when the value of a shareholder account falls below a specified level.

NOTE ON LOW BALANCE ACCOUNTS. Because of the high cost of maintaining smaller shareholder accounts, a LifePath Portfolio may redeem the shares in your account (without charging any deferred sales charge) if the NAV of your account falls below $500 due to redemptions you have made. You will be notified that the value of your account is less than $500 before a LifePath Portfolio makes an involuntary redemption. You will then have 60 days to make an additional investment to bring the value of your account to at least $500 before a LifePath Portfolio takes any action. This involuntary redemption does not apply to accounts of authorized qualified employee benefit plans, selected fee-based programs or accounts established under the Uniform Gifts or Transfers to Minors Acts.

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CALCULATING THE LIFEPATH PORTFOLIOS' SHARE PRICE

Each LifePath Portfolio's share price (also known as a LifePath Portfolio's NAV) is calculated by dividing the value of the net assets of the LifePath Portfolio (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the LifePath Portfolio, generally rounded to the nearest cent.

Each LifePath Portfolio's NAV is calculated at the close of regular trading on the NYSE (generally, 4:00 p.m. Eastern Time) on any Business Day. If regular trading on the NYSE closes early, the time for calculating each LifePath Portfolio's NAV and the deadline for share transactions will be accelerated to the earlier closing time. The NAV of each LifePath Portfolio is calculated based on the NAV of the Master Portfolio in which the LifePath Portfolio invests. The LifePath Portfolios' SAI includes a description of the methods for valuing the Master Portfolios' investments, including a description of the circumstances in which the Master Portfolios' investments would be valued using fair value pricing and the effects of using fair value pricing.

LIFEPATH PORTFOLIO DISTRIBUTIONS

The LifePath Portfolios distribute their net investment income to shareholders quarterly. The LifePath Portfolios distribute their net realized capital gains, if any, to shareholders at least annually. Distributions payable to you will be automatically reinvested in additional Class R Shares of your LifePath Portfolio, unless you have elected to receive distribution payments in cash.

SHORT-TERM TRADING POLICY

The Boards of Trustees of the Trust and MIP have determined that the interests of long-term shareholders and a LifePath Portfolio's ability to manage its investments may be adversely affected when shares are repeatedly bought, sold or exchanged in response to short-term market fluctuations -- also known as "market timing." The LifePath Portfolios are not designed for market timing organizations or other entities using programmed or frequent purchases and sales or exchanges. The exchange privilege is not intended as a vehicle for short-term trading. Excessive purchase and sale or exchange activity may interfere with portfolio management, increase expenses and taxes and may have an adverse effect on the performance of a LifePath Portfolio and its shareholders. For example, large flows of cash into and out of a LifePath Portfolio may require the management team to allocate a significant amount of assets to cash or other short-term investments or sell securities, rather than maintaining such assets in securities selected to achieve the LifePath Portfolio's investment goal. Frequent trading may cause a LifePath Portfolio to sell securities at less favorable prices, and transaction costs, such as brokerage commissions, can reduce the LifePath Portfolio's performance.

A fund that invests in non-U.S. securities is subject to the risk that an investor may seek to take advantage of a delay between the change in value of the fund's portfolio securities and the determination of the fund's net asset value as a result of different closing times of U.S. and non-U.S. markets by buying or selling fund shares at a price that does not reflect their true value. A similar risk exists for funds that invest in securities of small capitalization companies, securities of issuers located in emerging markets or high yield securities (junk bonds) that are thinly traded and therefore may have actual values that differ from their market prices. This short-term arbitrage activity can reduce the return received by long-term shareholders. Each LifePath Portfolio will seek to eliminate these opportunities by using fair value pricing, as described in "Valuation of LifePath Portfolio Investments" below.

Each LifePath Portfolio discourages market timing and seeks to prevent frequent purchases and sales or exchanges of LifePath Portfolio shares that it determines may be detrimental to the LifePath Portfolio or long-term shareholders. The Boards of Trustees of the Trust and MIP have approved the policies discussed below to seek to deter market timing activity. The Boards of Trustees of the Trust and MIP have not adopted any specific numerical restrictions on purchases, sales and exchanges of LifePath Portfolio shares because certain legitimate strategies will not result in harm to a LifePath Portfolio or shareholders.

If as a result of its own investigation, information provided by a financial intermediary or other third party, or otherwise, a LifePath Portfolio believes, in its sole discretion, that your short-term trading is excessive or that you are engaging in market timing activity, it reserves the right to reject any specific purchase or exchange order. If a LifePath Portfolio rejects your purchase or exchange order, you will not be able to execute that transaction, and the LifePath Portfolio will not be responsible for any losses you therefore may suffer. In addition, any redemptions or exchanges that you make (as a result of the activity described above or otherwise) will be subject to any and all redemption fees, as described below. For transactions placed directly with a LifePath Portfolio, the LifePath Portfolio may consider the trading history of accounts under common ownership or control for the purpose of enforcing these policies. Transactions placed through the same financial intermediary on an omnibus basis may be deemed part of a group for the purpose of this policy and may be rejected in whole or in part by a LifePath Portfolio. Certain accounts, such as omnibus accounts and accounts at financial intermediaries, however, include multiple investors and such accounts typically provide a LifePath Portfolio with net purchase or redemption and exchange requests on any given day where purchases, redemptions and exchanges of shares are netted against one another and the identity of individual purchasers, redeemers and exchangers whose orders are aggregated may not be known by the LifePath Portfolio. While each LifePath Portfolio monitors for market timing activity, a LifePath Portfolio may be unable to identify such activities because the netting effect in omnibus accounts often makes it more difficult to locate and eliminate market timers from the LifePath Portfolio. The Distributor has entered into agreements with respect to financial professionals, and other financial intermediaries that maintain omnibus accounts with the transfer agent pursuant to which such financial professionals and other financial intermediaries undertake to cooperate with the Distributor in monitoring purchase, exchange and redemption orders by their customers in order to detect and prevent short-term or excessive trading in a LifePath Portfolio's shares through such accounts. Identification of market timers may also be limited by operational systems and technical limitations. In the event that a financial intermediary is determined by a LifePath Portfolio to be engaged in market timing or other improper trading activity, the LifePath Portfolio's Distributor may terminate such financial intermediary's agreement with the Distributor, suspend such financial intermediary's trading privileges or take other appropriate actions.

Certain BlackRock Funds will automatically assess and retain a fee of 2% of the current net asset value, after excluding the effect of any contingent deferred sales charges, of shares being redeemed or exchanged within 30 days of acquisition (other than those acquired through reinvestment of dividends or other distributions).

There is no assurance that the methods described above will prevent market timing or other trading that may be deemed abusive.

A LifePath Portfolio may from time to time use other methods that it believes are appropriate to deter market timing or other trading activity that may be detrimental to a fund or long-term shareholders.

The LifePath Portfolios may from time to time implement various methods that the LifePath Portfolios believe are appropriate to deter market timing, frequent trading or other activity that may be detrimental to the LifePath Portfolios

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or long-term investors in the LifePath Portfolios. There is no assurance that any such methods will prevent such detrimental trading activity.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the LifePath Portfolios and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the LifePath Portfolios' SAI for additional U.S. federal income tax information.

Distributions from your LifePath Portfolio's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional LifePath Portfolio shares. The amount of taxes you owe will vary depending on your tax status and on your tax rate and the amount and character of the LifePath Portfolio's distributions to you. Normally, distributions are taxable to you when paid. However, when distributions are declared in the last three months of a year and paid in January of the next year, they are taxable as if paid on December 31 of the prior year.

Distributions from the LifePath Portfolios generally are taxable as follows:

DISTRIBUTION TYPE               TAX STATUS
------------------------------- --------------------------------
Qualified dividend income...... Qualified dividend income(1)(2)
Other income................... Ordinary income(2)
Short-term capital gain........ Ordinary income
Long-term capital gain......... Long-term capital gain(3)


(1) If you are an individual, your distributions attributable to the LifePath Portfolio's qualified dividend income generally are taxable to you at a maximum 15% U.S. federal income tax rate, as long as you meet certain holding period and other requirements. Qualified dividend income is, in general, dividend income received from taxable U.S. and certain foreign corporations. Absent further legislation, the reduced rates of tax for qualified dividend income will expire after December 31, 2010.

(2) A portion of distributions paid to corporate shareholders of the LifePath Portfolios may qualify for the dividends-received deduction available to corporations.

(3) An individual's net long-term capital gain currently is subject to a reduced maximum 15% U.S. federal income tax rate. Absent further legislation, this reduced 15% maximum tax rate on long-term capital gain is scheduled to expire after December 31, 2010.

In addition, if you sell your LifePath Portfolio shares you generally will have a taxable capital gain or loss in an amount equal to the difference between the net amount of sale proceeds that you receive and your tax basis for the shares that you sell. In certain circumstances, a loss on the sale may be disallowed.

If you buy a LifePath Portfolio's shares shortly before it makes a distribution, you will, in effect, receive part of your purchase back in the form of a taxable distribution. Similarly, if you buy shares of a LifePath Portfolio that holds appreciated securities, you will, in effect, receive part of your purchase back in a taxable distribution if and when the LifePath Portfolio sells the appreciated securities and distributes the realized gain on the sale. The LifePath Portfolios have built up, or have the potential to build up, high levels of unrealized appreciation in their investments.

After the end of each year, the LifePath Portfolios will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the LifePath Portfolios if you fail to provide the LifePath Portfolios with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Sales proceeds generally are taxable as follows:

TRANSACTION                                        TAX STATUS
-------------------------------------------------- --------------------------------
You sell shares owned for more than one year...... Long-term capital gain or loss

You sell shares owned for one year or less........ Short-term capital gain or loss

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

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Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING LIFEPATH PORTFOLIO SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL

INCOME TAX ON LIFEPATH PORTFOLIO DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF LIFEPATH PORTFOLIO SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER AND FUND OF FUNDS STRUCTURES


The LifePath Portfolios do not have their own investment adviser. Instead, each LifePath Portfolio invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the LifePath Portfolio. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the LifePath Portfolios.

FEEDER FUND EXPENSES

Feeder funds, including the LifePath Portfolios, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund- specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a LifePath Portfolio's assets from its Master Portfolio if it believes doing so is in the best interests of the LifePath Portfolio's shareholders. If the Trust's Board of Trustees decides to withdraw a LifePath Portfolio's assets, it would then consider whether the LifePath Portfolio should hire its own investment adviser, invest in another master portfolio or take other action.

FUND OF FUNDS

The Master Portfolios do not invest directly in a portfolio of securities. Instead, they invest in the Underlying Money Market Fund and other Underlying Funds that are also advised by BFA. Each Master Portfolio charges for its own direct expenses, in addition to bearing a PRO RATA share of the expenses charged by the Underlying Funds in which it invests.

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Management of the LifePath Portfolios

INVESTMENT ADVISER

Each LifePath Portfolio is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the LifePath Portfolio. The Master Portfolios, in turn, invest in a combination of Underlying Funds. BFA, a registered investment adviser, serves as investment adviser to each Master Portfolio, and also serves as investment adviser to each Underlying Fund, with the exception of the Underlying Money Market Fund, which invests in a master portfolio advised by BFA. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive an annual management fee of 0.35% of each Master Portfolio's average daily net assets.

For its services to the Underlying Funds, BFA receives fees that differ from the fees described for the LifePath Portfolios in this Prospectus. BFA provides investment advisory services for the Underlying Funds that differ from the investment advisory services it provides for the Master Portfolios. For services provided to the Underlying Funds, BFA receives investment advisory fees from the Underlying Funds. In addition, BTC provides administration services to certain of the Underlying Funds and, for those services, may receive administration fees from those Underlying Funds. BFA has contractually agreed to waive its management fees at the Master Portfolio level in an amount equal to management and administration fees, if any, paid by the Underlying Funds to BFA and BTC, respectively, through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.36 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the LifePath Portfolios' annual report for the year ended December 31, 2009.

PORTFOLIO MANAGERS

Dagmar Nikles, Leslie Gambon, Alan Mason and Amy Whitelaw (the "Portfolio Managers") are jointly and primarily responsible for the day-to-day management of the Master Portfolios and act collaboratively on all aspects concerning the Master Portfolios. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of their team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy, and overseeing members of his or her portfolio management team with more limited responsibilities.

Ms. Nikles has been employed as a Senior Investment Strategist in the defined contributions team at BFA (formerly, Barclays Global Fund Advisors ("BGFA")) and BTC (formerly, Barclays Global Investors, N.A (BGI)) since December 2009. From July 2003 to November 2009, Ms. Nikles was a member of the asset allocation portfolio management team at BGFA and BGI. Ms. Nikles has been a one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since June 2005.

Ms. Gambon has been employed as a member of the asset allocation portfolio management team at BFA and BTC since April 2007. From October 2004 to April 2007, Ms. Gambon was Head of Defined Contribution Portfolio Management at BGI. Ms. Gambon has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since May 2007.

Mr. Mason has been employed by BFA and BTC since December 2009. Mr. Mason is responsible for multi-asset class solutions for institutional clients. From 1991 to 2009, Mr. Mason served a variety of roles at BGFA and BGI, including eight years devoted to the development of transition management products. Mr. Mason has been one of the Portfolio Managers primarily responsible for the day-to-day management of the Master Portfolios since September 2009.

Ms. Whitelaw has been employed as Head of Defined Contributions Portfolio Management at BFA and BTC since December 2009. From October 2009 to November 2009, Ms. Whitelaw was Head of Defined Contributions Portfolio Management at BGFA and BGI. Ms. Whitelaw had been employed as a member of the portfolio management team at

56

BGFA and BGI since July 2006. From April 2002 to April 2005, Ms. Whitelaw worked as a transition manager and strategist in the Transition Services group at BGFA and BGI.

The LifePath Portfolios' SAI provides additional information about the Portfolio Managers' compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers' ownership of shares in the LifePath Portfolios.

ADMINISTRATIVE SERVICES

Pursuant to an Administration Agreement between the Trust, on behalf of the LifePath Portfolios, and BTC, BTC provides the following services, among others, as the LifePath Portfolios' administrator:

. Supervises the LifePath Portfolios' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the shareholder servicing agent ("Shareholder Servicing Agent") on behalf of the LifePath Portfolios.

BTC is entitled to receive fees for these services at the annual rate of 0.50% of the average daily net assets of Class R Shares of each LifePath Portfolio. In addition to performing these services, BTC has agreed to bear all costs of operating the LifePath Portfolios, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the LifePath Portfolios or the Trust as defined in the 1940 Act and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names.

Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

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Under a securities lending program approved by MIP's Board of Trustees, the Master Portfolios have retained an Affiliate of BFA to serve as the securities lending agent for the Master Portfolios to the extent that the Master Portfolios participate in the securities lending program. For these services, the lending agent may receive a fee from the Master Portfolios, including a fee based on the returns earned on the Master Portfolios' investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Master Portfolios may lend their portfolio securities under the securities lending program.

VALUATION OF LIFEPATH PORTFOLIO INVESTMENTS

When you buy shares, you pay the net asset value, plus any applicable sales charge. This is the offering price. Shares are also redeemed at their net asset value, minus any applicable deferred sales charge. Each LifePath Portfolio calculates the net asset value of each class of its shares (generally by using market quotations) each day the NYSE is open as of the close of business on the NYSE, based on prices at the time of closing. The NYSE generally closes at 4:00
p.m. Eastern time. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order is placed.

Each LifePath Portfolio's assets and liabilities are valued primarily on the basis of market quotations. Equity investments are valued at market value, which is generally determined using the last reported sale price on the exchange or market on which the security is primarily traded at the time of valuation. Each LifePath Portfolio values fixed income portfolio securities using market prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board of Trustees. Certain short-term debt securities are valued on the basis of amortized cost. If a LifePath Portfolio invests in foreign securities, these securities may trade on weekends or other days when the LifePath Portfolio does not price its shares. As a result, a LifePath Portfolio's net asset value may change on days when you will not be able to purchase or redeem the LifePath Portfolio's shares. In addition, foreign currency exchange rates are generally determined as of the close of business on the NYSE. Shares of underlying open-end funds are valued at net asset value.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a LifePath Portfolio's shares are determined as of such times.

When market quotations are not readily available or are not believed by BFA to be reliable, a LifePath Portfolio's investments are valued at fair value. Fair value determinations are made by BFA in accordance with procedures approved by the Trust's Board of Trustees. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of liquidity, if BFA believes a market quotation from a broker-dealer or other source is unreliable, where the security or other asset or liability is thinly traded (e.g., municipal securities and certain non-U.S. securities) or where there is a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BFA determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio's assets or liabilities, that it is likely that the event will cause a material change to the last closing market price of one or more assets or liabilities held by the LifePath Portfolio. Foreign securities whose values are affected by volatility that occurs in U.S. markets on a trading day after the close of foreign securities markets may be fair valued.

Fair value represents a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value.

A LifePath Portfolio may accept orders from certain authorized financial intermediaries or their designees. A LifePath Portfolio will be deemed to receive an order when accepted by the intermediary or designee and the order will receive the net asset value next computed by the LifePath Portfolio after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN LIFEPATH PORTFOLIO POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The LifePath Portfolios are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a LifePath Portfolio may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The LifePath Portfolios reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the LifePath Portfolios to verify their identity. The LifePath Portfolios also reserve the right to redeem any amounts in a LifePath Portfolio from persons whose identity it is unable to verify on a timely basis. It is the LifePath Portfolios' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

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BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

59

Financial Highlights


The financial highlights tables in this section are intended to help investors understand the financial performance of Institutional Shares of each LifePath Portfolio for the past five years or, if shorter, since inception. Certain information reflects financial results for a single Institutional Shares of each LifePath Portfolio. FINANCIAL PERFORMANCE FOR CLASS R SHARES WOULD DIFFER FROM THE FINANCIAL PERFORMANCE FOR INSTITUTIONAL SHARES BECAUSE THE CLASSES HAVE DIFFERENT EXPENSES. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Institutional Shares of a given LifePath Portfolio, assuming reinvestment of all distributions. The information for the period ended June 30, 2009, is unaudited; all other information has been audited by PricewaterhouseCoopers, LLP, whose report, along with the LifePath Portfolios' financial statements, is included in the LifePath Portfolios' annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-441-7762 (toll-free) Monday through Friday from 8:00 a.m. to 6:00 p.m. Eastern time on any business day.

LIFEPATH RETIREMENT PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                         INSTITUTIONAL SHARES
                                             ----------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                             ----------------------------------------------------------------------------
                                                  2009            2008           2007          2006          2005
                                             ----------------- --------------- -------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            ---               -               -             -             -
 Net asset value, beginning of year             $    9.42        $    11.46      $   11.59      $   11.22     $   11.18
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net investment income                               0.321              0.37           0.39          0.39          0.30
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Net realized and unrealized gain (loss)            1.37              (2.06)          0.12          0.58          0.17
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
Net increase (decrease) from investment
 operations                                         1.69           (   1.69)          0.51          0.97          0.47
--------------------------------------------    -----------      ----------      ---------      ---------     ---------
 Dividends and distributions from:
  Net investment income                          (   0.31)         (   0.31)       (   0.37)     (   0.39)     (   0.33)
  Net realized gain                              (   0.00)/2/      (   0.04)       (   0.27)     (   0.21)     (   0.10)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
Total dividends and distributions                (   0.31)         (   0.35)       (   0.64)     (   0.60)     (   0.43)
--------------------------------------------    ------------     ----------      ----------     ---------     ---------
 Net asset value, end of year                  $   10.80         $     9.42      $   11.46      $   11.59     $   11.22
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Based on net asset value                         18.25   %          (15.04)%          4.50%         8.80%         4.32%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Total expenses                                    1.10   %            1.11%           1.12%         1.13%         1.15%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Total expenses after expense reductions            0.76   %            0.76%           0.77%         0.78%         0.81%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net investment income                             3.13   %            3.29%           3.43%         3.28%         2.72%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
SUPPLEMENTAL DATA
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
 Net assets, end of year (000)                 $  438,987        $   92,717      $  136,923     $  91,518     $  99,349
--------------------------------------------   -------------     ----------      ----------     ---------     ---------
Portfolio turnover of the Master Portfolio              6%               11%              6%           10%           11%
--------------------------------------------   -------------     ----------      ----------     ---------     ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

60

LIFEPATH 2020 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  12.32         $   16.98      $  17.48      $  15.85     $  15.19
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.351              0.44          0.45          0.40         0.30
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.38              (4.67)         0.14          1.64         0.68
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.73            (  4.23)         0.59          2.04         0.98
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.43)         (  0.31)       (  0.44)      (  0.41)     (  0.32)
  Net realized gain                                     -          (  0.12)       (  0.65)            -            -
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.43)         (  0.43)       (  1.09)      (  0.41)     (  0.32)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  14.62         $   12.32      $  16.98      $  17.48     $  15.85
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         22.71   %         (25.42)%         3.34%        13.01%        6.54%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.08   %           1.07%          1.08%         1.08%        1.12%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.72   %           0.73%          0.74%         0.75%        0.78%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.65   %           2.65%          2.52%         2.37%        2.01%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 663,890        $ 432,717      $ 781,519     $ 598,633    $ 578,497
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              6%              13%             7%           16%          17%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

61

LIFEPATH 2030 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                       INSTITUTIONAL SHARES
                                             -------------------------------------------------------------------------
                                                                      YEAR ENDED DECEMBER 31,
                                             -------------------------------------------------------------------------
                                                          2009           2008          2007          2006         2005
                                             ----------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------            --               -              -             -            -
 Net asset value, beginning of year             $  10.92         $   16.19      $  16.90      $  15.39     $  14.87
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net investment income                              0.291              0.35          0.34          0.32         0.24
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           2.46              (5.29)         0.11          1.99         0.88
--------------------------------------------    ----------       ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        2.75            (  4.94)         0.45          2.31         1.12
--------------------------------------------    ----------       ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                           (  0.36)         (  0.25)       (  0.35)      (  0.36)     (  0.26)
  Net realized gain                                     -          (  0.08)       (  0.81)      (  0.44)     (  0.34)
  Return of capital                               (  0.00)/2/            -              -             -            -
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total dividends and distributions                 (  0.36)         (  0.33)       (  1.16)      (  0.80)     (  0.60)
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net asset value, end of year                   $  13.31         $   10.92      $  16.19      $  16.90     $  15.39
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/3/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Based on net asset value                         25.77   %         (31.03)%         2.64%        15.12%        7.63%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/4/
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Total expenses                                    1.06   %           1.06%          1.07%         1.08%        1.10%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Total expenses after expense reductions            0.70   %           0.72%          0.73%         0.74%        0.76%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net investment income                             2.47   %           2.29%          2.10%         1.95%        1.69%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                  $ 517,817        $ 315,028      $ 564,348     $ 408,564    $ 352,800
--------------------------------------------    ------------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio              7%              13%             7%           22%          24%
--------------------------------------------    ------------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Amount is less than $0.01 per share.

/3/ Includes the reinvestment of dividends and distributions.

/4/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

62

LIFEPATH 2040 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                     INSTITUTIONAL SHARES
                                             ---------------------------------------------------------------------
                                                                    YEAR ENDED DECEMBER 31,
                                             ---------------------------------------------------------------------
                                                      2009           2008          2007          2006         2005
                                             ------------- -------------- ------------- ------------- ------------
PER SHARE OPERATING PERFORMANCE
--------------------------------------------           -             -              -             -            -
 Net asset value, beginning of year            $  12.88      $   20.32      $  20.90      $  18.18     $  17.03
--------------------------------------------   --------      ---------      --------      --------     ---------
Net investment income                              0.321          0.35          0.34          0.31         0.21
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Net realized and unrealized gain (loss)           3.22          (7.45)         0.08          2.76         1.18
--------------------------------------------   ---------     ---------      --------      --------     ---------
Net increase (decrease) from investment
 operations                                        3.54        (  7.10)         0.42          3.07         1.39
--------------------------------------------   ---------     ---------      --------      --------     ---------
 Dividends and distributions from:
  Net investment income                          (  0.38)      (  0.26)       (  0.35)      (  0.35)     (  0.24)
  Net realized gain                                    -       (  0.08)       (  0.65)            -            -
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total dividends and distributions                (  0.38)      (  0.34)       (  1.00)      (  0.35)     (  0.24)
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net asset value, end of year                  $  16.04      $   12.88      $  20.32      $  20.90     $  18.18
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
TOTAL INVESTMENT RETURN/2/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Based on net asset value                          28.08%       (35.40)%         2.03%        16.97%        8.24%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
RATIOS TO AVERAGE NET ASSETS/3/
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Total expenses                                     1.05%         1.04%          1.06%         1.07%        1.09%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Total expenses after expense reductions             0.69%         0.69%          0.72%         0.73%        0.76%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net investment income                              2.33%         2.02%          1.71%         1.62%        1.45%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
SUPPLEMENTAL DATA
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
 Net assets, end of year (000)                 $ 435,317     $ 248,491      $ 383,391     $ 278,716    $ 221,359
--------------------------------------------   ---------     ---------      ---------     ---------    ---------
Portfolio turnover of the Master Portfolio             6%           14%             8%           29%          38%
--------------------------------------------   ---------     ---------      ---------     ---------    ---------


/1/ Based on average shares outstanding.

/2/ Includes the reinvestment of dividends and distributions.

/3/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

63

LIFEPATH 2050 PORTFOLIO

FINANCIAL HIGHLIGHTS

                                                                    INSTITUTIONAL SHARES
                                                         ------------------------------------------
                                                                                             PERIOD
                                                             YEAR ENDED              JUNE 30, 20081
                                                           DECEMBER 31,             TO DECEMBER 31,
                                                                   2009                        2008
                                                         --------------     -----------------------
PER SHARE OPERATING PERFORMANCE
----------------------------------------------------                -                       -
 Net asset value, beginning of period                      $    13.46          $     20.00
----------------------------------------------------       ----------          -------------
Net investment income                                           0.382                 0.10
----------------------------------------------------       ----------          -------------
 Net realized and unrealized gain (loss)                        3.68                    (6.52)
----------------------------------------------------       ----------          -------------
Net increase (decrease) from investment operations              4.06               (     6.42)
----------------------------------------------------       ----------          --------------
 Dividends and distributions from:
  Net investment income                                     (    0.16)             (     0.09)
  Net realized gain                                         (    0.55)             (     0.00)/3 /
  Return of capital                                                 -              (     0.03)
----------------------------------------------------       ----------          -----------------
Total dividends and distributions                           (    0.71)             (     0.12)
----------------------------------------------------       ----------          -----------------
 Net asset value, end of period                            $    16.81          $     13.46
----------------------------------------------------       ----------          -----------------
TOTAL INVESTMENT RETURN/4/
----------------------------------------------------       ----------          -----------------
 Based on net asset value                                       30.35%                 (32.18)%/5/
----------------------------------------------------       ----------          ------------------
RATIOS TO AVERAGE NET ASSETS/6/
----------------------------------------------------       ----------          ------------------
 Total expenses                                                  1.27%                  12.80%/7 /
----------------------------------------------------       ----------          ------------------
Total expenses after expense reductions                          0.67%                   0.68%/7 /
----------------------------------------------------       ----------          ------------------
 Net investment income                                           2.39%                   2.14%/7 /
----------------------------------------------------       ----------          ------------------
SUPPLEMENTAL DATA
----------------------------------------------------       ----------          ------------------
 Net assets, end of period (000)                           $   13,992          $          444
----------------------------------------------------       ----------          ------------------
Portfolio turnover of the Master Portfolio                         12%                      0%/8/
----------------------------------------------------       ----------          ------------------


/1/ Commencement of operations.

/2/ Based on average shares outstanding.

/3/ Amount is less than $0.01 per share.

/4/ Includes the reinvestment of dividends and distributions.

/5/ Not annualized.

/6/ Includes the LifePath Portfolio's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/7/ Annualized.

/8/ Rounds to less than 1% .

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DISCLAIMERS

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible

65

for and has not participated in the determination of the prices and amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

66

The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE Licensor Parties. None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/

NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of

67

Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about the LifePath Portfolios is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the LifePath Portfolio's investments. The annual report describes the LifePath Portfolio's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and LifePath Portfolio investment strategies that significantly affected the LifePath Portfolio's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION

A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each LifePath Portfolio, may be obtained free of charge, along with each LifePath Portfolio's annual and semi-annual reports, by calling (800) 441-7762, on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the LifePath Portfolios, please:

Call:       1-800-441-7762 (toll free)
            8:00 a.m. to 6:00 p.m. (Eastern time),
            on any business day

WORLD WIDE WEB

General LifePath Portfolio information and specific LifePath Portfolio performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com.

WRITTEN CORRESPONDENCE

BlackRock Funds III
PO Box 9819
Providence, RI 02940-8019

OVERNIGHT MAIL
BlackRock Funds III
101 Sabin Street
Pawtucket, RI 02860-1427

INTERNAL WHOLESALERS/BROKER DEALER SUPPORT
Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), on any business day. Call: (800) 882-0052.

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the LifePath Portfolios' policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 882-0052.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about a LifePath Portfolio, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address: publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-LPR-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

CAPITAL SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                  TICKER SYMBOL
-------------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Capital                  BCIXX
Shares
BlackRock Cash Funds: Prime - Capital Shares                   BCPXX
BlackRock Cash Funds: Treasury - Capital Shares                BCYXX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL.................... 1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................ 5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 9

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 13
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 14

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 16
SHAREHOLDER SERVICING PAYMENTS............. 18
CALCULATING THE FUNDS' SHARE PRICE......... 18
FUND DISTRIBUTIONS......................... 18
SHORT TERM TRADING POLICY.................. 19
TAXES...................................... 19
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 20

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 21
ADMINISTRATIVE SERVICES........ 21
CONFLICTS OF INTEREST.......... 21
VALUATION OF FUND SHARES....... 22
CERTAIN FUND POLICIES.......... 22

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 24

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Capital Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.07%
  Administration Fees                                                                          0.07%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.17%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03%)
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.14%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Capital Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Capital Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Capital Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  14         $  49         $  90        $  211

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities;

1

certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Capital Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Capital Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Capital Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund

2

expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Capital Shares

YEAR-BY-YEAR RETURNS (YEAR ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   0.41%

During the period shown in the bar chart, the highest return for a quarter was 0.21% (quarter ended March 31, 2009) and the lowest return for a quarter was 0.04% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.03%.

                                                                                    SINCE
                                                                                  INCEPTION
AS OF 12/31/09                                                                  (FEBRUARY 28,
AVERAGE ANNUAL TOTAL RETURNS                                   1 YEAR               2008)
 BlackRock Cash Funds: Institutional - Capital Shares             0.41%               1.38%
 MFR First Tier Institutional Average                             0.34%               1.35%(1)


(1) The MFR First Tier Institutional Average is calculated from February 1, 2008.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $25,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

3

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Capital Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.07%
  Administration Fees                                                                          0.07%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.17%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03%)
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.14%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Capital Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Capital Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Capital Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  14         $  49         $  90        $  211

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality

5

debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Capital Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Capital Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Capital Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund

6

expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Prime - Capital Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   0.30%

During the period shown in the bar chart, the highest return for a quarter was 0.14% (quarter ended March 31, 2009) and the lowest return for a quarter was 0.03% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.03%.

                                                                             SINCE
                                                                           INCEPTION
AS OF 12/31/09                                                           (FEBRUARY 28,
AVERAGE ANNUAL TOTAL RETURNS                           1 YEAR                2008)
 BlackRock Cash Funds: Prime - Capital Shares             0.30%             1.31    %
 MFR First Tier Institutional Average                     0.34%                1.35% (1)


(1) The MFR First Tier Institutional Average is calculated from February 1, 2008.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $25,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

7

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information..

8

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Capital Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.07%
  Administration Fees                                                                          0.07%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.17%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03%)
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.14%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Capital Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Capital Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Capital Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  14         $  49         $  90        $  211

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations

9

and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Capital Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Capital Shares of the

10

Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Capital Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Treasury - Capital Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2009   0.08%

During the period shown in the bar chart, the highest return for a quarter was 0.03% (quarter ended June 30, 2009) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                SINCE
                                                                              INCEPTION
AS OF 12/31/09                                                              (FEBRUARY 28,
AVERAGE ANNUAL TOTAL RETURNS                              1 YEAR                2008)
 BlackRock Cash Funds: Treasury - Capital Shares             0.08%             0.65%
 MFR Treasury and Repo Institutional Average                 0.05%             0.62% (1)


(1) The MFR Treasury and Repo Institutional Average is calculated from February 1, 2008.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $25,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

11

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

13

A FURTHER DISCUSSION OF PRINCIPAL RISKS

Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

14

FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

15

Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

The minimum initial investment amount for Capital Shares of each Fund is $25 million; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, your Shareholder Servicing Agent or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

Your Shareholder Servicing Agent may charge you a fee and may offer additional account services. Additionally, your Shareholder Servicing Agent may have procedures for placing orders for Capital Shares that differ from those of the Funds, such as different investment minimums or earlier trading deadlines. Please contact your Shareholder Servicing Agent directly for more information and details.

HOW TO BUY SHARES

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For

16

example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR DIRECT BUYERS

A direct buyer who has established an account with a Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Funds may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund of your choice and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:
Shareholder Account Number:
Fund Share Class Numbers:
1121 (BlackRock Cash Funds: Institutional - Capital Shares)

1991 (BlackRock Cash Funds: Prime - Capital Shares)

1101 (BlackRock Cash Funds: Treasury - Capital Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include your Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. A direct buyer can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When a direct buyer purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

17

SHAREHOLDER SERVICING PAYMENTS


The Funds have adopted a shareholder servicing plan (the "Plan") that allows each Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a Fund's shares. Because the fees paid by a Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Funds and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a Fund may pay to a Financial Intermediary pursuant to the Plan and fees a Fund pays to the Transfer Agent, BFA, on behalf of a Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Funds and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a Fund to you. Please contact your Financial Intermediary for details about payments it may receive from a Fund or from BFA or its affiliates. For more information, see the Funds' SAI.

CALCULATING THE FUNDS' SHARE PRICE


Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

18

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

19

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR INDIVIDUAL RETIREMENT ACCOUNT, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

20

Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.07% of the average daily net assets of Capital Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

21

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value (normally $1.00 per share) without a sales charge. This is the offering price. Shares are also redeemed at their net asset value. The Funds calculate the net asset value each day the NYSE or New York banks are open, as of the close of business on the NYSE (generally 4:00 p.m. Eastern time) or, on days when the NYSE is closed but New York banks are open, as of 4:00 p.m. Eastern time. Both the NYSE and New York banks are closed on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Currently, the only scheduled days on which the NYSE is open and New York banks are closed are Columbus Day and Veterans Day. The only scheduled day on which New York banks are open and the NYSE is closed is Good Friday. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order becomes effective. Share purchase orders are effective on the date Federal funds become available to the Funds.

The amortized cost method is used in calculating net asset value, meaning that the calculation is based on a valuation of the assets held by a Fund at cost, with an adjustment for any discount or premium on a security at the time of purchase.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a Fund's shares are determined as of such times.

A Fund may accept orders from certain authorized financial intermediaries or their designees. A Fund will be deemed to receive an order when accepted by the intermediary or designee, and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

22

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

23

Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Capital Shares of each Fund since inception. Certain information reflects financial results for a single Capital Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Capital Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each Fund's financial statements, is included in the Funds' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                                CAPITAL SHARES
                                              ---------------------------------------------------
                                                                                      PERIOD FROM
                                                         YEAR ENDED            FEBRUARY 28, 20081
                                                  DECEMBER 31, 2009          TO DECEMBER 31, 2008
                                              ---------------------     -------------------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------                    --                          ---
 Net asset value, beginning of period            $     1.00                 $      1.00
-----------------------------------------        --------------             ----------------
Net investment income                                 0.0041                      0.0200
 Net realized gain (loss)                             0.00002                      (0.0000)/2/
-----------------------------------------        --------------             -----------------
Net increase from investment operations               0.0041                      0.0200
-----------------------------------------        --------------             -----------------
 Dividends and distributions from:
  Net investment income                            (    0.0041)               (     0.0200)
  Net realized gain                                (    0.0000)/2/                       -
-----------------------------------------        ----------------           -----------------
Total dividends and distributions                  (    0.0041)               (     0.0200)
-----------------------------------------        ----------------           -----------------
 Net asset value, end of period                  $     1.00                 $      1.00
-----------------------------------------        ----------------           -----------------
TOTAL INVESTMENT RETURN
-----------------------------------------        ----------------           -----------------
 Based on net asset value                             0.41     %                      2.14%/3  /
-----------------------------------------        ----------------           -----------------
RATIOS TO AVERAGE NET ASSETS/4/
-----------------------------------------        ----------------           -----------------
 Total expenses                                       0.17     %                      0.19%/5  /
-----------------------------------------        ----------------           -----------------
Total expenses after expense reductions               0.14     %                      0.14%/5  /
-----------------------------------------        ----------------           -----------------
 Net investment income                                0.33     %                      2.57%/5  /
-----------------------------------------        ----------------           -----------------
SUPPLEMENTAL DATA
-----------------------------------------        ----------------           -----------------
 Net assets, end of period (000)                 $     277,382              $          101
-----------------------------------------        ----------------           -----------------


/1/ Commencement of operations.

/2/ Less than $0.00005 or $(0.00005) per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/5/ Annualized.

24

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                                CAPITAL SHARES
                                               -------------------------------------------------
                                                                                     PERIOD FROM
                                                        YEAR ENDED            FEBRUARY 28, 20081
                                                 DECEMBER 31, 2009          TO DECEMBER 31, 2008
                                               -------------------     -------------------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------                   -                          ---
 Net asset value, beginning of period             $      1.00              $      1.00
------------------------------------------        -----------              ----------------
Net investment income                                    0.0030                  0.0200
 Net realized gain (loss)                               0.00002                   (0.0000)/2/
------------------------------------------        -------------            -----------------
Net increase from investment operations                 0.0030                   0.0200
 Dividends from net investment income                  (0.0030)                   (0.0200)
------------------------------------------        -------------            -----------------
Net asset value, end of period                    $     1.00               $      1.00
------------------------------------------        -------------            -----------------
 TOTAL INVESTMENT RETURN
------------------------------------------        -------------            -----------------
Based on net asset value                                0.30   %                     2.13%/3  /
------------------------------------------        -------------            -----------------
 RATIOS TO AVERAGE NET ASSETS/4/
------------------------------------------        -------------            -----------------
Total expenses                                          0.19   %                     0.21%/5  /
------------------------------------------        -------------            -----------------
 Total expenses after expense reductions                0.16   %                     0.15%/5  /
------------------------------------------        -------------            -----------------
Net investment income                                   0.27   %                     2.23%/5  /
------------------------------------------        -------------            -----------------
 SUPPLEMENTAL DATA
------------------------------------------        -------------            -----------------
Net assets, end of period (000)                   $    673,375             $      226,487
------------------------------------------        -------------            -----------------


/1/ Commencement of operations.

/2/ Less than $0.00005 or $(0.00005) per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/5/ Annualized.

25

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                              CAPITAL SHARES
                                               ---------------------------------------------
                                                                                 PERIOD FROM
                                                        YEAR ENDED        FEBRUARY 28, 20081
                                                 DECEMBER 31, 2009      TO DECEMBER 31, 2008
                                               -------------------     ---------------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------                   -                        -
 Net asset value, beginning of period             $      1.00             $      1.00
------------------------------------------        -----------             ------------
Net investment income                                    0.0008                  0.0100
 Net realized gain                                      0.00002                       -
------------------------------------------        -------------           -------------
Net increase from investment operations                 0.0008                   0.0100
 Dividends from net investment income                  (0.0008)                 (0.0100)
------------------------------------------        -------------           -------------
Net asset value, end of period                    $     1.00              $      1.00
------------------------------------------        -------------           -------------
 TOTAL INVESTMENT RETURN
------------------------------------------        -------------           -------------
Based on net asset value                                0.08   %                   1.12%/3/
------------------------------------------        -------------           ----------------
 RATIOS TO AVERAGE NET ASSETS/4/
------------------------------------------        -------------           ----------------
Total expenses                                          0.17   %                   0.19%/5/
------------------------------------------        -------------           ----------------
 Total expenses after expense reductions                0.08   %                   0.05%/5/
------------------------------------------        -------------           ----------------
Net investment income                                   0.07   %                   0.37%/5/
------------------------------------------        -------------           ----------------
 SUPPLEMENTAL DATA
------------------------------------------        -------------           ----------------
Net assets, end of period (000)                   $     32,419            $      44,698
------------------------------------------        -------------           ----------------


/1/ Commencement of operations.

/2/ Less than $0.00005 per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

/5/ Annualized.

26

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-CAP-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

INSTITUTIONAL SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                      TICKER SYMBOL
-----------------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Institutional                BGIXX
Shares
BlackRock Cash Funds: Prime - Institutional                        BPIXX
Shares
BlackRock Cash Funds: Government - Institutional                   BVIXX
Shares
BlackRock Cash Funds: Treasury - Institutional                     BRIXX
Shares

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL....................  1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................  5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT.......................  9
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 13

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 17
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 17

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 19
SHAREHOLDER SERVICING PAYMENTS............. 20
CALCULATING THE FUNDS' SHARE PRICE......... 21
FUND DISTRIBUTIONS......................... 21
SHORT TERM TRADING POLICY.................. 21
TAXES...................................... 22
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 23

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 24
ADMINISTRATIVE SERVICES........ 24
CONFLICTS OF INTEREST.......... 24
VALUATION OF FUND SHARES....... 25
CERTAIN FUND POLICIES.......... 25

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 27

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


[THIS PAGE INTENTIONALLY LEFT BLANK]


Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.05%
  Administration Fees                                                                          0.05%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.15%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.12%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Institutional Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  12         $  42         $  78        $  186

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities;

1

certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each of the last ten calendar years. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during

2

these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    6.55%
2001    4.23%
2002    1.83%
2003    1.14%
2004    1.39%
2005    3.29%
2006    5.11%
2007    5.36%
2008    2.85%
2009    0.43%

During the periods shown in the bar chart, the highest return for a quarter was 1.68% (quarter ended December 31, 2000) and the lowest return for a quarter was 0.04% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.04%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                         1 YEAR           5 YEARS         10 YEARS
 BlackRock Cash Funds: Institutional - Institutional Shares             0.43%            3.39%            3.20%
 MFR First Tier Institutional Average                                   0.34%            3.13%            2.90%

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

3

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.05%
  Administration Fees                                                                          0.05%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.15%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03%)
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.12%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Institutional Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  12         $  42         $  78        $  186

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at

5

least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR")

6

First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Prime - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2004    1.40%
2005    3.26%
2006    5.07%
2007    5.32%
2008    2.83%
2009    0.32%

During the periods shown in the bar chart, the highest return for a quarter was 1.34% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.04% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.03%.

                                                                                                  SINCE
                                                                                                INCEPTION
AS OF 12/31/09                                                                                  (APRIL 16,
AVERAGE ANNUAL TOTAL RETURNS                                 1 YEAR           5 YEARS             2003)
 BlackRock Cash Funds: Prime - Institutional Shares             0.32%            3.35%              2.82%
 MFR First Tier Institutional Average                           0.34%            3.13%              2.55%(1)


(1) The MFR First Tier Institutional Average is calculated from March 31, 2003.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

7

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

8

Fund Overview

KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Government (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.05%
  Administration Fees                                                                          0.05%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.15%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.12%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Government Money Market Master Portfolio (the "Government Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Government Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Government Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Government Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Institutional Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  12         $  42         $  78        $  186

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to

9

maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Government Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Government Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Government Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Government Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") Government Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed

10

certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Government - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005   3.28%
2006   5.04%
2007   5.15%
2008   1.96%
2009   0.09%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.02% (quarters ended September 30, 2009 and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                      SINCE
                                                                                                    INCEPTION
AS OF 12/31/09                                                                                    (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                                      1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Government - Institutional Shares            0.09%            3.09%              3.01%
 MFR Government Institutional Average                               0.17%            2.80%              2.61%(1)


(1) The MFR Government Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Government Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

11

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Institutional Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.05%
  Administration Fees                                                                          0.05%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.15%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03%)
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.12%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Institutional Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Institutional Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Institutional Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  12         $  42         $  78        $  186

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's

13

assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

14

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Treasury - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.20%
2006    5.04%
2007    4.95%
2008    1.61%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                    SINCE
                                                                                                  INCEPTION
AS OF 12/31/09                                                                                  (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                                    1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Treasury - Institutional Shares            0.08%            2.96%              2.89%
 MFR Treasury and Repo Institutional Average                      0.05%            2.66%              2.58%(1)

------- (1)The MFR Treasury and Repo Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net

15

asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

16

Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Government invests all of its assets in Government Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: GOVERNMENT

BlackRock Cash Funds: Government seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

A FURTHER DISCUSSION OF PRINCIPAL RISKS


Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

17

Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: GOVERNMENT AND BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

18

Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

The minimum initial investment amount for Institutional Shares of each Fund is $100 million; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, your Shareholder Servicing Agent or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

Your Shareholder Servicing Agent may charge you a fee and may offer additional account services. Additionally, your Shareholder Servicing Agent may have procedures for placing orders for Institutional Shares that differ from those of the Funds, such as different investment minimums or earlier trading deadlines. Please contact your Shareholder Servicing Agent directly for more information and details.

HOW TO BUY SHARES

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For

19

example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR DIRECT BUYERS

A direct buyer who has established an account with a Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Funds may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund of your choice and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:
Shareholder Account Number:
Fund Share Class Numbers:
1127 (BlackRock Cash Funds: Institutional - Institutional Shares) 1197 (BlackRock Cash Funds: Prime - Institutional Shares) 1097 (BlackRock Cash Funds: Government - Institutional Shares) 1107 (BlackRock Cash Funds: Treasury - Institutional Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include your Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. A direct buyer can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When a direct buyer purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

SHAREHOLDER SERVICING PAYMENTS


The Funds have adopted a shareholder servicing plan (the "Plan") that allows each Fund to pay shareholder servicing fees for certain services provided to its shareholders.

20

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (including BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a Fund's shares. Because the fees paid by a Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Funds and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a Fund may pay to a Financial Intermediary pursuant to the Plan and fees a Fund pays to the Transfer Agent, BFA, on behalf of a Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Funds and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a Fund to you. Please contact your Financial Intermediary for details about payments it may receive from a Fund or from BFA or its affiliates. For more information, see the Funds' SAI.

CALCULATING THE FUNDS' SHARE PRICE


Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

21

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

22

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR INDIVIDUAL RETIREMENT ACCOUNT, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

23

Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.05% of the average daily net assets of Institutional Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") (for convenience, the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity") in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow an investment programs similar to those of the Funds. The BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker,

24

trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Funds will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Funds. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliates or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Affiliate or an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate advised clients may adversely impact the Funds. Transactions by one or more Affiliates or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or an Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliate or an Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds and their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided

25

to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

26

Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Institutional Shares of each Fund for the past five years. Certain information reflects financial results for a single Institutional Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Institutional Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each Fund's financial statements, is included in the Funds' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                   INSTITUTIONAL SHARES
                                          --------------------------------------
                                                 YEAR ENDED DECEMBER 31,
                                          --------------------------------------
                                                        2009                2008
                                          ------------------ -------------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------              -                  ---
 Net asset value, beginning of year          $  1.00            $  1.00
-----------------------------------------    -----------        -------------
Net investment income                           0.0043             0.0300
 Net realized gain (loss)                       0.00001             (0.0000)/1/
-----------------------------------------    -----------        --------------
Net increase from investment operations         0.0043             0.0300
-----------------------------------------    -----------        --------------
 Dividends and distributions from:
  Net investment income                         ( 0.0043)          ( 0.0300)
  Net realized gain                             ( 0.0000)/1/              -
-----------------------------------------    --------------     --------------
Total dividends and distributions               ( 0.0043)          ( 0.0300)
-----------------------------------------    --------------     --------------
 Net asset value, end of year                $  1.00            $  1.00
-----------------------------------------    --------------     --------------
TOTAL INVESTMENT RETURN
-----------------------------------------    --------------     --------------
 Based on net asset value                       0.43     %         2.85     %
-----------------------------------------    --------------     --------------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    --------------     --------------
 Total expenses                                 0.15     %         0.15     %
-----------------------------------------    --------------     --------------
Total expenses after expense reductions         0.12     %         0.12     %
-----------------------------------------    --------------     --------------
 Net investment income                          0.78     %         2.65     %
-----------------------------------------    --------------     --------------
SUPPLEMENTAL DATA
-----------------------------------------    --------------     --------------
 Net assets, end of year (000)               $   973,221        $ 20,223,437
-----------------------------------------    --------------     --------------

                                                          INSTITUTIONAL SHARES
                                          -----------------------------------------------------
                                                         YEAR ENDED DECEMBER 31,
                                          -----------------------------------------------------
                                                      2007             2006                2005
                                          ---------------- ---------------- -------------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------             -                -                  -
 Net asset value, beginning of year          $   1.00         $   1.00         $   1.00
-----------------------------------------    --------         --------         ------------
Net investment income                            0.0500           0.0500           0.0300
 Net realized gain (loss)                        0.00001          0.00001           (0.0000)/1/
-----------------------------------------    -----------      -----------      ---------------
Net increase from investment operations          0.0500           0.0500           0.0300
-----------------------------------------    -----------      -----------      ---------------
 Dividends and distributions from:
  Net investment income                        ( 0.0500)        ( 0.0500)          ( 0.0300)
  Net realized gain                                   -                -                  -
-----------------------------------------    -----------      -----------      ---------------
Total dividends and distributions              ( 0.0500)        ( 0.0500)          ( 0.0300)
-----------------------------------------    -----------      -----------      ---------------
 Net asset value, end of year                $   1.00         $   1.00         $   1.00
-----------------------------------------    -----------      -----------      ---------------
TOTAL INVESTMENT RETURN
-----------------------------------------    -----------      -----------      ---------------
 Based on net asset value                        5.36   %         5.11   %         3.29     %
-----------------------------------------    -----------      -----------      ---------------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    -----------      -----------      ---------------
 Total expenses                                  0.16   %         0.14   %         0.12     %
-----------------------------------------    -----------      -----------      ---------------
Total expenses after expense reductions          0.11   %         0.10   %         0.05     %
-----------------------------------------    -----------      -----------      ---------------
 Net investment income                           5.25   %         4.97   %         3.26     %
-----------------------------------------    -----------      -----------      ---------------
SUPPLEMENTAL DATA
-----------------------------------------    -----------      -----------      ---------------
 Net assets, end of year (000)               $ 6,653,737      $ 4,198,724      $  3,485,876
-----------------------------------------    -----------      -----------      ---------------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

27

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                                          INSTITUTIONAL SHARES
                                           -----------------------------------------------------------------------------------
                                                                         YEAR ENDED DECEMBER 31,
                                           -----------------------------------------------------------------------------------
                                                      2009                2008            2007            2006            2005
                                           --------------- ------------------- --------------- --------------- ---------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------            -                 --                -               -               -
 Net asset value, beginning of year           $   1.00        $  1.00             $   1.00        $   1.00        $   1.00
------------------------------------------    --------        ------------        --------        --------        --------
Net investment income                             0.0032         0.0300               0.0500          0.0500          0.0300
 Net realized gain (loss)                        0.00001          (0.0000)/1/        0.00001         0.00001         0.00001
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net increase from investment operations          0.0032          0.0300              0.0500          0.0500          0.0300
 Dividends from net investment income           (0.0032)          (0.0300)          (0.0500)        (0.0500)        (0.0300)
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net asset value, end of year                  $  1.00         $  1.00             $  1.00         $  1.00         $  1.00
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 TOTAL INVESTMENT RETURN
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Based on net asset value                         0.32   %        2.83     %          5.32   %        5.07   %        3.26   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Total expenses                                   0.17   %        0.15     %          0.15   %        0.14   %        0.12   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 Total expenses after expense reductions         0.14   %        0.11     %          0.12   %        0.11   %        0.08   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net investment income                            0.39   %        2.80     %          5.19   %        4.93   %        3.28   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 SUPPLEMENTAL DATA
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net assets, end of year (000)                 $3,014,591      $10,812,890         $8,363,790      $5,915,836      $6,521,818
------------------------------------------    ----------      --------------      ----------      ----------      ----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

28

BLACKROCK CASH FUNDS: GOVERNMENT

FINANCIAL HIGHLIGHTS

                                                                    INSTITUTIONAL SHARES
                                           -----------------------------------------------------------------------
                                                                   YEAR ENDED DECEMBER 31,
                                           -----------------------------------------------------------------------
                                                    2009            2008          2007          2006          2005
                                           ------------- --------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -              -              -             -             -
 Net asset value, beginning of year          $   1.00       $   1.00       $   1.00      $   1.00      $   1.00
------------------------------------------   --------       --------       --------      --------      --------
Net investment income                            0.0009         0.0200         0.0500        0.0492        0.0300
 Dividends from net investment income          (0.0009)       (0.0200)       (0.0500)      (0.0492)      (0.0300)
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net asset value, end of year                 $   1.00       $   1.00       $   1.00      $   1.00      $   1.00
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Based on net asset value                         0.09  %        1.96  %        5.15  %       5.04  %       3.28  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/1/
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Total expenses                                   0.15  %        0.16  %        0.18  %       0.16  %       0.12  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 Total expenses after expense reductions         0.08  %        0.10  %        0.12  %       0.12  %       0.03  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net investment income                            0.11  %        0.29  %        4.67  %       4.75  %       3.04  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net assets, end of year (000)                $  10,496      $1,594,728     $   3,031     $     395     $ 169,200
------------------------------------------   ----------     ----------     ----------    ----------    ----------


/1/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

29

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                                    INSTITUTIONAL SHARES
                                           -----------------------------------------------------------------------
                                                                   YEAR ENDED DECEMBER 31,
                                           -----------------------------------------------------------------------
                                                    2009            2008          2007          2006          2005
                                           ------------- --------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -              -              -             -             -
 Net asset value, beginning of year          $   1.00       $   1.00       $   1.00      $   1.00      $   1.00
------------------------------------------   --------       --------       --------      --------      --------
Net investment income                            0.0008         0.0200         0.0500        0.0500        0.0300
 Net realized gain                              0.00001             -              -             -             -
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net increase from investment operations         0.0008          0.0200         0.0500        0.0500        0.0300
 Dividends from net investment income          (0.0008)       (0.0200)       (0.0500)      (0.0500)      (0.0300)
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net asset value, end of year                 $  1.00        $   1.00       $   1.00      $   1.00      $   1.00
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Based on net asset value                        0.08   %        1.61  %        4.95  %       5.04  %       3.20  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Total expenses                                  0.12   %        0.15  %        0.18  %       0.19  %       0.12  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 Total expenses after expense reductions        0.04   %        0.04  %        0.04  %       0.00  %       0.00  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net investment income                           0.09   %        0.39  %        4.74  %       5.03  %       4.03  %
------------------------------------------   ----------     ----------     ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------     ----------     ----------    ----------    ----------
Net assets, end of year (000)                $  30,011      $1,305,944     $ 131,190     $ 126,518     $ 100,343
------------------------------------------   ----------     ----------     ----------    ----------    ----------


/1/ Less than $0.00005 per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

30

[THIS PAGE INTENTIONALLY LEFT BLANK]


ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-INST-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

SELECT SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                 TICKER SYMBOL
------------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Select                  BGLXX
Shares
BlackRock Cash Funds: Prime - Select Shares                   BPLXX
BlackRock Cash Funds: Government - Select                     BVSXX
Shares
BlackRock Cash Funds: Treasury - Select Shares                BRSXX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL....................  1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................  5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT.......................  9
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 13

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 17
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 18

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 20
SHAREHOLDER SERVICING PAYMENTS............. 22
CALCULATING THE FUNDS' SHARE PRICE......... 23
FUND DISTRIBUTIONS......................... 23
SHORT TERM TRADING POLICY.................. 23
TAXES...................................... 23
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 24

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 26
ADMINISTRATIVE SERVICES........ 26
CONFLICTS OF INTEREST.......... 26
VALUATION OF FUND INVESTMENTS.. 26
CERTAIN FUND POLICIES.......... 27

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 29

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


[THIS PAGE INTENTIONALLY LEFT BLANK]


Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Select Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF YOUR INVESTMENT)
 Management Fee(1)                                                                  0.10%
 Distribution and/or Service (12b-1) Fees                                    None
 Other Expenses                                                                     0.15%
  Administration Fees (1)                                                           0.15%
  Independent Expenses(2)(3)                                                        0.00%
 Total Annual Class Operating Expenses(1)(3)(4)                                     0.25%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                   (0.05)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense             0.20%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), the administrator of the Fund, has contractually agreed to waive a portion of its administration fees through the close of business on November 30, 2011. After giving effect to such contractual waivers, the management fee will be 0.07% and the administration fees will be 0.13%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Select Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Select Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Select Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  20         $  70        $  130        $  308

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the

1

Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Select Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Select Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the

2

average annual total return of Select Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Select Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.19%
2006    5.00%
2007    5.26%
2008    2.76%
2009    0.35%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.02% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                  SINCE
                                                                                                INCEPTION
AS OF 12/31/09                                                                                 (JANUARY 26,
AVERAGE ANNUAL TOTAL RETURNS                                  1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Institutional - Select Shares            0.35%            3.30%              2.98%
 MFR First Tier Institutional Average                           0.34%            3.13%              2.78%(1)


(1) The MFR First Tier Institutional Average is calculated from December 31, 2003.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is 1,000,000 although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Select Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA") or maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to

3

purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Select Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF YOUR INVESTMENT)
 Management Fee(1)                                                                  0.10%
 Distribution and/or Service (12b-1) Fees                                    None
 Other Expenses                                                                     0.15%
  Administration Fees(1)                                                            0.15%
  Independent Expenses(2)(3)                                                        0.00%
 Total Annual Class Operating Expenses(4)                                           0.25%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                   (0.05)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense             0.20%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), the administrator of the Fund, has contractually agreed to waive a portion of its administration fees through the close of business on November 30, 2011.After giving effect to such contractual waivers, the management fee will be 0.07% and the administration fees will be 0.13%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Select Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Select Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Select Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  20         $  70        $  130        $  308

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at

5

least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Select Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Select Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Select Shares of the Fund to that of the Money Fund Report ("MFR") First Tier

6

Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Prime - Select Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.16%
2006    4.97%
2007    5.24%
2008    2.75%
2009    0.24%

During the periods shown in the bar chart, the highest return for a quarter was 1.32% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.02% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.01%.

                                                                                          SINCE
                                                                                        INCEPTION
AS OF 12/31/09                                                                         (JANUARY 26,
AVERAGE ANNUAL TOTAL RETURNS                          1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Prime - Select Shares            0.24%            3.26%              2.95%
 MFR First Tier Institutional Average                   0.34%            3.13%              2.78%(1)


(1) The MFR First Tier Institutional Average is calculated from December 31, 2003.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is 1,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Select Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to

7

purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

8

Fund Overview

KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Government (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Select Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF YOUR INVESTMENT)
 Management Fee (1)                                                                 0.10%
 Distribution and/or Service (12b-1) Fees                                    None
 Other Expenses                                                                     0.15%
  Administration Fees (1)                                                           0.15%
  Independent Expenses(2)(3)                                                        0.00%
 Total Annual Class Operating Expenses(1)(3)(4)                                     0.25%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                   (0.05)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense             0.20%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Government Money Market Master Portfolio (the "Government Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.), the administrator of the Fund, has contractually agreed to waive a portion of its administration fees through the close of business on November 30, will be 2011. After giving effect to such contractual waivers, the management fee 0.07% and the administration fees will be 0.13%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Government Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Government Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Government Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Select Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Select Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Select Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  20         $  70        $  130        $  308

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's

9

assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Government Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Government Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Government Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Government Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Select Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Select Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Select Shares of the Fund to that of the Money Fund Report ("MFR") Government Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

10

BlackRock Cash Funds: Government - Select Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.18%
2006    4.94%
2007    5.06%
2008    1.89%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.31% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.02% (quarters ended March 31, 2009, September 30, 2009, and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                               SINCE
                                                                                             INCEPTION
AS OF 12/31/09                                                                             (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                               1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Government - Select Shares            0.08%            3.01%              2.94%
 MFR Government Institutional Average                        0.17%            2.80%              2.61%(1)


(1) The MFR Government Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Government Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is 1,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Select Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

11

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Select Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF YOUR INVESTMENT)
 Management Fee(1)                                                                  0.10%
 Distribution and/or Service (12b-1) Fees                                    None
 Other Expenses                                                                     0.15%
  Administration Fees(1)                                                            0.15%
  Independent Expenses(2)(3)                                                        0.00%
 Total Annual Class Operating Expenses(4)                                           0.25%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                   (0.05)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense             0.20%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors), the administrator of the Fund, has contractually agreed to waive a portion of its administration fees through the close of business on November 30, 2011. After giving effect to such contractual waivers, the management fee will be 0.07% and the administration fees will be 0.13%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BTC and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Select Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Select Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Select Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  20         $  70        $  130        $  308

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's

13

assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

14

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Select Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Select Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Select Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Treasury - Select Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.10%
2006    4.94%
2007    4.86%
2008    1.55%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.31% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                             SINCE
                                                                                           INCEPTION
AS OF 12/31/09                                                                           (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                             1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Treasury - Select Shares            0.08%            2.88%              2.81%
 MFR Treasury and Repo Institutional Average               0.05%            2.66%              2.58%(1)


(1) The MFR Treasury and Repo Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $1 million, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Select Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the

15

"Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

16

Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Government invests all of its assets in Government Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: GOVERNMENT

BlackRock Cash Funds: Government seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

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A FURTHER DISCUSSION OF PRINCIPAL RISKS

Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: GOVERNMENT AND BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

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FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

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Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

To be eligible to purchase Select Shares, you must:

. Invest through an employer-sponsored or individual retirement savings plan;

. Invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA");

. Maintain an account with the Transfer Agent, or with one of the Funds' Shareholder Servicing Agents; or

. Initially invest a minimum of $1 million directly through the Transfer Agent.

The minimum initial investment amount for Select Shares of each Fund is $1 million; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, your Shareholder Servicing Agent or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

Your Shareholder Servicing Agent may charge you a fee and may offer additional account services. Additionally, your Shareholder Servicing Agent may have procedures for placing orders for Select Shares that differ from those of the Funds, such as different investment minimums or earlier trading deadlines. Please contact your Shareholder Servicing Agent directly for more information and details.

HOW TO BUY SHARES

. PLAN PARTICIPANT. Invest through payroll deductions or make a direct contribution by rolling over an amount from another 401(k) plan or from a rollover IRA (make arrangements through your employer). If you are investing through a Shareholder Servicing Agent, your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. TAX-DEFERRED INVESTOR. Invest through a Shareholder Servicing Agent as provided in your benefit plan documents. Your Shareholder Servicing Agent, plan sponsor or administrator is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline for purchase and redemption orders than the Funds, as described below.

. QUALIFIED BUYER. Invest through an account set up with your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds:

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Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

. PLAN PARTICIPANT AND TAX-DEFERRED INVESTOR. Contact your plan sponsor, administrator or Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. QUALIFIED BUYER. Contact your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR DIRECT BUYERS

A direct buyer who has established an account with a Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Funds may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund of your choice and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

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State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:
Shareholder Account Number:
Fund Share Class Numbers:
1122 (BlackRock Cash Funds: Institutional - Select Shares) 1199 (BlackRock Cash Funds: Prime - Select Shares) 1099 (BlackRock Cash Funds: Government - Select Shares) 1109 (BlackRock Cash Funds: Treasury - Select Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include your Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. A direct buyer can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When a direct buyer purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

SHAREHOLDER SERVICING PAYMENTS


The Funds have adopted a shareholder servicing plan (the "Plan") that allows each Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a Fund's shares. Because the fees paid by a Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Funds and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a Fund may pay to a Financial Intermediary pursuant to the Plan and fees a Fund pays to the Transfer Agent, BFA, on behalf of a Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Funds and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by,

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customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a Fund to you. Please contact your Financial Intermediary for details about payments it may receive from a Fund or from BFA or its affiliates. For more information, see the Funds' SAI.

CALCULATING THE FUNDS' SHARE PRICE


Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern Time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds

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and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

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FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

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Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.15% of the average daily net assets of Select Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level. BTC has contractually agreed to waive 0.02% of its administration fee through the close of business on November 30, 2011.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") (for convenience, the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity") in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow an investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more Affiliates or Entities act or

26

may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Funds will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Funds. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities, therefore, may differ from those of an Affiliate or an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In Addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or an Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds and their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value (normally $1.00 per share) without a sales charge. This is the offering price. Shares are also redeemed at their net asset value. The Funds calculate the net asset value each day the NYSE or New York banks are open, as of the close of business on the NYSE (generally 4:00 p.m. Eastern time) or, on days when the NYSE is closed but New York banks are open, as of 4:00 p.m. Eastern time. Both the NYSE and New York banks are closed on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Currently, the only scheduled days on which the NYSE is open and New York banks are closed are Columbus Day and Veterans Day. The only scheduled day on which New York banks are open and the NYSE is closed is Good Friday. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order becomes effective. Share purchase orders are effective on the date Federal funds become available to the Funds.

The amortized cost method is used in calculating net asset value, meaning that the calculation is based on a valuation of the assets held by a Fund at cost, with an adjustment for any discount or premium on a security at the time of purchase.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a Fund's shares are determined as of such times.

A Fund may accept orders from certain authorized financial intermediaries or their designees. A Fund will be deemed to receive an order when accepted by the intermediary or designee, and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided

27

to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

28

Financial Highlights


The financial highlights tables are intended to help investors understand the financial performance of Select Shares of each Fund for the past five years. Certain information reflects financial results for a single Select Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Select Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each Fund's financial statements, is included in the Funds' combined annual report. You may obtain copies of the annual report, at no cost, by calling

1-800-768-2836 (toll-free) from 8:30 a.m. to 6:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                                            SELECT SHARES
                                          ----------------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                          ----------------------------------------------------------------------------------
                                                        2009                2008           2007          2006           2005
                                          ------------------ ------------------- -------------- ------------- --------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------             --                  --               -             -              -
 Net asset value, beginning of year          $  1.00            $  1.00            $  1.00        $  1.00       $  1.00
-----------------------------------------    -----------        ------------       -------        -------       -------
Net investment income                          0.0035              0.0300             0.0500         0.0500        0.0300
 Net realized gain (loss)                      0.00001              (0.0000)/1/       0.00001            -         0.00001
-----------------------------------------    -----------        --------------     ----------     ---------     ----------
Net increase from investment operations        0.0035              0.0300             0.0500         0.0500        0.0300
-----------------------------------------    -----------        --------------     ----------     ---------     ----------
 Dividends and distributions from:
  Net investment income                        ( 0.0035)           ( 0.0300)        ( 0.0500)     ( 0.0500)      ( 0.0300)
  Net realized gain                            ( 0.0000)/1/               -                -             -              -
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
Total dividends and distributions              ( 0.0035)           ( 0.0300)        ( 0.0500)     ( 0.0500)      ( 0.0300)
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
 Net asset value, end of year                $  1.00            $  1.00            $  1.00        $  1.00       $  1.00
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
TOTAL INVESTMENT RETURN
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
 Based on net asset value                      0.35     %          2.76     %         5.26   %       5.00  %       3.19   %
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
 Total expenses                                0.23     %          0.28     %         0.25   %       0.23  %       0.22   %
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
Total expenses after expense reductions        0.20     %          0.23     %         0.20   %       0.19  %       0.15   %
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
 Net investment income                         0.57     %          2.05     %         5.11   %       4.55  %       3.50   %
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
SUPPLEMENTAL DATA
-----------------------------------------    -------------      --------------     ----------     ---------     ----------
 Net assets, end of year (000)               $   23,204         $    10,014        $   4,807      $  1,229      $  24,940
-----------------------------------------    -------------      --------------     ----------     ---------     ----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

29

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                                          SELECT SHARES
                                           ---------------------------------------------------------------------------
                                                                     YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------------
                                                    2009                2008          2007          2006          2005
                                           ------------- ------------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -                --               -             -             -
 Net asset value, beginning of year          $   1.00       $  1.00            $   1.00      $   1.00      $   1.00
------------------------------------------   --------       ------------       --------      --------      --------
Net investment income                            0.0024        0.0280              0.0500        0.0500        0.0312
 Net realized gain (loss)                       0.00001         (0.0000)/1/       0.00001       0.00001       0.00001
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net increase from investment operations         0.0024         0.0280             0.0500        0.0500        0.0312
 Dividends from net investment income          (0.0024)         (0.0280)         (0.0500)      (0.0500)      (0.0312)
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net asset value, end of year                 $  1.00        $  1.00            $  1.00       $  1.00       $  1.00
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Based on net asset value                        0.24   %       2.75     %         5.24   %      4.97   %      3.16   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Total expenses                                  0.27   %       0.25     %         0.25   %      0.24   %      0.22   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 Total expenses after expense reductions        0.22   %       0.18     %         0.20   %      0.21   %      0.18   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net investment income                           0.24   %       2.95     %         5.06   %      4.67   %      3.05   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net assets, end of year (000)                $  73,810      $   143,150        $ 268,352     $  21,642     $  81,359
------------------------------------------   ----------     --------------     ----------    ----------    ----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

30

BLACKROCK CASH FUNDS: GOVERNMENT

FINANCIAL HIGHLIGHTS

                                                                       SELECT SHARES
                                           ---------------------------------------------------------------------
                                                                  YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------
                                                    2009          2008          2007          2006          2005
                                           ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year          $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   --------      --------      --------      --------      --------
Net investment income                            0.0008        0.0200        0.0500        0.0483        0.0300
 Dividends from net investment income          (0.0008)      (0.0200)      (0.0500)      (0.0483)      (0.0300)
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net asset value, end of year                 $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Based on net asset value                         0.08  %       1.89  %       5.06  %       4.94  %       3.18  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/1/
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Total expenses                                   0.25  %       0.23  %       0.28  %       0.26  %       0.22  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 Total expenses after expense reductions         0.09  %       0.07  %       0.20  %       0.21  %       0.13  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net investment income                            0.08  %       0.82  %       5.03  %       4.84  %       3.90  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net assets, end of year (000)                $  69,139     $  81,424     $  14,269     $  42,683     $  40,712
------------------------------------------   ----------    ----------    ----------    ----------    ----------


/1/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

31

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                                       SELECT SHARES
                                           ---------------------------------------------------------------------
                                                                  YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------
                                                    2009          2008          2007          2006          2005
                                           ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year          $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   --------      --------      --------      --------      --------
Net investment income                            0.0007        0.0200        0.0500        0.0500        0.0300
 Net realized gain                              0.00001            -             -             -             -
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net increase from investment operations         0.0007         0.0200        0.0500        0.0500        0.0300
 Dividends from net investment income          (0.0007)      (0.0200)      (0.0500)      (0.0500)      (0.0300)
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net asset value, end of year                 $  1.00       $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Based on net asset value                        0.08   %       1.55  %       4.86  %       4.94  %       3.10  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Total expenses                                  0.25   %       0.25  %       0.27  %       0.30  %       0.22  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 Total expenses after expense reductions        0.08   %       0.09  %       0.10  %       0.10  %       0.10  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net investment income                           0.08   %       0.92  %       5.06  %       5.15  %       3.06  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net assets, end of year (000)                $   4,815     $  24,340     $  10,050     $  55,919     $     103
------------------------------------------   ----------    ----------    ----------    ----------    ----------


/1/ Less than $0.00005 per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

32

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-SEL-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

PREMIUM SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                TICKER SYMBOL
-----------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Premium                BSSXX
Shares
BlackRock Cash Funds: Prime - Premium Shares                 BPSXX
BlackRock Cash Funds: Treasury - Premium                     BSPXX
Shares

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL.................... 1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................ 5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 9

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 13
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 14

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 16
SHAREHOLDER SERVICING PAYMENTS............. 18
CALCULATING THE FUNDS' SHARE PRICE......... 19
FUND DISTRIBUTIONS......................... 19
SHORT TERM TRADING POLICY.................. 19
TAXES...................................... 19
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 20

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 22
ADMINISTRATIVE SERVICES........ 22
CONFLICTS OF INTEREST.......... 22
VALUATION OF FUND SHARES....... 23
CERTAIN FUND POLICIES.......... 23

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 25

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Premium Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                       0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                          0.10%
  Administration Fees                                                                    0.10%
  Independent Expenses(2)(3)                                                             0.00%
 Total Annual Class Operating Expenses(4)                                                0.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                        (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                  0.17%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Premium Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Premium Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Premium Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  17         $  58        $  106        $  249

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities;

1

certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Premium Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Premium Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Premium Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund

2

expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Premium Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2003    1.10%
2004    1.34%
2005    3.24%
2006    5.05%
2007    5.31%
2008    2.80%
2009    0.38%

During the periods shown in the bar chart, the highest return for a quarter was 1.34% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.03% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                   SINCE
                                                                                                 INCEPTION
AS OF 12/31/09                                                                                  (DECEMBER 2,
AVERAGE ANNUAL TOTAL RETURNS                                   1 YEAR          5 YEARS             2002)
 BlackRock Cash Funds: Institutional - Premium Shares            0.38%            3.34%              2.71%
 MFR First Tier Institutional Average                            0.34%            3.13%              2.48%(1)


(1) The MFR First Tier Institutional Average is calculated from November 30, 2002.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Premium Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA") or maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

3

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Premium Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.10%
  Administration Fees                                                                          0.10%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.17%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Premium Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Premium Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Premium Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  17         $  58        $  106        $  249

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality

5

debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Premium Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Premium Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Premium Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund

6

expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Prime - Premium Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2004    1.35%
2005    3.21%
2006    5.02 %
2007    5.27%
2008    2.78%
2009    0.27%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.03% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                            SINCE
                                                                                          INCEPTION
AS OF 12/31/09                                                                            (APRIL 16,
AVERAGE ANNUAL TOTAL RETURNS                           1 YEAR           5 YEARS             2003)
 BlackRock Cash Funds: Prime - Premium Shares             0.27%            3.29%              2.76%
 MFR First Tier Institutional Average                     0.34%            3.13%              2.55%(1)


(1) The MFR First Tier Institutional Average is calculated from March 31, 2003.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Premium Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA") or maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

7

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information..

8

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Premium Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.10%
  Administration Fees                                                                          0.10%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.20%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.17%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Premium Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Premium Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Premium Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  17         $  58        $  106        $  249

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations

9

and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Premium Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Premium Shares of

10

the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Premium Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Treasury - Premium Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.15%
2006    4.99%
2007    4.90%
2008    1.57%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.32% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                              SINCE
                                                                                            INCEPTION
AS OF 12/31/09                                                                            (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                              1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Treasury - Premium Shares            0.08%            2.92%              2.85%
 MFR Treasury and Repo Institutional Average                0.05%            2.66%              2.58%(1)


(1) The MFR Treasury and Repo Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Premium Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA") or maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00

11

p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

13

A FURTHER DISCUSSION OF PRINCIPAL RISKS

Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

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FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

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Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

To be eligible to purchase Premium Shares, you must:

. Invest through an employer-sponsored or individual retirement savings plan;

. Invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA");

. Maintain an account with the Transfer Agent, or with one of the Funds' Shareholder Servicing Agents; or

. Initially invest a minimum of $10 million directly through the Transfer Agent.

The minimum initial investment amount for Premium Shares of each Fund is $10 million; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, your Shareholder Servicing Agent or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

Your Shareholder Servicing Agent may charge you a fee and may offer additional account services. Additionally, your Shareholder Servicing Agent may have procedures for placing orders for Premium Shares that differ from those of the Funds, such as different investment minimums or earlier trading deadlines. Please contact your Shareholder Servicing Agent directly for more information and details.

HOW TO BUY SHARES

. PLAN PARTICIPANT. Invest through payroll deductions or make a direct contribution by rolling over an amount from another 401(k) plan or from a rollover IRA (make arrangements through your employer). If you are investing through a Shareholder Servicing Agent, your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. TAX-DEFERRED INVESTOR. Invest through a Shareholder Servicing Agent as provided in your benefit plan documents. Your Shareholder Servicing Agent, plan sponsor or administrator is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline for purchase and redemption orders than the Funds, as described below.

. QUALIFIED BUYER. Invest through an account set up with your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds:

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Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

. PLAN PARTICIPANT AND TAX-DEFERRED INVESTOR. Contact your plan sponsor, administrator or Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. QUALIFIED BUYER. Contact your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR DIRECT BUYERS

A direct buyer who has established an account with a Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Funds may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund of your choice and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

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State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:
Shareholder Account Number:
Fund Share Class Numbers:
1128 (BlackRock Cash Funds: Institutional - Premium Shares)

1198 (BlackRock Cash Funds: Prime - Premium Shares)

1108 (BlackRock Cash Funds: Treasury - Premium Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include your Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. A direct buyer can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When a direct buyer purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

SHAREHOLDER SERVICING PAYMENTS


The Funds have adopted a shareholder servicing plan (the "Plan") that allows each Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a Fund's shares. Because the fees paid by a Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Funds and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a Fund may pay to a Financial Intermediary pursuant to the Plan and fees a Fund pays to the Transfer Agent, BFA, on behalf of a Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Funds and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be

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substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a Fund to you. Please contact your Financial Intermediary for details about payments it may receive from a Fund or from BFA or its affiliates. For more information, see the Funds' SAI.

CALCULATING THE FUNDS' SHARE PRICE


Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds

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and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

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FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

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Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.10% of the average daily net assets of Premium Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") (for convenience, the Affiliates, BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity") in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow an investment programs similar to of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies

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and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Funds will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Funds. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or an Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds and their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

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If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

24

Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Premium Shares of each Fund for the past five years. Certain information reflects financial results for a single Premium Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Premium Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each Fund's financial statements, is included in the Funds' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                                              PREMIUM SHARES
                                          ---------------------------------------------------------------------------------------
                                                                          YEAR ENDED DECEMBER 31,
                                          ---------------------------------------------------------------------------------------
                                                        2009                2008           2007             2006             2005
                                          ------------------ ------------------- -------------- ---------------- ----------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------             --                  --               -                -                -
 Net asset value, beginning of year          $  1.00            $  1.00            $  1.00         $   1.00         $   1.00
-----------------------------------------    -----------        ------------       --------        --------         --------
Net investment income                          0.0038              0.0300             0.0500           0.0500           0.0300
 Net realized gain (loss)                      0.00001              (0.0000)/1/       0.00001          0.00001          0.00001
-----------------------------------------    -----------        --------------     ----------      -----------      -----------
Net increase from investment operations        0.0038              0.0300             0.0500           0.0500           0.0300
-----------------------------------------    -----------        --------------     ----------      -----------      -----------
 Dividends and distributions from:
  Net investment income                        ( 0.0038)           ( 0.0300)        ( 0.0500)        ( 0.0500)        ( 0.0300)
  Net realized gain                            ( 0.0000)/1/               -                -                -                -
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
Total dividends and distributions              ( 0.0038)           ( 0.0300)        ( 0.0500)        ( 0.0500)        ( 0.0300)
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
 Net asset value, end of year                $  1.00            $  1.00            $  1.00         $   1.00         $   1.00
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
TOTAL INVESTMENT RETURN
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
 Based on net asset value                      0.38     %          2.80     %         5.31   %         5.05   %         3.24   %
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
 Total expenses                                0.20     %          0.21     %         0.21   %         0.19   %         0.17   %
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
Total expenses after expense reductions        0.17     %          0.18     %         0.16   %         0.15   %         0.10   %
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
 Net investment income                         0.48     %          2.79     %         5.21   %         4.93   %         3.24   %
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
SUPPLEMENTAL DATA
-----------------------------------------    -------------      --------------     ----------      -----------      -----------
 Net assets, end of year (000)               $   97,513         $ 1,021,216        $ 746,582       $ 1,321,042      $ 1,803,171
-----------------------------------------    -------------      --------------     ----------      -----------      -----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

25

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                                             PREMIUM SHARES
                                           -----------------------------------------------------------------------------------
                                                                         YEAR ENDED DECEMBER 31,
                                           -----------------------------------------------------------------------------------
                                                      2009                2008            2007            2006            2005
                                           --------------- ------------------- --------------- --------------- ---------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------            -                 --                -               -               -
 Net asset value, beginning of year           $   1.00        $  1.00             $   1.00        $   1.00        $   1.00
------------------------------------------    --------        ------------        --------        --------        --------
Net investment income                             0.0027         0.0270               0.0500          0.0500          0.0317
 Net realized gain (loss)                        0.00001          (0.0000)/1/        0.00001         0.00001         0.00001
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net increase from investment operations          0.0027          0.0270              0.0500          0.0500          0.0317
 Dividends from net investment income           (0.0027)          (0.0270)          (0.0500)        (0.0500)        (0.0317)
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net asset value, end of year                  $  1.00         $  1.00             $  1.00         $  1.00         $  1.00
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 TOTAL INVESTMENT RETURN
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Based on net asset value                         0.27   %        2.78     %          5.27   %        5.02   %        3.21   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Total expenses                                   0.23   %        0.21     %          0.20   %        0.19   %        0.17   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 Total expenses after expense reductions         0.20   %        0.17     %          0.17   %        0.16   %        0.13   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net investment income                            0.34   %        2.60     %          5.14   %        4.88   %        3.08   %
------------------------------------------    ----------      --------------      ----------      ----------      ----------
 SUPPLEMENTAL DATA
------------------------------------------    ----------      --------------      ----------      ----------      ----------
Net assets, end of year (000)                 $1,817,088      $ 4,304,633         $1,795,477      $1,551,648      $3,233,738
------------------------------------------    ----------      --------------      ----------      ----------      ----------


/1/ Less than $0.00005 or $(0.00005) per share

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

26

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                                      PREMIUM SHARES
                                           ---------------------------------------------------------------------
                                                                  YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------
                                                    2009          2008          2007          2006          2005
                                           ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year          $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   --------      --------      --------      --------      --------
Net investment income                            0.0007        0.0200        0.0500        0.0500        0.0300
 Net realized gain                              0.00001            -             -             -             -
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net increase from investment operations         0.0007         0.0200        0.0500        0.0500        0.0300
 Dividends from net investment income          (0.0007)      (0.0200)      (0.0500)      (0.0500)      (0.0300)
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net asset value, end of year                 $  1.00       $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Based on net asset value                        0.08   %       1.57  %       4.90  %       4.99  %       3.15  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Total expenses                                  0.19   %       0.20  %       0.23  %       0.23  %       0.17  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 Total expenses after expense reductions        0.08   %       0.07  %       0.09  %       0.05  %       0.05  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net investment income                           0.09   %       1.17  %       4.44  %       4.61  %       3.83  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net assets, end of year (000)                $   2,542     $  65,095     $  61,513     $   2,112     $   2,546
------------------------------------------   ----------    ----------    ----------    ----------    ----------


/1/ Less than $0.00005 per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

27

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-PRE-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVES BLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

SL AGENCY SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND
-------------------------------------------------
BlackRock Cash Funds: Institutional - SL Agency
Shares
BlackRock Cash Funds: Prime - SL Agency Shares
BlackRock Cash Funds: Government - SL Agency
Shares
BlackRock Cash Funds: Treasury - SL Agency
Shares

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL....................  1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................  5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT.......................  9
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 13

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 17
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 17

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 19
CALCULATING THE FUNDS' SHARE PRICE......... 20
FUND DISTRIBUTIONS......................... 20
SHORT TERM TRADING POLICY.................. 20
TAXES...................................... 20
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 21

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 23
ADMINISTRATIVE SERVICES........ 23
CONFLICTS OF INTEREST.......... 23
VALUATION OF FUND SHARES....... 24
CERTAIN FUND POLICIES.......... 24

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 26

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold SL Agency Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                       0.10%
 Distribution and/or Service (12b-1) Fees                                                None
 Other Expenses                                                                          0.02%
  Administration Fees                                                                    0.02%
  Independent Expenses(2)(3)                                                             0.00%
 Total Annual Class Operating Expenses(4)                                                0.12%
 Fee Waivers and/or Expense Reimbursements(1)(3)(4)                                     (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                  0.09%
  Reimbursements(1)(3)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in SL Agency Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in SL Agency Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that SL Agency Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
 $  9         $  32         $  61        $  148

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities;

1

certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


SL Agency Shares of the Fund commenced operation on February 4, 2009 and do not have a full calendar year of operation. As a result, the performance shown is that of Institutional Shares of the Fund, which are offered by a separate prospectus. Institutional Shares and SL Agency Shares of the Fund should have returns that are substantially similar because they represent interests in the same portfolio securities and their performance should differ only to the extent that they bear different expenses.

2

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each of the last ten calendar years. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000     6.55%
2001     4.23%
2002     1.83%
2003     1.14%
2004     1.39%
2005     3.29%
2006     5.11%
2007     5.36%
2008     2.85%
2009     0.43%

During the periods shown in the bar chart, the highest return for a quarter was 1.68% (quarter ended December 31, 2000) and the lowest return for a quarter was 0.04% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.04%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                         1 YEAR           5 YEARS         10 YEARS
 BlackRock Cash Funds: Institutional - Institutional Shares             0.43%            3.39%            3.20%
 MFR First Tier Institutional Average                                   0.34%            3.13%            2.90%

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

Currently, the only eligible investors for SL Agency Shares of the Fund are investment companies for which (i) BFA, BTC, or an affiliate provides investment advisory or administrative services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in SL Agency Shares of the Fund. Please contact BTC or State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), for more information.

You may purchase or sell shares without paying a sales charge. Your order to buy or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time, on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

3

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold SL Agency Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                                      None
 Other Expenses                                                                                0.02%
  Administration Fees                                                                          0.02%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.12%
 Fee Waivers and/or Expense Reimbursements(1)(3)(4)                                           (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.09%
  Reimbursements(1)(3)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in SL Agency Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in SL Agency Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that SL Agency Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
 $  9         $  32         $  61        $  148

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality

5

debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


SL Agency Shares of the Fund commenced operation on February 4, 2009 and do not have a full calendar year of operation. As a result, the performance shown is that of Institutional Shares of the Fund, which are offered by a separate prospectus. Institutional Shares and SL Agency Shares of the Fund should have returns that are substantially similar because they represent interests in the same portfolio securities and their performance should differ only to the extent that they bear different expenses.

6

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future.If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Prime - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2004     1.40%
2005     3.26%
2006     5.07%
2007     5.32%
2008     2.83%
2009     0.32%

During the periods shown in the bar chart, the highest return for a quarter was 1.34% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.04% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.03%.

                                                                                                  SINCE
                                                                                                INCEPTION
AS OF 12/31/09                                                                                  (APRIL 16,
AVERAGE ANNUAL TOTAL RETURNS                                 1 YEAR           5 YEARS             2003)
 BlackRock Cash Funds: Prime - Institutional Shares             0.32%            3.35%              2.82%
 MFR First Tier Institutional Average                           0.34%            3.13%              2.55%(1)


(1) The MFR First Tier Institutional Average is calculated from March 31, 2003.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

Currently, the only eligible investors for SL Agency Shares of the Fund are investment companies for which (i) BFA, BTC, or an affiliate provides investment advisory or administrative services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in SL Agency Shares of the Fund. Please contact BTC or State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), for more information.

You may purchase or sell shares without paying a sales charge. Your order to buy or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time, on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

7

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

8

Fund Overview

KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Government (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold SL Agency Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                                      None
 Other Expenses                                                                                0.02%
  Administration Fees                                                                          0.02%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.12%
 Fee Waivers and/or Expense Reimbursements(1)(3)(4)                                           (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.09%
  Reimbursements(1)(3)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Government Money Market Master Portfolio (the "Government Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Government Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Government Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Government Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in SL Agency Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in SL Agency Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that SL Agency Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
 $  9         $  32         $  61        $  148

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's

9

assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Government Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Government Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Government Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Government Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


SL Agency Shares of the Fund commenced operation on February 4, 2009 and do not have a full calendar year of operation. As a result, the performance shown is that of Institutional Shares of the Fund, which are offered by a separate prospectus. Institutional Shares and SL Agency Shares of the Fund should have returns that are substantially similar because they represent interests in the same portfolio securities and their performance should differ only to the extent that they bear different expenses.

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the

10

Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") Government Institutional Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Government - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    3.28%
2006    5.04%
2007    5.15%
2008    1.96%
2009    0.09%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.02% (quarters ended September 30, 2009 and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                      SINCE
                                                                                                    INCEPTION
AS OF 12/31/09                                                                                    (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                                      1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Government - Institutional Shares            0.09%            3.09%              3.01%
 MFR Government Institutional Average                               0.17%            2.80%              2.61%(1)


(1) The MFR Government Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Government Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

Currently, the only eligible investors for SL Agency Shares of the Fund are investment companies for which (i) BFA, BTC, or an affiliate provides investment advisory or administrative services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in SL Agency Shares of the Fund. Please contact BTC or State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), for more information.

You may purchase or sell shares without paying a sales charge. Your order to buy or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time, on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

11

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold SL Agency Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                                      None
 Other Expenses                                                                                0.02%
  Administration fees                                                                          0.02%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.12%
 Fee Waivers and/or Expense Reimbursements(1)(3)(4)                                           (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.09%
  Reimbursements(1)(3)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in SL Agency Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in SL Agency Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that SL Agency Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
 $  9         $  32         $  61        $  148

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations

13

and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

PERFORMANCE INFORMATION

SL Agency Shares of the Fund commenced operation on February 4, 2009 and do not have a full calendar year of operation. As a result, the performance shown is that of Institutional Shares of the Fund, which are offered by a

14

separate prospectus. Institutional Shares and SL Agency Shares of the Fund should have returns that are substantially similar because they represent interests in the same portfolio securities and their performance should differ only to the extent that they bear different expenses.

The bar chart and table in this section provide some indication of the risks of investing in Institutional Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Institutional Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Institutional Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Institutional Average, a service of iMoneyNet. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower. How the Fund performed in the past is not necessarily an indication of how it will perform in the future.

BlackRock Cash Funds: Treasury - Institutional Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005     3.20%
2006     5.04%
2007     4.95%
2008     1.61%
2009     0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.33% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                                    SINCE
                                                                                                  INCEPTION
AS OF 12/31/09                                                                                  (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                                    1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Treasury - Institutional Shares            0.08%            2.96%              2.89%
 MFR Treasury and Repo Institutional Average                      0.05%            2.66%              2.58%(1)


(1) The MFR Treasury and Repo Institutional Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

Currently, the only eligible investors for SL Agency Shares of the Fund are investment companies for which (i) BFA, BTC, or an affiliate provides investment advisory or administrative services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in SL Agency Shares of the Fund. Please contact BTC or State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), for more information.

You may purchase or sell shares without paying a sales charge. Your order to buy or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time, on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time)

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to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Government invests all of its assets in Government Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: GOVERNMENT

BlackRock Cash Funds: Government seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

A FURTHER DISCUSSION OF PRINCIPAL RISKS


Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: GOVERNMENT AND BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

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Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

Currently, the only eligible investors for SL Agency Shares of the Funds are investment companies for which (i) BFA, BTC, or an affiliate provides investment advisory or administrative services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in the Funds. Please contact BTC or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, BTC or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

HOW TO BUY SHARES

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or BTC, as intermediary, pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

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In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

CALCULATING THE FUNDS' SHARE PRICE

Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern Time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

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Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR INDIVIDUAL RETIREMENT ACCOUNT, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

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FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

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Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services; and

. Preparation of proxy statements and shareholder reports.

BTC is entitled to receive fees for these services at the annual rate of 0.02% of the average daily net assets of SL Agency Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") for convenience the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity" in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more of the Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or on Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

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VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value (normally $1.00 per share) without a sales charge. This is the offering price. Shares are also redeemed at their net asset value. The Funds calculate the net asset value each day the NYSE or New York banks are open, as of the close of business on the NYSE (generally 4:00 p.m. Eastern time) or, on days when the NYSE is closed but New York banks are open, as of 4:00 p.m. Eastern time. Both the NYSE and New York banks are closed on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Currently, the only scheduled days on which the NYSE is open and New York banks are closed are Columbus Day and Veterans Day. The only scheduled day on which New York banks are open and the NYSE is closed is Good Friday. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order becomes effective. Share purchase orders are effective on the date Federal funds become available to the Funds.

The amortized cost method is used in calculating net asset value, meaning that the calculation is based on a valuation of the assets held by a Fund at cost, with an adjustment for any discount or premium on a security at the time of purchase.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a Fund's shares are determined as of such times.

A Fund may accept orders from certain authorized financial intermediaries or their designees. A Fund will be deemed to receive an order when accepted by the intermediary or designee, and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

24

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

25

Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of SL Agency Shares of each Fund for the period of the Fund's operations. Certain information reflects financial results for a single SL Agency Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in SL Agency Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers, LLP, whose report, along with the Funds' financial statements, is included in the Funds' annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) Monday through Friday from 8:30 a.m. to 5:30 p.m. Eastern Time.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                   SL AGENCY SHARES
                                              --------------------------
                                                             PERIOD FROM
                                                       FEBRUARY 4, 20091
                                                    TO DECEMBER 31, 2009
                                              --------------------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------                        --
 Net asset value, beginning of period             $        1.00
-----------------------------------------         -----------------
Net investment income                                      0.0035
 Net realized gain                                         0.00002
-----------------------------------------         -----------------
Net increase from investment operations                    0.0035
-----------------------------------------         -----------------
 Dividends and distributions from:
  Net investment income                             (       0.0035)
  Net realized gain                                 (       0.0000)2
-----------------------------------------         ------------------
Total dividends and distributions                   (       0.0035)
-----------------------------------------         ------------------
 Net asset value, end of period                   $        1.00
-----------------------------------------         ------------------
TOTAL INVESTMENT RETURN
-----------------------------------------         ------------------
 Based on net asset value                                     0.36%/3 /
-----------------------------------------         -------------------
RATIOS TO AVERAGE NET ASSETS4,5
-----------------------------------------         -------------------
 Total expenses                                            0.12    %
-----------------------------------------         -------------------
Total expenses after expense reductions                    0.09    %
-----------------------------------------         -------------------
 Net investment income                                     0.38    %
-----------------------------------------         -------------------
SUPPLEMENTAL DATA
-----------------------------------------         -------------------
 Net assets, end of period (000)                  $       18,832,492
-----------------------------------------         -------------------


/1/ Commencement of operations.

/2/ Less than $0.00005 or $(0.00005) per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income(loss).

/5/ Annualized.

26

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                   SL AGENCY SHARES
                                               -----------------------
                                                           PERIOD FROM
                                                     FEBRUARY 4, 20091
                                                  TO DECEMBER 31, 2009
                                               -----------------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------                      --
 Net asset value, beginning of period             $        1.00
------------------------------------------        ----------------
Net investment income                                      0.0028
 Net realized gain                                         0.00002
------------------------------------------        ----------------
Net increase from investment operations                    0.0028
 Dividends from net investment income                     (0.0028)
------------------------------------------        ----------------
Net asset value, end of period                    $        1.00
------------------------------------------        ----------------
 TOTAL INVESTMENT RETURN
------------------------------------------        ----------------
Based on net asset value                                     0.28%/3/
------------------------------------------        ------------------
 RATIOS TO AVERAGE NET ASSETS4,5
------------------------------------------        ------------------
Total expenses                                             0.14   %
------------------------------------------        ------------------
 Total expenses after expense reductions                   0.11   %
------------------------------------------        ------------------
Net investment income                                      0.31   %
------------------------------------------        ------------------
 SUPPLEMENTAL DATA
------------------------------------------        ------------------
Net assets, end of period (000)                   $     5,860,881
------------------------------------------        ------------------


/1/ Commencement of operations.

/2/ Less than $0.00005 per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income(loss).

/5/ Annualized.

27

BLACKROCK CASH FUNDS: GOVERNMENT

FINANCIAL HIGHLIGHTS

                                                   SL AGENCY SHARES
                                               ------------------------
                                                            PERIOD FROM
                                                      FEBRUARY 4, 20091
                                                   TO DECEMBER 31, 2009
                                               ------------------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------                       --
 Net asset value, beginning of period             $         1.00
------------------------------------------        -----------------
Net investment income                                       0.0009
 Dividends from net investment income                      (0.0009)
------------------------------------------        -----------------
Net asset value, end of period                    $         1.00
------------------------------------------        -----------------
 TOTAL INVESTMENT RETURN
------------------------------------------        -----------------
Based on net asset value                                      0.09%/2/
------------------------------------------        -------------------
 RATIOS TO AVERAGE NET ASSETS3,4
------------------------------------------        -------------------
Total expenses                                              0.12   %
------------------------------------------        -------------------
 Total expenses after expense reductions                    0.07   %
------------------------------------------        -------------------
Net investment income                                       0.10   %
------------------------------------------        -------------------
 SUPPLEMENTAL DATA
------------------------------------------        -------------------
Net assets, end of period (000)                   $        563,288
------------------------------------------        -------------------


/1/ Commencement of operations.

/2/ Aggregate total investment return.

/3/ Annualized.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income(loss).

28

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                   SL AGENCY SHARES
                                               -----------------------
                                                           PERIOD FROM
                                                     FEBRUARY 4, 20091
                                                  TO DECEMBER 31, 2009
                                               -----------------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------                      --
 Net asset value, beginning of period             $        1.00
------------------------------------------        ----------------
Net investment income                                      0.0008
 Net realized gain                                         0.00002
------------------------------------------        ----------------
Net increase from investment operations                    0.0008
 Dividends from net investment income                     (0.0008)
------------------------------------------        ----------------
Net asset value, end of period                    $        1.00
------------------------------------------        ----------------
 TOTAL INVESTMENT RETURN
------------------------------------------        ----------------
Based on net asset value                                     0.09%/3/
------------------------------------------        ------------------
 RATIOS TO AVERAGE NET ASSETS4,5
------------------------------------------        ------------------
Total expenses                                             0.12   %
------------------------------------------        ------------------
 Total expenses after expense reductions                   0.07   %
------------------------------------------        ------------------
Net investment income                                      0.08   %
------------------------------------------        ------------------
 SUPPLEMENTAL DATA
------------------------------------------        ------------------
Net assets, end of period (000)                   $     4,009,074
------------------------------------------        ------------------


/1/ Commencement of operations.

/2/ Less than $0.00005 per share.

/3/ Aggregate total investment return.

/4/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income(loss).

/5/ Annualized.

29

30

[THIS PAGE INTENTIONALLY LEFT BLANK]


ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-SLA-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

TRUST SHARES PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                     TICKER SYMBOL
----------------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Trust Shares                BGTXX
BlackRock Cash Funds: Prime - Trust Shares                        BPEXX
BlackRock Cash Funds: Government - Trust Shares                   BVTXX
BlackRock Cash Funds: Treasury - Trust Shares                     BYTXX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUNDS, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL....................  1
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME............................  5
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT.......................  9
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY......................... 13

DETAILS ABOUT THE FUNDS

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES........ 17
A FURTHER DISCUSSION OF PRINCIPAL RISKS............... 18

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION.................... 20
SHAREHOLDER SERVICING PAYMENTS............. 22
CALCULATING THE FUNDS' SHARE PRICE......... 23
FUND DISTRIBUTIONS......................... 23
SHORT TERM TRADING POLICY.................. 23
TAXES...................................... 23
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 24

MANAGEMENT OF THE FUNDS

INVESTMENT ADVISER............. 26
ADMINISTRATIVE SERVICES........ 26
CONFLICTS OF INTEREST.......... 26
VALUATION OF FUND INVESTMENTS.. 26
CERTAIN FUND POLICIES.......... 27

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUNDS........ 29

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


[THIS PAGE INTENTIONALLY LEFT BLANK]


Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Trust Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.38%
  Administration Fees                                                                          0.38%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.48%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.45%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%.

(2) Independent Expenses have been restated to reflect current fees. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Trust Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Trust Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Trust Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  46        $  148        $  262        $  598

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities;

1

certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Trust Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Trust Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Trust Shares of the Fund to that of the Money Fund Report ("MFR") All Taxable Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication or now it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these How the Fund performed in the past is not necessarily an indication of how it will perform in the future.

2

periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Institutional - Trust Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    2.96%
2006    4.76%
2007    5.01%
2008    2.51%
2009    0.18%

During the periods shown in the bar chart, the highest return for a quarter was 1.27% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.01% (quarters ended September 30, 2009 and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.01%.

                                                                                                  SINCE
                                                                                                INCEPTION
AS OF 12/31/09                                                                                  (JUNE 10,
AVERAGE ANNUAL TOTAL RETURNS                                 1 YEAR           5 YEARS             2004)
 BlackRock Cash Funds: Institutional - Trust Shares             0.18%            3.07%              2.89%
 MFR All Taxable Average                                        0.38%            2.85%              2.75%(1)


(1) The MFR All Taxable Average is calculated from May 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Trust Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with one of the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

3

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

4

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: PRIME

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Prime (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Trust Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.38%
  Administration Fees                                                                          0.38%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.48%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.45%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Prime Money Market Master Portfolio (the "Prime Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Prime Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Prime Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Prime Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Trust Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Trust Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Trust Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  46        $  148        $  262        $  598

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality

5

debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Prime Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Prime Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Prime Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Prime Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Trust Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Trust Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Trust Shares of the Fund to that of the Money Fund Report ("MFR") All Taxable Average, a service of iMoneyNet. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these

6

periods, the Fund's returns would have been lower. How the Fund performed in the past is not necessarily an indication of how it will perform in the future.

BlackRock Cash Funds: Prime - Trust Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    2.93%
2006    4.72%
2007    4.98%
2008    2.49%
2009    0.11%

During the periods shown in the bar chart, the highest return for a quarter was 1.26% (quarter ended September 30, 2007) and the lowest return for a quarter was 0.01% (quarters ended September 30, 2009 and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.01%.

                                                                                          SINCE
                                                                                        INCEPTION
AS OF 12/31/09                                                                          (JUNE 10,
AVERAGE ANNUAL TOTAL RETURNS                         1 YEAR           5 YEARS             2004)
 BlackRock Cash Funds: Prime - Trust Shares             0.11%            3.03%              2.86%
 MFR All Taxable Average                                0.38%            2.85%              2.75%(1)


(1) The MFR All Taxable Average is calculated from May 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Prime Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Trust Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with one of the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

7

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

8

Fund Overview

KEY FACTS ABOUT BLACKROCK CASH FUNDS: GOVERNMENT

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Government (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Trust Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.38%
  Administration Fees                                                                          0.38%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.48%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.45%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Government Money Market Master Portfolio (the "Government Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Government Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Government Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Government Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Trust Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Trust Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Trust Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  46        $  148        $  262        $  598

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's

9

assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Government Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Government Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Government Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Government Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Trust Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Trust Shares of the Fund for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Trust Shares of the Fund to that of the Money Fund Report ("MFR") All Government Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

10

BlackRock Cash Funds: Government - Trust Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    2.94%
2006    4.69%
2007    4.80%
2008    1.69%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.24% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.02% (quarters ended March 31, 2009, September 30, 2009, and December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                              SINCE
                                                                                            INCEPTION
AS OF 12/31/09                                                                            (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                              1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Government - Trust Shares            0.08%            2.82%              2.75%
 MFR All Government Average                                 0.36%            2.91%              2.82%(1)


(1) The MFR All Government Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Government Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Trust Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with one of the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00
p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

11

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

12

Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: TREASURY

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Treasury (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of current income consistent with the preservation of capital and liquidity.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Trust Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                             0.10%
 Distribution and/or Service (12b-1) Fees                                               None
 Other Expenses                                                                                0.38%
  Administration Fees                                                                          0.38%
  Independent Expenses(2)(3)                                                                   0.00%
 Total Annual Class Operating Expenses(4)                                                      0.48%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                              (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                        0.45%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA"), the investment adviser to Treasury Money Market Master Portfolio (the "Treasury Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Treasury Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Treasury Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Treasury Master Portfolio in which it invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Trust Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Trust Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Trust Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  46        $  148        $  262        $  598

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations

13

and in other money market funds that have substantially the same investment objective and strategies as the Fund. It is further intended that under normal circumstances, 100% of the Fund's investments will be invested in such securities.

U.S. Treasury obligations are backed by the full faith and credit of the U.S. government. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Treasury Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Treasury Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Treasury Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Treasury Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. INVESTMENT IN OTHER INVESTMENT COMPANIES RISK - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

The Fund minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

PERFORMANCE INFORMATION

The bar chart and table in this section provide some indication of the risks of investing in Trust Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the returns of Trust Shares of the Fund

14

for each complete calendar year since the Fund's inception. The average annual total return table compares the average annual total return of Trust Shares of the Fund to that of the Money Fund Report ("MFR") Treasury and Repo Retail Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

BlackRock Cash Funds: Treasury - Trust Shares

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2005    2.86%
2006    4.70%
2007    4.61%
2008    1.45%
2009    0.08%

During the periods shown in the bar chart, the highest return for a quarter was 1.25% (quarter ended December 31, 2006) and the lowest return for a quarter was 0.01% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.02%.

                                                                                            SINCE
                                                                                          INCEPTION
AS OF 12/31/09                                                                          (SEPTEMBER 1,
AVERAGE ANNUAL TOTAL RETURNS                            1 YEAR          5 YEARS             2004)
 BlackRock Cash Funds: Treasury - Trust Shares            0.08%            2.72%              2.64%
 MFR Treasury and Repo Retail Average                     0.02%            2.37%              2.28%(1)


(1) The MFR Treasury and Repo Retail Average is calculated from August 31, 2004.

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Treasury Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $100,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

To be eligible to purchase Trust Shares of the Fund, you must invest through an employer-sponsored or individual retirement savings plan; invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA"); maintain an account with State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent"), or with one of the Fund's shareholder servicing agent (the "Shareholder Servicing Agent"). Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00

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p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and SEI Investments Distribution Co. ("SEI" or the "Distributor"), or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the Funds

DETAILS ABOUT THE FUNDS' INVESTMENT STRATEGIES

Each of BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds") is a "feeder" fund that invests all of its assets in a corresponding "master" portfolio (each, a "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. BlackRock Cash Funds: Institutional invests all of its assets in Money Market Master Portfolio. BlackRock Cash Funds: Prime invests all of its assets in Prime Master Portfolio. BlackRock Cash Funds: Government invests all of its assets in Government Master Portfolio. BlackRock Cash Funds: Treasury invests all of its assets in Treasury Master Portfolio. All discussion of the investment objective, strategies and risks of a particular Fund refers also to the investment objective, strategies and risks of its Master Portfolio, unless otherwise indicated. A description of the relationship of the Funds to their respective Master Portfolios appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH FUNDS: PRIME

BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime seek to achieve their investment objectives by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. Each Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, BlackRock Cash Funds: Prime expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, each Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime reserves the right to invest 25% or more of its total assets in the obligations of domestic banks. The principal and interest of all securities held by the Funds are payable in U.S. dollars.

BLACKROCK CASH FUNDS: GOVERNMENT

BlackRock Cash Funds: Government seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in certain obligations of the U.S. government, its agencies and instrumentalities; repurchase agreements with regard to such obligations; and other money market funds that have substantially the same investment objective and strategies as the Fund. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

BLACKROCK CASH FUNDS: TREASURY

BlackRock Cash Funds: Treasury seeks to achieve its investment objective by investing only in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. In general, the Fund expects to maintain an average weighted maturity of 60 days or less. Under normal circumstances, at least 80% of the Fund's assets will be invested in U.S. Treasury obligations, in repurchase agreements with regard to U.S. Treasury obligations and in other money market funds that have substantially the same investment objective and strategies as the Fund. The Fund currently has an operating policy to invest 100% of its net assets in such securities. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

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A FURTHER DISCUSSION OF PRINCIPAL RISKS

Risk is inherent in all investing. The value of your investment in the Funds, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Funds or your investment may not perform as well as other similar investments. An investment in the Funds is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Funds is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although each Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Funds. The following is a description of certain risks of investing in the Funds.

CONCENTRATION RISK (BLACKROCK CASH FUNDS: INSTITUTIONAL AND BLACKROCK CASH
FUNDS: PRIME) - Each of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may concentrate its investments in the U.S. banking industry, which means that its performance will be closely tied to the performance of a particular market segment. Each Fund's concentration in these companies may present more risks than if it was broadly diversified over numerous industries and sectors of the economy. A downturn in these companies would have a larger impact on a Fund than on a mutual fund that does not concentrate in such companies. At times, the performance of these companies will lag the performance of other industries or the broader market as a whole.

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of a Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - Each Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of a Fund.

INVESTMENT IN OTHER INVESTMENT COMPANIES RISK (BLACKROCK CASH FUNDS: GOVERNMENT AND BLACKROCK CASH FUNDS: TREASURY) - As with other investments, investments in other investment companies are subject to market and selection risk. In addition, if a Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in a Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which a Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

BlackRock Cash Funds: Treasury minimizes these risks to the extent that it invests in U.S. Treasury obligations backed by the full faith and credit of the U.S. government or repurchase agreements with respect to U.S. Treasury obligations.

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FOR A DESCRIPTION OF THE FUNDS' POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUNDS' MASTER PORTFOLIOS' PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUNDS' INVESTMENTS AND RISKS, PLEASE REFER TO THE FUNDS' COMBINED STATEMENT OF ADDITIONAL INFORMATION ("SAI").

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Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

To be eligible to purchase Trust Shares, you must:

. Invest through an employer-sponsored or individual retirement savings plan;

. Invest the proceeds rolled over from such retirement savings plan into an individual retirement account ("IRA");

. Maintain an account with the Transfer Agent, or with one of the Funds' Shareholder Servicing Agents; or

. Initially invest a minimum of $100,000 directly through the Transfer Agent.

The minimum initial investment amount for Trust Shares of each Fund is $100,000; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Funds offer additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

In order to invest, a completed account application form must be submitted to, and processed by, your Shareholder Servicing Agent or the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

Your Shareholder Servicing Agent may charge you a fee and may offer additional account services. Additionally, your Shareholder Servicing Agent may have procedures for placing orders for Trust Shares that differ from those of the Funds, such as different investment minimums or earlier trading deadlines. Please contact your Shareholder Servicing Agent directly for more information and details.

HOW TO BUY SHARES

. PLAN PARTICIPANT. Invest through payroll deductions or make a direct contribution by rolling over an amount from another 401(k) plan or from a rollover IRA (make arrangements through your employer). If you are investing through a Shareholder Servicing Agent, your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. TAX-DEFERRED INVESTOR. Invest through a Shareholder Servicing Agent as provided in your benefit plan documents. Your Shareholder Servicing Agent, plan sponsor or administrator is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline for purchase and redemption orders than the Funds, as described below.

. QUALIFIED BUYER. Invest through an account set up with your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your purchase order to the Transfer Agent and may impose an earlier deadline than the Funds, as described below.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Funds are generally open Monday through Friday and are closed on weekends and generally closed on all other days that the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00
p.m. Eastern time) on such Business Day. BlackRock Cash Funds:

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Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day.

Each Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

. PLAN PARTICIPANT AND TAX-DEFERRED INVESTOR. Contact your plan sponsor, administrator or Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. QUALIFIED BUYER. Contact your Shareholder Servicing Agent. Your Shareholder Servicing Agent is responsible for properly transmitting your sale order to the Transfer Agent.

. DIRECT BUYER. See the "Special Instructions for Direct Buyers" section of this Prospectus.

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. Each Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For example, a Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

In addition, each Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR DIRECT BUYERS

A direct buyer who has established an account with a Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Funds may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund of your choice and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

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State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:
Shareholder Account Number:
Fund Share Class Numbers:
1124 (BlackRock Cash Funds: Institutional - Trust Shares) 1194 (BlackRock Cash Funds: Prime - Trust Shares) 1094 (BlackRock Cash Funds: Government - Trust Shares) 1104 (BlackRock Cash Funds: Treasury - Trust Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include your Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. A direct buyer can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When a direct buyer purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

SHAREHOLDER SERVICING PAYMENTS


The Funds have adopted a shareholder servicing plan (the "Plan") that allows each Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (such as BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not costs which are primarily intended to result in the sale of a Fund's shares. Because the fees paid by a Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Funds and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that a Fund may pay to a Financial Intermediary pursuant to the Plan and fees a Fund pays to the Transfer Agent, BFA, on behalf of a Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Funds and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by,

22

customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of a Fund to you. Please contact your Financial Intermediary for details about payments it may receive from a Fund or from BFA or its affiliates. For more information, see the Funds' SAI.

CALCULATING THE FUNDS' SHARE PRICE


Each Fund's share price (also known as a Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Each Fund's NAV is calculated at 5:00 p.m. Eastern Time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of each Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Funds' SAI includes a description of the methods for valuing the Master Portfolios' investments.

The Funds seek to maintain a constant NAV of $1.00 per share, although they can offer no assurance that they will be able to do so.

FUND DISTRIBUTIONS

Each Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. A Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by a Fund will be automatically reinvested in additional shares of that Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

Each Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, each Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, each Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Funds

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and their U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Funds' SAI for additional U.S. federal income tax information.

Distributions from your Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Funds generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Funds paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since each Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of each Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Funds are able to maintain a constant NAV of $1.00 per share, sales of the Funds' shares generally will not result in taxable gain or loss. After the end of each year, the Funds will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Funds if you fail to provide the Funds with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR IRA, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Funds do not have their own investment adviser. Instead, each Fund invests all of its assets in the corresponding Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to each Master Portfolio. The Master Portfolios may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolios and, therefore, the Funds.

FEEDER FUND EXPENSES

Feeder funds, including the Funds, bear their respective master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

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FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw a Fund's assets from its Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw a Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

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Management of the Funds

INVESTMENT ADVISER


Each Fund is a "feeder" fund that invests all of its assets in a Master Portfolio that has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolios. BFA manages the investment of the Master Portfolios' assets and provides the Master Portfolios with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolios, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolios invest.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreements with BFA is available in the Funds' annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Funds' administrator:

. Supervises the Funds' administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive fees for these services at the annual rate of 0.38% of the average daily net assets of Trust Shares of each Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Funds, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Funds or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") (for convenience, the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity") in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Funds and their shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow investment programs similar to those of the Funds. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Funds. One or more Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies

26

and other instruments in which the Funds directly and indirectly invest. Thus, it is likely that the Funds will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Funds and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Funds. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Funds and may result in an Affiliate or an Entity having positions that are adverse to those of the Funds.

No Affiliate or Entity is under any obligation to share any investment opportunity, idea or strategy with the Funds. As a result, an Affiliate or an Entity may compete with the Funds for appropriate investment opportunities. The results of the Funds' investment activities may differ from those of an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Funds could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Funds may, from time to time, enter into transactions in which an Affiliate or an Entity other clients have an adverse interest. Furthermore, transactions undertaken or its Affiliate-advised clients may adversely impact the Funds. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Funds.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Funds' activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Funds may invest in securities of companies with which an Affiliate or an Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Funds also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Funds or who engage in transactions with or for the Funds, and may receive compensation for such services. The Funds may also make brokerage and other payments to Affiliates or Entities in connection with the Funds' portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Funds and their shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value (normally $1.00 per share) without a sales charge. This is the offering price. Shares are also redeemed at their net asset value. The Funds calculate the net asset value each day the NYSE or New York banks are open, as of the close of business on the NYSE (generally 4:00 p.m. Eastern time) or, on days when the NYSE is closed but New York banks are open, as of 4:00 p.m. Eastern time. Both the NYSE and New York banks are closed on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Currently, the only scheduled days on which the NYSE is open and New York banks are closed are Columbus Day and Veterans Day. The only scheduled day on which New York banks are open and the NYSE is closed is Good Friday. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order becomes effective. Share purchase orders are effective on the date Federal funds become available to the Funds.

The amortized cost method is used in calculating net asset value, meaning that the calculation is based on a valuation of the assets held by a Fund at cost, with an adjustment for any discount or premium on a security at the time of purchase.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a Fund's shares are determined as of such times.

A Fund may accept orders from certain authorized financial intermediaries or their designees. A Fund will be deemed to receive an order when accepted by the intermediary or designee, and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Funds are subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, a Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Funds reserve the right to reject purchase orders from persons who have not submitted information sufficient to allow the Funds to verify their identity. The Funds also reserve the right to redeem any amounts in a Fund from persons whose identity it is unable to verify on a timely basis. It is the Funds' policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

27

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

28

Financial Highlights

The financial highlights tables are intended to help investors understand the financial performance of Trust Shares of each Fund for the past five years. Certain information reflects financial results for a single Trust Share of each Fund. The total returns in the tables represent the rate of return that an investor would have earned (or lost) on an investment in Trust Shares of a given Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with each Fund's financial statements, is included in the Funds' combined annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                                             TRUST SHARES
                                          ----------------------------------------------------------------------------------
                                                                       YEAR ENDED DECEMBER 31,
                                          ----------------------------------------------------------------------------------
                                                        2009                2008           2007           2006          2005
                                          ------------------ ------------------- -------------- -------------- -------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------             --                  --               -              -             -
 Net asset value, beginning of year          $  1.00            $  1.00            $  1.00        $  1.00        $  1.00
-----------------------------------------    -----------        ------------       -------        --------       -------
Net investment income                          0.0018              0.0200             0.0500         0.0500         0.0300
 Net realized gain (loss)                      0.00001              (0.0000)/1/       0.00001        0.00001            -
-----------------------------------------    -----------        --------------     ----------     ----------     ---------
Net increase from investment operations        0.0018              0.0200             0.0500         0.0500         0.0300
-----------------------------------------    -----------        --------------     ----------     ----------     ---------
 Dividends and distributions from:
  Net investment income                        ( 0.0018)           ( 0.0200)        ( 0.0500)      ( 0.0500)     ( 0.0300)
  Net realized gain                            ( 0.0000)/1/               -                -              -             -
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
Total dividends and distributions              ( 0.0018)           ( 0.0200)        ( 0.0500)      ( 0.0500)     ( 0.0300)
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
 Net asset value, end of year                $  1.00            $  1.00            $  1.00        $  1.00        $  1.00
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
TOTAL INVESTMENT RETURN
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
 Based on net asset value                      0.18     %          2.51     %         5.01   %       4.76   %       2.96  %
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
 Total expenses                                0.48     %          0.49     %         0.48   %       0.47   %       0.45  %
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
Total expenses after expense reductions        0.40     %          0.46     %         0.43   %       0.43   %       0.38  %
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
 Net investment income                         0.22     %          2.50     %         4.93   %       4.95   %       2.92  %
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
SUPPLEMENTAL DATA
-----------------------------------------    -------------      --------------     ----------     ----------     ---------
 Net assets, end of year (000)               $   19,713         $    76,334        $  85,774      $ 197,480      $    103
-----------------------------------------    -------------      --------------     ----------     ----------     ---------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

29

BLACKROCK CASH FUNDS: PRIME

FINANCIAL HIGHLIGHTS

                                                                          TRUST SHARES
                                           ---------------------------------------------------------------------------
                                                                     YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------------
                                                    2009                2008          2007          2006          2005
                                           ------------- ------------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -                --               -             -             -
 Net asset value, beginning of year          $   1.00       $  1.00            $   1.00      $   1.00      $   1.00
------------------------------------------   --------       ------------       --------      --------      --------
Net investment income                            0.0011        0.0200              0.0500        0.0500        0.0289
 Net realized gain (loss)                       0.00001         (0.0000)/1/       0.00001       0.00001       0.00001
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net increase from investment operations         0.0011         0.0200             0.0500        0.0500        0.0289
 Dividends from net investment income          (0.0011)         (0.0200)         (0.0500)      (0.0500)      (0.0289)
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net asset value, end of year                 $  1.00        $  1.00            $  1.00       $  1.00       $  1.00
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Based on net asset value                        0.11   %       2.49     %         4.98   %      4.72   %      2.93   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Total expenses                                  0.51   %       0.52     %         0.48   %      0.47   %      0.45   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 Total expenses after expense reductions        0.36   %       0.48     %         0.45   %      0.45   %      0.41   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net investment income                           0.09   %       1.34     %         4.89   %      4.63   %      2.89   %
------------------------------------------   ----------     --------------     ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------     --------------     ----------    ----------    ----------
Net assets, end of year (000)                $  96,349      $     3,370        $      50     $     108     $     103
------------------------------------------   ----------     --------------     ----------    ----------    ----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

30

BLACKROCK CASH FUNDS: GOVERNMENT

FINANCIAL HIGHLIGHTS

                                                                       TRUST SHARES
                                           ---------------------------------------------------------------------
                                                                  YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------
                                                    2009          2008          2007          2006          2005
                                           ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year          $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   --------      --------      --------      --------      --------
Net investment income                            0.0008        0.0200        0.0500        0.0459        0.0300
 Dividends from net investment income          (0.0008)      (0.0200)      (0.0500)      (0.0459)      (0.0300)
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net asset value, end of year                 $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Based on net asset value                         0.08  %       1.69  %       4.80  %       4.69  %       2.94  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/1/
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Total expenses                                   0.48  %       0.47  %       0.51  %       0.49  %       0.45  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 Total expenses after expense reductions         0.09  %       0.07  %       0.45  %       0.45  %       0.36  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net investment income                            0.08  %       0.16  %       4.78  %       4.60  %       2.91  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net assets, end of year (000)                $  13,462     $  12,380     $      50     $     108     $     103
------------------------------------------   ----------    ----------    ----------    ----------    ----------


/1/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

31

BLACKROCK CASH FUNDS: TREASURY

FINANCIAL HIGHLIGHTS

                                                                       TRUST SHARES
                                           ---------------------------------------------------------------------
                                                                  YEAR ENDED DECEMBER 31,
                                           ---------------------------------------------------------------------
                                                    2009          2008          2007          2006          2005
                                           ------------- ------------- ------------- ------------- -------------
PER SHARE OPERATING PERFORMANCE
------------------------------------------           -             -             -             -             -
 Net asset value, beginning of year          $   1.00      $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   --------      --------      --------      --------      --------
Net investment income                            0.0007        0.0100        0.0500        0.0500        0.0300
 Net realized gain                              0.00001            -             -             -             -
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net increase from investment operations         0.0007         0.0100        0.0500        0.0500        0.0300
 Dividends from net investment income          (0.0007)      (0.0100)      (0.0500)      (0.0500)      (0.0300)
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net asset value, end of year                 $  1.00       $   1.00      $   1.00      $   1.00      $   1.00
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 TOTAL INVESTMENT RETURN
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Based on net asset value                        0.08   %       1.45  %       4.61  %       4.70  %       2.86  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 RATIOS TO AVERAGE NET ASSETS/2/
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Total expenses                                  0.47   %       0.47  %       0.51  %       0.52  %       0.45  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 Total expenses after expense reductions        0.08   %       0.01  %       0.36  %       0.33  %       0.33  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net investment income                           0.08   %       0.05  %       4.65  %       4.60  %       2.83  %
------------------------------------------   ----------    ----------    ----------    ----------    ----------
 SUPPLEMENTAL DATA
------------------------------------------   ----------    ----------    ----------    ----------    ----------
Net assets, end of year (000)                $  55,618     $  94,654     $      50     $     108     $     103
------------------------------------------   ----------    ----------    ----------    ----------    ----------


/1/ Less than $0.00005 per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

32

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about each Fund, may be obtained free of charge, along with each Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Funds, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of each Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about each Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-TRU-0510


EQUITIES FIXED INCOME REAL ESTATE
LIQUIDITY ALTERNATIVESBLACKROCK SOLUTIONS

[GRAPHIC APPEARS HERE]

BLACKROCK FUNDS III
BLACKROCK CASH FUNDS

PROSPECTUS | MAY 1, 2010

This Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.

FUND                                                     TICKER SYMBOL
----------------------------------------------------     --------------
BlackRock Cash Funds: Institutional - Aon Captives                AOCXX
Shares

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED | MAY LOSE VALUE | NO BANK GUARANTEE


Table of Contents

BLACKROCK CASH FUNDS

  KEY FACTS AND DETAILS ABOUT THE FUND, INCLUDING INVESTMENT OBJECTIVES,
FUND OVERVIEW
  PRINCIPAL STRATEGIES, RISK FACTORS, FEE AND EXPENSE INFORMATION, AND
  HISTORICAL PERFORMANCE INFORMATION
  KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL................... 1

DETAILS ABOUT THE FUND

A FURTHER DISCUSSION OF PRINCIPAL RISKS........ 5

ACCOUNT INFORMATION

SHAREHOLDER INFORMATION....................  7
SHAREHOLDER SERVICING PAYMENTS.............  8
CALCULATING THE FUND'S SHARE PRICE.........  9
FUND DISTRIBUTIONS.........................  9
SHORT TERM TRADING POLICY..................  9
TAXES...................................... 10
MASTER/FEEDER MUTUAL FUND STRUCTURE........ 11

MANAGEMENT OF THE FUND

INVESTMENT ADVISER............. 12
ADMINISTRATIVE SERVICES........ 12
CONFLICTS OF INTEREST.......... 12
VALUATION OF FUND INVESTMENTS.. 12
CERTAIN FUND POLICIES.......... 13

FINANCIAL HIGHLIGHTS

FINANCIAL PERFORMANCE OF THE FUND........ 15

FOR MORE INFORMATION ADDITIONAL INFORMATION............BACK COVER


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Fund Overview


KEY FACTS ABOUT BLACKROCK CASH FUNDS: INSTITUTIONAL

INVESTMENT OBJECTIVE

The investment objective for BlackRock Cash Funds: Institutional (the "Fund"), a series of BlackRock Funds III (the "Trust"), is to seek a high level of income consistent with liquidity and the preservation of capital.

FEES AND EXPENSES OF THE FUND

The table below describes the fees and expenses that you may pay if you buy and hold Aon Captives Shares of the Fund.

ANNUAL CLASS OPERATING EXPENSES
(EXPENSES THAT YOU PAY EACH YEAR AS A PERCENTAGE OF THE VALUE OF YOUR INVESTMENT)
 Management Fee(1)                                                                       0.10%
 Distribution and/or Service (12b-1) Fees                                                0.10%
 Other Expenses                                                                          0.05%
  Administration Fees                                                                    0.05%
  Independent Expenses(2)(3)                                                             0.00%
 Total Annual Class Operating Expenses(4)                                                0.25%
 Fee Waivers and/or Expense Reimbursements(1)(3)                                        (0.03)%
 Total Annual Class Operating Expenses After Fee Waivers and/or Expense                  0.22%
  Reimbursements(1)(3)(4)


(1) BlackRock Fund Advisors ("BFA") (formerly, Barclays Global Fund Advisors), the investment adviser to Money Market Master Portfolio (the "Money Market Master Portfolio"), a series of Master Investment Portfolio ("MIP"), has contractually agreed to waive a portion of its management fee through the close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%. The contractual waiver may not be terminated prior to November 30, 2011 without the consent of the Board of Trustees of MIP.

(2) Independent Expenses have been restated to reflect current fees.

(3) "Independent Expenses" consist of the Fund's allocable portion of the fees and expenses of the independent trustees of the Trust and MIP, counsel to such independent trustees and the independent registered public accounting firm that provides audit services to the Fund and Money Market Master Portfolio. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and BFA have contractually agreed to reimburse, or provide offsetting credits to, the Fund and Money Market Master Portfolio, as applicable, for Independent Expenses through the close of business on November 30, 2011. After giving effect to such contractual arrangements, Independent Expenses will be 0.00%. Such contractual arrangements may not be terminated prior to November 30, 2011 without consent of the Board of Trustees of MIP.

(4) Total Annual Class Operating Expenses in the table above and the following example reflect the expenses of both the Fund and Money Market Master Portfolio in which the Fund invests.

EXAMPLE:

This Example is intended to help you compare the cost of investing in Aon Captives Shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in Aon Captives Shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that Aon Captives Shares' operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 YEAR       3 YEARS       5 YEARS       10 YEARS
$  23         $  74        $  134        $  312

PRINCIPAL INVESTMENT STRATEGIES OF THE FUND

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include

1

certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

The Fund is a "feeder" fund that invests all of its investable assets in the Money Market Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Money Market Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Money Market Master Portfolio. For simplicity, the prospectus ("Prospectus") uses the name of the Fund or the term "Fund" (as applicable) to include Money Market Master Portfolio.

PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock, Inc. ("BlackRock") or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation ("FDIC") or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a summary description of certain risks of investing in the Fund.

. CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

. CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer.

. INCOME RISK - Income risk is the risk that the Fund's yield will vary as short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

. INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

. MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

. U.S. GOVERNMENT OBLIGATIONS RISK - Certain securities in which the Fund may invest, including securities issued by certain U.S. government agencies and U.S. government sponsored enterprises, are not guaranteed by the U.S. government or supported by the full faith and credit of the United States.

PERFORMANCE INFORMATION


The bar chart and table in this section provide some indication of the risks of investing in Aon Captives Shares of the Fund by showing the changes in its performance from year to year. The bar chart shows the return of Aon Captives Shares of the Fund for each of the last ten calendar years. The average annual total return table compares the average annual total return of Aon Captives Shares of the Fund to that of the Money Fund Report ("MFR") First Tier Institutional

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Average, a service of iMoneyNet. How the Fund performed in the past is not necessarily an indication of how it will perform in the future. If BFA and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower.

YEAR-BY-YEAR RETURNS (YEARS ENDED DECEMBER 31)

[GRAPHIC APPEARS HERE]

2000    6.46%
2001    4.12%
2002    1.70%
2003    1.04%
2004    1.29%
2005    3.19%
2006    5.00%
2007    5.26%
2008    2.74%
2009    0.33%

During the periods shown in the bar chart, the highest return for a quarter was 1.66% (quarter ended December 31, 2000) and the lowest return for a quarter was 0.02% (quarter ended December 31, 2009). The year-to-date return as of March 31, 2010 was 0.01%.

AS OF 12/31/09
AVERAGE ANNUAL TOTAL RETURNS                                        1 YEAR           5 YEARS         10 YEARS
 BlackRock Cash Funds: Institutional - Aon Captives Shares             0.33%            3.29%            3.09%
 MFR First Tier Institutional Average                                  0.34%            3.13%            2.90%

The Fund's 7-day yield, also called the current yield, annualizes the amount of income the Fund generates over a 7-day period by projecting the amount for an entire year. To obtain the Fund's current 7-day yield, call 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day or

visit www.blackrock.com/cash.

Because the current yields on high-quality, short-term money market instruments in which the Fund invests are generally lower than yields on such instruments during the periods shown in the foregoing bar chart and table, the current performance of the Fund is generally lower than that shown in the bar chart and table.

INVESTMENT ADVISER

Money Market Master Portfolio's investment adviser is BFA.

PURCHASE AND SALE OF SHARES

The Fund's minimum initial investment is $500,000, although the Fund may reduce or waive the minimum in some cases. You may purchase or redeem shares of the Fund each day the New York Stock Exchange (the "NYSE" or "Exchange") is open. To purchase or sell shares you should contact your financial intermediary or financial professional, or, if you hold your shares through the Fund, you should contact the Fund by phone at 1-888-204-3956, or by mail to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642.

You may purchase or sell shares without paying a sales charge. Your order to purchase or sell shares must be received in proper form, as determined by State Street Bank and Trust Company, the Fund's transfer agent (the "Transfer Agent") or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any day the Fund is open (a "Business Day") (or, if the Fund closes early, by such closing time) to purchase or sell shares at that day's net asset value ("NAV"). Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

TAX INFORMATION

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a retirement plan, in which case you may be subject to U.S. federal income tax upon withdrawal from such tax deferred arrangements.

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PAYMENTS TO BROKER/DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary, the Fund and BlackRock Investments, LLC (the "Distributor"), the Fund's distributor, or its affiliates may pay the intermediary for the sale of Fund shares and other services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

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Details About the Fund

The Fund is a "feeder" fund that invests all of its assets in a separate "master" portfolio (the "Master Portfolio") of MIP, a mutual fund that has an investment objective and strategies substantially identical to the Fund. All discussion of the investment objective, strategies and risks of the Fund refers also to the investment objective, strategies and risks of the Master Portfolio, unless otherwise indicated. A description of the relationship of the Fund to the Master Portfolio appears below under the heading "Account Information - Master/Feeder Mutual Fund Structure."

The Fund seeks to achieve its investment objective by investing in high-quality, short-term money market instruments that, at the time of investment, have remaining maturities of 397 calendar days or less from the date of acquisition. The Fund's portfolio will maintain an average weighted maturity of 90 days or less. Under normal circumstances, the Fund expects to invest at least 95% of its assets in any combination of such investments, which may include certificates of deposit; high-quality debt obligations, such as corporate debt and certain asset-backed securities; certain obligations of U.S. and foreign banks; certain repurchase agreements; and certain obligations of the U.S. government, its agencies and instrumentalities (including government-sponsored enterprises).

The Fund reserves the right to concentrate its investments (I.E., invest 25% or more of its total assets in securities of issuers in a particular industry) in the obligations of domestic banks. The principal and interest of all securities held by the Fund are payable in U.S. dollars.

A FURTHER DISCUSSION OF PRINCIPAL RISKS

Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. An investment in the Fund is not a bank deposit in BTC or its subsidiaries or affiliates, BlackRock or its subsidiaries or affiliates, including any other bank or BFA. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Although the Fund seeks to preserve the value of your investment at $1.00 per share, all money market instruments can change in value when interest rates or an issuer's creditworthiness changes, if an issuer or guarantor of a security fails to pay interest or principal when due, or if the liquidity of such instruments decreases. If these changes in value were substantial, the Fund's value could deviate from $1.00 per share. In that event, you may lose money by investing in the Fund. The following is a description of certain risks of investing in the Fund.

CONCENTRATION RISK - The Fund may concentrate its investments in the U.S. banking industry which would subject it to the risks generally associated with investments in the U.S. banking industry (I.E., interest rate risk, credit risk and the risk of negative regulatory or market developments affecting the industry).

CREDIT RISK - Credit risk refers to the possibility that the issuer of a security will not be able to make principal and interest payments when due. Changes in an issuer's credit rating or the market's perception of an issuer's creditworthiness may also affect the value of the Fund's investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.

INCOME RISK - The Fund's yield will vary as the short term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

INTEREST RATE RISK - Interest rate risk is the risk that the value of a debt security may fall when interest rates rise. In general, the market price of debt securities with longer maturities will go up or down more in response to changes in interest rates than the market price of shorter term securities.

Additionally, securities issued or guaranteed by the U.S. government, its agencies, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period shareholders own shares of the Fund.

MARKET RISK AND SELECTION RISK - Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. Selection risk is the risk that the securities selected by fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

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U.S. GOVERNMENT OBLIGATIONS RISK - Obligations of U.S. government agencies, authorities, instrumentalities and sponsored enterprises have historically involved little risk of loss of principal if held to maturity. However, not all U.S. government securities are backed by the full faith and credit of the United States. Obligations of certain agencies, authorities, instrumentalities and sponsored enterprises of the U.S. government are backed by the full faith and credit of the United States (E.G., the Government National Mortgage Association); other obligations are backed by the right of the issuer to borrow from the U.S. Treasury (E.G., the Federal Home Loan Banks); and others are supported by the discretionary authority of the U.S. government to purchase an agency's obligations. Still others are backed only by the credit of the agency, authority, instrumentality or sponsored enterprise issuing the obligation. No assurance can be given that the U.S. government would provide financial support to any of these entities if it is not obligated to do so by law.

FOR A DESCRIPTION OF THE FUND'S POLICIES AND PROCEDURES WITH RESPECT TO DISCLOSURE OF THE FUND'S MASTER PORTFOLIO'S PORTFOLIO HOLDINGS, AND A DISCUSSION OF THE FUND'S INVESTMENTS AND RISKS, PLEASE REFER TO THE FUND'S STATEMENT OF ADDITIONAL INFORMATION ("SAI").

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Account Information

SHAREHOLDER INFORMATION


WHO IS ELIGIBLE TO INVEST?

Aon Captives Shares are sold primarily to captive insurance companies administered by Aon Captive Managers, the captive management and risk finance consulting arm of Aon.

The minimum initial investment amount for the Shares of the Fund is $500,000; however, in certain situations, this minimum initial investment amount may be reduced or waived. Please contact your Shareholder Servicing Agent or the Transfer Agent for more information.

The Fund offers additional share classes with different expenses and expected returns, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll free) for additional information.

In order to invest, a completed account application form must be submitted to and processed by the Transfer Agent and an account number assigned. You may be asked to provide information to verify your identity when opening an account.

HOW TO BUY SHARES

You may purchase Fund shares without paying a sales charge. Your purchase order must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) to purchase shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day. The Fund is generally open Monday through Friday and is closed on weekends and generally closed on all other days that the primary markets for the Master Portfolio's portfolio securities (I.E., the bond markets) are closed or the Fedwire Funds Service is closed. The holidays on which both the Fedwire and the bond markets are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Fund is also closed on Good Friday. The Fund does not intend to (but reserves the right to) close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00 p.m. Eastern time) on such Business Day.

The Fund reserves the right to suspend or discontinue the offer and sale of its shares and reject or cancel any purchase order for any reason.

Purchases generally must be made in U.S. dollars and funds must be received via the Fedwire Funds Service by its close, or by such other means as the Funds may from time to time determine. You may be charged for any costs incurred in connection with a purchase order that has been placed but for which the Fund has not received full payment.

HOW TO SELL SHARES

You may sell Fund shares without paying a sales charge. Your order to sell shares must be received in proper form, as determined by the Transfer Agent or an intermediary pursuant to an appropriate agreement, by 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, by such closing time) to sell shares at that day's NAV. Orders received after 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time) will be executed on the next Business Day.

The Fund generally remits the proceeds from a sale the same Business Day after receiving a properly executed order to sell. The Fund can delay payment for one Business Day. In addition, the Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances and subject to applicable law. Generally, those extraordinary circumstances are when: (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of the Fund's investment is not reasonably practicable; or (iv) for such other periods as the Securities and Exchange Commission ("SEC") by order may permit. The Fund reserves the right to redeem your shares automatically and close your account for any reason, subject to applicable law, and send you the proceeds, which would reflect the NAV on the day the Fund automatically redeems your shares. For example, the Fund may redeem your shares automatically to reimburse the Fund for any losses sustained by reason of your failure to make full payment for shares purchased or to collect any charge relating to a transaction effected for your benefit that is applicable to the Fund's shares, as provided from time to time in this Prospectus.

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In addition, the Fund reserves the right to send your redemption proceeds in the form of securities from its Master Portfolio.

Upon redemption, the identity of the holder of the account to which the proceeds are being sent may need to be verified.

SPECIAL INSTRUCTIONS FOR EXISTING SHAREHOLDERS

An existing shareholder who has established an account with the Fund can add to or redeem from that account by phone or through the mail.

. To add or redeem shares by phone, call 1-888-204-3956 between 8:30 a.m. and 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The Transfer Agent will employ procedures designed to confirm that your order is valid. These may include asking for identifying information and recording the phone call. Neither the Transfer Agent nor the Fund may be held liable for acting on telephone instructions that the Transfer Agent reasonably believes to be valid. For redemptions, the Transfer Agent will wire proceeds directly to your designated bank account.(1)

. To invest by mail, make your check payable to the Fund and mail it to State Street Bank and Trust Company, P.O. Box 642, Boston, MA 02117-0642. Please include the Fund's Share Class number and your account number on your check. You will find the numbers on your monthly statements.

For purchases, you should instruct your bank to wire funds as follows:

State Street Bank and Trust Company
ABA # 011000028

Attn: Transfer Agent
Account # DDA 00330860
For Further Credit to: BlackRock Funds III Shareholder Account Name:

Shareholder Account Number:
Fund Share Class Number:
1126 (BlackRock Cash Funds: Institutional - Aon Captives Shares)

. To redeem shares by mail, indicate the dollar amount you wish to receive or the number of shares you wish to sell in your order to sell. Include the Fund's Share Class number and your account and taxpayer identification numbers. All account signatories must sign the order.

. To invest or redeem shares online, please contact the Transfer Agent for information on how to access online trading features.

. An existing shareholder can ask the Transfer Agent to wire proceeds directly to its designated bank account.(2)

. When an existing shareholder purchases Fund shares and then quickly sells (E.G., sells before clearance of the purchase check), the Fund may delay the payment of proceeds for up to ten days to ensure that purchase checks have cleared.


(1) The following procedures are intended to help prevent fraud. If you wish to make a change to your list of authorized traders, you must provide a written request signed by an authorized signer on your account. If you wish to change your bank wire instructions or list of authorized signers, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.
(2) To help prevent fraud, if you direct the sale proceeds to someone other than your account's owner of record, to an address other than your account's address of record or to a bank not designated previously, you must make your request in writing and include a medallion signature guarantee or provide a corporate resolution of a recent date or other documentation as determined by the Transfer Agent. You can obtain a medallion signature guarantee from most banks and securities dealers. A medallion signature guarantee is not a notarized signature.

SHAREHOLDER SERVICING PAYMENTS


The Fund has adopted a shareholder servicing plan (the "Plan") that allows the Fund to pay shareholder servicing fees for certain services provided to its shareholders.

The shareholder servicing fees payable pursuant to the Plan are paid to compensate brokers, dealers, financial institutions and industry professionals (including BlackRock, The PNC Financial Services Group, Inc. ("PNC"), Merrill Lynch & Co, Inc. ("Merrill Lynch"), Bank of America Corporation ("BAC"), Barclays Bank PLC and their respective affiliates) (each, a "Financial Intermediary") for the administration and servicing of shareholder accounts and are not

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costs which are primarily intended to result in the sale of the Fund's shares. Because the fees paid by the Fund under the Plan are paid out of the Fund's assets on an ongoing basis, over time these fees will increase the cost of your investment in the Fund and may cost you more than paying other types of sales charges.

In addition to, rather than in lieu of, shareholder servicing fees that the Fund may pay to a Financial Intermediary pursuant to the Plan and fees the Fund pays to the Transfer Agent, BFA, on behalf of the Fund, may enter into non-Plan agreements with a Financial Intermediary pursuant to which the Fund will pay a Financial Intermediary for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Financial Intermediary or (2) a fixed dollar amount for each account serviced by a Financial Intermediary. The aggregate amount of these payments may be substantial.

From time to time, BFA or its affiliates also may pay a portion of the fees for administrative, networking, recordkeeping, sub-transfer agency and shareholder services described above at its or their own expense and out of its or their legitimate profits. BFA or its affiliates may compensate affiliated and unaffiliated Financial Intermediaries for these other services to the Fund and shareholders. These payments would be in addition to the Fund payments described in this Prospectus and may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Financial Intermediary, or may be based on a percentage of the value of shares sold to, or held by, customers of the Financial Intermediary. The aggregate amount of these payments by BFA, and its affiliates may be substantial. Payments by BFA may include amounts that are sometimes referred to as "revenue sharing" payments. In some circumstances, these revenue sharing payments may create an incentive for a Financial Intermediary, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Financial Intermediary for details about payments it may receive from the Fund or from BFA or its affiliates. For more information, see the Fund's SAI.

CALCULATING THE FUND'S SHARE PRICE


The Fund's share price (also known as the Fund's NAV) is calculated by dividing the value of the net assets of the Fund (I.E., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

The Fund's NAV is calculated at 5:00 p.m. Eastern time on any Business Day (or, if the Fund closes early, at such closing time). The NAV of the Fund is calculated based on the net asset value of the Master Portfolio in which the Fund invests. The Fund's SAI includes a description of the methods for valuing the Master Portfolio's investments.

The Fund seeks to maintain a constant NAV of $1.00 per share, although it can offer no assurance that it will be able to do so.

FUND DISTRIBUTIONS

The Fund declares distributions of its net investment income daily and distributes them monthly to shareholders. The Fund distributes its net realized capital gains, if any, to shareholders at least annually. Distributions payable to you by the Fund will be automatically reinvested in additional shares of the Fund unless you have elected to receive distribution payments in cash.

You begin earning distributions on your shares the day your purchase order takes effect. You continue earning daily distributions on your shares up to but not including the date you sell them.

The Fund credits distributions earned on weekends and holidays to the preceding Business Day. If you sell shares before the monthly distribution payment date, the Fund remits any distributions declared but not yet paid on the next distribution payment date. If you sell all shares before the monthly distribution payment date, the Fund remits all distributions accrued with the sale proceeds.

SHORT-TERM TRADING POLICY

Market timing is an investment technique involving frequent short-term trading of mutual fund shares designed to exploit market movements or inefficiencies in the way a mutual fund prices its shares. The Boards of Trustees of the Trust and MIP have evaluated the risks of market timing activities by the Funds' shareholders and have determined that due to (i) each Fund's policy of seeking to maintain the Fund's net asset value per share at $1.00 each day, (ii) the nature of each Fund's portfolio holdings and (iii) the nature of each Fund's shareholders, it is unlikely that (a) market timing would be attempted by a Fund's shareholders or (b) any attempts to market time a Fund by shareholders would result in a negative impact to the Fund or its shareholders. As a result, the Boards of Trustees of the Trust and MIP has not adopted policies and procedures to deter short-term trading in the Funds. There can be no assurances, however, that the Funds may not, on occasion, serve as a temporary or short-term investment vehicle for those who seek to market time funds offered by other investment companies.

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TAXES

The following discussion regarding U.S. federal income taxes is based upon laws in effect as of the date of this Prospectus and summarizes only some of the important U.S. federal income tax considerations affecting the Fund and its U.S. shareholders. This discussion is not intended as a substitute for careful tax planning. Please see the Fund's SAI for additional U.S. federal income tax information.

Distributions from the Fund's net investment income and net realized capital gains are taxable, whether you choose to receive them in cash or automatically reinvest them in additional Fund shares. The amount of taxes you owe will vary depending on your tax status and based on the amount and character of the Fund's distributions to you and your tax rate.

Distributions from the Fund generally are taxable as follows:

DISTRIBUTION TYPE             TAX STATUS
----------------------------- --------------------------
Income....................... Ordinary income(1)
Short-term capital gain...... Ordinary income
Long-term capital gain....... Long-term capital gain(2)


(1) Distributions from the Fund paid to corporate shareholders will not qualify for the dividends-received deduction generally available to corporate taxpayers. Since the Fund's income is derived from sources that do not pay "qualified dividend income," income distributions from the net investment income of the Fund generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

(2) Normally, the Fund does not expect to realize or distribute a significant amount of long-term capital gains (if any).

Provided the Fund is able to maintain a constant NAV of $1.00 per share, sales of the Fund's shares generally will not result in taxable gain or loss. After the end of each year, the Fund will send to you a notice that tells you how much you have received in distributions during the year and their U.S. federal income tax status. You could also be subject to foreign, state and local taxes on such distributions.

In certain circumstances, you may be subject to back-up withholding taxes on distributions to you from the Fund if you fail to provide the Fund with your correct social security number or other taxpayer identification number, or to make required certifications, or if you have been notified by the U.S. Internal Revenue Service ("IRS") that you are subject to back-up withholding.

Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012 to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

TAX CONSIDERATIONS FOR TAX-EXEMPT OR FOREIGN INVESTORS OR THOSE HOLDING FUND SHARES THROUGH A TAX-DEFERRED ACCOUNT, SUCH AS A 401(K) PLAN OR INDIVIDUAL RETIREMENT ACCOUNT, WILL BE DIFFERENT. FOR EXAMPLE, SHAREHOLDERS THAT ARE EXEMPT FROM U.S. FEDERAL INCOME TAX, SUCH AS RETIREMENT PLANS THAT ARE QUALIFIED UNDER SECTION 401 OF THE INTERNAL REVENUE CODE GENERALLY ARE NOT

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SUBJECT TO U.S. FEDERAL INCOME TAX ON FUND DIVIDENDS OR DISTRIBUTIONS OR ON SALES OF FUND SHARES. BECAUSE EACH INVESTOR'S TAX CIRCUMSTANCES ARE UNIQUE AND BECAUSE TAX LAWS ARE SUBJECT TO CHANGE, YOU SHOULD CONSULT YOUR TAX ADVISOR ABOUT YOUR INVESTMENT.

MASTER/FEEDER MUTUAL FUND STRUCTURE

The Fund does not have its own investment adviser. Instead, the Fund invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to the Fund. BFA serves as investment adviser to the Master Portfolio. The Master Portfolio may accept investments from other feeder funds. Certain actions involving other feeder funds, such as a substantial withdrawal, could affect the Master Portfolio and, therefore, the Fund.

FEEDER FUND EXPENSES

Feeder funds, including the Fund, bear the master portfolio's expenses in proportion to the amount of assets each invests in the master portfolio. The feeder fund can set its own transaction minimums, fund-specific expenses and conditions.

FEEDER FUND RIGHTS

Under the master/feeder structure, the Trust's Board of Trustees retains the right to withdraw the Fund's assets from the Master Portfolio if it believes doing so is in the best interests of the Fund's shareholders. If the Trust's Board of Trustees decides to withdraw the Fund's assets, it would then consider whether the Fund should hire its own investment adviser, invest in another master portfolio or take other action.

SHARE CLASS

The Fund offers additional share classes with different expenses and expected returns than those described in this Prospectus, including share classes you may be eligible to purchase. Call 1-800-768-2836 (toll-free) for additional information.

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Management of the Fund

INVESTMENT ADVISER

The Fund is a "feeder" fund that invests all of its assets in the Master Portfolio, which has an investment objective, strategies and policies substantially identical to those of the Fund. BFA, a registered investment adviser, serves as investment adviser to the Master Portfolio. BFA manages the investment of the Master Portfolio's assets and provides the Master Portfolio with investment guidance and policy direction in connection with daily portfolio management, subject to the supervision of MIP's Board of Trustees. For its services to the Master Portfolio, BFA is entitled to receive a management fee at the annual rate of 0.10% of the Master Portfolio's average daily net assets. BFA has contractually agreed to waive 0.03% of its management fee through the close of business on November 30, 2011.

BFA is located at 400 Howard Street, San Francisco, CA 94105. BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock. As of March 31, 2010, BTC and its affiliates, including BFA, had approximately $3.364 trillion in investment company and other portfolio assets under management. BFA, BTC, BlackRock Execution Services, BlackRock and their affiliates deal, trade and invest for their own accounts in the types of securities in which the Master Portfolio invests.

A discussion regarding the basis for MIP's Board of Trustees' approval of the investment advisory agreement with BFA is available in the Fund's annual report for the year ended December 31, 2009.

ADMINISTRATIVE SERVICES

BTC provides the following services, among others, as the Fund's administrator:

. Supervises the Fund's administrative operations;

. Provides or causes to be provided management reporting and treasury administration services;

. Financial reporting;

. Legal, blue sky and tax services;

. Preparation of proxy statements and shareholder reports; and

. Engaging and supervising the Shareholder Servicing Agent on behalf of the Fund.

BTC is entitled to receive a fee for these services at the annual rate of 0.05% of the average daily net assets of the Fund. In addition to performing these services, BTC has agreed to bear all costs of operating the Fund, other than brokerage expenses, management fees, 12b-1 distribution or service fees, certain fees and expenses related to the Trust's trustees who are not "interested persons" of the Fund or the Trust as defined in the Investment Company Act of 1940, as amended, (the "1940 Act") and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. No additional administration fees are charged at the Master Portfolio level.

CONFLICTS OF INTEREST

The investment activities of BFA and its affiliates (including BlackRock and PNC and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the "Affiliates")) and of BlackRock's significant shareholders, Merrill Lynch and its affiliates, including BAC (each, a "BAC Entity"), and Barclays Bank PLC and its affiliates, including Barclays PLC (each, a "Barclays Entity") (for convenience, the BAC Entities and Barclays Entities are collectively referred to in this section as the "Entities" and each separately is referred to as an "Entity") in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BlackRock and its Affiliates or the Entities provide investment management services to other funds and discretionary managed accounts that follow an investment programs similar to those of the Fund. BlackRock and its Affiliates or the Entities are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. One or more Affiliates or Entities act or may act as an investor, investment banker, research provider, investment manager, financier, advisor, market maker, trader, prime broker, lender, agent and principal, and have other direct and indirect interests, in securities, currencies and other instruments in which the Fund directly and indirectly invests. Thus, it is likely that the Fund will have multiple

12

business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from entities for which an Affiliate or an Entity performs or seeks to perform investment banking or other services.

One or more Affiliates or Entities may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Fund and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. The trading activities of these Affiliates or Entities are carried out without reference to positions held directly or indirectly by the Fund and may result in an Entity having positions that are adverse to those of the Fund.

No Affiliates or Entity is under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, an Affiliate or an Entity may compete with the Fund for appropriate investment opportunities. The results of the Fund's investment activities, therefore, may differ from those of an Affiliate or an Entity and of other accounts managed by an Affiliate or an Entity, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates or Entities and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Fund may, from time to time, enter into transactions in which an Affiliate or an Entity or its other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate advised clients may adversely impact the Fund. Transactions by one or more Affiliate or Entity-advised clients or BFA may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Fund.

An Entity may maintain securities indexes as part of its product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including Entities, may be paid licensing fees for use of their indexes or index names. Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with the Entities will be as favorable as those terms offered to other index licensees.

The Fund's activities may be limited because of regulatory restrictions applicable to one or more Affiliates or Entities, and/or their internal policies designed to comply with such restrictions. In addition, the Fund may invest in securities of companies with which an Affiliate or an Entity has or is trying to develop investment banking relationships or in which an Affiliate or an Entity has significant debt or equity investments. The Fund also may invest in securities of companies for which an Affiliate or an Entity provides or may some day provide research coverage. An Affiliate or an Entity may have business relationships with and purchase or distribute or sell services or products from or to distributors, consultants or others who recommend the Fund or who engage in transactions with or for the Fund, and may receive compensation for such services. The Fund may also make brokerage and other payments to Affiliates or Entities in connection with the Fund's portfolio investment transactions.

The activities of Affiliates may give rise to other conflicts of interest that could disadvantage the Fund and its shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest.

VALUATION OF FUND INVESTMENTS

When you buy shares, you pay the net asset value (normally $1.00 per share) without a sales charge. This is the offering price. Shares are also redeemed at their net asset value. The Funds calculate the net asset value each day the NYSE or New York banks are open, as of the close of business on the NYSE (generally 4:00 p.m. Eastern time) or, on days when the NYSE is closed but New York banks are open, as of 4:00 p.m. Eastern time. Both the NYSE and New York banks are closed on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Currently, the only scheduled days on which the NYSE is open and New York banks are closed are Columbus Day and Veterans Day. The only scheduled day on which New York banks are open and the NYSE is closed is Good Friday. The net asset value used in determining your share price is the next one calculated after your purchase or redemption order becomes effective. Share purchase orders are effective on the date Federal funds become available to the Funds.

The amortized cost method is used in calculating net asset value, meaning that the calculation is based on a valuation of the assets held by a Fund at cost, with an adjustment for any discount or premium on a security at the time of purchase.

Generally, trading in foreign securities, U.S. government securities and money market instruments and certain fixed income securities is substantially completed each day at various times prior to the close of business on the NYSE. The values of such securities used in computing the net asset value of a Fund's shares are determined as of such times.

A Fund may accept orders from certain authorized financial intermediaries or their designees. A Fund will be deemed to receive an order when accepted by the intermediary or designee, and the order will receive the net asset value next computed by the Fund after such acceptance. If the payment for a purchase order is not made by a designated later time, the order will be canceled and the financial intermediary could be held liable for any losses.

CERTAIN FUND POLICIES


ANTI-MONEY LAUNDERING REQUIREMENTS

The Fund is subject to the USA PATRIOT Act (the "Patriot Act"). The Patriot Act is intended to prevent the use of the U.S. financial system in furtherance of money laundering, terrorism or other illicit activities. Pursuant to requirements under the Patriot Act, the Fund may request information from shareholders to enable it to form a reasonable belief that it knows the true identity of its shareholders. This information will be used to verify the identity of investors or, in some cases, the status of financial professionals; it will be used only for compliance with the requirements of the Patriot Act.

The Fund reserves the right to reject purchase orders from persons who have not submitted information sufficient to allow the Fund to verify their identity. The Fund also reserves the right to redeem any amounts in the Fund from persons whose identity it is unable to verify on a timely basis. It is the Fund's policy to cooperate fully with appropriate regulators in any investigations conducted with respect to potential money laundering, terrorism or other illicit activities.

BLACKROCK PRIVACY PRINCIPLES

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, "Clients") and to safeguarding their nonpublic personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

13

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal nonpublic information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our website.

BlackRock does not sell or disclose to nonaffiliated third parties any nonpublic personal information about its Clients, except as permitted by law, or as is necessary to respond to regulatory requests or to service Client accounts. These nonaffiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to nonpublic personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the nonpublic personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

14

Financial Highlights

The financial highlights table is intended to help investors understand the financial performance of Aon Captives Shares of the Fund for the past five years. Certain information reflects financial results for a single Aon Captives Share of the Fund. The total returns in the table represent the rate of return that an investor would have earned (or lost) on an investment in Aon Captives Shares of the Fund, assuming reinvestment of all dividends and distributions. The information has been audited by PricewaterhouseCoopers LLP, whose report, along with the Fund's financial statements, is included in the Fund's annual report. You may obtain copies of the annual report, at no cost, by calling 1-800-768-2836 (toll-free) from 8:30 a.m. to 5:30 p.m. Eastern time on any business day.

BLACKROCK CASH FUNDS: INSTITUTIONAL

FINANCIAL HIGHLIGHTS

                                                                          AON CAPTIVES SHARES
                                          -----------------------------------------------------------------------------------
                                                                        YEAR ENDED DECEMBER 31,
                                          -----------------------------------------------------------------------------------
                                                        2009                2008           2007           2006           2005
                                          ------------------ ------------------- -------------- -------------- --------------
PER SHARE OPERATING PERFORMANCE
-----------------------------------------             --                  --               -              -              -
 Net asset value, beginning of year          $  1.00            $  1.00            $  1.00        $  1.00        $  1.00
-----------------------------------------    -----------        ------------       -------        -------        -------
Net investment income                          0.0033              0.0300             0.0500         0.0500         0.0300
 Net realized gain (loss)                      0.00001              (0.0000)/1/       0.00001        0.00001        0.00001
-----------------------------------------    -----------        --------------     ----------     ----------     ----------
Net increase from investment operations        0.0033              0.0300             0.0500         0.0500         0.0300
-----------------------------------------    -----------        --------------     ----------     ----------     ----------
 Dividends and distributions from:
  Net investment income                        ( 0.0033)           ( 0.0300)        ( 0.0500)      ( 0.0500)      ( 0.0300)
  Net realized gain                            ( 0.0000)/1/               -                -              -              -
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
Total dividends and distributions              ( 0.0033)           ( 0.0300)        ( 0.0500)      ( 0.0500)      ( 0.0300)
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
 Net asset value, end of year                $  1.00            $  1.00            $  1.00        $  1.00        $  1.00
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
TOTAL INVESTMENT RETURN
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
 Based on net asset value                      0.33     %          2.74     %         5.26   %       5.00   %       3.19   %
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
RATIOS TO AVERAGE NET ASSETS/2/
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
 Total expenses                                0.25     %          0.26     %         0.26   %       0.23   %       0.22   %
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
Total expenses after expense reductions        0.22     %          0.23     %         0.21   %       0.19   %       0.15   %
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
 Net investment income                         0.35     %          2.67     %         5.12   %       4.86   %       3.07   %
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
SUPPLEMENTAL DATA
-----------------------------------------    -------------      --------------     ----------     ----------     ----------
 Net assets, end of year (000)               $   72,949         $    97,273        $  90,192      $  69,083      $  77,899
-----------------------------------------    -------------      --------------     ----------     ----------     ----------


/1/ Less than $0.00005 or $(0.00005) per share.

/2/ Includes the Fund's share of the Master Portfolio's allocated net expenses and/or net investment income (loss).

15

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ADDITIONAL INFORMATION

This Prospectus contains important information you should know before investing, including information about risks. Read it carefully and keep it for future reference. More information about BlackRock Funds III is available at no charge upon request. This information includes:

ANNUAL/SEMI-ANNUAL REPORTS
These reports contain additional information about each of the Fund's investments. The annual report describes the Fund's performance, lists portfolio holdings, and discusses recent market conditions, economic trends and Fund investment strategies that significantly affected the Fund's performance for the last fiscal year.

STATEMENT OF ADDITIONAL INFORMATION
A Statement of Additional Information (SAI), dated May 1, 2010, has been filed with the Securities and Exchange Commission (SEC). The SAI, which includes additional information about the Fund, may be obtained free of charge, along with the Fund's annual and semi-annual reports, by calling (800) 768-2836 on any business day. The SAI, as supplemented from time to time, is incorporated by reference into this Prospectus.

QUESTIONS
If you have any questions about the Fund, please:

Call:       1-800-768-2836 (toll-free)
            8:30 a.m. to 5:30 p.m. (Eastern time)
            on any business day

WORLD WIDE WEB
General fund information and specific fund performance, including SAI and annual/semi-annual reports, can be accessed free of charge at www.blackrock.com/cash. Mutual fund prospectuses and literature can also be requested via this website.

WRITTEN CORRESPONDENCE

Write:       BlackRock Funds III
             c/o SEI Investments Distribution Co.
             One Freedom Valley Drive
             Oaks, PA 19456

PORTFOLIO CHARACTERISTICS AND HOLDINGS
A description of the Fund's policies and procedures related to disclosure of portfolio characteristics and holdings is available in the SAI.

For information about portfolio holdings and characteristics, BlackRock fund shareholders and prospective investors may call (800) 768-2836.

SECURITIES AND EXCHANGE COMMISSION
You may also view and copy public information about the Fund, including the SAI, by visiting the EDGAR database on the SEC website (http://www.sec.gov) or the SEC's Public Reference Room in Washington, D.C. Information about the operation of the Public Reference Room can be obtained by calling the SEC directly at (202) 551-8090. Copies of this information can be obtained, for a duplicating fee, by electronic request at the following E-mail address:
publicinfo@sec.gov, or by writing to the Public Reference Room of the SEC, Washington, D.C. 20549.

YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS. NO ONE IS AUTHORIZED TO PROVIDE YOU WITH INFORMATION THAT IS DIFFERENT FROM INFORMATION CONTAINED IN THIS PROSPECTUS.

The SEC has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

INVESTMENT COMPANY ACT FILE # 811-07332

[GRAPHIC APPEARS HERE]

PR-CF-AON-0510


BLACKROCK FUNDS III

Statement of Additional Information

Dated May 1, 2010

FUND                                                                      TICKER
-----------------------------------------------------------------------  -------
BlackRock Bond Index Fund                                                 WFBIX
BlackRock S&P 500 Stock Fund                                              WFSPX

BlackRock Funds III (the "Trust") is an open-end, series management investment company. This combined Statement of Additional Information ("SAI") contains additional information about two series of the Trust - BlackRock Bond Index Fund and BlackRock S&P 500 Stock Fund (each, a "Fund" and collectively, the "Funds").

Each of BlackRock Bond Index Fund and BlackRock S&P 500 Stock Fund invests substantially all of its assets in Bond Index Master Portfolio and S&P 500 Stock Master Portfolio (each, a "Master Portfolio" and collectively, the "Master Portfolios"), respectively, of Master Investment Portfolio ("MIP"), each of which has an investment objective substantially similar to that of the corresponding Fund. MIP is an open-end, series management investment company. BlackRock Fund Advisors ("BFA" or the "Investment Adviser") (formerly, Barclays Global Fund Advisors) serves as investment adviser to the Master Portfolios. References to the investments, investment policies and risks of a Fund, unless otherwise indicated, should be understood to include references to the investments, investment policies and risks of such Fund's Master Portfolio.

This SAI is not a prospectus and should be read in conjunction with each Fund's current prospectus, also dated May 1, 2010, (each, a "Prospectus" and collectively, the "Prospectuses"). All terms used in this SAI that are defined in the Prospectus have the meanings assigned in the Prospectus. The audited financial statements for the Funds, which include the schedule of investments and report of the independent registered public accounting firm for the fiscal year ended December 31, 2009, are hereby incorporated by reference to the Funds' annual reports and semi-annual reports. The Prospectus and copies of the annual report may be obtained without charge by calling 1-800-441-7762 (toll-free).


TABLE OF CONTENTS

                                                                                      PAGE
                                                                                     -----
History of the Trust                                                                    1
Description of the Funds and their Investments and Risks                                1
   Investment Objectives and Policies                                                   1
Investment Restrictions                                                                 1
   Fundamental Investment Restrictions of the Funds                                     1
   Non-Fundamental Investment Restrictions of the Funds                                 2
   Fundamental Investment Restrictions of the Master Portfolios                         3
   Non-Fundamental Restrictions of the Master Portfolios                                4
Investments and Risks of the Master Portfolios                                          4
   Asset-Backed Securities and Commercial Mortgage-Backed Securities                    4
   Bonds                                                                                5
   Borrowing                                                                            5
   Equity Securities                                                                    5
   Floating-Rate and Variable-Rate Obligations                                          5
   Forward Commitments, When-Issued Purchases and Delayed-Delivery Transactions         6
   Futures Contracts and Options Transactions                                           6
   Hybrid ARM Securities                                                                7
   Illiquid Securities                                                                  7
   Interest-Rate and Index Swaps                                                        7
   Interest-Rate Futures Contracts and Options on Interest-Rate Futures Contracts       8
   Investment Companies and Exchange-Traded Funds                                       8
   Letters of Credit                                                                    8
   Loans of Portfolio Securities                                                        8
   Mortgage Pass-Through Securities                                                     9
   Mortgage Securities                                                                 10
   Municipal Securities                                                                11
   Repurchase Agreements                                                               11
   Restricted Securities                                                               11
   Reverse Repurchase Agreements                                                       12
   Securities of Non-U.S. Issuers                                                      12
   Short-Term Instruments                                                              13
   Stock Index Futures and Options on Stock Index Futures                              13
   Unrated, Downgraded and Below Investment-Grade Investments                          13
   U.S. Government Obligations                                                         14
   Warrants                                                                            14
   BlackRock S&P 500 Stock Fund and S&P 500 Stock Master Portfolio                     14

i

                                                                                      PAGE
                                                                                     -----
Portfolio Holdings Information                                                         15
   Service Providers                                                                   15
   Third-Party Feeder Funds                                                            16
   Securities and Exchange Commission Filings                                          16
   Other Public Disclosure                                                             16
   Approved Recipients                                                                 16
Management                                                                             16
   Share Ownership Information                                                         27
   Ownership of Securities of Certain Entities                                         28
   Compensation of Trustees                                                            28
   Master/Feeder Structure                                                             29
   Codes of Ethics                                                                     30
   Proxy Voting Policies of the Master Portfolios                                      30
   Shareholder Communication to the Board of Trustees                                  31
Control Persons and Principal Holders of Securities                                    31
Investment Adviser and Other Service Providers                                         38
   Investment Adviser                                                                  38
   Advisory Fees                                                                       39
   Administrator                                                                       39
   Shareholder Servicing Agents                                                        40
   Distributor                                                                         42
   Custodian                                                                           42
   Transfer and Dividend Disbursing Agent                                              42
   Independent Registered Public Accounting Firm                                       42
   Legal Counsel                                                                       42
Portfolio Managers                                                                     42
Determination of Net Asset Value                                                       47
Purchase, Redemption and Pricing of Shares                                             49
   Terms of Purchase and Redemption                                                    49
   In-Kind Purchases                                                                   50
   Suspension of Redemption Rights or Payment of Redemption Proceeds                   50
   Declaration of Trust Provisions Regarding Redemptions at Option of Trust            50
Portfolio Transactions                                                                 50
   General                                                                             50
   Portfolio Turnover                                                                  51
   Brokerage Commissions                                                               51
   Brokerage Commissions Paid to Affiliates                                            52

ii

                                                                                      PAGE
                                                                                     -----
   Securities of Regular Brokers-Dealers                                               52
Distributions and Taxes                                                                53
   Qualification as a Regulated Investment Company                                     53
   Excise Tax                                                                          54
   Capital Loss Carry-Forwards                                                         54
   Equalization Accounting                                                             55
   Investment through Master Portfolios                                                55
   Taxation of Fund Investments                                                        55
   Taxation of Distributions                                                           57
   Sales of Fund Shares                                                                58
   Foreign Taxes                                                                       58
   Federal Income Tax Rates                                                            58
   Back-Up Withholding                                                                 59
   Tax-Deferred Plans                                                                  59
   Corporate Shareholders                                                              59
   Foreign Shareholders                                                                59
   Recently Enacted Legislation                                                        60
Capital Stock                                                                          60
   Voting                                                                              60
   Dividends and Distributions                                                         61
   Master Portfolios                                                                   61
Additional Information on the Funds                                                    61
Financial Statements                                                                   62
APPENDIX A                                                                            A-1
APPENDIX B                                                                            B-1

iii

History of the Trust

The Trust was organized on December 4, 2001 as a statutory trust under the laws of the State of Delaware. On August 21, 2001, the Board of Directors of Barclays Global Investors Funds, Inc. (the "Company") approved a proposal to redomicile the Company from a Maryland corporation to a Delaware statutory trust (the "Redomiciling"). Shareholders of the Company approved the Redomiciling on November 16, 2001. The Trust was established with multiple series, including the Funds, corresponding to, and having identical designations as, the Company's series. The Redomiciling was effected on January 11, 2002, at which time the Trust assumed the operations of the Company and adopted the Company's registration statement. Shortly thereafter, the Company was dissolved.

The Trust consists of multiple series, including the Funds. The Trust's principal office is located at 400 Howard Street, San Francisco, CA 94105. Each Fund invests all of its assets in a Master Portfolio of MIP (as shown below), which has the same or substantially same investment objective, policies and restrictions as the related Fund.

FUND                                   MASTER PORTFOLIO IN WHICH THE FUND INVESTS
-------------------------------------  -------------------------------------------
       BlackRock Bond Index Fund       Bond Index Master Portfolio
       BlackRock S&P 500 Stock Fund    S&P 500 Stock Master Portfolio

On December 1, 2009, the Trust was renamed BlackRock Funds III and certain of its series were also renamed. Bond Index Fund was renamed BlackRock Bond Index Fund and S&P 500 Stock Fund was renamed to BlackRock S&P 500 Stock Fund.

Description of the Funds and their Investments and Risks

INVESTMENT OBJECTIVES AND POLICIES. The Trust is an open-end, series management investment company. Each Fund and Master Portfolio has adopted an investment objective and investment policies that may be fundamental or non-fundamental. Fundamental policies cannot be changed without approval by the holders of a majority (as defined in the Investment Company Act of 1940, as amended (the "1940 Act")) of the outstanding voting securities of such Fund or Master Portfolio, as the case may be. Non-fundamental policies may be changed without shareholder approval by the vote of a majority of the trustees of the Trust or of MIP (the "Trustees"), as the case may be, at any time.

The Funds and the Master Portfolios in which they invest are diversified funds as defined in the 1940 Act. Each Fund's investment objective is set forth in its Prospectus. The investment objective of each Fund is non-fundamental, which means it can be changed by the Trust's board of trustees (the "Board of Trustees" or the "Board") without shareholder approval. The investment objective and investment policies of a Fund determine the types of portfolio securities in which the Fund invests, the degree of risk to which the Fund is subject and, ultimately, the Fund's performance. There can be no assurance that the investment objective of either Fund will be achieved.

Investment Restrictions

FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds are subject to the following investment restrictions, all of which are fundamental policies. Each Fund may not:

(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of the Fund's investments in that industry would equal or exceed 25% of the current value of the Fund's total assets, provided that this restriction does not limit the Fund's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities, and provided further that the Fund reserves the right to concentrate in any industry in which the index that the Fund tracks becomes concentrated to approximately the same degree during the same period;

1

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of the Fund's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the Fund's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit the Fund's cash or cash items, investments in securities issued or guaranteed by the U.S. government, its agencies and instrumentalities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with the Fund's investment program may be deemed to be an underwriting; and provided further, that the purchase by the Fund of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Fund shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the Fund from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business);

(7) Purchase or sell commodities, provided that: (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments; and

(8) Purchase securities on margin (except for short-term credits necessary for the clearance of transactions and except for margin payments in connection with options, futures and options on futures) or make short sales of securities.

With respect to paragraph (3) above, the 1940 Act currently allows each Fund to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of each Fund's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds have adopted the following investment restrictions as non-fundamental policies. These restrictions may be changed without shareholder approval by a majority of the Trustees of the Trust at any time.

(1) The Funds may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder; provided, however, that a Fund, if it has knowledge that its beneficial interests are purchased by another investment company investor pursuant to Section 12(d)(1)(G) of the 1940 Act, will not acquire any securities of registered open-end management investment companies or registered unit investment trusts in reliance on Section 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act. Other investment companies in which the Funds invest can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Funds;

(2) Each Fund may not invest more than 15% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others,
(i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale, (ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each Fund may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of a Fund's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked to market daily;

(4) Each Fund may not purchase interests, leases, or limited partnership interests in oil, gas, or other mineral exploration or development programs;

2

(5) Each Fund may not write, purchase or sell puts, calls, straddles, spreads, warrants, options or any combination thereof, except that a Fund may enter into futures and options contracts in accordance with its investment policies; and

(6) Each Fund will provide shareholders with at least 60 days' notice of any change to the Fund's non-fundamental policy to invest at least 90% of the value of the Fund's net assets, plus the amount of any borrowing for investment purposes, in securities comprising the index that the Fund tracks. The notice will be provided in plain English in a separate written document, and will contain the following prominent statement or similar statement in bold-face type: "Important Notice Regarding Change in Investment Policy." This statement will appear on both the notice and the envelope in which it is delivered, unless it is delivered separately from other communications to investors, in which case the statement will appear either on the notice or the envelope in which the notice is delivered.

Notwithstanding any other investment policy or restriction (whether or not fundamental), each Fund may (and does) invest all of its assets in the securities of a single open-end management investment company with substantially the same investment objective, policies and limitations as the Fund. See "Management - Master/Feeder Structure."

FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE MASTER PORTFOLIOS. The Master Portfolios are subject to the following investment restrictions, all of which are fundamental policies. These restrictions cannot be changed, as to a Master Portfolio, without approval by the holders of a majority (as described in the 1940 Act) of the Master Portfolio's outstanding voting interest. Each Master Portfolio may not:

(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of a Master Portfolio's investments in that industry would equal or exceed 25% of the current value of the Master Portfolio's total assets, provided that this restriction does not limit a Master Portfolio's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities, and provided further that the Master Portfolios reserve the right to concentrate in any industry in which the index that each respective Master Portfolio tracks becomes concentrated to approximately the same degree during the same period;

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of a Master Portfolio's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the Master Portfolio's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit a Master Portfolio's cash or cash items, investments in securities issued or guaranteed by the U.S. government, its agencies and instrumentalities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with a Master Portfolio's investment program may be deemed to be an underwriting; and provided further, that the purchase by the Master Portfolios of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Master Portfolios shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the Master Portfolios from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business);

(7) Purchase or sell commodities, provided that (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments; and

(8) Purchase securities on margin, but each Master Portfolio may make margin deposits in connection with transactions in options, forward contracts, futures contracts, including those related to indexes, and options on futures contracts or indexes.

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With respect to paragraph (3) above, the 1940 Act currently allows a Master Portfolio to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of a Master Portfolio's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL RESTRICTIONS OF THE MASTER PORTFOLIOS.

(1) Each Master Portfolio may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder; provided, however, that a Master Portfolio, if it has knowledge that its beneficial interests are purchased by another investment company investor pursuant to Section 12(d)(1)(G) of the 1940 Act, will not acquire any securities of registered open-end management investment companies or registered unit investment trusts in reliance on
Section 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act. Other investment companies in which the Master Portfolios invest can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Master Portfolios;

(2) Each Master Portfolio may not invest more than 15% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others, (i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale,
(ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each Master Portfolio may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of the Master Portfolio's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked-to-market daily;

(4) Each Master Portfolio may not purchase interests, leases, or limited partnership interests in oil, gas, or other mineral exploration or development programs; and

(5) Each Master Portfolio will provide interestholders with at least 60 days' notice of any change to the Master Portfolio's non-fundamental policy to invest at least 90% of the value of the Master Portfolio's net assets, plus the amount of any borrowing for investment purposes, in securities comprising the index that the Master Portfolio tracks. The notice will be provided in plain English in a separate written document, and will contain the following prominent statement or similar statement in bold-face type: "Important Notice Regarding Change in Investment Policy." This statement will appear on both the notice and the envelope in which it is delivered, unless it is delivered separately from other communications to investors, in which case the statement will appear either on the notice or the envelope in which the notice is delivered.

Investments and Risks of the Master Portfolios

The Master Portfolios in which the Funds invest may invest in the securities described below. To avoid the need to refer to both the Funds and the Master Portfolios in every instance, references in the following sections to a Fund generally include the Fund and the corresponding Master Portfolio.

ASSET-BACKED SECURITIES AND COMMERCIAL MORTGAGE-BACKED SECURITIES. BlackRock Bond Index Fund may invest in asset-backed and commercial mortgage-backed securities. Asset-backed securities are securities backed by installment contracts, credit-card receivables or other assets. Commercial mortgage-backed securities are securities backed by commercial real estate properties. Both asset-backed and commercial mortgage-backed securities represent interests in "pools" of assets in which payments of both interest and principal on the securities are made on a regular basis. The payments are, in effect, "passed through" to the holder of the securities (net of any fees paid to the issuer or guarantor of the securities). The average life of asset-backed and commercial mortgage-backed securities varies with the maturities of the underlying instruments and, as a result of prepayments or extensions, can often be shorter or longer (as the case may be) than the original maturity of the assets underlying the securities. For this and other reasons, an asset-backed and commercial mortgage-backed security's stated maturity may be shortened or extended, and the security's total return may be difficult to predict precisely. Changes in liquidity may result in significant, rapid and unpredictable changes in the prices for credit-linked securities. Also see "Mortgage Pass-Through Securities" and "Mortgage Securities."

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BONDS. BlackRock Bond Index Fund invests a substantial portion of its assets in U.S. registered, dollar-denominated bonds. A bond is an interest-bearing security issued by a company or governmental unit. The issuer of a bond has a contractual obligation to pay interest at a stated rate on specific dates and to repay principal (the bond's face value) periodically or on a specified maturity date. An issuer may have the right to redeem or "call" a bond before maturity, in which case the investor may have to reinvest the proceeds at lower market rates. Most bonds bear interest income at a "coupon" rate that is fixed for the life of the bond. The value of a fixed-rate bond usually rises when market interest rates fall, and falls when market interest rates rise. Accordingly, a fixed-rate bond's yield (income as a percent of the bond's current value) may differ from its coupon rate as its value rises or falls. When an investor purchases a fixed-rate bond at a price that is greater than its face value, the investor is purchasing the bond at a premium. Conversely, when an investor purchases a fixed-rate bond at a price that is less than its face value, the investor is purchasing the bond at a discount. Fixed-rate bonds that are purchased at a discount pay less current income than securities with comparable yields that are purchased at face value, with the result that prices for such fixed-rate securities can be more volatile than prices for such securities that are purchased at face value. Other types of bonds bear income at an interest rate that is adjusted periodically. Because of their adjustable interest rates, the value of "floating-rate" or "variable-rate" bonds fluctuates much less in response to market interest rate movements than the value of fixed-rate bonds. See "Floating-Rate and Variable-Rate Obligations" below. The Fund may treat some of these bonds as having a shorter maturity for purposes of calculating the weighted average maturity of its investment portfolio. Bonds may be senior or subordinated obligations. Senior obligations generally have the first claim on a corporation's earnings and assets and, in the event of liquidation, are paid before subordinated debt. Bonds may be unsecured (backed only by the issuer's general creditworthiness) or secured (also backed by specified collateral).

BORROWING. Each Fund may borrow money for temporary or emergency purposes, including the meeting of redemption requests. Borrowing involves special risk considerations. Interest costs on borrowings may fluctuate with changing market rates of interest and may partially offset or exceed the return earned on borrowed funds (or on the assets that were retained rather than sold to meet the needs for which funds were borrowed). Under adverse market conditions, a Fund might have to sell portfolio securities to meet interest or principal payments at a time when investment considerations would not favor such sales. Reverse repurchase agreements, short sales not against the box, dollar roll transactions and other similar investments that involve a form of leverage
(I.E., risk of gain or loss disproportionately higher than the amount invested)
have characteristics similar to borrowings. The Funds maintain liquid assets in connection with those types of transactions.

EQUITY SECURITIES. Equity securities generally have greater price volatility than fixed income securities. The market price of equity securities may go up or down, sometimes rapidly or unpredictably. Equity securities may decline in value due to factors affecting equity securities markets generally, particular industries, sectors or geographic regions represented in those markets, or individual issuers. The types of developments that may affect an issuer of an equity security include management performance, financial leverage and reduced demand for the issuer's goods or services. Common and preferred stock represent equity or ownership interests in an issuer. Preferred stock, however, pays dividends at a specified rate and has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds and preferred stock take precedence over the claims of those who own common stock.

FLOATING-RATE AND VARIABLE-RATE OBLIGATIONS. BlackRock Bond Index Fund may purchase floating-rate and variable-rate demand notes and bonds, which are obligations ordinarily having stated maturities in excess of thirteen months, but which permit the holder to demand payment of principal at any time, or at specified intervals not exceeding 397 days, as defined in Rule 2a-7 of the 1940 Act. Variable-rate demand notes including master demand notes are demand obligations that permit a Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between the Fund, as lender, and the borrower. The interest rates on these notes fluctuate from time to time. The issuer of such obligations ordinarily has a corresponding right, after a given period, to prepay in its discretion the outstanding principal amount of the obligations plus accrued interest upon a specified number of days' notice to the holders of such obligations. The interest rate on a floating-rate demand obligation is based on a known lending rate, such as a bank's prime rate, and is adjusted automatically each time such rate is adjusted. The interest rate on a variable-rate demand obligation is adjusted automatically at specified intervals. Frequently, such obligations are secured by letters of credit or other credit support arrangements provided by banks.

These obligations are direct lending arrangements between the lender and borrower. There may not be an established secondary market for these obligations, although they are redeemable at face value. Accordingly, where these obligations are not secured by letters of credit or other credit support arrangements, a Fund's right to redeem is dependent on the ability of the borrower to pay principal and interest on demand. Such obligations frequently are not rated by credit rating agencies and the Fund may invest in obligations that are not so rated only if BFA determines that at the time of investment the obligations

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are of comparable quality to the other obligations in which the Fund may invest. BFA considers on an ongoing basis the creditworthiness of the issuers of the floating-rate and variable-rate demand obligations in the Fund's portfolio.

FORWARD COMMITMENTS, WHEN-ISSUED PURCHASES AND DELAYED-DELIVERY TRANSACTIONS.
Each Fund may purchase or sell securities on a when-issued or delayed-delivery basis and make contracts to purchase or sell securities for a fixed price at a future date beyond customary settlement time. Securities purchased or sold on a when-issued, delayed-delivery or forward commitment basis involve a risk of loss if the value of the security to be purchased declines, or the value of the security to be sold increases, before the settlement date. Although a Fund will generally purchase securities with the intention of acquiring them, a Fund may dispose of securities purchased on a when-issued, delayed-delivery or a forward commitment basis before settlement when deemed appropriate by BFA.

FUTURES CONTRACTS AND OPTIONS TRANSACTIONS. Each Fund may enter into futures contracts and may purchase and write (I.E., sell) options. A futures contract is an agreement between two parties, a buyer and a seller, to exchange a particular commodity or financial instrument at a specific price on a specific date in the future. An option transaction generally involves a right, which may or may not be exercised, to buy or sell a commodity or financial instrument at a particular price on a specified future date. Options on futures contracts are similar to options on securities or currencies except that options on futures contracts give the purchaser the right, in return for the premium paid, to assume a position in a futures contract (a long position if the option is a call and a short position if the option is a put) at a specified exercise price at any time during the period of the option. Futures contracts and options are standardized and traded on exchanges, where the exchange serves as the ultimate counterparty for all contracts. Consequently, the primary credit risk on futures contracts is the creditworthiness of the exchange. Futures contracts are also subject to market risk (I.E., exposure to adverse price changes). In addition, in employing futures contracts as a hedge against cash market price volatility, futures prices may correlate imperfectly with the prices of securities held by a Fund. Similarly, in employing futures contracts as a substitute for purchasing the designated underlying securities, the performance of the futures contract may correlate imperfectly with the performance of the direct investments for which the futures contract is a substitute.

Each Fund may engage only in futures contract transactions involving: (i) the sale of a futures contract (I.E., a short position) to hedge the value of securities held by the Fund; (ii) the purchase of a futures contract when the Fund holds a short position having the same delivery month (I.E., a long position offsetting a short position); or (iii) the purchase of a futures contract to permit the Fund to, in effect, participate in the market for the designated securities underlying the futures contract without actually owning such designated securities. If a Fund enters into a short position in a futures contract as a hedge against anticipated adverse market movements and the market then rises, the increase in the value of the hedged securities will be offset, in whole or in part, by a loss on the futures contract. If, instead, a Fund purchases a futures contract as a substitute for investing in the designated underlying securities, the Fund will experience gains or losses that correspond generally to gains or losses in the underlying securities.

Although each Fund intends to purchase or sell futures contracts only if there is an active market for such contracts, no assurance can be given that a liquid market will exist for any particular contract at any particular time. Many futures exchanges and boards of trade limit the amount of fluctuation permitted in futures contract prices during a single trading day. Once the daily limit has been reached in a particular contract, no trades may be made that day at a price beyond that limit or trading may be suspended for specified periods during the trading day. Futures contract prices could move to the limit for several consecutive trading days with little or no trading, thereby preventing prompt liquidation of futures positions and potentially subjecting a Fund to substantial losses. If it is not possible, or if a Fund determines not to close a futures position in anticipation of adverse price movements, the Fund will be required to make daily cash payments on variation margin.

Upon the exercise of an option on a futures contract, the writer of the option delivers to the holder of the option the futures position and the accumulated balance in the writer's futures margin account, which represents the amount by which the market price of the futures contract exceeds (in the case of a call) or is less than (in the case of a put) the exercise price of the option on the futures contract. The potential loss related to the purchase of options on futures contracts is limited to the premium paid for the option (plus transaction costs). Because the value of the option is fixed at the time of sale, there are no daily cash payments to reflect changes in the value of the underlying contract; however, the value of the option may change daily and that change would be reflected in the value of a Fund. The potential for loss related to writing call options is unlimited. The potential for loss related to writing put options is limited to the agreed upon price per share times the number of shares minus the premium received from writing the put.

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Each Fund has filed a notice of eligibility for exclusion from the definition of the term "commodity pool operator" in accordance with Rule 4.5 of the U.S. Commodity Exchange Act, as amended (the "Commodity Exchange Act"), and, therefore, neither Fund is subject to registration or regulation as a commodity pool operator under the Commodity Exchange Act.

Each Fund may take advantage of opportunities in the area of options and futures contracts and options on futures contracts and any other derivative investments that are not presently contemplated for use by the Fund or that are not currently available but which may be developed, to the extent such opportunities are both consistent with the Fund's investment objective and legally permissible for the Fund.

HYBRID ARM SECURITIES. Hybrid ARM securities are interests in pools of hybrid adjustable-rate mortgages ("hybrid ARMs"). A hybrid ARM is a mortgage in which the interest rate is fixed for a specified period and then resets periodically, or floats, for the remaining mortgage term. After the initial fixed-interest rate period, the interest rate on a hybrid ARM can be reset by a maximum specified amount to an adjustable rate based on a margin over an identified index. As with other adjustable rate mortgages, the adjustable interest rates on hybrid ARMs are subject to periodic and lifetime caps on the increased rates that mortgagors are required to pay.

Hybrid ARM securities are subject to a combination of the risks associated with fixed-rate and adjustable-rate mortgage-backed securities. If a greater percentage of the mortgage pool backing a hybrid ARM security consists of hybrid ARMS in their initial fixed-rate mode, the hybrid ARM securities will be more susceptible to the risks associated with fixed-rate bonds and mortgage-backed securities. These risks would include possible reductions in market value (i) during periods of rising interest rates and (ii) due to the unanticipated shortening or extension of the security's average life resulting from unforeseen mortgage prepayment patterns. If a greater percentage of the underlying mortgage pool consists of hybrid ARMs in their adjustable-rate mode, the hybrid ARM securities will be more susceptible to the risks associated with capped adjustable-rate securities. These risks include (i) the possibility of reduced yields during periods of falling interest rates, (ii) possible reductions in market value if market interest rates rise above the interest rate caps on the underlying hybrid ARMs, and (iii) possible increases in mortgage default rates to the extent that mortgagors are unable to afford higher adjustable mortgage rates.

Because hybrid ARM securities are more complex than conventional fixed-rate and adjustable-rate mortgage-backed securities, it may be more difficult for investors to analyze and predict how the values of hybrid ARM securities will change in response to market interest rate and credit conditions. As a result of this uncertainty, a hybrid ARM security could suffer from a disproportionate reduction in value or loss of market liquidity during periods of volatile interest rates or credit market disruptions.

ILLIQUID SECURITIES. Each Fund may invest up to 15% of the value of its net assets in securities for which a liquid trading market does not exist, provided such investments are consistent with its investment objective. Such securities may include securities that are not readily marketable, such as privately issued securities and other securities that are subject to legal or contractual restrictions on resale, floating-rate and variable-rate demand obligations as to which a Fund cannot exercise a demand feature on not more than seven days' notice and as to which there is no secondary market, and repurchase agreements providing for settlement more than seven days after notice.

INTEREST-RATE AND INDEX SWAPS. BlackRock Bond Index Fund may enter into interest-rate and index swaps. Interest-rate swaps involve the exchange by the Fund with another party of their respective commitments to pay or receive interest (for example, an exchange of floating-rate payments for fixed-rate payments). Index swaps (sometimes referred to as total return swaps) involve the exchange by the Fund with another party of cash flows based upon the performance of an index of securities or a portion of an index of securities that usually include, but are not limited to, dividends or income. In each case, the exchange of commitments can involve payments to be made in the same currency or in different currencies. If there is a default by the other party to such a transaction, the Fund will have contractual remedies pursuant to the agreements related to the transaction. The use of interest-rate and index swaps is a highly specialized activity that involves investment techniques and risks different from those associated with ordinary portfolio security transactions.

Swap transactions generally do not involve the delivery of securities or other underlying assets or principal. If a Fund enters into a swap transaction, cash or securities may be posted by or to the Fund as collateral in accordance with the terms of the swap agreement. Upon early termination of a swap agreement due to an event of default or termination event with respect to the Fund or other party, the risk of loss to the Fund would generally be limited to the net amount of payments that the Fund is contractually obligated to make if, after exercising in accordance with the swap agreement the rights with respect to

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early close-out of the swap transaction or swap transactions, it is determined that the Fund would be obligated to make a net payment with respect to the swap transaction or swap transactions. In the event the other party to the swap transaction or swap transactions were to owe a net amount to the Fund upon an early termination of the swap agreements as described above, the Fund could be exposed to the risk of loss in the event that any collateral held by the Fund would be insufficient.

INTEREST-RATE FUTURES CONTRACTS AND OPTIONS ON INTEREST-RATE FUTURES CONTRACTS. BlackRock Bond Index Fund may invest in interest-rate futures contracts and options on interest-rate futures contracts as a substitute for a comparable market position in the underlying securities. The Fund may also sell options on interest-rate futures contracts as part of closing purchase transactions to terminate its options positions. No assurance can be given that such closing transactions can be effected or the degree of correlation between price movements in the options on interest-rate futures and price movements in the Fund's portfolio securities which are the subject of the transaction.

INVESTMENT COMPANIES AND EXCHANGE-TRADED FUNDS. Each Fund may invest in securities issued by other open-end and closed-end investment management companies, including investment companies that are affiliated with the Funds and BFA, to the extent permitted under the 1940 Act. As a general matter, under the 1940 Act, investment in such securities is limited to: (i) 3% of the outstanding voting stock of any one investment company, (ii) 5% of the Fund's total assets with respect to any one investment company, and (iii) 10% of a Fund's total assets with respect to all such companies in the aggregate. Other investment companies in which the Funds invest can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Fund. To the extent allowed by law or regulation, each Fund may invest its assets in securities of money market funds, including those advised by BFA or otherwise affiliated with BFA, in excess of the limits discussed above.

The Funds may purchase shares of exchange-traded funds ("ETFs"). Typically, a Fund would purchase ETF shares for the same reason it would purchase (and as an alternative to purchasing) futures contracts-to obtain relatively low-cost exposure to the stock market while maintaining flexibility to meet the liquidity needs of the Fund. ETF shares enjoy several advantages over futures. Depending on the market, the holding period, and other factors, ETF shares can be less costly than futures. In addition, ETF shares can be purchased for smaller sums and offer exposure to market sectors and styles for which there is no suitable or liquid futures contract. A Fund may also purchase ETF shares for other purposes, including improving its ability to track its underlying index. The Funds may invest a portion of their assets in shares of ETFs that are advised by BFA. BFA will receive investment advisory fees at both the Fund level and the ETF level for investments by a Fund in shares of an ETF advised by BFA. Because most ETFs are investment companies, a Fund's purchases of ETF shares generally are subject to the 3/5/10% limitations described above. An investment in an ETF generally presents the same primary risks as an investment in a conventional fund (I.E., one that is not exchange traded) that has the same investment objectives, strategies, and policies. The price of an ETF can fluctuate within a wide range, and a Fund could lose money investing in an ETF if the prices of the stocks owned by the ETF decrease. In addition, ETFs are subject to the following risks that do not apply to conventional funds: (i) the market price of the ETF's shares may trade at a discount to their net asset value ("NAV"); (ii) an active trading market for an ETF's shares may not develop or be maintained; or (iii) trading of an ETF's shares may be halted if the listing exchange's officials deem such action appropriate, the shares are delisted from the exchange, or the activation of market-wide "circuit breakers" (which are tied to large decreases in stock prices) halts stock trading generally.

LETTERS OF CREDIT. Certain of the debt obligations (including municipal securities, certificates of participation, commercial paper and other short-term obligations) that BlackRock Bond Index Fund may purchase may be backed by an unconditional and irrevocable letter of credit issued by a bank, savings and loan association or insurance company that assumes the obligation for payment of principal and interest in the event of default by the issuer. Only banks, savings and loan associations and insurance companies that, in the opinion of BFA, are of comparable quality to issuers of other permitted investments of such Fund may be used for letter of credit-backed investments.

LOANS OF PORTFOLIO SECURITIES. Each Fund may lend portfolio securities to certain creditworthy borrowers, including borrowers affiliated with BFA. The borrowers provide collateral that is maintained in an amount at least equal to the current market value of the securities loaned plus any accrued interest or dividends. A Fund may terminate a loan at any time and obtain the return of the securities loaned. Each Fund receives the value of any interest or cash or non-cash distributions paid on the loaned securities.

With respect to loans that are collateralized by cash, the borrower will be entitled to receive a fee based on the amount of cash collateral. The Fund is compensated by the difference between the amount earned on the reinvestment of cash collateral and the fee paid to the borrower. In the case of collateral other than cash, the Fund is compensated by a fee paid by

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the borrower equal to a percentage of the market value of the loaned securities. Any cash collateral may be reinvested in certain short-term instruments either directly on behalf of each lending Fund or through one or more joint accounts or money market funds, including those managed by BFA; such reinvestments are subject to investment risk.

Securities lending involves exposure to certain risks, including operational risk (I.E., the risk of losses resulting from problems in the settlement and accounting process), "gap" risk (I.E., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Fund has agreed to pay a borrower), and credit, legal, counterparty and market risk. In the event a borrower does not return a Fund's securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated plus the transaction costs incurred in purchasing replacement securities.

A Fund may pay a portion of the interest or fees earned from securities lending to a borrower as described above, and to a securities lending agent who administers the lending program in accordance with guidelines approved by MIP's Board of Trustees. BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) acts as securities lending agent for the Funds, subject to the overall supervision of BFA. BTC receives a portion of the revenues generated by securities lending activities as compensation for its services in this regard.

MORTGAGE PASS-THROUGH SECURITIES. BlackRock Bond Index Fund may invest in mortgage pass-through securities, which are a category of pass-through securities backed by pools of mortgages and issued by the Government National Mortgage Association ("Ginnie Mae") or by one of several U.S. Government-sponsored entities, such as the Federal National Mortgage Association ("Fannie Mae"), the Federal Home Loan Mortgage Corporation ("Freddie Mac") or the Federal Home Loan Banks ("FHLBs"). In the basic mortgage pass-through structure, mortgages with similar issuer, term and coupon characteristics are collected and aggregated into a "pool" consisting of multiple mortgage loans. The pool is assigned a CUSIP number and undivided interests in the pool are traded and sold as pass-through securities. The holder of the security is entitled to a PRO RATA share of principal and interest payments (including unscheduled prepayments) from the pool of mortgage loans.

A significant portion of the Barclays Capital U.S. Aggregate Bond Index (the "Barclays Aggregate Index") (about 35.68%, as of March 31, 2010) represents the U.S. agency mortgage pass-through segment of the U.S. investment-grade bond market. Therefore, a substantial portion of BlackRock Bond Index Fund is invested to seek exposure to a representative sample of U.S. agency mortgage pass-through securities. The portion of the Barclays Aggregate Index representing the mortgage pass-through segment of the U.S. investment-grade bond market is comprised of multiple pools of mortgage pass-through securities.

Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information required to evaluate the practices of these mortgage originators. In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate, and investors in mortgage securities may have to accept, less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Should the government adopt new laws providing mortgage borrowers with additional rights to renegotiate interest rates, alter terms, obtain orders to modify their mortgage terms through the bankruptcy courts, or otherwise allow borrowers to modify or restructure existing mortgages, this may negatively impact mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate.

An investment in a specific pool of pass-through securities requires an analysis of the specific prepayment risk of mortgages within the covered pool (since mortgagors typically have the option to prepay their loans). The level of prepayments on a pool of mortgage securities is difficult to predict and can impact the subsequent cash flows and value of the mortgage pool. In addition, when trading specific mortgage pools, precise execution, delivery and settlement arrangements must be negotiated for each transaction. These factors combine to make trading in mortgage pools somewhat cumbersome. For these and other reasons, the Fund may obtain exposure to U.S. agency mortgage pass-through securities primarily through the use of "to-be-announced" or "TBA" transactions. "TBA" refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Most

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transactions in mortgage pass-through securities occur through the use of TBA transactions. TBA transactions generally are conducted in accordance with widely accepted guidelines that establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined two days prior to the settlement date. The Fund may use TBA transactions in several ways. For example, the Fund may regularly enter into TBA agreements and "roll over" such agreements prior to the settlement date stipulated in such agreements. This type of TBA transaction is sometimes known as a "TBA roll." In a TBA roll, the Fund generally will sell the obligation to purchase the pools stipulated in the TBA agreement prior to the stipulated settlement date and will enter into a new TBA agreement for future delivery of pools of mortgage pass-through securities. In addition, the Fund may enter into TBA agreements and settle such transactions on the stipulated settlement date by accepting actual receipt or delivery of the pools of mortgage pass-through securities stipulated in the TBA agreement. Default by or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible loss because of adverse market action, expenses, or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction. To minimize this risk, the Fund will enter into TBA transactions only with established counterparties (such as major broker-dealers) and BFA will monitor the creditworthiness of such counterparties. The use of TBA rolls may cause the Master Portfolio to experience higher portfolio turnover and to pay higher capital gain distributions, which may result in larger amounts of short-term capital gains allocable to interestholders.

MORTGAGE SECURITIES. Mortgage securities are issued by government and non-government entities such as banks, mortgage lenders, or other institutions. A mortgage security is an obligation of the issuer backed by a mortgage or pool of mortgages or a direct interest in an underlying pool of mortgages. Some mortgage securities, such as collateralized mortgage obligations, make payments of both principal and interest at a range of specified intervals; others make semi-annual interest payments at a predetermined rate and repay principal at maturity (like a typical bond). Mortgage securities are based on different types of mortgages, including those on commercial real estate or residential properties. Stripped mortgage securities are created when the interest and principal components of a mortgage security are separated and sold as individual securities. In the case of a stripped mortgage security, the holder of the "principal-only" security (PO) receives the principal payments made by the underlying mortgage, while the holder of the "interest-only" security (IO) receives interest payments from the same underlying mortgage.

The value of mortgage securities may change due to shifts in the market's perception of the creditworthiness of issuers and changes in interest rates or liquidity. The value of some mortgage-backed securities may be particularly sensitive to changes in prevailing interest rates. In addition, regulatory or tax changes may adversely affect the mortgage securities market as a whole. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information required to evaluate the practices of these mortgage originators. In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate.

Non-government mortgage securities may be subject to greater price changes than government issues. Mortgage securities are subject to prepayment risk. Prepayment risk is the risk that early principal payments made on the underlying mortgages, usually in response to a reduction in interest rates, will result in the return of principal to the investor, causing it to be invested subsequently at a lower current interest rate. Alternatively, in a rising interest rate environment, mortgage security values may be adversely affected when prepayments on underlying mortgages do not occur as anticipated, resulting in the extension of the security's effective maturity and the related increase in interest rate sensitivity of a longer-term instrument. The prices of stripped mortgage securities tend to be more volatile in response to changes in interest rates than those of non-stripped mortgage securities. In addition, although mortgages and mortgage-related securities are generally supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Also see "Asset-Backed Securities and Commercial Mortgage-Backed Securities," "Hybrid ARM Securities" and "Mortgage Pass-Through Securities."

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MUNICIPAL SECURITIES. Municipal securities are generally issued by states and local governments and their agencies, authorities and other instrumentalities. Municipal bonds are subject to interest rate, credit and market risk. The ability of a municipal security issuer to make payments on that security could be affected by litigation, legislation or other political events or the bankruptcy of the issuer. Lower-rated municipal bonds are subject to greater credit and market risk than higher quality municipal bonds. Municipal securities in which BlackRock Bond Index Fund may invest include, but are not limited to, municipal lease obligations and securities issued by entities whose underlying assets are municipal bonds. There is no guarantee that income from municipal securities will be exempt from federal and state taxes. Changes in federal or state tax treatment of municipal securities may make municipal securities less attractive as investments or cause them to lose value.

In addition, the Fund may invest in residual interest bonds, which are created by depositing municipal securities in a trust and dividing the income stream of an underlying municipal bond in two parts, one, a variable-rate security and the other, a residual interest bond. The interest rate for the variable-rate security is determined by an index or an auction process held approximately every seven to 35 days, while the residual interest bond holder receives the balance of the income from the underlying municipal bond less an auction fee. The market prices of residual interest bonds may be highly sensitive to changes in market rates and may decrease significantly when market rates increase.

REPURCHASE AGREEMENTS. The Funds may enter into repurchase agreements. A repurchase agreement is an instrument under which the purchaser (i.e., the Fund) acquires the security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price, thereby determining the yield during the purchaser's holding period. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by each Fund but only to constitute collateral for the seller's obligation to pay the repurchase price, and, in the event of a default by the seller, each Fund may suffer time delays and incur costs or losses in connection with the disposition of the collateral.

In any repurchase transaction, the collateral for a repurchase agreement may include (i) cash items; (ii) obligations issued by the U.S. Government or its agencies or instrumentalities; or (iii) obligations that, at the time the repurchase agreement is entered into, are rated in the highest rating category generally by at least two nationally recognized statistical rating organizations ("NRSRO"), or, if unrated, determined to be of comparable quality by BFA. Collateral, however, is not limited to the foregoing and may include for example obligations rated below the highest category by NRSROs. Collateral for a repurchase agreement may also include securities that a Fund could not hold directly without the repurchase obligation. Irrespective of the type of collateral underlying the repurchase agreement, in the case of a repurchase agreement entered into by a non-money market fund, the repurchase obligation of a seller must be of comparable credit quality to securities which are rated in one of the two highest rating categories by any NRSRO.

Repurchase agreements pose certain risks for a Fund that utilizes them. Such risks are not unique to the Fund but are inherent in repurchase agreements. The Funds seek to minimize such risks but because of the inherent legal uncertainties involved in repurchase agreements, such risks cannot be eliminated. Lower quality collateral and collateral with longer maturities may be subject to greater price fluctuations than higher quality collateral and collateral with shorter maturities. If the repurchase agreement counterparty were to default, lower quality collateral may be more difficult to liquidate than higher quality collateral. Should the counterparty default and the amount of collateral not be sufficient to cover the counterparty's repurchase obligation, the Fund would retain the status of an unsecured creditor of the counterparty (i.e., the position the Fund would normally be in if it were to hold, pursuant to its investment policies, other unsecured debt securities of the defaulting counterparty) with respect to the amount of the shortfall. As an unsecured creditor, a Fund would be at risk of losing some or all of the principal and income involved in the transaction.

RESTRICTED SECURITIES. Restricted securities are subject to legal restrictions on their sale. Difficulty in selling restricted securities may result in a loss or be costly to a Fund. Restricted securities generally can be sold in privately negotiated transactions, pursuant to an exemption from registration under the Securities Act of 1933, as amended (the "1933 Act"), or in a registered public offering. Where registration is required, the restricted security's holder may be obligated to pay all or part of the registration expense and a considerable period may elapse between the time the holder decides to seek registration and the time the holder may be permitted to sell the security under an effective registration statement. If, during that period, adverse market conditions were to develop, the holder might obtain a less favorable price than prevailed when it decided to seek registration of the security.

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REVERSE REPURCHASE AGREEMENTS. Each Fund may enter into reverse repurchase agreements, which involve the sale of securities with an agreement to repurchase the securities at an agreed-upon price, date and interest payment and have the characteristics of borrowing. Generally, the effect of such transactions is that a Fund can recover all or most of the cash invested in the portfolio securities involved during the term of the reverse repurchase agreement, while in many cases the Fund is able to keep some of the interest income associated with those securities. Such transactions are only advantageous if a Fund has an opportunity to earn a greater rate of interest on the cash derived from these transactions than the interest cost of obtaining the same amount of cash. Opportunities to realize earnings from the use of the proceeds equal to or greater than the interest required to be paid may not always be available and each Fund intends to use the reverse repurchase technique only when BFA believes it will be advantageous to the Fund. The use of reverse repurchase agreements may exaggerate any interim increase or decrease in the value of a Fund's assets. Each Fund will maintain liquid assets having a value equal to or greater than such commitments. Under the 1940 Act, reverse repurchase agreements are considered borrowings.

SECURITIES OF NON-U.S. ISSUERS. Each Fund may invest in certain securities of non-U.S. issuers. Investing in the securities of non-U.S. issuers involves special risks and considerations not typically associated with investing in U.S. issuers. These include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or potentially confiscatory taxation or war, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, potential restrictions of the flow of international capital, transaction costs of foreign currency conversions, generally less liquid and less efficient securities markets, generally greater price volatility, less publicly available information about issuers, the imposition of withholding or other taxes, higher transaction and custody costs, delays and risks attendant in settlement procedures, difficulties in enforcing contractual obligations, significantly smaller market capitalization of most non-U.S. securities markets, lesser levels of regulation of the securities markets, and more substantial government interference with the economy. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy with respect to growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions. In addition, changes in foreign exchange rates also will affect the value of securities denominated or quoted in currencies other than the U.S. dollar.

Securities issued by certain companies organized outside the United States may not be deemed to be foreign securities (but rather deemed to be U.S. securities) if the company's principal operations are conducted from the U.S., the company's equity securities trade principally on a U.S. stock exchange, or the company does a substantial amount of business in the U.S.

OBLIGATIONS OF FOREIGN GOVERNMENTS, SUPRANATIONAL ENTITIES AND BANKS. Each Fund may invest in U.S. dollar-denominated short-term obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions, agencies or instrumentalities that are determined by BFA to be of comparable quality to the other obligations in which such Fund may invest. The Funds may also invest in debt obligations of supranational entities. Supranational entities include international organizations designated or supported by governmental entities to promote economic reconstruction or development and international banking institutions and related government agencies. Examples include the International Bank for Reconstruction and Development (the World Bank), the Asian Development Bank and the InterAmerican Development Bank. The percentage of each Fund's assets invested in obligations of foreign governments and supranational entities will vary depending on the relative yields of such securities, the economic and financial markets of the countries in which the investments are made and the interest rate climate of such countries.

Each Fund may invest a portion of its total assets in high-quality, short-term (one year or less) debt obligations of foreign branches of U.S. banks or U.S. branches of foreign banks that are denominated in and pay interest in U.S. dollars.

FOREIGN EQUITY SECURITIES AND DEPOSITARY RECEIPTS. BlackRock S&P 500 Stock Fund's assets may be invested in the securities of foreign issuers and American Depositary Receipts ("ADRs") and European Depositary Receipts ("EDRs," sometimes referred to as Continental Depositary Receipts ("CDRs")) of such issuers (ADRs and EDRs or CDRs, collectively "Depositary Receipts").

ADRs and EDRs may not necessarily be denominated in the same currency as the securities into which they may be converted. ADRs are receipts typically issued by a United States bank or trust company which evidence ownership of underlying securities issued by a foreign corporation. EDRs and CDRs are receipts issued in Europe typically by non-United States banks and trust companies that evidence ownership of either foreign or domestic securities. Generally, ADRs in registered form are designed for use in the U.S. securities markets and EDRs and CDRs in bearer form are designed for use in Europe. The Fund may invest in ADRs, EDRs and CDRs through "sponsored" or "unsponsored" facilities. A sponsored facility

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is established jointly by the issuer of the underlying security and a depositary, whereas a depositary may establish an unsponsored facility without participation by the issuer of the deposited security. Holders of unsponsored depositary receipts generally bear all the costs of such facilities and the depositary of an unsponsored facility frequently is under no obligation to distribute interestholder communications received from the issuer of the deposited security or to pass through voting rights to the holders of such receipts in respect of the deposited securities. The issuers of unsponsored depositary receipts are not obligated to disclose material information in the United States, and therefore, there may be less information available regarding such issuers and there may not be a correlation between such information and the market value of the depositary receipts.

SHORT-TERM INSTRUMENTS. Each Fund may invest in various money market instruments. Money market instruments are generally short-term investments that may include but are not limited to: (i) obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities (including government-sponsored enterprises); (ii) negotiable certificates of deposit (CDs), bankers' acceptances, fixed time deposits and other obligations of domestic banks (including non-U.S. branches); (iii) commercial paper; (iv) non-convertible corporate debt securities (E.G., bonds and debentures); (v) repurchase agreements; and (vi) U.S. dollar-denominated obligations of non-U.S. banks (including U.S. branches) that, in the opinion of BFA, are of comparable quality to obligations of U.S. banks which may be purchased by the Fund. Any of these instruments may be purchased on a current or a forward-settled basis. Money market instruments also include shares of money market mutual funds, including those managed by BFA.

STOCK INDEX FUTURES AND OPTIONS ON STOCK INDEX FUTURES. BlackRock S&P 500 Stock Fund may invest in stock index futures and options on stock index futures as a substitute for a comparable market position in the underlying securities. An index futures contract is a standardized agreement between two parties that commits one party to buy and the other party to sell a stipulated quantity of a market index at a set price on or before a given date in the future. The seller never actually delivers "shares" of the index or shares of all the stocks in the index. Instead, the buyer and the seller settle the difference between the contract price and the market price in cash on the agreed-upon date, with the buyer paying the difference if the actual price is lower than the contract price and the seller paying the difference if the actual price is higher. The Fund intends to purchase and sell futures contracts on the stock index for which it can obtain the best price with consideration also given to liquidity.

An option on a stock index is similar to an option on a stock except that (a) the expiration cycles of stock index options are monthly, while those of stock options are currently quarterly, and (b) the delivery requirements are different. Instead of giving the right to take or make delivery of stock at a specified price, an option on a stock index gives the holder the right to receive a cash "exercise settlement amount" equal to (i) the amount, if any, by which the fixed exercise price of the option exceeds (in the case of a put) or is less than (in the case of a call) the closing value of the underlying index on the date of exercise, multiplied by (ii) a fixed "index multiplier." Receipt of this cash amount depends upon the closing level of the stock index upon which the option is based being greater than (in the case of a call) or less than (in the case of a put) the exercise price of the option. The amount of cash received is equal to such difference between the closing price of the index and the exercise price of the option expressed in dollars, multiplied by a specified multiplier. The writer of the option is obligated, in return for the premium received, to make delivery of this amount. The writer may offset a position in stock index options prior to expiration by entering into a closing transaction on an exchange or the writer may let the option expire unexercised.

UNRATED, DOWNGRADED AND BELOW INVESTMENT-GRADE INVESTMENTS. The Funds may purchase an instrument that is not rated if, in the opinion of BFA, such obligation is of an investment quality that is comparable to other rated investments that are permitted to be purchased by such Fund. After purchase by a Fund, a security may cease to be rated or its rating may be reduced below the minimum required for purchase by such Fund. Neither event will require a sale of such security by the Fund provided that the amount of such securities held by a Fund does not exceed 5% of the Fund's net assets. To the extent the ratings given by Moody's(Reg. TM) Investors Service, Inc. ("Moody's") or Standard & Poor's(Reg. TM), a division of The McGraw-Hill Companies, Inc. ("S&P") may change as a result of changes in such organizations or their rating systems, each Fund will attempt to use comparable ratings as standards for investments in accordance with the investment policies contained in its Prospectus and in this SAI.

The Funds are not required to sell downgraded securities, and each Fund could hold up to 5% of its net assets in debt securities rated below "Baa" by Moody's or below "BBB" by S&P or, if unrated, low quality (below investment-grade) securities.

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Although they may offer higher yields than do higher-rated securities, low-rated and unrated low quality debt securities generally involve greater volatility of price and risk of principal and income, including the possibility of default by, or bankruptcy of, the issuers of the securities. In addition, the markets in which low-rated and unrated low quality debt are traded are more limited than those in which higher-rated securities are traded. The existence of limited markets for particular securities may diminish a Fund's ability to sell the securities at fair value either to meet redemption requests or to respond to changes in the economy or in the financial markets and could adversely affect and cause fluctuations in the daily net asset value of a Fund's interests.

Adverse publicity and investor perceptions, whether or not based on fundamental analysis, may decrease the values and liquidity of low-rated or unrated low quality debt securities, especially in a thinly traded market. Analysis of the creditworthiness of issuers of low-rated or unrated low quality debt securities may be more complex than for issuers of higher-rated securities, and the ability of a Fund to achieve its investment objective may, to the extent it holds low-rated or unrated low quality debt securities, be more dependent upon such creditworthiness analysis than would be the case if the Fund held exclusively higher-rated or higher quality securities.

Low-rated or unrated low quality debt securities may be more susceptible to real or perceived adverse economic and competitive industry conditions than investment-grade securities. The prices of such debt securities have been found to be less sensitive to interest rate changes than higher-rated or higher quality investments, but more sensitive to adverse economic downturns or individual corporate developments. A projection of an economic downturn or of a period of rising interest rates, for example, could cause a decline in low-rated or unrated low quality debt securities prices because the advent of a recession could dramatically lessen the ability of a highly leveraged company to make principal and interest payments on its debt securities. If the issuer of the debt securities defaults, the Funds may incur additional expenses to seek recovery.

U.S. GOVERNMENT OBLIGATIONS. The Funds may invest in various types of U.S. government obligations. A U.S. government obligation is a type of bond. U.S. government obligations include securities issued or guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities. Payment of principal and interest on U.S. government obligations (i) may be backed by the full faith and credit of the United States (as with U.S. Treasury obligations and Ginnie Mae certificates) or (ii) may be backed solely by the issuing or guaranteeing agency or instrumentality itself (as with Fannie Mae, Freddie Mac or FHLB notes). In the latter case, the investor must look principally to the agency or instrumentality issuing or guaranteeing the obligation for ultimate repayment, which agency or instrumentality may be privately owned. There can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. As a general matter, the value of debt instruments, including U.S. government obligations, declines when market interest rates increase and rises when market interest rates decrease. Certain types of U.S. government obligations are subject to fluctuations in yield or value due to their structure or contract terms.

WARRANTS. BlackRock S&P 500 Stock Fund may invest up to 5% of net assets at the time of purchase in warrants (other than those that have been acquired in units or attached to other securities), including not more than 2% of its net assets in warrants which are not listed on the New York Stock Exchange ("NYSE") or the NYSE Amex Equities (f/k/a American Stock Exchange). A warrant is an instrument issued by a corporation that gives the holder the right to subscribe to a specified amount of the corporation's capital stock at a set price for a specified period of time. The prices of warrants do not necessarily correlate with the prices of the underlying securities. The Fund may only purchase warrants on securities in which the Fund may invest directly.

BLACKROCK S&P 500 STOCK FUND AND S&P 500 STOCK MASTER PORTFOLIO. Neither the Fund nor the Master Portfolio is sponsored, endorsed, sold or promoted by S&P. S&P makes no representation or warranty, express or implied, to the Fund, the Master Portfolio or any member of the public regarding the advisability of investing in securities generally or in the Fund particularly or the ability of the S&P 500 Index to track general stock market performance. S&P's only relationship to the Fund is the licensing of certain trademarks and trade names of S&P and of the S&P 500 Index that is determined, composed and calculated by S&P without regard to the Fund. S&P has no obligation to take the needs of the Fund into consideration in determining, composing or calculating the S&P 500 Index. S&P is not responsible for and has not participated in the determination of the prices and amount of the Fund's shares or the timing of the issuance or sale of the Fund's shares or in the determination or calculation of the equation by which the Fund's shares are to be converted into cash. S&P has no obligation or liability in connection with the administration, marketing or trading of the Fund's shares.

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S&P does not guarantee the accuracy and/or the completeness of the S&P 500 Index or any data included therein and S&P shall have no liability for any errors, omissions, or interruptions therein. S&P makes no warranty, express or implied, as to results to be obtained by the Fund, or any other person or entity from the use of the S&P 500 Index or any data included therein. S&P makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the S&P 500 Index or any data included therein. Without limiting any of the foregoing, in no event shall S&P have any liability for any special, punitive, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

Portfolio Holdings Information

SELECTIVE DISCLOSURE OF PORTFOLIO HOLDINGS

Pursuant to policies and procedures adopted by the Trust, MIP and BFA, the Trust, MIP and BFA may, under certain circumstances as set forth below, make selective disclosure with respect to a Fund's or Master Portfolio's portfolio holdings. The Boards of Trustees of the Trust and MIP have approved the adoption by the Trust and MIP of the policies and procedures set forth below, and have delegated to BFA the responsibility for ongoing monitoring and supervision to ensure compliance with these policies and procedures. The Boards of Trustees provide ongoing oversight of the Trust's, MIP's and BFA's compliance with the policies and procedures. As part of this oversight function, the Trustees receive from the Trust's and MIP's Chief Compliance Officer at least quarterly and more often, as necessary, reports on compliance with these policies and procedures, including reports on any violations of these policies and procedures that may occur. In addition, the Trustees receive an annual assessment of the adequacy and effectiveness of the policies and procedures with respect to the Trust and MIP, and any changes thereto, and an annual review of the operation of the policies and procedures.

Examples of the information that may be disclosed pursuant to the Trust's and MIP's policies and procedures would include (but is not limited to) specific portfolio holdings -- including the number of shares held, weightings of particular holdings, specific sector and industry weightings, trading details, and the portfolio manager's discussion of Fund or Master Portfolio performance and reasoning for significant changes in portfolio composition. This information may be both material non-public information ("Confidential Information") and proprietary information of the firm. The Trust or MIP may disclose such information to individual investors, institutional investors, financial advisers and other financial intermediaries that sell the Trust's shares, affiliates of the Trust or MIP, third party service providers to the Trust or MIP, lenders to the Trust or MIP, and independent rating agencies and ranking organizations. The Trust, MIP, BFA and its affiliates receive no compensation or other consideration with respect to such disclosures.

Subject to the exceptions set forth below, Confidential Information relating to a Fund or Master Portfolio may not be disclosed to persons not employed by BFA or its affiliates unless such information has been publicly disclosed via a filing with the Commission (e.g., Trust annual report), a press release or placement on a publicly-available internet website. If the Confidential Information has not been publicly disclosed, an employee of BFA who wishes to distribute Confidential Information relating to the Trust or MIP must first do

the following: (i) require the person or company receiving the Confidential Information to sign, before BFA will provide disclosure of any such information, a confidentiality agreement approved by an attorney in BFA's Legal Department in which the person or company (a) agrees to use the Confidential Information solely in connection with a legitimate business use (i.e., due diligence, etc.) and (b) agrees not to trade on the basis of the information so provided; (ii) obtain the authorization of an attorney in BFA's Legal Department prior to disclosure; and (iii) only distribute Confidential Information that is at least thirty (30) calendar days old unless a shorter period has specifically been approved by an attorney in BFA's Legal Department.

Prior to providing any authorization for such disclosure of Confidential Information, an attorney in BFA's Legal Department must review the proposed arrangement and make a determination that it is in the best interests of the Trust's shareholders. In connection with day-to-day portfolio management, the Trust or MIP may disclose Confidential Information to executing broker-dealers that is less than 30 days old in order to facilitate the purchase and sale of portfolio holdings. The Trust and MIP have adopted policies and procedures, including a Code of Ethics, Code of Conduct, and various policies regarding securities trading and trade allocations, to address potential conflicts of interest that may arise in connection with disclosure of Confidential Information. These procedures are designed, among other things, to prohibit personal trading based on Confidential Information, to ensure that portfolio transactions are conducted in the best interests of the Trust and its shareholders and to prevent portfolio management from using Confidential Information for the benefit of one Fund, Master Portfolio or account at the expense of another. In addition, as noted, an attorney in BFA's Legal Department must determine that disclosure of Confidential Information is for a legitimate business purpose and is in the best interests of the Trust's shareholders, and that any conflicts of interest created by release of the Confidential Information have been addressed by BFA's existing policies and procedures. For more information with respect to potential conflicts of interest, see the section entitled "Management-- Potential Conflicts of Interest" in this Statement of Additional Information.

Confidential Information -- whether or not publicly disclosed -- may be disclosed to Trust Trustees, the independent Trustees' counsel, the Trust's outside counsel, accounting services provider and independent registered public accounting firm without meeting the conditions outlined above. Confidential Information may, with the prior approval of the Trust's Chief Compliance Officer or BFA's General Counsel, also be disclosed to any auditor of the parties to a service agreement involving the Trust or MIP, or as required by judicial or administrative process or otherwise by applicable law or regulation. If Confidential Information is disclosed to such persons, each such person will be subject to restrictions on trading in the subject securities under either the Trust's, MIP's and BFA's Code of Ethics or an applicable confidentiality agreement, or under applicable laws or regulations or court order.

BFA has entered into ongoing arrangements to provide monthly and quarterly selective disclosure of Trust and MIP portfolio holdings to the following persons or entities:

Trust's and MIP's Boards of Trustees and, if necessary independent Trustees' counsel and Trust counsel

Trust's Transfer Agent

Trust's and MIP's independent registered public accounting firm

Trust's and MIP's accounting services provider

MIP Custodian

MIP's pricing services - Interactive Data Corp. and Reuters, Inc.

Independent rating agencies -- Morningstar, Inc., Lipper Inc., Moody's Investors Service, Inc. and Standard & Poor's

Information aggregators -- Wall Street on Demand, Thomson Financial, eVestment Alliance, informa PSN investment solutions, Micropal, iMoneyNet and Bloomberg

Sponsors of 401(k) plans that include BlackRock-advised Funds -- E.I. Dupont de Nemours and Company, Inc.

Consultants for pension plans that invest in BlackRock-advised Funds -- Rocaton Investment Advisors, LLC; Mercer Investment Consulting; Watson Wyatt Investment Consulting; Towers Perrin HR Services; Pinnacle West; Callan Associates; Brockhouse & Cooper; Cambridge Associates; Mercer; Morningstar/Investorforce; Russell Investments (Mellon Analytical Solutions); and Wilshire Associates

Portfolio Compliance Consultants -- i-Flex Solutions, Inc.

Third-party feeder funds---Hewitt Money Market Fund, Hewitt Series Trust, Hewitt Financial Services LLC, PayPal Money Market Fund, PayPal Funds, PayPal Asset Management, Inc. Homestead, Inc., Transamerica and State Farm Mutual Fund Trust, and their respective boards, sponsors, administrators and other service providers

Affiliated feeder funds---BlackRock Cayman Prime Money Market Fund, Ltd. And BlackRock Cayman Treasury Money Market Fund Ltd., and their respective boards, sponsors, administrators and other service providers

Other --- Chicago Mercantile Exchange, Inc., Be Creative, Inc. and Investment Company Institute

Other than with respect to the Board of Trustees, each of the persons or entities set forth above is subject to an agreement to keep the information disclosed confidential and to use it only for legitimate business purposes. Each Trustee has a fiduciary duty as a trustee to act in the best interests of the Trust and its shareholders. Selective disclosure is made to the Board of Trustees and independent registered public accounting firm at least quarterly and otherwise as frequently as necessary to enable such persons or entities to provide services to the Trust. Selective disclosure is made to the Trust's Transfer Agent, accounting services provider, and Custodian as frequently as necessary to enable such persons or entities to provide services to the Trust, typically on a daily basis. Disclosure is made to Lipper Inc. and Wall Street on Demand on a monthly basis and to Morningstar and Thomson Financial on a quarterly basis, and to each such firm upon specific request with the approval of BFA's Legal Department. Disclosure is made to 401(k) plan sponsors on a yearly basis and pension plan consultants on a quarterly basis.

The Trust and BFA monitor, to the extent possible, the use of Confidential Information by the individuals or firms to which it has been disclosed. To do so, in addition to the requirements of any applicable confidentiality agreement and/or the terms and conditions of the Trust's and BFA's Code of Ethics and Code of Conduct -- all of which require persons or entities in possession of Confidential Information to keep such information confidential and not to trade on such information for their own benefit -- BFA's compliance personnel under the supervision of the Trust's Chief Compliance Officer, monitor BFA's securities trading desks to determine whether individuals or firms who have received Confidential Information have made any trades on the basis of that information. In addition, BFA maintains an internal restricted list to prevent trading by the personnel of BFA or its affiliates in securities -- including securities held by the Trust or MIP -- about which BFA has Confidential Information. There can be no assurance, however, that the Trust's policies and procedures with respect to the selective disclosure of Trust portfolio holdings will prevent the misuse of such information by individuals or firms that receive such information

15

Management

The Board of Trustees of the Trust, consists of thirteen individuals (each, a "Trustee"), eleven of whom are Independent Trustees. The same individuals serve on the Board of Trustees of MIP. The registered investment companies advised by BFA or its affiliates (the "BlackRock-advised Funds") are organized into one complex of closed-end funds, two complexes of open-end funds (the Equity-Liquidity Complex and the Equity-Bond Complex) and one complex of ETFs (each, a "BlackRock Fund

16

Complex"). The Trust and MIP are included in the BlackRock Fund Complex referred to as the Equity-Liquidity Complex. The Trustees also oversee as board members the operations of the other open-end registered investment companies included in the Equity-Liquidity Complex. The address for each Trustee and officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055.

The Board of Trustees has overall responsibility for the oversight of the Trust and the Funds. The Co-Chairs of the Board are Independent Trustees, and the Chair of each Board committee (each, a "Committee") is an Independent Trustee. The Board has five standing Committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight and Contract Committee and an Executive Committee. The Board also has one ad hoc committee, the Joint Product Pricing Committee. The role of the Co-Chairs of the Board is to preside at all meetings of the Board and to act as a liaison with service providers, officers, attorneys, and other Trustees generally between meetings. The Chair of each Committee performs a similar role with respect to the Committee. The Co-Chairs of the Board or the Chair of a Committee may also perform such other functions as may be delegated by the Board or the Committee from time to time. The Independent Trustees meet regularly outside the presence of Trust management, in executive session or with other service providers to the Trust and the Funds. The Board has regular meetings five times a year, and may hold special meetings if required before its next regular meeting. Each Committee meets regularly to conduct the oversight functions delegated to that Committee by the Board and reports its findings to the Board. The Board and each standing Committee conduct annual assessments of their oversight function and structure. The Board has determined that the Board's leadership structure is appropriate because it allows the Board to exercise independent judgment over management and to allocate areas of responsibility among Committees and the full Board to enhance effective oversight.

The Board has engaged BFA to manage the Funds on a day-to-day basis. The Board is responsible for overseeing BFA, other service providers, the operations of the Funds and associated risk in accordance with the provisions of the 1940 Act, state law, other applicable laws, the Trust's charter, and the Funds' investment objectives and strategies. The Board reviews, on an ongoing basis, the Funds' performance, operations, and investment strategies and techniques. The Board also conducts reviews of BFA and its role in running the operations of the Funds.

Day-to-day risk management with respect to the Funds is the responsibility of BFA or of sub-advisers or other service providers (depending on the nature of the risk), subject to the supervision of BFA. The Funds are subject to a number of risks, including investment, compliance, operational and valuation risks, among others. While there are a number of risk management functions performed by BFA and the sub-advisers or other service providers, as applicable, it is not possible to eliminate all of the risks applicable to the Funds. Risk oversight forms part of the Board's general oversight of the Funds and is addressed as part of various Board and Committee activities. The Board, directly or through a Committee, also reviews reports from, among others, management, the independent registered public accounting firm for the Funds, sub-advisers, and internal auditors for the investment adviser or its affiliates, as appropriate, regarding risks faced by the Funds and management's or the service provider's risk functions. The Committee system facilitates the timely and efficient consideration of matters by the Trustees, and facilitates effective oversight of compliance with legal and regulatory requirements and of the Funds' activities and associated risks. The Board has appointed a Chief Compliance Officer, who oversees the implementation and testing of the Funds' compliance program and reports to the Board regarding compliance matters for the Funds and their service providers. The Independent Trustees have engaged independent legal counsel to assist them in performing their oversight responsibilities.

The members of the Audit Committee are Kenneth L. Urish (Chair), Herbert I. London and Frederick W. Winter, all of whom are Independent Trustees. The principal responsibilities of the Audit Committee are to approve the selection, retention, termination and compensation of the Trust's independent registered public accounting firm (the "independent auditors") and to oversee the independent auditors' work. The Audit Committee's responsibilities include, without limitation, to (1) evaluate the qualifications and independence of the independent auditors; (2) approve all audit engagement terms and fees for each Fund; (3) review the conduct and results of each independent audit of each Fund's financial statements; (4) review any issues raised by the independent auditors or Trust management regarding the accounting or financial reporting policies and practices of each Fund and the internal controls of each Fund and certain service providers; (5) oversee the performance of each Fund's internal audit function provided by its investment adviser, administrator, pricing agent or other service provider; (6) discuss with Trust management its policies regarding risk assessment and risk management and (7) resolve any disagreements between Trust management and the independent auditors regarding financial reporting. The Board has adopted a written charter for the Audit Committee. During the period December 1, 2009 through December 31, 2009, the Audit Committee met one time.

17

The members of the Governance and Nominating Committee (the "Governance Committee") are Dr. Matina Horner (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The principal responsibilities of the Governance Committee are to (1) identify individuals qualified to serve as Independent Trustees of the Trust and recommend Independent Trustee nominees for election by shareholders or appointment by the Board; (2) advise the Board with respect to Board composition, procedures and committees (other than the Audit Committee); (3) oversee periodic self-assessments of the Board and committees of the Board (other than the Audit Committee); (4) review and make recommendations regarding Independent Trustee compensation; and (5) monitor corporate governance matters and develop appropriate recommendations to the Board. The Governance Committee may consider nominations for the office of Trustee made by Fund shareholders as it deems appropriate. Fund shareholders who wish to recommend a nominee should send nominations to the Secretary of the Trust that include biographical information and set forth the qualifications of the proposed nominee. The Board has adopted a written charter for the Governance Committee. During the period December 1, 2009 through December 31, 2009, the Governance Committee met one time.

The members of the Compliance Committee are Joseph P. Platt, Jr. (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The Compliance Committee's purpose is to assist the Board in fulfilling its responsibility to oversee regulatory and fiduciary compliance matters involving the Trust, the Fund-related activities of BFA and the Trust's third party service providers. The Compliance Committee's responsibilities include, without limitation, to (1) oversee the compliance policies and procedures of the Trust and its service providers and recommend changes or additions to such policies and procedures; (2) review information on and, where appropriate recommend policies concerning, the Trust's compliance with applicable law; and (3) review reports from, oversee the annual performance review of, and make certain recommendations regarding the Trust's Chief Compliance Officer. The Board has adopted a written charter for the Compliance Committee. During the period December 1, 2009 through December 31, 2009, the Compliance Committee met two times.

The members of the Performance Oversight and Contract Committee (the "Performance Oversight Committee") are David O. Beim (Chair), Toby Rosenblatt (Vice Chair), Ronald W. Forbes and Rodney D. Johnson, all of whom are Independent Trustees. The Performance Oversight Committee's purpose is to assist the Board in fulfilling its responsibility to oversee each Fund's investment performance relative to its agreed-upon performance objectives and to assist the Independent Trustees in their consideration of investment advisory agreements. The Performance Oversight Committee's responsibilities include, without limitation, to (1) review each Fund's investment objectives, policies and practices and each Fund's investment performance; (2) review personnel and resources devoted to management of each Fund and evaluate the nature and quality of information furnished to the Performance Oversight Committee; (3) recommend any required action regarding change in fundamental and non-fundamental investment policies and restrictions, fund mergers or liquidations; (4) request and review information on the nature, extent and quality of services provided to the shareholders; and (5) make recommendations to the Board concerning the approval or renewal of investment advisory agreements. The Board has adopted a written charter for the Performance Oversight Committee. During the period December 1, 2009 through December 31, 2009, the Performance Oversight Committee met one time.

The Boards of the Equity-Liquidity Complex, the Equity-Bond Complex and the closed-end BlackRock Fund Complex, established the ad hoc Joint Product Pricing Committee (the "Product Pricing Committee") comprised of eight members drawn from the independent board members serving on the boards of these BlackRock Fund Complexes. Ronald W. Forbes and Rodney D. Johnson are members of the Product Pricing Committee representing the Equity-Liquidity Complex. One independent board member representing the closed-end BlackRock Fund Complex and five independent board members representing the Equity-Bond Complex serve on the Product Pricing Committee. The Product Pricing Committee is chaired by an independent board member from the Equity-Bond Complex. The purpose of the Product Pricing Committee is to review the components and pricing structure of the non-money market funds in the BlackRock Fund Complexes. During the period from December 1, 2009 through December 31, 2009, the Product Pricing Committee did not meet.

The members of the Executive Committee are Ronald W. Forbes and Rodney D. Johnson, both of whom are Independent Trustees, and Richard S. Davis, who serves as an interested Trustee. The principal responsibilities of the Executive Committee are to (1) act on routine matters between meetings of the Board; (2) act on such matters as may require urgent action between meetings of the Board; and (3) exercise such other authority as may from time to time be delegated to the Executive Committee by the Board. The Board has adopted a written charter for the Executive Committee. During the period December 1, 2009 through December 31, 2009, the Executive Committee met one time.

18

The Governance Committee has adopted a statement of policy that describes the experience, qualifications, skills and attributes that are necessary and desirable for potential Independent Trustee candidates (the "Statement of Policy"). The Board believes that each Independent Trustee satisfied, at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. Furthermore, in determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, skills, attributes and qualifications, which allow the Board to operate effectively in governing the Trust and protecting the interests of shareholders. Among the attributes common to all Trustees are their ability to review critically, evaluate, question and discuss information provided to them, to interact effectively with the Trust's investment adviser, sub-advisers, other service providers, counsel and independent auditors, and to exercise effective business judgment in the performance of their duties as Trustees. Each Trustee's ability to perform his or her duties effectively is evidenced by his or her educational background or professional training; business, consulting, public service or academic positions; experience from service as a board member of the Trust and the other funds in the BlackRock Fund Complex (and any predecessor funds), other investment funds, public companies, or non-profit entities or other organizations; ongoing commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout the years; or other relevant life experiences. Information about the specific experience, skills, attributes and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a Trustee of the Trust, is provided below.

Certain biographical and other information relating to the Trustees of the Trust is set forth below, including their ages, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
           NAME             HELD WITH          TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
         AND AGE            THE TRUST       SERVED/2/         DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- --------------
INDEPENDENT TRUSTEES/1/
David O. Beim/3/          Trustee       2009 to present   Professor of Finance and       36 RICs          None
(69)                                                      Economics at the Columbia      consisting of
                                                          University Graduate School     104 Portfolios
                                                          of Business since 1991;
                                                          Trustee, Phillips Exeter
                                                          Academy since 2002;
                                                          Chairman, Wave Hill, Inc.
                                                          (public garden and cultural
                                                          center) from 1990 to 2006.

Ronald W. Forbes/4/       Trustee       2009 to present   Professor Emeritus of          36 RICs          None
(69)                                                      Finance, School of Business,   consisting of
                                                          State University of New York   104 Portfolios
                                                          at Albany since 2000.

Dr. Matina S. Horner/5/   Trustee       2009 to present   Executive Vice President of    36 RICs          NSTAR
(70)                                                      Teachers Insurance and         consisting of    (electric and
                                                          Annuity Association and        104 Portfolios   gas utility)
                                                          College Retirement Equities
                                                          Fund from 1989 to 2003.

19

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
         NAME               HELD WITH          TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")         PUBLIC
        AND AGE             THE TRUST       SERVED(2)         DURING PAST FIVE YEARS         OVERSEEN        DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- -------------------
Rodney D. Johnson/4/      Trustee       2009 to present   President, Fairmont Capital    36 RICs          None
(68)                                                      Advisors, Inc. since 1987;     consisting of
                                                          Director, Fox Chase Cancer     104 Portfolios
                                                          Center since 2004; Member
                                                          of Archdiocesan Investment
                                                          Committee of the
                                                          Archdiocese of Philadelphia
                                                          since 2004; Director, The
                                                          Committee of Seventy (civic)
                                                          since 2006.

Herbert I. London         Trustee       2009 to present   Professor Emeritus, New        36 RICs          AIMS
(70)                                                      York University since 2005;    consisting of    Worldwide,
                                                          John M. Olin Professor of      104 Portfolios   Inc.
                                                          Humanities, New York                                (marketing)
                                                          University from 1993 to 2005
                                                          and Professor thereof from
                                                          1980 to 2005; President,
                                                          Hudson Institute (policy
                                                          research organization) since
                                                          1997 and Trustee thereof
                                                          since 1980; Chairman of the
                                                          Board of Trustees for
                                                          Grantham University since
                                                          2006; Director, InnoCentive,
                                                          Inc. (strategic solutions
                                                          company) since 2005;
                                                          Director of Cerego, LLC
                                                          (software development and
                                                          design) since 2005.

Cynthia A.                Trustee       2009 to present   Professor, Harvard Business    36 RICs          Newell
Montgomery                                                School since 1989; Director,   consisting of    Rubbermaid,
(57)                                                      Harvard Business School        104 Portfolios   Inc.
                                                          Publishing since 2005;                          (manufacturing)
                                                          Director, McLean Hospital
                                                          since 2005.

20

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
           NAME             HELD WITH          TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")        PUBLIC
         AND AGE            THE TRUST       SERVED(2)          DURING PAST FIVE YEARS        OVERSEEN       DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- -------------------
Joseph P. Platt, Jr./6/   Trustee       2009 to present   Director, The West Penn        36 RICs          Greenlight
(62)                                                      Allegheny Health System (a     consisting of    Capital Re,
                                                          not-for-profit health system)  104 Portfolios   Ltd
                                                          since 2008; Director, Jones                     (reinsurance
                                                          and Brown (Canadian                             company);
                                                          insurance broker) since                         WQED Multi-
                                                          1998; General Partner, Thorn                    Media (public
                                                          Partner, LP (private                            broadcasting
                                                          investment) since 1998;                         not-for-
                                                          Partner Amarna Corporation,                     profit)
                                                          LLC (private investment
                                                          company) from 2002 to
                                                          2008.

Robert C. Robb, Jr.       Trustee       2009 to present   Partner, Lewis, Eckert, Robb   36 RICs          None
(64)                                                      and Company (management        consisting of
                                                          and financial consulting       104 Portfolios
                                                          firm) since 1981.

Toby Rosenblatt/7/        Trustee       2009 to present   President, Founders            36 RICs          A.P. Pharma
(71)                                                      Investments Ltd. (private      consisting of    Inc. (specialty
                                                          investments) since 1999;       104 Portfolios   pharmaceuticals)
                                                          Director, College Access
                                                          Foundation of California
                                                          (philanthropic foundation)
                                                          since 2009; Director, Forward
                                                          Management, LLC since
                                                          2007; Director, the James
                                                          Irvine Foundation
                                                          (philanthropic foundation)
                                                          from 1998 to 2008.

21

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
         NAME               HELD WITH          TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
       AND AGE              THE TRUST       SERVED(2)          DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- -------------------
Kenneth L. Urish/8/       Trustee       2009 to present   Managing Partner, Urish        36 RICs          None
(59)                                                      Popeck & Co., LLC (certified   consisting of
                                                          public accountants and         104 Portfolios
                                                          consultants) since 1976;
                                                          Member of External Advisory
                                                          Board, the Pennsylvania
                                                          State University Accounting
                                                          Department since 2001;
                                                          Trustee, The Holy Family
                                                          Foundation since 2001;
                                                          Committee Member,
                                                          Professional Ethics
                                                          Committee of the
                                                          Pennsylvania Institute of
                                                          Certified Public Accountants
                                                          from 2007 to 2010; President
                                                          and Trustee, Pittsburgh
                                                          Catholic Publishing
                                                          Associates from 2003 to
                                                          2008; Director, Inter-Tel from
                                                          2006 to 2007.

Frederick W. Winter       Trustee       2009 to present   Professor and Dean Emeritus    36 RICs          None
(65)                                                      of the Joseph M. Katz School   consisting of
                                                          of Business, University of     104 Portfolios
                                                          Pittsburgh since 2005 and
                                                          dean thereof from 1997 to
                                                          2005; Director, Alkon
                                                          Corporation (pneumatics)
                                                          since 1992; Director
                                                          Tippman Sports (recreation)
                                                          since 2005; Director,
                                                          Indotronix International (IT
                                                          services) from 2004 to 2008.

22

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
       NAME                 HELD WITH          TIME            PRINCIPAL OCCUPATION(S)    ("PORTFOLIOS")      PUBLIC
      AND AGE               THE TRUST       SERVED(2)          DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- -------------------
INTERESTED TRUSTEES/1/,/9/
Richard S. Davis          Trustee       2009 to present   Managing Director,             169 RICs         None
(64)                                                      BlackRock, Inc. since 2005;    consisting of
                                                          Chief Executive Officer, State 298 Portfolios
                                                          Street Research &
                                                          Management Company from
                                                          2000 to 2005; Chairman of
                                                          the Board of Trustees, State
                                                          Street Research Mutual
                                                          Funds from 2000 to 2005;
                                                          Chairman, SSR Realty from
                                                          2000 to 2004.

Henry Gabbay              Trustee       2009 to present   Consultant, BlackRock, Inc.    169 RICs         None
(62)                                                      from 2007 to 2008;             consisting of
                                                          Managing Director,             298 Portfolios
                                                          BlackRock, Inc. from 1989 to
                                                          2007; Chief Administrative
                                                          Officer, BlackRock Advisors,
                                                          LLC from 1998 to 2007;
                                                          President of BlackRock
                                                          Funds and BlackRock Bond
                                                          Allocation Target Shares
                                                          from 2005 to 2007 and
                                                          Treasurer of certain closed-
                                                          end funds in the BlackRock
                                                          fund complex from 1989 to
                                                          2006.


/1/ Trustees serve until their resignation, removal or death, or until December 31 of the year in which they turn 72. The Board of Trustees has approved one-year extensions in the terms of Trustees who turn 72 prior to December 31, 2013.
/2/ In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, the Trustees were elected to the Trust's Board. As a result, although the chart shows the Trustees as joining the Trust's Board in 2009, each Trustee first became a member of the boards of other funds advised by BlackRock Advisors, LLC or its affiliates as follows: David O. Beim, 1998; Ronald W. Forbes, 1977; Dr. Matina Horner, 2004; Rodney D. Johnson, 1995; Herbert I. London, 1987; Cynthia A. Montgomery, 1994; Joseph P. Platt, Jr., 1999; Robert C. Robb, Jr., 1999; Toby Rosenblatt, 2005; Kenneth L. Urish, 1999; and Frederick W. Winter, 1999.
/3/ Chair of the Performance Oversight Committee. /4/ Co-Chair of the Board of Trustees. /5/ Chair of the Governance Committee. /6/ Chair of the Compliance Committee.
/7/ Vice Chair of the Performance Oversight Committee. /8/ Chair of the Audit Committee.
/9/ Mr. Davis is an "interested person," as defined in the 1940 Act, of the Trust based on his position with BlackRock, Inc. and its affiliates. Mr. Gabbay is an "interested person" of the Trust based on his former positions with BlackRock, Inc. and its affiliates as well as his ownership of BlackRock, Inc. and The PNC Financial Services Group, Inc. securities.

23

Certain biographical and other information relating to the officers of the Trust is set forth below, including their year of birth, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                   NUMBER OF
                                                                                                  BLACKROCK-
                                                                                                    ADVISED
                                                                                                  REGISTERED
                                                                                                  INVESTMENT
                                                                                                   COMPANIES
                                                                                                    ("RICS"
                                                                                                 CONSISTING OF
                                                                                                  INVESTMENT
                                                                                                  PORTFOLIOS
         NAME               POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
   AND YEAR OF BIRTH         WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
-------------------------  ------------------ ----------------- ------------------------------ ---------------- --------------
Trust Officers/1/
----------------------

Anne F. Ackerley           President and      2009 to present   Managing Director of           169 RICs         None
1962                       Chief Executive                      BlackRock, Inc. since 2000;    consisting of
                           Officer                              Vice President of the          298 Portfolios
                                                                BlackRock-advised Funds
                                                                from 2007 to 2009; Chief
                                                                Operating Officer of
                                                                BlackRock's Global Client
                                                                Group (GCG) since 2009;
                                                                Chief Operating Officer of
                                                                BlackRock's U.S. Retail Group
                                                                from 2006 to 2009; Head of
                                                                BlackRock's Mutual Fund
                                                                Group from 2000 to 2006.

Richard Hoerner, CFA       Vice President     2009 to present   Managing Director of           24 RICs          None
1958                                                            BlackRock, Inc. since 2000;    consisting of
                                                                Co-head of BlackRock's Cash    73 Portfolios
                                                                Management Portfolio
                                                                Management Group since
                                                                2002; Member of the Cash
                                                                Management Group
                                                                Executive Committee since
                                                                2005.

Jeffrey Holland, CFA       Vice President     2009 to present   Managing Director of           70 RICs          None
1971                                                            BlackRock, Inc. since 2010;    consisting of
                                                                Director of BlackRock, Inc.    201 Portfolios
                                                                from 2006 to 2009; Chief
                                                                Operating Officer of
                                                                BlackRock's U.S. Retail Group
                                                                since 2009; Co-head of
                                                                Product Development and
                                                                Management for BlackRock's
                                                                U.S. Retail Group from 2007
                                                                to 2009; Product Manager of
                                                                Raymond James &
                                                                Associates from 2003 to
                                                                2006.

24

                                                                                                   NUMBER OF
                                                                                                  BLACKROCK-
                                                                                                    ADVISED
                                                                                                  REGISTERED
                                                                                                  INVESTMENT
                                                                                                   COMPANIES
                                                                                                    ("RICS"
                                                                                                 CONSISTING OF
                                                                                                  INVESTMENT
                                                                                                  PORTFOLIOS
        NAME               POSITION(S) HELD       LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
 AND YEAR OF BIRTH          WITH THE TRUST       TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------- ----------------- ------------------------------ ---------------- --------------
Brendan Kyne              Vice President      2009 to present   Managing Director of           169 RICs         None
1977                                                            BlackRock, Inc. since 2010;    consisting of
                                                                Director of BlackRock, Inc.    298 Portfolios
                                                                from 2008 to 2009; Head of
                                                                Product Development and
                                                                Management for BlackRock's
                                                                U.S. Retail Group since 2009,
                                                                co-head thereof from 2007
                                                                to 2009; Vice President of
                                                                BlackRock, Inc. from 2005 to
                                                                2008.

Simon Mendelson           Vice President      2009 to present   Managing Director of           24 RICs          None
1964                                                            BlackRock, Inc. since 2005;    consisting of
                                                                Chief Operating Officer and    73 Portfolios
                                                                head of the Global Client
                                                                Group for BlackRock's Global
                                                                Cash Management Business
                                                                since 2007; Head of
                                                                BlackRock's Strategy and
                                                                Development Group from
                                                                2005 to 2007.

Brian Schmidt             Vice President      2009 to present   Managing Director of           70 RICs          None
1958                                                            BlackRock, Inc. since 2004;    consisting of
                                                                Various positions with U.S.    201 Portfolios
                                                                Trust Company from 1991 to
                                                                2003: Director from 2001 to
                                                                2003, Senior Vice President
                                                                from 1998 to 2003; Vice
                                                                President, Chief Financial
                                                                Officer and Treasurer of
                                                                Excelsior Funds, Inc.,
                                                                Excelsior Tax-Exempt Funds,
                                                                Inc. and Excelsior Funds
                                                                Trust from 2001 to 2003.

25

                                                                                                   NUMBER OF
                                                                                                  BLACKROCK-
                                                                                                    ADVISED
                                                                                                  REGISTERED
                                                                                                  INVESTMENT
                                                                                                   COMPANIES
                                                                                                    ("RICS"
                                                                                                 CONSISTING OF
                                                                                                  INVESTMENT
                                                                                                  PORTFOLIOS
          NAME             POSITION(S) HELD       LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST       TIME SERVED         DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ------------------- ----------------- ------------------------------ ---------------- --------------
Christopher Stavrakos,    Vice President      2009 to present   Managing Director of           24 RICs          None
CFA                                                             BlackRock, Inc. since 2006;    consisting of
1959                                                            Co-head of BlackRock's Cash    73 Portfolios
                                                                Management Portfolio
                                                                Management Group since
                                                                2006; Senior Vice President,
                                                                CIO, and Director of Liability
                                                                Management for the
                                                                Securities Lending Group at
                                                                Mellon Bank from 1999 to
                                                                2006.

Neal J. Andrews           Chief Financial     2009 to present   Managing Director of           169 RICs         None
1966                      Officer and                           BlackRock, Inc. since 2006;    consisting of
                          Assistant                             Senior Vice President and      298 Portfolios
                          Treasurer                             Line of Business Head of
                                                                Fund Accounting and
                                                                Administration at PNC
                                                                Global Investment Servicing
                                                                (U.S.) Inc. from 1992 to
                                                                2006.

Jay M. Fife               Treasurer           2009 to present   Managing Director of           169 RICs         None
1970                                                            BlackRock, Inc. since 2007     consisting of
                                                                and Director in 2006;          298 Portfolios
                                                                Assistant Treasurer of the
                                                                Merrill Lynch Investment
                                                                Managers, L.P. ("MLIM") and
                                                                Fund Asset Management,
                                                                L.P. advised funds from 2005
                                                                to 2006; Director of MLIM
                                                                Fund Services Group from
                                                                2001 to 2006.

Brian P. Kindelan         Chief               2009 to present   Chief Compliance Officer of    169 RICs         None
1959                      Compliance                            the BlackRock-advised funds    consisting of
                          Officer and                           since 2007; Managing           298 Portfolios
                          Anti-Money                            Director and Senior Counsel
                          Laundering                            of BlackRock, Inc. since
                          Compliance                            2005.
                          Officer

26

                                                                                                   NUMBER OF
                                                                                                  BLACKROCK-
                                                                                                    ADVISED
                                                                                                  REGISTERED
                                                                                                  INVESTMENT
                                                                                                   COMPANIES
                                                                                                    ("RICS"
                                                                                                 CONSISTING OF
                                                                                                  INVESTMENT
                                                                                                  PORTFOLIOS
        NAME               POSITION(S) HELD       LENGTH OF        PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")      PUBLIC
 AND YEAR OF BIRTH          WITH THE TRUST       TIME SERVED       DURING PAST FIVE YEARS          OVERSEEN      DIRECTORSHIPS
------------------------- ------------------- ----------------- ------------------------------ ---------------- --------------
Howard B. Surloff         Secretary           2009 to present   Managing Director and          169 RICs         None

1965                                                            General Counsel of U.S.        consisting of
                                                                Funds at BlackRock, Inc.       298 Portfolios
                                                                since 2006; General Counsel
                                                                (U.S.) of Goldman Sachs
                                                                Asset Management, L.P.
                                                                from 1993 to 2006.


/1/ Officers of the Trust serve at the pleasure of the Board of Trustees.

SHARE OWNERSHIP INFORMATION. Information relating to each Trustee's share ownership in the Funds and in all BlackRock-advised Funds that are overseen by the respective Trustee ("Supervised Funds") as of December 31, 2009 is set forth in the chart below:

                               DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------
Interested Trustee      BlackRock Bond Index Fund    BlackRock S&P 500    Aggregate Dollar
                                                     Stock Fund           Range of Securities
                                                                          in the Supervised
                                                                          Funds

Richard S. Davis        None                         None                 over $100,000

Henry Gabbay            None                         None                 over $100,000

                               DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------
Independent             BlackRock Bond Index Fund    BlackRock S&P 500    Aggregate Dollar
Trustees                                             Stock Fund           Range of Securities
                                                                          in the Supervised
                                                                          Funds

David O. Beim           None                         None                 0

Ronald W. Forbes        None                         None                 over $100,000

Dr. Matina S. Horner    None                         None                 over $100,000

Rodney D. Johnson       None                         None                 over $100,000

Herbert I. London       None                         None                 $50,001
                                                                          - $100,000

Cynthia A.              None                         None                 over $100,000
Montgomery

Joseph P. Platt, Jr.    None                         None                 over $100,000

Robert C. Robb, Jr.     None                         None                 over $100,000

Toby Rosenblatt         None                         None                 over $100,000

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                               DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------
Kenneth L. Urish        None                         None                 $50,001
                                                                          - $100,000

Frederick W. Winter     None                         None                 over $100,000

OWNERSHIP OF SECURITIES OF CERTAIN ENTITIES. As of March 31, 2010, the Trustees and officers of the Trust as a group owned an aggregate of less than 1% of the outstanding shares of any Fund. As of March 31, 2010, none of the Independent Trustees or their immediate family members owned beneficially or of record any securities of affiliates of the Investment Adviser.

COMPENSATION OF TRUSTEES. Each current Trustee who is an Independent Trustee is paid as compensation an annual retainer of $250,000 per year for his or her services as a Board member to the BlackRock-advised Funds in the Equity-Liquidity Complex, including the Trust and MIP, and a $5,000 Board meeting fee to be paid for each in-person Board meeting attended (a $2,500 Board meeting fee for telephonic attendance at regular Board meetings), for up to five Board meetings held in a calendar year (compensation for meetings in excess of this number to be determined on a case by case basis), together with out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. The Co-Chairs of the Boards of Trustees are each paid an additional annual retainer of $45,000. The Chairs of the Audit Committees, Compliance Committees, Governance Committees and Performance Oversight Committees and the Vice-Chair of the Performance Oversight Committees are each paid an additional annual retainer of $25,000. The Chair of the Product Pricing Committee, who oversees funds in the Equity-Bond Complex, is paid an annual retainer of $25,000 that is allocated among all of the non-money market funds in the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes.

Mr. Gabbay is an interested Trustee of the Trust and serves as an interested board member of the other funds which comprise the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes. Mr. Gabbay receives as compensation for his services as a board member of each of these three BlackRock Fund Complexes, (i) an annual retainer of $487,500, paid quarterly in arrears, allocated to the BlackRock-advised Funds in these three BlackRock Fund Complexes, including the Trust and MIP, and (ii) with respect to each of the two open-end BlackRock Fund Complexes, a board meeting fee of $3,750 (with respect to meetings of the Equity-Liquidity Complex) and $18,750 (with respect to meetings of the Equity-Bond Complex) to be paid for attendance at each board meeting up to five board meetings held in a calendar year by each such Complex (compensation for meetings in excess of this number to be determined on a case by case basis). Mr. Gabbay will also be reimbursed for out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. Mr. Gabbay's compensation for serving on the boards of funds in these three BlackRock Fund Complexes (including the Trust and MIP) is equal to 75% of each retainer and, as applicable, of each meeting fee (without regard to additional fees paid to Board and Committee chairs) received by the independent board members serving on such boards. The Board or any other BlackRock-advised Fund may modify the board members' compensation from time to time depending on market conditions and Mr. Gabbay's compensation would be impacted by those modifications.

Each of the Independent Trustees and Mr. Gabbay agreed to a 10% reduction in their compensation described above for the period December 1, 2009 through December 31, 2009.

From January 1, 2009 through November 30, 2009, the Trust paid each Independent Trustee then in office the Trust's allocable share of the following Independent Trustee fees and expenses: (i) an annual base fee of $60,000; (ii) a per meeting fee of $6,000 for meetings of the Board attended by the Trustee; (iii) a committee meeting fee of $2,500 for each Audit Committee meeting attended by the Trustee; and (iv) a committee meeting fee of $2,000 for each Nominating and Governance Committee meeting attended by the Trustee. The Chairperson of the Audit Committee was paid the Trust's allocable share of an annual fee of $10,000 and the Chairperson of the Nominating and Governance Committee was paid the Trust's allocable share of an annual fee of $5,000. The Lead Independent Trustee was paid the Trust's allocable share of an additional annual base fee of $17,500. These Independent Trustee fees and expenses were allocated between the Trust and MIP, based on their respective assets under management.

The Trust reimburses each Trustee for travel and other out-of-pocket expenses incurred by him/her in connection with attending Board and committee meetings. Currently, the Trustees do not receive any retirement benefits or deferred compensation from the fund complex, as defined in Form N-1A under the 1940 Act.

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As of December 1, 2009, the members of the Board of Trustees of the Trust listed below resigned (each, a "Previous Trustee"). The table below indicates the amount of compensation each Previous Trustee was paid as of December 31, 2009. Compensation is not shown for the New Trustees because they did not serve as Trustees of the Trust until December 1, 2009, and the New Trustees did not receive compensation from the Trust in 2009.

COMPENSATION
FOR THE FISCAL YEAR ENDED DECEMBER 31, 2009

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INTERESTED TRUSTEE          FROM THE TRUST        FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Lee T. Kranefuss                           $0                       $0
H. Michael Williams                        $0                       $0

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INDEPENDENT TRUSTEES        FROM THE TRUST        FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Mary G. F. Bitterman/2/         $78,394                          $157,000
A. John Gambs/3/                $72,310                          $157,500
Hayne E. Leland                 $60,640                          $132,000
Jeffrey M. Lyons                $67,078                          $146,000
Wendy Paskin-Jordan             $64,552                          $140,500
Leo Soong/4/                    $72,584                          $158,000


/1/ Includes compensation for serving on the Board of Trustees of MIP. /2/ Previously the Nominating and Governance Committee Chair. /3/ Previously the Audit Committee Chair. /4/ Previously the Lead Independent Trustee.

MASTER/FEEDER STRUCTURE. Each Fund seeks to achieve its investment objective by investing all of its assets in the corresponding Master Portfolio of MIP. In other words, the Funds are "Feeder Funds" into the Master Portfolios. The Trust's Board of Trustees believes that neither a Fund nor its shareholders will be adversely affected by investing its assets in a Master Portfolio. However, if another feeder fund or other investor withdraws its investment from such Master Portfolio, the economic efficiencies (E.G., spreading fixed expenses among a larger asset base) that the Trust's Board of Trustees believes may be available through investment in the Master Portfolio may not be fully achieved. In addition, although it is unlikely, the master/feeder structure may give rise to accounting or operational difficulties.

A Fund may withdraw its investment in the corresponding Master Portfolio only if the Trust's Board of Trustees determines that such action is in the best interests of such Fund and its shareholders. Prior to any such withdrawal, the Board of Trustees would consider alternative investments, including investing all of the Fund's assets in another investment company with substantially the same investment objective as the Fund or hiring an investment adviser to manage the Fund's assets in accordance with the investment policies described above with respect to the Fund and its Master Portfolios.

The fundamental policies of a Master Portfolio cannot be changed without approval by the holders of a majority (as defined in the 1940 Act) of the Master Portfolio's outstanding interests. Whenever a Fund, as an interestholder of a Master Portfolio, is requested to vote on any matter submitted to interestholders of the Master Portfolio, the Fund either will hold a meeting of its shareholders to consider such matters and cast its votes in proportion to the votes received from its shareholders (shares for which the Fund receives no voting instructions will be voted in the same proportion as the votes received from the other Fund shareholders) or cast its votes, as an interestholder of the Master Portfolio, in proportion to the votes received by the Master Portfolios from all other interestholders of the Master Portfolio.

Certain policies of the Master Portfolios that are non-fundamental may be changed by the vote of a majority of MIP's Trustees without interestholder approval. If a Master Portfolio's investment objective or fundamental or non-fundamental policies are changed, the corresponding Fund may elect to change its investment objective or policies to correspond to those of the Master Portfolio.

A Fund also may elect to redeem its interests from its Master Portfolio and either seek a new investment company with a matching investment objective in which to invest or retain its own investment adviser to manage its portfolio in accordance

29

with its investment objective. In the latter case, a Fund's inability to find a substitute investment company in which to invest or equivalent management services could adversely affect shareholders' investments in the Fund. Each Fund will provide its shareholders with written notice 30 days prior to the implementation of any change in the investment objective of the Fund or the corresponding Master Portfolio, to the extent possible.

CODES OF ETHICS. The Trust, BFA and BRIL have adopted Codes of Ethics pursuant to Rule 17j-1 under the 1940 Act. The Codes of Ethics permit personnel subject to the Codes of Ethics to invest in securities, subject to certain limitations, including securities that may be purchased or held by the Funds. The Codes of Ethics are on public file with, and are available from, the SEC.

PROXY VOTING POLICIES OF THE MASTER PORTFOLIOS. The Board of Trustees of MIP has delegated the voting of proxies for each Master Portfolio's securities to BFA pursuant to MIP's proxy voting guidelines. Under these guidelines, BFA will vote proxies related to the securities held by each Master Portfolio in the best interests of the Master Portfolio and its stockholders. From time to time, a vote may present a conflict between the interests of the Master Portfolio's stockholders, on the one hand, and those of BFA, or any affiliated person of MIP or BFA, on the other. In such event, provided that Blackrock's Equity Investment Policy Oversight Committee, or a sub-committee thereof (the "Committee") is aware of the real or potential conflict or material non-routine matter and if the Committee does not reasonably believe it is able to follow its general voting guidelines (or if the particular proxy matter is not addressed in the guidelines) and vote impartially, the Committee may retain an independent fiduciary to advise the Committee on how to vote or to cast votes on behalf of BFA's clients. If BFA determines not to retain an independent fiduciary, or does not desire to follow the advice of such independent fiduciary, the Committee shall determine how to vote the proxy after consulting with BlackRock's Portfolio Management Group and/or BlackRock's Legal and Compliance Department and concluding that the vote cast is in its client's best interest notwithstanding the conflict. A copy of MIP's Proxy Voting Policies is attached as Appendix B.

Information on how a Master Portfolio voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available without charge, (i) at www.blackrock.com and (ii) on the SEC's website at http://www.sec.gov.

30

SHAREHOLDER COMMUNICATION TO THE BOARD OF TRUSTEES. The Board of Trustees has established a process for shareholders to communicate with the Board of Trustees. Shareholders may contact the Board of Trustees by mail. Correspondence should be addressed to BlackRock Funds III Board of Trustees, c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055. Shareholder communication to the Board of Trustees should include the following information: (a) the name and address of the shareholder; (b) the number of shares owned by the shareholder; (c) the Fund(s) of which the shareholder owns shares; and (d) if these shares are owned indirectly through a broker, financial intermediary or other record owner, the name of the broker, financial intermediary or other record owner. All correspondence received as set forth above shall be reviewed by the Secretary of the Trust and reported to the Board of Trustees.

Control Persons and Principal Holders of Securities

As of March 31, 2010, the shareholders identified below were known by the Trust to own 5% or more of the indicated Fund's outstanding shares in the following capacity:

                                                                                PERCENTAGE    NATURE OF
         NAME OF FUND                  NAME AND ADDRESS OF SHAREHOLDER            OF FUND     OWNERSHIP
------------------------------  ---------------------------------------------  ------------  ----------
BlackRock Bond Index Fund       Bank of America                                      5%        Record
                                411 Akard Street, 5th Floor
                                Dallas, Texas 75201
                                Merrill Lynch, Pierce, Fenner & Smith                8%        Record
                                4800 Deer Lake Drive East 3rd Floor
                                Jacksonville, FL 32246
                                SEI Private Trust Company                           22%        Record
                                One Freedom Valley Drive
                                Oaks, PA 19456
                                Charles Schwab & Co., Inc.                          41%        Record
                                101 Montgomery Street
                                San Francisco, CA 94104
BlackRock S&P 500 Stock Fund    PIMS/Prudential Retirement                           5%        Record
                                40650 Encyclopedia Circle
                                Fremont, CA 94538
                                Oklahoma Public Employees Retirement System          6%        Record
                                8515 East Orchard Road # 2T2
                                Greenwood Village, CO 80111
                                The New England Life Insurance Co.                   6%        Record
                                8515 East Orchard Road # 2T2
                                Greenwood Village, CO 80111
                                Evercore Trust Company, NA                           9%        Record
                                601 S Figueroa Street, 44th Floor
                                Los Angeles, CA 90017
                                Crown Equipment Corporation                         10%        Record
                                P.O. Box 419784
                                Kansas City, MO 64141
                                Merrill Lynch, Pierce, Fenner & Smith               14%        Record
                                4800 Deer Lake Drive East 3rd Floor
                                Jacksonville, FL 32246

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                                                                                PERCENTAGE    NATURE OF
 NAME OF FUND                    NAME AND ADDRESS OF SHAREHOLDER                 OF FUND      OWNERSHIP
------------------------------  ---------------------------------------------  ------------  -----------
                                Northern Trust Company                             14%          Record
                                P.O. Box 92956
                                Chicago, IL 60675

For purposes of the 1940 Act, any person who owns directly or through one or more controlled companies more than 25% of the voting securities of a company is presumed to "control" such company. Accordingly, to the extent that a shareholder identified in the foregoing table is identified as the beneficial holder of more than 25% of a Fund, or is identified as the holder of record of more than 25% of a Fund and has voting and/or investment powers, it may be presumed to control such Fund.

As of March 31, 2010, Trustees and officers of the Trust, as a group, beneficially owned less than 1% of the outstanding shares of the Trust.

POTENTIAL CONFLICTS OF INTEREST. The Bank of America Corporation ("BAC"), through its subsidiary Merrill Lynch & Co., Inc. ("Merrill Lynch"), Barclays PLC ("Barclays"), and The PNC Financial Services Group, Inc. ("PNC"), each have a significant economic interest in BlackRock, Inc., the parent of BFA, the Trust's investment adviser. PNC is considered to be an affiliate of BlackRock, Inc., under the 1940 Act. Certain activities of BFA, BlackRock Advisors, LLC, BlackRock, Inc. and their affiliates (collectively, "BlackRock") and PNC and its affiliates (collectively, "PNC" and together with BlackRock, "Affiliates"), and those of BAC, Merrill Lynch and their affiliates (collectively, the "BAC Entities") and Barclays and its affiliates (collectively, the "Barclays Entities") (BAC Entities and Barclays Entities, collectively, the "BAC/Barclays Entities"), with respect to the Funds and/or other accounts managed by BlackRock, PNC or BAC/Barclays Entities, may give rise to actual or perceived conflicts of interest such as those described below.

BlackRock is one of the world's largest asset management firms. BAC is a national banking corporation which through its affiliates and subsidiaries, including Merrill Lynch, provides a full range of financial services. Merrill Lynch is a full service investment banking, broker-dealer, asset management and financial services organization. PNC is a diversified financial services organization spanning the retail, business and corporate markets. Barclays is a major global financial services provider engaged in a range of activities including retail and commercial banking, credit cards, investment banking, and wealth management. BlackRock, BAC, Merrill Lynch, PNC, Barclays and their respective affiliates (including, for these purposes, their directors, partners, trustees, managing members, officers and employees), including the entities and personnel who may be involved in the investment activities and business operations of a Fund, are engaged worldwide in businesses, including equity, fixed income, cash management and alternative investments, and have interests other than those of managing the Funds. These are considerations of which investors in a Fund should be aware, and which may cause conflicts of interest that could disadvantage the Fund and its shareholders. These activities and interests include potential multiple advisory, transactional, financial and other interests in securities and other instruments, and companies that may be purchased or sold by a Fund.

BlackRock and its Affiliates, as well as the BAC/Barclays Entities, have proprietary interests in, and may manage or advise with respect to, accounts or funds (including separate accounts and other funds and collective investment vehicles) that have investment objectives similar to those of a Fund and/or that engage in transactions in the same types of securities, currencies and instruments as the Fund. One or more Affiliates and BAC/Barclays Entities are also major participants in the global currency, equities, swap and fixed income markets, in each case both on a proprietary basis and for the accounts of customers. As such, one or more Affiliates or BAC/Barclays Entities are or may be actively engaged in transactions in the same securities, currencies, and instruments in which a Fund invests. Such activities could affect the prices and availability of the securities, currencies, and instruments in which a Fund invests, which could have an adverse impact on the Fund's performance. Such transactions, particularly in respect of most proprietary accounts or customer accounts, will be executed independently of a Fund's transactions and thus at prices or rates that may be more or less favorable than those obtained by the Fund. When BlackRock and its Affiliates or the BAC/Barclays Entities seek to purchase or sell the same assets for their managed accounts, including a Fund, the assets actually purchased or sold may be allocated among the accounts on a basis determined in their good faith discretion to be equitable. In some cases, this system may adversely affect the size or price of the assets purchased or sold for a Fund. In addition, transactions in investments by one or more other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of a Fund, particularly, but not limited to, with respect to small capitalization, emerging market or less liquid strategies. This may occur when investment decisions regarding a Fund are based on research or other information that is also used to support decisions for other accounts. When BlackRock or its Affiliates or a BAC/Barclays

32

Entity implements a portfolio decision or strategy on behalf of another account ahead of, or contemporaneously with, similar decisions or strategies for a Fund, market impact, liquidity constraints, or other factors could result in the Fund receiving less favorable trading results and the costs of implementing such decisions or strategies could be increased or the Fund could otherwise be disadvantaged. BlackRock or it Affiliates or a BAC/Barclays Entity may, in certain cases, elect to implement internal policies and procedures designed to limit such consequences, which may cause a Fund to be unable to engage in certain activities, including purchasing or disposing of securities, when it might otherwise be desirable for it to do so.

Conflicts may also arise because portfolio decisions regarding a Fund may benefit other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity. For example, the sale of a long position or establishment of a short position by a Fund may impair the price of the same security sold short by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts, and the purchase of a security or covering of a short position in a security by a Fund may increase the price of the same security held by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts.

BlackRock and its Affiliates or a BAC/Barclays Entity and their clients may pursue or enforce rights with respect to an issuer in which a Fund has invested, and those activities may have an adverse effect on the Fund. As a result, prices, availability, liquidity and terms of the Fund's investments may be negatively impacted by the activities of BlackRock or its Affiliates or a BAC/Barclays Entity or their clients, and transactions for the Fund may be impaired or effected at prices or terms that may be less favorable than would otherwise have been the case.

The results of a Fund's investment activities may differ significantly from the results achieved by BlackRock and its Affiliates or the BAC/Barclays Entities for their proprietary accounts or other accounts (including investment companies or collective investment vehicles) managed or advised by them. It is possible that one or more Affiliate- or BAC/Barclays Entity-managed accounts and such other accounts will achieve investment results that are substantially more or less favorable than the results achieved by a Fund. Moreover, it is possible that a Fund will sustain losses during periods in which one or more Affiliates or BAC/Barclays Entity-managed accounts achieve significant profits on their trading for proprietary or other accounts. The opposite result is also possible. The investment activities of one or more Affiliates or BAC/Barclays Entities for their proprietary accounts and accounts under their management may also limit the investment opportunities for a Fund in certain emerging and other markets in which limitations are imposed upon the amount of investment, in the aggregate or in individual issuers, by affiliated foreign investors.

From time to time, a Fund's activities may also be restricted because of regulatory restrictions applicable to one or more Affiliates or BAC/Barclays Entities, and/or their internal policies designed to comply with such restrictions. As a result, there may be periods, for example, when BlackRock, and/or one or more Affiliates or BAC/Barclays Entities, will not initiate or recommend certain types of transactions in certain securities or instruments with respect to which BlackRock and/or one or more Affiliates or BAC/Barclays Entities are performing services or when position limits have been reached.

In connection with its management of a Fund, BlackRock may have access to certain fundamental analysis and proprietary technical models developed by one or more Affiliates or BAC/Barclays Entities. BlackRock will not be under any obligation, however, to effect transactions on behalf of a Fund in accordance with such analysis and models. In addition, neither BlackRock nor any of its Affiliates, nor any BAC/Barclays Entity, will have any obligation to make available any information regarding their proprietary activities or strategies, or the activities or strategies used for other accounts managed by them, for the benefit of the management of a Fund and it is not anticipated that BlackRock will have access to such information for the purpose of managing the Fund. The proprietary activities or portfolio strategies of BlackRock and its Affiliates and the BAC/Barclays Entities, or the activities or strategies used for accounts managed by them or other customer accounts could conflict with the transactions and strategies employed by BlackRock in managing a Fund.

In addition, certain principals and certain employees of BlackRock are also principals or employees of BlackRock or another Affiliate. As a result, the performance by these principals and employees of their obligations to such other entities may be a consideration of which investors in a Fund should be aware.

BlackRock may enter into transactions and invest in securities, instruments and currencies on behalf of a Fund in which customers of BlackRock or its Affiliates or a BAC/Barclays Entity, or, to the extent permitted by the SEC, BlackRock or another Affiliate or a BAC/Barclays Entity, serves as the counterparty, principal or issuer. In such cases, such party's interests in the transaction will be adverse to the interests of the Fund, and such party may have no incentive to assure that the Fund obtains the best possible prices or terms in connection with the transactions. In addition, the purchase, holding and sale of such investments by a Fund may enhance the profitability of BlackRock or its Affiliates or a BAC/Barclays Entity. One or more

33

Affiliates or BAC/Barclays Entities may also create, write or issue derivatives for their customers, the underlying securities, currencies or instruments of which may be those in which a Fund invests or which may be based on the performance of the
Fund. A Fund may, subject to applicable law, purchase investments that are the subject of an underwriting or other distribution by one or more Affiliates or BAC/Barclays Entities and may also enter into transactions with other clients of an Affiliate or BAC/Barclays Entity where such other clients have interests adverse to those of the Fund.

At times, these activities may cause departments of BlackRock or its Affiliates or a BAC/Barclays Entity to give advice to clients that may cause these clients to take actions adverse to the interests of the Fund. To the extent affiliated transactions are permitted, a Fund will deal with BlackRock and its Affiliates or BAC/Barclays Entities on an arms-length basis. BlackRock or its Affiliates or a BAC/Barclays Entity may also have an ownership interest in certain trading or information systems used
by a Fund. A Fund's use of such trading or information systems may enhance the profitability of BlackRock and its Affiliates or BAC/Barclays Entities.

One or more Affiliates or one of the BAC/Barclays Entities may act as broker, dealer, agent, lender or adviser or in other commercial capacities for a Fund. It is anticipated that the commissions, mark-ups, mark-downs, financial advisory fees, underwriting and placement fees, sales fees, financing and commitment fees, brokerage fees, other fees, compensation or profits, rates, terms and conditions charged by an Affiliate or BAC/Barclays Entity will be in its view commercially reasonable, although each Affiliate or BAC/Barclays Entity, including its sales personnel, will have an interest in obtaining fees and other amounts that are favorable to the Affiliate or BAC/Barclays Entity and such sales personnel.

Subject to applicable law, the Affiliates and BAC/Barclays Entities (and their personnel and other distributors) will be entitled to retain fees and other amounts that they receive in connection with their service to the Funds as broker, dealer, agent, lender, adviser or in other commercial capacities and no accounting to the Funds or their shareholders will be required, and no fees or other compensation payable by the Funds or their shareholders will be reduced by reason of receipt by an Affiliate or BAC/Barclays Entity of any such fees or other amounts.

When an Affiliate or BAC/Barclays Entity acts as broker, dealer, agent, adviser or in other commercial capacities in relation to the Funds, the Affiliate or BAC/Barclays Entity may take commercial steps in its own interests, which may have an adverse
effect on the Funds. A Fund will be required to establish business relationships with its counterparties based on the Fund's own credit standing. Neither BlackRock nor any of the Affiliates, nor any BAC/Barclays Entity, will have any obligation to allow their credit to be used in connection with a Fund's establishment of its business relationships, nor is it expected that the Fund's counterparties will rely on the credit of BlackRock or any of the Affiliates or BAC/Barclays Entities in evaluating the Fund's creditworthiness.

Purchases and sales of securities for a Fund may be bunched or aggregated with orders for other BlackRock client accounts. BlackRock and its Affiliates and the BAC/Barclays Entities, however, are not required to bunch or aggregate orders if portfolio management decisions for different accounts are made separately, or if they determine that bunching or aggregating is not practicable, required or with cases involving client direction.

Prevailing trading activity frequently may make impossible the receipt of the same price or execution on the entire volume of securities purchased or sold. When this occurs, the various prices may be averaged, and the Funds will be charged or credited with the average price. Thus, the effect of the aggregation may operate on some occasions to the disadvantage of the Funds. In addition, under certain circumstances, the Funds will not be charged the same commission or commission equivalent rates in connection with a bunched or aggregated order.

BlackRock may select brokers (including, without limitation, Affiliates or BAC/Barclays Entities) that furnish BlackRock, the Funds, other BlackRock client accounts or other Affiliates or BAC/Barclays Entities or personnel, directly or through correspondent relationships, with research or other appropriate services which provide, in BlackRock's view, appropriate assistance to BlackRock in the investment decision-making process (including with respect to futures, fixed-price offerings and over-the-counter transactions). Such research or other services may include, to the extent permitted by law, research reports on companies, industries and securities; economic and financial data; financial publications; proxy analysis; trade industry seminars; computer data bases; research-oriented software and other services and products. Research or other services obtained in this manner may be used in servicing any or all of the Funds and other BlackRock client accounts, including in connection with BlackRock client accounts other than those that pay commissions to the broker relating to the research or other service arrangements. Such products and services may disproportionately benefit other BlackRock client accounts relative to the Funds based on the amount of brokerage commissions paid by the Funds and such other BlackRock client accounts. For example, research or other services that are paid for through one client's commissions may not be used

34

in managing that client's account. In addition, other BlackRock client accounts may receive the benefit, including disproportionate benefits, of economies of scale or price discounts in connection with products and services that may be provided to the Funds and to such other BlackRock client accounts. To the extent that BlackRock uses soft dollars, it will not have to pay for those products and services itself.

BlackRock may receive research that is bundled with the trade execution, clearing, and/or settlement services provided by a particular broker-dealer. To the extent that BlackRock receives research on this basis, many of the same conflicts related to traditional soft dollars may exist. For example, the research effectively will be paid by client commissions that also will be used to pay for the execution, clearing, and settlement services provided by the broker-dealer and will not be paid by BlackRock.

BlackRock may endeavor to execute trades through brokers who, pursuant to such arrangements, provide research or other services in order to ensure the continued receipt of research or other services BlackRock believes are useful in its investment decision-making process. BlackRock may from time to time choose not to engage in the above described arrangements to varying degrees. BlackRock may also enter into commission sharing arrangements under which BlackRock may execute transactions through a broker-dealer, including, where permitted, an Affiliate or BAC/Barclays Entity, and request that the broker-dealer allocate a portion of the commissions or commission credits to another firm that provides research to BlackRock. To the extent that BlackRock engages in commission sharing arrangements, many of the same conflicts related to traditional soft dollars may exist.

BlackRock may utilize certain electronic crossing networks ("ECNs") in executing client securities transactions for certain types of securities. These ECNs may charge fees for their services, including access fees and transaction fees. The transaction fees, which are similar to commissions or markups/markdowns, will generally be charged to clients and, like commissions and markups/markdowns, would generally be included in the cost of the securities purchased. Access fees may be paid by BlackRock even though incurred in connection with executing transactions on behalf of clients, including the Funds. In certain circumstances, ECNs may offer volume discounts that will reduce the access fees typically paid by BlackRock. This would have the effect of reducing the access fees paid by BlackRock. BlackRock will only utilize ECNs consistent with its obligation to seek to obtain best execution in client transactions.

BlackRock has adopted policies and procedures designed to prevent conflicts of interest from influencing proxy voting decisions that it makes on behalf of advisory clients, including the Funds, and to help ensure that such decisions are made in accordance with BlackRock's fiduciary obligations to its clients. Nevertheless, notwithstanding such proxy voting policies and procedures, actual proxy voting decisions of BlackRock may have the effect of favoring the interests of other clients or businesses of other divisions or units of BlackRock and/or its Affiliates or a BAC/Barclays Entity, provided that BlackRock believes such voting decisions to be in accordance with its fiduciary obligations. For a more detailed discussion of these policies and procedures, see "Proxy Voting Policies of the Master Portfolios."

It is also possible that, from time to time, BlackRock or its Affiliates or a BAC/Barclays Entity may, although they are not required to, purchase and hold shares of a Fund. Increasing a Fund's assets may enhance investment flexibility and diversification and may contribute to economies of scale that tend to reduce the Fund's expense ratio. BlackRock and its Affiliates or BAC/Barclays Entities reserve the right to redeem at any time some or all of the shares of a Fund acquired for their own accounts. A large redemption of shares of a Fund by BlackRock or its Affiliates or by a BAC/Barclays Entity could significantly reduce the asset size of the Fund, which might have an adverse effect on the Fund's investment flexibility, portfolio diversification and expense ratio. BlackRock will consider the effect of redemptions on a Fund and other shareholders in deciding whether to redeem its shares.

It is possible that a Fund may invest in securities of companies with which an Affiliate or a BAC/Barclays Entity has or is trying to develop investment banking relationships as well as securities of entities in which BlackRock or its Affiliates or a BAC/Barclays Entity has significant debt or equity investments or in which an Affiliate or BAC/Barclays Entity makes a market. A Fund also may invest in securities of companies to which an Affiliate or a BAC/Barclays Entity provides or may some day provide research coverage. Such investments could cause conflicts between the interests of a Fund and the interests of other clients of BlackRock or its Affiliates or a BAC/Barclays Entity. In making investment decisions for a Fund, BlackRock is not permitted to obtain or use material non-public information acquired by any division, department or Affiliate of BlackRock or of a BAC/Barclays Entity in the course of these activities. In addition, from time to time, the activities of an

35

Affiliate or a BAC/Barclays Entity may limit a Fund's flexibility in purchases and sales of securities. When an Affiliate is engaged in an underwriting or other distribution of securities of an entity, BlackRock may be prohibited from purchasing or recommending the purchase of certain securities of that entity for a Fund.

BlackRock and its Affiliates and the BAC/Barclays Entities, their personnel and other financial service providers have interests in promoting sales of the Funds. With respect to BlackRock and its Affiliates and BAC/Barclays Entities and their personnel, the remuneration and profitability relating to services to and sales of the Funds or other products may be greater than remuneration and profitability relating to services to and sales of certain funds or other products that might be provided or offered. BlackRock and its Affiliates or BAC/Barclays Entities and their sales personnel may directly or indirectly receive a portion of the fees and commissions charged to the Funds or their shareholders. BlackRock and its advisory or other personnel may also benefit from increased amounts of assets under management. Fees and commissions may also be higher than for other products or services, and the remuneration and profitability to BlackRock or its Affiliates or a BAC/Barclays Entity and such personnel resulting from transactions on behalf of or management of the Funds may be greater than the remuneration and profitability resulting from other funds or products.

BlackRock and its Affiliates or a BAC/Barclays Entity and their personnel may receive greater compensation or greater profit in connection with an account for which BlackRock serves as an adviser than with an account advised by an unaffiliated investment adviser. Differentials in compensation may be related to the fact that BlackRock may pay a portion of its management fee to its Affiliate or to a BAC/Barclays Entity, or relate to compensation arrangements, including for portfolio management, brokerage transactions or account servicing. Any differential in compensation may create a financial incentive on the part of BlackRock or its Affiliates or BAC/Barclays Entities and their personnel to recommend BlackRock over unaffiliated investment advisers or to effect transactions differently in one account over another.

BlackRock and its Affiliates or a BAC/Barclays Entity may provide valuation assistance to certain clients with respect to certain securities or other investments and the valuation recommendations made for their clients' accounts may differ from the valuations for the same securities or investments assigned by a Fund's pricing vendors, especially if such valuations are based on broker-dealer quotes or other data sources unavailable to the Fund's pricing vendors. While BlackRock will generally communicate its valuation information or determinations to a Fund's pricing vendors and/or fund accountants, there may be instances where the Fund's pricing vendors or fund accountants assign a different valuation to a security or other investment than the valuation for such security or investment determined or recommended by BlackRock.

As disclosed in more detail in "Determination of Net Asset Value" in this SAI, when market quotations are not readily available or are believed by BlackRock to be unreliable, a Fund's investments may be valued at fair value by BlackRock, pursuant to procedures adopted by the Trust's Board of Trustees. When determining an asset's "fair value," BlackRock seeks to determine the price that a Fund might reasonably expect to receive from the current sale of that asset in an arm's-length transaction. The price generally may not be determined based on what a Fund might reasonably expect to receive for selling an asset at a later time or if it holds the asset to maturity. While fair value determinations will be based upon all available factors that BlackRock deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models, fair value represents only a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a Fund's net asset value. As a result, a Fund's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued by BlackRock (pursuant to Board-adopted procedures) at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

To the extent permitted by applicable law, a Fund may invest all or some of its short term cash investments in any money market fund or similarly-managed private fund advised or managed by BlackRock. In connection with any such investments, a Fund, to the extent permitted by the 1940 Act, may pay its share of expenses of a money market fund in which it invests, which may result in a Fund bearing some additional expenses.

BlackRock and its Affiliates or a BAC/Barclays Entity and their directors, officers and employees, may buy and sell securities or other investments for their own accounts, and may have conflicts of interest with respect to investments made on behalf of a Fund. As a result of differing trading and investment strategies or constraints, positions may be taken by directors, officers, employees and Affiliates of BlackRock or by BAC/Barclays Entities that are the same, different from or made at different times than positions taken for a Fund. To lessen the possibility that a Fund will be adversely affected by this personal trading, the Trust, BRIL and BFA each have adopted a Code of Ethics in compliance with Section 17(j) of the 1940 Act that restricts

36

securities trading in the personal accounts of investment professionals and others who normally come into possession of information regarding the Fund's portfolio transactions. Each Code of Ethics can be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling the SEC at (202) 551-8090. Each Code of Ethics is also available on the EDGAR Database on the SEC's Internet site at http://www.sec.gov, and copies may be obtained, after paying a duplicating fee, by e-mail at publicinfo@sec.gov or by writing the SEC's Public Reference Section, Washington, DC 20549-1520.

BlackRock and its Affiliates will not purchase securities or other property from, or sell securities or other property to, a Fund, except that the Fund may in accordance with rules adopted under the 1940 Act engage in transactions with accounts that are affiliated with the Fund as a result of common officers, directors, or investment advisers or pursuant to exemptive orders granted to the Funds and/or BlackRock by the SEC. These transactions would be affected in circumstances in which BlackRock determined that it would be appropriate for a Fund to purchase and another client of BlackRock to sell, or a Fund to sell and another client of BlackRock to purchase, the same security or instrument on the same day. From time to time, the activities of a Fund may be restricted because of regulatory requirements applicable to BlackRock or its Affiliates or a BAC/Barclays Entity and/or BlackRock's internal policies designed to comply with, limit the applicability of, or otherwise relate to such requirements. A client not advised by BlackRock would not be subject to some of those considerations. There may be periods when BlackRock may not initiate or recommend certain types of transactions, or may otherwise restrict or limit their advice in certain securities or instruments issued by or related to companies for which an Affiliate or a BAC/Barclays Entity is performing investment banking, market making, advisory or other services or has proprietary positions. For example, when an Affiliate is engaged in an underwriting or other distribution of securities of, or advisory services for, a company, the Funds may be prohibited from or limited in purchasing or selling securities of that company. In addition, when BlackRock is engaged to provide advisory or risk management services for a company, BlackRock may be prohibited from or limited in purchasing or selling securities of that company on behalf of a Fund, particularly where such services result in BlackRock obtaining material non-public information about the company. Similar situations could arise if personnel of BlackRock or its Affiliates or a BAC/Barclays Entity serve as directors of companies the securities of which the Funds wish to purchase or sell. However, if permitted by applicable law, and where consistent with BlackRock's policies and procedures (including the necessary implementation of appropriate information barriers), the Funds may purchase securities or instruments that are issued by such companies, are the subject of an underwriting, distribution, or advisory assignment by an Affiliate or a BAC/Barclays Entity or are the subject of an advisory or risk management assignment by BlackRock, or where personnel of BlackRock or its Affiliates or of BAC/Barclays Entities are directors or officers of the issuer.

In certain circumstances where the Funds invest in securities issued by companies that operate in certain regulated industries, in certain emerging or international markets, or are subject to corporate or regulatory ownership definitions, there may be limits on the aggregate amount invested by Affiliates (including BlackRock) or BAC/Barclays Entities for their proprietary accounts and for client accounts (including the Funds) that may not be exceeded without the grant of a license or other regulatory or corporate consent, or, if exceeded, may cause BlackRock, the Funds or other client accounts to suffer disadvantages or business restrictions. As a result, BlackRock on behalf of its clients (including the Funds) may limit purchases, sell existing investments, or otherwise restrict or limit the exercise of rights (including voting rights) when BlackRock, in its sole discretion, deems it appropriate in light of potential regulatory or other restrictions on ownership or other consequences resulting from reaching investment thresholds.

In those circumstances where ownership thresholds or limitations must be observed, BlackRock seeks to equitably allocate limited investment opportunities among clients (including the Funds), taking into consideration benchmark weight and investment strategy. When ownership in certain securities nears an applicable threshold, BlackRock may limit purchases in such securities to the issuer's weighting in the applicable benchmark used by BlackRock to manage the Fund. If client (including Fund) holdings of an issuer exceed an applicable threshold and BlackRock is unable to obtain relief to enable the continued holding of such investments, it may be necessary to sell down these positions to meet the applicable limitations. In these cases, benchmark overweight positions will be sold prior to benchmark positions being reduced to meet applicable limitations.

In addition to the foregoing, other ownership thresholds may trigger reporting requirements to governmental and regulatory authorities, and such reports may entail the disclosure of the identity of a client or BlackRock's intended strategy with respect to such security or asset.

BlackRock and its Affiliates and BAC/Barclays Entities may maintain securities indexes as part of their product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index

37

providers, including BlackRock and its Affiliates and BAC/Barclays Entities may be paid licensing fees for use of their index or index name. BlackRock and its Affiliates and BAC/Barclays Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with BlackRock and its Affiliates and BAC/Barclays Entities will be as favorable as those terms offered to other index licensees.

BlackRock and its Affiliates and BAC/Barclays Entities may serve as authorized participants in the creation and redemption of ETFs, including funds advised by affiliates of BlackRock. BlackRock and its Affiliates and BAC/Barclays Entities may therefore be deemed to be participants in a distribution of such ETFs, which could render them statutory underwriters.

The custody arrangement described in "Investment Adviser and Other Service Providers" may lead to potential conflicts of interest with BFA where BFA has agreed to waive fees and/or reimburse ordinary operating expenses in order to cap expenses of the Funds. This is because the custody arrangements with the Funds' custodian may have the effect of reducing custody fees when the Funds leave cash balances uninvested. When a Fund's actual operating expense ratio exceeds a stated cap, a reduction in custody fees reduces the amount of waivers and/or reimbursements BFA would be required to make to the Fund. This could be viewed as having the potential to provide BFA an incentive to keep high positive cash balances for Funds with expense caps in order to offset fund custody fees that BFA might otherwise reimburse. However, portfolio managers of BFA do not intentionally keep uninvested balances high, but rather make investment decisions that they anticipate will be beneficial to fund performance.

Present and future activities of BlackRock and its Affiliates and BAC/Barclays Entities, including BlackRock Advisors, LLC, in addition to those described in this section, may give rise to additional conflicts of interest.

Investment Adviser and Other Service Providers

INVESTMENT ADVISER. BFA provides investment advisory services to each Master Portfolio pursuant to an investment advisory contract (each, an "Advisory Contract") with MIP. Pursuant to the Advisory Contracts, BFA furnishes to MIP's Board of Trustees periodic reports on the investment strategy and performance of each Master Portfolio.

BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc.

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The applicable Advisory Contract is subject to annual approval by (i) MIP's Board of Trustees or (ii) vote of a majority (as defined in the 1940 Act) of the outstanding voting interests of such Master Portfolio, provided that in either event the continuance also is approved by a majority of Independent Trustees of MIP, by a vote cast in person at a meeting called for the purpose of voting on such approval. The applicable Advisory Contract is terminable without penalty on 60 days' written notice by either party. The applicable Advisory Contract will terminate automatically, as to the relevant Master Portfolio, in the event of its assignment (as defined in the 1940 Act).

ADVISORY FEES. BFA is entitled to receive monthly fees at the annual rate of 0.05% of the average daily net assets of S&P 500 Stock Master Portfolio and 0.08% of the average daily net assets of Bond Index Master Portfolio. From time to time, BFA may waive such fees in whole or in part. Any such waiver will reduce the expenses of a Master Portfolio and, accordingly, have a favorable impact on its performance.

For the fiscal years shown below, the related Master Portfolio of each Fund paid the following management fee to BFA, net of waivers and/or offsetting credits:

                                 FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                 12/31/2007           12/31/2008          12/31/2009
------------------------------  -------------------  -------------------  ------------------
BlackRock Bond Index Fund             $ 55,816             $ 79,815             $94,206
BlackRock S&P 500 Stock Fund          $134,756             $126,312             $90,063

The fees and expenses of the Independent Trustees of MIP, counsel to the Independent Trustees of MIP and the independent registered public accounting firm that provides audit services in connection with the Master Portfolios (collectively referred to as the "MIP Independent Expenses") are paid directly by the Master Portfolios. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to each Master Portfolio for such MIP Independent Expenses.

For the fiscal years shown below, BFA provided an offsetting credit for MIP Independent Expenses, in the amounts shown, against management fees paid by the Master Portfolios in which the Funds invest:

                                 FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                 12/31/2007           12/31/2008          12/31/2009
------------------------------  -------------------  -------------------  ------------------
BlackRock Bond Index Fund              $32,059              $21,382              $21,135
BlackRock S&P 500 Stock Fund           $ 6,002              $ 5,426              $ 4,424

ADMINISTRATOR. The Trust has engaged BTC to provide certain administration services to the Funds. BTC and its affiliates provide the Funds with administration services, including provision of management reporting and treasury administration services, financial reporting, legal and tax services, and supervision of the Funds' administrative operations, preparation of proxy statements and shareholder reports. BTC and its affiliates also furnish office space and certain facilities to conduct the Funds' business and compensate the Trust's Trustees, officers and employees who are affiliated with BTC. BTC is entitled to receive an annual administration fee of 0.15% of each Fund's average daily net assets for providing administration services.

BTC also may engage and supervise Shareholder Servicing Agents, as defined in "Shareholder Servicing Agents" below, on behalf of the Funds.

BTC has engaged State Street to provide certain sub-administrative services to the Funds. BTC, not the Funds, is responsible for providing compensation to State Street for such services.

BTC has also agreed to bear all costs of the Funds' operations, other than brokerage expenses, management fees, distribution plan expenses, certain fees and expenses related to the Trust's Independent Trustees and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. BTC has contracted with State Street to provide certain sub-administration services for the Funds, and BTC pays State Street for these services.

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For the fiscal years shown below, the Funds paid the following administration fees to BTC, net of waivers and/or offsetting credits:

                                 FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                 12/31/2007           12/31/2008          12/31/2009
------------------------------  -------------------  -------------------  ------------------
BlackRock Bond Index Fund             $146,680             $177,074            $203,528
BlackRock S&P 500 Stock Fund          $401,986             $380,680            $270,219

The fees and expenses of the Independent Trustees of the Trust, counsel to the Independent Trustees of the Trust and the independent registered public accounting firm that provides audit services in connection with the Funds (collectively referred to as the "Independent Expenses") are paid directly by the Funds. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to the Funds for such Independent Expenses.

For the fiscal years shown below, BTC provided an offsetting credit, in the amounts shown, against administration fees paid with respect to the Funds:

FUND
------------------------------   12/31/2007    12/31/2008    12/31/2009
BlackRock Bond Index Fund          $17,993       $12,590      $12,655
BlackRock S&P 500 Stock Fund       $19,625       $14,565      $13,119

SHAREHOLDER SERVICING AGENTS. The Board of Trustees has adopted a Shareholder Servicing Plan pursuant to which the Funds have entered into Shareholder Servicing Agreements with BTC and other entities, and BTC may also enter into Shareholder Servicing Agreements with such other entities (including BlackRock, BRIL, BAC, Merrill Lynch, PNC, Barclays and their affiliates) (collectively, "Shareholder Servicing Agents") for the provision of certain services to Fund shareholders. The services provided by BTC or Shareholder Servicing Agents may include serving as an agent of the Funds for purposes of accepting orders for purchases and redemptions of Fund shares, providing administrative support and account service such as processing purchases and redemptions of shares on behalf of individual and omnibus Fund accounts, answering shareholder inquiries, keeping records, transmitting reports and communications from the Funds, and providing reports on the status of individual and omnibus accounts. Shareholder Servicing Agents may provide these services, in whole or in part, by operating electronic transaction systems or websites through which shareholders may obtain information or engage in purchase or redemption transactions of Fund shares. By operating these systems or providing other services described above, the Shareholder Servicing Agents make the Funds available to their clients.

A Shareholder Servicing Agent may make decisions about which investment options it will service and make available to its clients based on the payments the Shareholder Servicing Agent may be eligible to receive for its services. Therefore, payments to a Shareholder Servicing Agent may create potential conflicts of interest between the Shareholder Servicing Agent and its clients where the Shareholder Servicing Agent determines which investment options it will make available to those clients.

Pursuant to its Administration Agreement with the Trust, as described in the section entitled "Administrator," BTC pays shareholder servicing fees to certain Shareholder Servicing Agents in amounts not exceeding maximum fee rates approved by the Trust's Board of Trustees for those shareholder servicing, sub-administration, recordkeeping, sub-transfer agency and processing services that the Shareholder Servicing Agents perform for their clients that would otherwise be performed by BTC or the Funds' other service providers. For providing some or all of these services, each Shareholder Servicing Agent is entitled to receive a monthly fee at the annual rate of up to 0.15% of the average daily net assets of the Fund represented by shares owned during the period for which payment is being made by investors with whom the Shareholder Servicing Agent maintains a servicing relationship, or an amount that equals the maximum amount payable to the Shareholder Servicing Agent under applicable laws, regulations or rules, including the Conduct Rules of the Financial Industry Regulatory Authority, Inc. ("FINRA" and f/k/a the National Association of Securities Dealers, Inc. ("NASD")), whichever is less.

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For the fiscal years shown below, BTC paid shareholder servicing fees on behalf of the Funds in the following amounts:

                                 FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                 12/31/2007           12/31/2008          12/31/2009
------------------------------  -------------------  -------------------  ------------------
BlackRock Bond Index Fund             $ 42,313             $ 50,551             $51,533
BlackRock S&P 500 Stock Fund          $140,584             $171,065             $89,211

A Shareholder Servicing Agent also may impose certain conditions on its customers, subject to the terms of the Funds' Prospectus and this SAI, that are in addition to or different from those imposed by the Trust, such as requiring a minimum initial investment or payment of a separate fee for additional services.

NON-PLAN PAYMENTS. BlackRock may make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to a Fund). From time to time, BlackRock or its affiliates may compensate affiliated and unaffiliated entities (including BlackRock, BRIL, BAC, Merrill Lynch, PNC, Barclays and their affiliates, and entities that may also be serving as distribution agents or Shareholder Servicing Agents of the Fund) (collectively, "Service Organizations") for the sale and distribution of shares of a Fund or for services to a Fund and its shareholders. These payments that are not associated with a Shareholder Servicing Plan or distribution plan and are therefore referred to as "non-Plan payments". The non-Plan payments would be in addition to a Fund's payments described in this SAI for distribution (if the Fund has adopted a distribution plan pursuant to Rule 12b-1) and shareholder servicing. These non-Plan payments may take the form of, among other things, "due diligence" payments for a dealer's examination of the Funds and payments for providing extra employee training and information relating to Funds; "listing" fees for the placement of the Funds on a dealer's list of mutual funds available for purchase by its customers; "finders" fees for directing investors to the Fund; "distribution and marketing support" fees or "revenue sharing" for providing assistance in promoting the sale of the Funds' shares; payments for the sale of shares and/or the maintenance of share balances; CUSIP fees; maintenance fees; and set-up fees regarding the establishment of new accounts. The payments made by BlackRock and its affiliates may be a fixed dollar amount or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization involved, and may be different for different Service Organizations. The payments described above are made from BlackRock's or its affiliates' own assets pursuant to agreements with Service Organizations and do not change the price paid by investors for the purchase of the Fund's shares or the amount the Fund will receive as proceeds from such sales.

The payments described above may be made, at the discretion of BlackRock or its affiliates, to Service Organizations in connection with the sale and distribution of Fund shares. Pursuant to applicable FINRA regulations, the details of certain of these payments, including the Service Organizations receiving such payments in connection with the sale and distribution of Fund shares, are required to be disclosed. The level of payments made to these Service Organizations in any year will vary and normally will not exceed the sum of (a) 0.25% of such year's Fund sales by that Service Organization, and
(b) 0.21% of the assets attributable to that Service Organization invested in a Fund. As of the date of this SAI, as amended or supplemented from time to time, the following Service Organizations are receiving such payments in association with sale and distribution of products other than the Funds, that are advised or offered by BlackRock or its affiliates: Ameriprise Financial Services, Inc., AXA Advisors, LLC, Banc of America Investment Services, Inc., Citigroup, LPL Financial Corporation, Financial Network Investment Corporation, Merrill Lynch, MetLife Securities, Inc., Morgan Stanley, Multi-Financial Services Corporation, New England Securities Corporation, Oppenheimer & Co. Inc., PrimeVest Financial Services, Raymond James & Associates, Inc., Raymond James Financial Services, Inc., RBC Capital Markets, Tower Square Securities Inc., UBS, Wachovia Securities, Walnut Street Securities Inc., Commonwealth Equity Services, LLP (Commonwealth Financial Network), Wells Fargo and/or broker-dealers and other financial services firms under common control with the above organizations (or their assignees).

OTHER DISTRIBUTION ARRANGEMENTS. If investment advisers, distributors or affiliates of mutual funds pay bonuses and incentives in differing amounts, financial firms and their financial consultants may have financial incentives for recommending a particular mutual fund over other mutual funds. In addition, depending on the arrangements in place at any particular time, a financial firm and its financial consultants may also have a financial incentive for recommending a particular share class over other share classes. You should consult your financial adviser and review carefully any disclosure by the financial firm as to compensation received by your financial adviser for more information about the payments described above.

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Furthermore, BlackRock and its affiliates may contribute to various non-cash and cash incentive arrangements to promote the sale of shares, and may sponsor various contests and promotions subject to applicable FINRA regulations in which participants may receive prizes such as travel awards, merchandise and cash. Subject to applicable FINRA regulations, BlackRock and its affiliates may also: (i) pay for the travel expenses, meals, lodging and entertainment of broker/dealers, financial institutions and their salespersons in connection with educational and sales promotional programs, (ii) sponsor speakers, educational seminars and charitable events and (iii) provide other sales and marketing conferences and other resources to broker-dealers, financial institutions and their salespersons.

DISTRIBUTOR. BlackRock Investments, LLC is the distributor for the Funds' shares. The Distributor is a registered broker-dealer located at 40 East 52nd Street, New York, New York 10022.

Each Fund has entered into a distribution agreement with the Distributor in connection with the continuous offering of shares of the Fund (the "Distribution Agreement"). The Distribution Agreement obligates the Distributor to pay certain expenses in connection with the offering of shares of the Funds. After the prospectuses, statements of additional information and periodic reports have been prepared, set in type and mailed to shareholders, the Distributor pays for the printing and distribution of these documents used in connection with the offering to dealers and investors. The Distributor also pays for other supplementary sales literature and advertising costs.

CUSTODIAN. State Street is the custodian for each Fund and Master Portfolio and is located at 200 Clarendon Street, Boston, MA 02116. The custodian, among other things, maintains a custody account or accounts in the name of each Fund and Master Portfolio; receives and delivers all assets for each Fund and Master Portfolio upon purchase and upon sale or maturity; collects and receives all income and other payments and distributions on account of the assets of each Fund and Master Portfolio and pays all expenses of each Fund and Master Portfolio. State Street is not entitled to receive compensation for its services as custodian so long as it is entitled to receive fees from BTC for providing sub-administration services to the Funds.

TRANSFER AND DIVIDEND DISBURSING AGENT. PNC Global Investment Servicing (U.S.) Inc., a subsidiary of PNC, acts as each Fund's transfer agent pursuant to a Transfer Agency, Dividend Disbursing Agency and Shareholder Servicing Agency Agreement (the "Transfer Agency Agreement") with the Funds. Pursuant to the Transfer Agency Agreement, the Transfer Agent is responsible for the issuance, transfer and redemption of shares and the opening and maintenance of shareholder accounts. PNC GIS is paid fees for the services it provides based on the type of account and the level of services provided. PNC GIS is also entitled to be reimbursed for its reasonable out-of-pocket expenses. BTC has agreed to pay these fees and expenses pursuant to its Administration Agreement with the Trust. PNC GIS may be paid fees for certain accounts that participate in certain fee-based programs sponsored by BFA or its affiliates. For purposes of the Transfer Agency Agreement, the term "account" includes a shareholder account maintained directly by the Transfer Agent and any other account representing the beneficial interest of a person in the relevant share class on a recordkeeping system.

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM. PricewaterhouseCoopers LLP, located at Three Embarcadero Center, San Francisco, CA 94111, serves as the independent registered public accounting firm for the Trust.

LEGAL COUNSEL. Sidley Austin LLP, located at 787 Seventh Avenue, New York, NY 10019, serves as legal counsel to the Trust, MIP and BFA.

Portfolio Managers

As of December 31, 2009, the individuals named in BlackRock Bond Index Fund's Prospectus as members of the Portfolio Management Team for Bond Index Master Portfolio were primarily responsible for the day-to-day management of certain types of other portfolios and/or accounts, as indicated in the table below:

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
LEE STERNE            ------------------  ---------------------  ----------------  -----------------
Number of Accounts            26                 31                  12                  9

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                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
LEE STERNE            ------------------  ---------------------  ----------------  -----------------
Net Assets              $76,097,112,241      $69,388,533,026      $1,173,462,009     $6,637,006,448

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
JOHN SULSKI           ------------------  ---------------------  ----------------  -----------------
Number of Accounts         N/A                     N/A                  N/A                 N/A
Net Assets                 N/A               $17,451,584,019       $1,724,147,238           N/A

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
SCOTT RADELL          ------------------  ---------------------  ----------------  -----------------
Number of Accounts           N/A                    3                    7                  2
Net Assets                   N/A              $1,663,922,398       $1,664,711,887    $1,493,503,959

As of December 31, 2009, the individuals named in BlackRock S&P 500 Stock Fund's Prospectus as members of the Portfolio Management Team for S&P 500 Stock Master Portfolio were primarily responsible for the day-to-day management of certain types of other portfolios and/or accounts, as indicated in the table below:

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
DIANE HSIUNG          ------------------  ---------------------  ----------------  -----------------
Number of Accounts           163                   N/A                      3                 N/A
Net Assets            $289,813,269,757             N/A               $358,999                 N/A

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
GREG SAVAGE           ------------------  ---------------------  ----------------  -----------------

Number of Accounts           163                    N/A                      4                 N/A
Net Assets            $289,813,269,757              N/A               $411,886                 N/A

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT          OTHER POOLED                          INCENTIVE-BASED
                           COMPANIES      INVESTMENT VEHICLES      OTHER ACCOUNTS   FEE ARRANGEMENTS
EDWARD CORALLO        ------------------  ---------------------  -----------------  -----------------
Number of Accounts            N/A                 156                   42                 12
Net Assets                    N/A         $393,930,446,775       $102,307,141,326   $19,136,181,495

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT           OTHER POOLED                         INCENTIVE-BASED
                           COMPANIES       INVESTMENT VEHICLES     OTHER ACCOUNTS   FEE ARRANGEMENTS
CHRISTOPHER BLISS     ------------------  ---------------------  -----------------  -----------------
Number of Accounts            N/A                 100                   21                   4
Net Assets                    N/A         $188,909,282,818       $35,915,394,377     $13,068,141,326

43

                          REGISTERED                                                 ACCOUNTS WITH
                          INVESTMENT          OTHER POOLED                          INCENTIVE-BASED
                           COMPANIES      INVESTMENT VEHICLES      OTHER ACCOUNTS   FEE ARRANGEMENTS
JENNIFER HSUI         ------------------  ---------------------  -----------------  -----------------
Number of Accounts            N/A                  50                   37                   8
Net Assets                    N/A         $286,007,260,359       $59,955,121,616     $16,222,256,989

Certain of the portfolios or accounts for which the portfolio managers are primarily responsible for the day-to-day management seek to track the rate of return, risk profile and other characteristics of independent third-party indexes by either replicating the same combination of securities that compose those indexes or sampling the securities that compose those indexes based on objective criteria and data.

BFA or BTC, as applicable, are required to manage each portfolio or account to meet those objectives. Pursuant to BTC and BFA policy, investment opportunities are allocated equitably among the Master Portfolios and other portfolios and accounts. For example, under certain circumstances, an investment opportunity may be restricted due to limited supply on the market, legal constraints or other factors, in which event the investment opportunity will be allocated equitably among those portfolios and accounts, including the Master Portfolios, seeking such investment opportunity. As a consequence, from time to time each Master Portfolio may receive a smaller allocation of an investment opportunity than they would have if the portfolio managers and BFA and its affiliates did not manage other portfolios or accounts.

Like the Master Portfolios, the other portfolios or accounts for which the portfolio managers are primarily responsible for the day-to-day portfolio management generally pay an asset-based fee to BFA or BTC, as applicable, for its advisory services. One or more of those other portfolios or accounts, however, may pay BTC an incentive-based fee in lieu of, or in addition to, an asset-based fee for its advisory services. A portfolio or account with an incentive-based fee would pay BTC a portion of that portfolio's or account's gains, or would pay BTC more for its services than would otherwise be the case if BTC meets or exceeds specified performance targets. By their very nature, incentive-based fee arrangements could present an incentive for BTC to devote greater resources, and allocate more investment opportunities, to the portfolios or accounts that have those fee arrangements, relative to other portfolios or accounts, in order to earn larger fees. Although BTC has an obligation to allocate resources and opportunities equitably among portfolios and accounts and intends to do so, interestholders of the Master Portfolios should be aware that, as with any group of portfolios and accounts managed by an investment adviser and/or its affiliates pursuant to varying fee arrangements, including incentive-based fee arrangements, there is the potential for a conflict of interest that may result in the portfolio managers favoring those portfolios or accounts with incentive-based fee arrangements.

The below table reflects, for the listed Portfolio Management Team members of Bond Index Master Portfolio, the number of portfolios or accounts of the types enumerated in the above table and the aggregate of total assets in those portfolios or accounts with respect to which the investment management fees are based on the performance of those portfolios or accounts, as of December 31, 2009:

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
LEE STERNE                          ------------------------------  --------------------
Registered Investment Companies                   N/A                      N/A
Other Pooled Investment Vehicles                   2                         N/A
Other Accounts                                     7                 $6,637,006,447.88

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
JOHN SULSKI                         ------------------------------  --------------------
Registered Investment Companies                  N/A                     N/A
Other Pooled Investment Vehicles                 N/A                     N/A

44

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
JOHN SULSKI                         ------------------------------  --------------------
Other Accounts                                   N/A                         N/A

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
SCOTT RADELL                        ------------------------------  --------------------
Registered Investment Companies                   N/A                        N/A
Other Pooled Investment Vehicles                   2                  $1,493,503,958.64
Other Accounts                                    N/A                        N/A

The below table reflects, for the listed Portfolio Management Team members of S&P 500 Stock Master Portfolio, the number of portfolios or accounts of the types enumerated in the above table and the aggregate of total assets in those portfolios or accounts with respect to which the investment management fees are based on the performance of those portfolios or accounts, as of the dates indicated below:

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
DIANE HSIUNG                        ------------------------------  --------------------
Registered Investment Companies                  N/A                        N/A
Other Pooled Investment Vehicles                 N/A                        N/A
Other Accounts                                   N/A                        N/A

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
GREG SAVAGE                         ------------------------------  --------------------
Registered Investment Companies                  N/A                        N/A
Other Pooled Investment Vehicles                 N/A                        N/A
Other Accounts                                   N/A                        N/A

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
EDWARD CORALLO                      ------------------------------  --------------------
Registered Investment Companies                   N/A                        N/A
Other Pooled Investment Vehicles                   7                 $ 6,068,040,169.42
Other Accounts                                     5                 $13,068,141,325.51

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
CHRISTOPHER BLISS                   ------------------------------  --------------------
Registered Investment Companies                   N/A                         N/A
Other Pooled Investment Vehicles                   4                    $13,068,141,326
Other Accounts                                    N/A                         N/A

45

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES          AGGREGATE OF
                                     MANAGED BY PORTFOLIO MANAGER       TOTAL ASSETS
JENNIFER HSUI                       ------------------------------  --------------------
Registered Investment Companies                   N/A                      N/A
Other Pooled Investment Vehicles                   3                 $ 3,185,008,057
Other Accounts                                     5                 $13,037,248,932

The discussion below describes the Portfolio Manager's compensation as of December 1, 2009.

PORTFOLIO MANAGER COMPENSATION OVERVIEW. BFA's financial arrangements with its portfolio managers, its competitive compensation and its career path emphasis at all levels reflect the value senior management places on key resources. Compensation may include a variety of components and may vary from year to year based on a number of factors. The principal components of compensation include a base salary, a performance-based discretionary bonus, and participation in various benefits programs. In addition, a Portfolio Manager may have been paid a signing bonus or awarded sign-on equity in connection with initiation of employment with BlackRock.

BASE COMPENSATION. Generally, portfolio managers receive base compensation based on their seniority and/or their position with the firm. Senior portfolio managers who perform additional management functions within the portfolio management group or within BlackRock may receive additional compensation for serving in these other capacities.

DISCRETIONARY INCENTIVE COMPENSATION. Discretionary incentive compensation is a function of several components: the performance of BlackRock, the performance of the portfolio manager's group within BlackRock, the investment performance, including risk-adjusted returns, of the firm's assets under management or supervision by that portfolio manager relative to predetermined benchmarks, and the individual's seniority, role within the portfolio management team, teamwork and contribution to the overall performance of these portfolios and BlackRock.

DISTRIBUTION OF DISCRETIONARY INCENTIVE COMPENSATION. Discretionary incentive compensation is distributed to portfolio managers in a combination of cash and BlackRock, Inc. restricted stock units which vest ratably over a number of years. The BlackRock restricted stock units, if properly vested, will be settled in BlackRock, Inc. common stock. Typically, the cash bonus, when combined with base salary, represents more than 60% of total compensation for the portfolio managers. Paying a portion of annual bonuses in stock puts compensation earned by a portfolio manager for a given year "at risk" based on BlackRock's ability to sustain and improve its performance over future periods.

From time to time long-term incentive equity awards are granted to certain key employees to aid in retention, align their interests with long-term shareholder interests and motivate performance. Equity awards are generally granted in the form of BlackRock, Inc. restricted stock units that, once vested, settle in BlackRock common stock.

As of December 31, 2009, the listed Portfolio Management Team members of Bond Index Master Portfolio beneficially owned shares in BlackRock Bond Index Fund that invests in the Master Portfolio in amounts reflected in the following table:

BLACKROCK BOND INDEX FUND
                                                        $10,001     $50,001    $100,001    $500,001    OVER
                                 NONE    $1 TO $ 10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                                ------  -------------  ---------  ----------  ----------  ----------  -----
Lee Sterne                      X
John Sulski                     X
Scott Radell                    X

As of December 31, 2009, the listed Portfolio Management Team members of S&P 500 Stock Master Portfolio beneficially owned shares in BlackRock S&P 500 Stock Fund that invests in the Master Portfolio in amounts reflected in the following table:

46

BLACKROCK S&P 500 STOCK FUND
                                                        $10,001     $50,001    $100,001    $500,001    OVER
                                 NONE    $1 TO $ 10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                                ------  -------------  ---------  ----------  ----------  ----------  -----
Diane Hsiung                    X
Greg Savage                     X
Edward Corallo                  X
Christopher Bliss               X
Jennifer Hsui                   X

Determination of Net Asset Value

VALUATION OF SHARES. The aggregate net asset value of each Fund is calculated based on the net asset value of the corresponding Master Portfolio and is determined once daily Monday through Friday as of the close of business on the NYSE on each day the NYSE is open for trading based upon prices at the time of closing. The NYSE generally closes at 4:00 p.m. Eastern time. The price at which a purchase or redemption is effected is based on the next calculation of net asset value after such an order is placed. Any assets or liabilities initially expressed in terms of non-U.S. dollar currencies are translated into U.S. dollars at the prevailing market rates as quoted by one or more banks or dealers on the day of valuation. The NYSE is not open for trading on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.

The aggregate net asset value of the Master Portfolio is the value of the securities held by the Master Portfolio plus any cash or other assets (including interest and dividends accrued but not yet received) minus all liabilities (including accrued expenses). Expenses, including the fee payable to BlackRock, are accrued daily. Each investor in the Master Portfolio may add to or reduce its investment in the Master Portfolio on each day the NYSE is open for trading. The value of each investor's interest in the Master Portfolio will be determined after the close of business on the NYSE by multiplying the aggregate net asset value of the Master Portfolio by the percentage, effective for that day, that represents the investor's share of the aggregate interests in the Master Portfolio. Any additions or withdrawals to be effected on that day will then be effected. The investor's percentage of the aggregate interests in the Master Portfolio will then be recomputed as the percentage equal to the fraction (i) the numerator of which is the value of such investor's investment in the Master Portfolio as of the time of determination on such day plus or minus, as the case may be, the amount of any additions to or withdrawals from the investor's investment in the Master Portfolio effected on such day, and
(ii) the denominator of which is the aggregate net asset value of the Master Portfolio as of such time on such day plus or minus, as the case may be, the amount of the net additions to or withdrawals from the aggregate investments in the Master Portfolio by all investors in the Master Portfolio. The percentage so determined will then be applied to determine the value of the investor's interest in the Master Portfolio after the close of business on the NYSE or the next determination of the aggregate net asset value of the Master Portfolio.

Valuation of securities held by each Fund or Master Portfolio is as follows:

EQUITY INVESTMENTS. Equity securities traded on a recognized securities exchange (e.g., NYSE), separate trading boards of a securities exchange or through a market system that provides contemporaneous transaction pricing information (an "Exchange") are valued via independent pricing services generally at the Exchange closing price or if an Exchange closing price is not available, the last traded price on that Exchange prior to the time as of which the assets or liabilities are valued, however, under certain circumstances other means of determining current market value may be used. If an equity security is traded on more than one Exchange, the current market value of the security where it is primarily traded generally will be used. In the event that there are no sales involving an equity security held by a Fund on a day on which the Fund values such security, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such security. If a Fund holds both long and short positions in the same security, the last bid price will be applied to securities held long and the last ask price will be applied to securities sold short. If no bid or ask price is available on a day on which a Fund values such security, the prior day's price will be used, unless BlackRock determines that such prior day's price no longer reflects the fair value of the security, in which case such asset would be treated as a fair value asset.

47

FIXED-INCOME INVESTMENTS. Fixed-income securities for which market quotations are readily available are generally valued using such securities' most recent bid prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board. The amortized cost method of valuation may be used with respect to debt obligations with 60 days or less remaining to maturity unless BFA determines such method does not represent fair value. Loan participation notes are generally valued at the mean of the last available bid prices from one or more brokers or dealers as obtained from independent third-party pricing services. Certain fixed-income investments, including asset-backed and mortgage-related securities, may be valued based on valuation models that consider the estimated cash flows of each tranche of the entity, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche. Fixed-income securities for which market quotations are not readily available may be valued by third-party pricing services that make a valuation determination by securing transaction data (e.g., recent representative bids), credit quality information, perceived market movements, news, and other relevant information and by other methods, which may include consideration of: yields or prices of securities of comparable quality, coupon, maturity and type; indications as to values from dealers; and general market conditions.

OPTIONS, FUTURES, SWAPS AND OTHER DERIVATIVES. Exchange-traded equity options for which market quotations are readily available are valued at the mean of the last bid and ask prices as quoted on the Exchange or the board of trade on which such options are traded. In the event that there is no mean price available for an exchange traded equity option held by a Fund on a day on which the Fund values such option, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such option. If no bid or ask price is available on a day on which a Fund values such option, the prior day's price will be used, unless BlackRock determines that such prior day's price no longer reflects the fair value of the option in which case such option will be treated as a fair value asset. Over-the-counter ("OTC") options may be valued using a mathematical model which incorporates a number of market data factors. Financial futures contracts and options thereon, which are traded on exchanges, are valued at their last sale price or settle price as of the close of such exchanges. Swap agreements and other derivatives are generally valued daily based upon quotations from market makers or by a pricing service in accordance with the valuation procedures approved by the Board.

UNDERLYING FUNDS. Shares of underlying open-end funds are valued at net asset value. Shares of underlying exchange-traded closed-end funds or other exchange-traded funds will be valued at their most recent closing price.

GENERAL VALUATION INFORMATION

In determining the market value of portfolio investments, the Funds may employ independent third party pricing services, which may use, without limitation, a matrix or formula method that takes into consideration market indexes, matrices, yield curves and other specific adjustments. This may result in the securities being valued at a price different from the price that would have been determined had the matrix or formula method not been used. All cash, receivables and current payables are carried on each Fund's books at their face value.

Prices obtained from independent third party pricing services, broker-dealers or market makers to value each Fund's securities and other assets and liabilities are based on information available at the time the Fund values its assets and liabilities. In the event that a pricing service quotation is revised or updated subsequent to the day on which the Fund valued such security, the revised pricing service quotation generally will be applied prospectively. Such determination shall be made considering pertinent facts and circumstances surrounding such revision.

In the event that application of the methods of valuation discussed above result in a price for a security which is deemed not to be representative of the fair market value of such security, the security will be valued by, under the direction of or in accordance with a method specified by the Trust's Board as reflecting fair value. All other assets and liabilities (including securities for which market quotations are not readily available) held by a Fund (including restricted securities) are valued at fair value as determined in good faith by the Trust's Board or by BlackRock (its delegate). Any assets and liabilities which are denominated in a foreign currency are translated into U.S. dollars at the prevailing rates of exchange.

Certain of the securities acquired by the Funds may be traded on foreign exchanges or OTC markets on days on which a Fund's net asset value is not calculated. In such cases, the net asset value of a Fund's shares may be significantly affected on days when investors can neither purchase nor redeem shares of the Fund.

48

FAIR VALUE. When market quotations are not readily available or are believed by BlackRock to be unreliable, a Fund's investments are valued at fair value ("Fair Value Assets"). Fair Value Assets are valued by BlackRock in accordance with procedures approved by the Trust's Board. BlackRock may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its complete lack of trading, if BlackRock believes a market quotation from a broker-dealer or other source is unreliable (e.g., where it varies significantly from a recent trade, or no longer reflects the fair value of the security or other asset or liability subsequent to the most recent market quotation), where the security or other asset or liability is only thinly traded or due to the occurrence of a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BlackRock determines, in its business judgment prior to or at the time of pricing a Fund's assets or liabilities, that it is likely that the event will cause a material change to the last exchange closing price or closing market price of one or more assets or liabilities held by the Fund. On any date the NYSE is open and the primary exchange on which a foreign asset or liability is traded is closed, such asset or liability will be valued using the prior day's price, provided that BlackRock is not aware of any significant event or other information that would cause such price to no longer reflect the fair value of the asset or liability, in which case such asset or liability would be treated as a Fair Value Asset. For certain foreign securities, a third-party vendor supplies evaluated, systematic fair value pricing based upon the movement of a proprietary multi-factor model after the relevant foreign markets have closed. This systematic fair value pricing methodology is designed to correlate the prices of foreign securities following the close of the local markets to the price that might have prevailed as of a Fund's pricing time.

BlackRock, with input from the BlackRock Portfolio Management Group, will submit its recommendations regarding the valuation and/or valuation methodologies for Fair Value Assets to BlackRock's Valuation Committee. The Valuation Committee may accept, modify or reject any recommendations. In addition, the Funds' accounting agent periodically endeavors to confirm the prices it receives from all third party pricing services, index providers and broker-dealers, and, with the assistance of BlackRock, to regularly evaluate the values assigned to the securities and other assets and liabilities held by the Funds. The pricing of all Fair Value Assets is subsequently reported to and ratified by the Board or a Committee thereof.

When determining the price for a Fair Value Asset, the BlackRock Valuation Committee (or the Pricing Group) shall seek to determine the price that a Fund might reasonably expect to receive from the current sale of that asset or liability in an arm's-length transaction. The price generally may not be determined based on what a Fund might reasonably expect to receive for selling an asset or liability at a later time or if it holds the asset or liability to maturity. Fair value determinations shall be based upon all available factors that the Valuation Committee (or Pricing Group) deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models.

Fair value represents a good faith approximation of the value of an asset or liability. The fair value of one or more assets or liabilities may not, in retrospect, be the price at which those assets or liabilities could have been sold during the period in which the particular fair values were used in determining a Fund's net asset value. As a result, a Fund's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

Each Fund's annual audited financial statements, which are prepared in accordance with generally accepted accounting principles ("GAAP"), follow the requirements for valuation set forth in Statement on Financial Accounting Standards No. 157, "Fair Value Measurements" ("FAS 157"), which defines and establishes a framework for measuring fair value under GAAP and expands financial statement disclosure requirements relating to fair value measurements.

Generally, FAS 157 and other accounting rules applicable to mutual funds and various assets in which they invest are evolving. Such changes may adversely affect a Fund. For example, the evolution of rules governing the determination of the fair market value of assets or liabilities to the extent such rules become more stringent would tend to increase the cost and/or reduce the availability of third-party determinations of fair market value. This may in turn increase the costs associated with selling assets or affect their liquidity due to the Fund's inability to obtain a third-party determination of fair market value.

Purchase, Redemption and Pricing of Shares

TERMS OF PURCHASE AND REDEMPTION. The Funds are generally open Monday through Friday and are closed on weekends and are generally closed on all other days on which the NYSE is closed for regular trading. The holidays on which the NYSE is closed currently are: New Year's Day, Martin Luther King, Jr.'s Day, Presidents' Day, Good Friday, Memorial Day, Independence

49

Day, Labor Day, Thanksgiving Day and Christmas Day. Each Fund reserves the right to change the minimum amounts required for initial investment and subsequent investment, if any. On any day the Funds close early, purchase and redemption orders received after a Fund's closing time will be executed on the next business day. In addition, each Fund reserves the right to advance the time by which purchase and redemption orders must be received to be executed on the same business day as permitted by the SEC.

IN-KIND PURCHASES. Payment for shares of a Fund may, at the discretion of BFA, be made in the form of securities that are permissible investments for the Fund and must meet the investment objective, policies and limitations of the Fund as described in the Prospectus and this SAI. In connection with an in-kind securities payment, a Fund may require, among other things, that the securities
(i) be valued on the day of purchase in accordance with the pricing methods used by the Fund or its Master Portfolio ; (ii) are accompanied by satisfactory assurance that the Fund will have good and marketable title to such securities received by it; (iii) are not subject to any restrictions upon resale by the Fund; (iv) be in proper form for transfer to the Fund; and (v) are accompanied by adequate information concerning the basis and other tax matters relating to the securities. All dividends, interest, subscription or other rights pertaining to such securities shall become the property of the Fund engaged in the in-kind purchase transaction and must be delivered to such Fund by the investor upon receipt from the issuer. Securities acquired through an in-kind purchase will be acquired for investment and not for immediate resale. Each Fund immediately will transfer to its Master Portfolio any and all securities received by it in connection with an in-kind purchase transaction, in exchange for interests in such Master Portfolio. Shares purchased in exchange for securities generally cannot be redeemed until the transfer has settled.

SUSPENSION OF REDEMPTION RIGHTS OR PAYMENT OF REDEMPTION PROCEEDS. The Trust may suspend the right of redemption or postpone redemption payments for longer than seven days for any period during which (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Master Portfolio's investments is not reasonably practicable; or
(iv) for such other periods as the SEC by order may permit, as permitted under
Section 22(e) of the 1940 Act, and other applicable laws.

DECLARATION OF TRUST PROVISIONS REGARDING REDEMPTIONS AT OPTION OF TRUST. As provided in the Trust's Declaration of Trust, the Trustees may require shareholders to redeem shares for any reason under terms set by the Trustees, including, but not limited to, the failure of a shareholder to supply a taxpayer identification number if required to do so, or to have the minimum investment required, or to pay when due for the purchase of shares issued to such shareholder.

Portfolio Transactions

Since each Fund invests all of its assets in a Master Portfolio, set forth below is a description of the Master Portfolios' policies governing portfolio securities transactions.

GENERAL. Subject to policies established by the Board of Trustees, BFA is primarily responsible for the execution of a Master Portfolio's portfolio transactions and the allocation of brokerage. BFA does not execute transactions through any particular broker or dealer, but seeks to obtain the best net results for the Master Portfolio, taking into account such factors as price (including the applicable brokerage commission or dealer spread), size of order, difficulty of execution, operational facilities of the firm and the firm's risk and skill in positioning blocks of securities. While BFA generally seeks reasonable trade execution costs, a Master Portfolio does not necessarily pay the lowest spread or commission available, and payment of the lowest commission or spread is not necessarily consistent with obtaining the best price and execution in particular transactions.

BFA does not consider the provision or value of research, products or services a broker or dealer may provide, if any, as a factor in the selection of a broker or dealer or the determination of the reasonableness of commissions paid in connection with portfolio transactions. BFA does not consider sales of shares of the mutual funds it advises as a factor in the selection of brokers or dealers to execute portfolio transactions for a Master Portfolio; however, whether or not a particular broker or dealer sells shares of the mutual funds advised by BFA neither qualifies nor disqualifies such broker or dealer to execute transactions for those mutual funds.

A Master Portfolio's purchase and sale orders for securities may be combined with those of other accounts that BFA manages or advises, and for which it has brokerage placement authority. If purchases or sales of portfolio securities of a Master Portfolio and one or more other accounts managed or advised by BFA are considered at or about the same time, transactions in such securities are allocated among the Master Portfolio and the other accounts in a manner deemed equitable to all by BFA. In some cases, this procedure could have a detrimental effect on the price or volume of the security as

50

far as a Master Portfolio is concerned. However, in other cases, it is possible that the ability to participate in volume transactions and to negotiate lower brokerage commissions will be beneficial to a Master Portfolio.

Payments of commissions to brokers who are affiliated persons of the Master Portfolio with respect to the Fund (or affiliated persons of such persons), will be made in accordance with Rule 17e-1 under the 1940 Act.

Each Master Portfolio anticipates that its brokerage transactions involving foreign securities generally will be conducted primarily on the principal stock exchanges of the applicable country. Foreign equity securities may be held by a Master Portfolio in the form of depositary receipts, or other securities convertible into foreign equity securities. Depositary receipts may be listed on stock exchanges, or traded in over-the-counter markets in the United States or Europe, as the case may be. American Depositary Receipts, like other securities traded in the United States, will be subject to negotiated commission rates. Because the shares of each Fund and interests of the Master Portfolios are redeemable on a daily basis in U.S. dollars, each Master Portfolio intends to manage its portfolio so as to give reasonable assurance that it will be able to obtain U.S. dollars to the extent necessary to meet anticipated redemptions. Under present conditions, it is not believed that these considerations will have a significant effect on a Master Portfolio's portfolio strategies.

Each Master Portfolio may invest in certain securities traded in the OTC market and intends to deal directly with the dealers who make a market in the particular securities, except in those circumstances in which better prices and execution are available elsewhere. Under the 1940 Act, persons affiliated with a Master Portfolio and persons who are affiliated with such affiliated persons are prohibited from dealing with the Master Portfolio as principal in the purchase and sale of securities unless a permissive order allowing such transactions is obtained from the SEC. Since transactions in the OTC market usually involve transactions with the dealers acting as principal for their own accounts, the Master Portfolios will not deal with affiliated persons, including PNC and its affiliates, in connection with such transactions. However, an affiliated person of a Master Portfolio may serve as its broker in OTC transactions conducted on an agency basis provided that, among other things, the fee or commission received by such affiliated broker is reasonable and fair compared to the fee or commission received by non-affiliated brokers in connection with comparable transactions. In addition, a Master Portfolio may not purchase securities during the existence of any underwriting syndicate for such securities of which PNC is a member or in a private placement in which PNC serves as placement agent except pursuant to procedures approved by the Board that either comply with rules adopted by the SEC or with interpretations of the SEC staff.

OTC issues, including most fixed-income securities such as corporate debt and U.S. government securities, are normally traded on a "net" basis without a stated commission, through dealers acting for their own account and not as brokers. The Master Portfolios will primarily engage in transactions with these dealers or deal directly with the issuer unless a better price or execution could be obtained by using a broker. Prices paid to a dealer with respect to both foreign and domestic securities will generally include a "spread," which is the difference between the prices at which the dealer is willing to purchase and sell the specific security at the time, and includes the dealer's normal profit.

Purchases of money market instruments by a Master Portfolio are made from dealers, underwriters and issuers. The Master Portfolios do not currently expect to incur any brokerage commission expense on such transactions because money market instruments are generally traded on a "net" basis with dealers acting as principal for their own accounts without a stated commission. The price of the security, however, usually includes a profit to the dealer.

A Master Portfolio will not purchase securities during the existence of any underwriting or selling group relating to such securities of which BFA, PNC or any affiliated person (as defined in the 1940 Act) thereof is a member except pursuant to procedures adopted by the Board in accordance with Rule 10f-3 under the 1940 Act. In no instance will portfolio securities be purchased from or sold to BFA, PNC or any affiliated person of the foregoing entities except as permitted by SEC exemptive order or by applicable law.

PORTFOLIO TURNOVER. Portfolio turnover may vary from year to year, as well as within a year. High portfolio turnover rates may result in comparatively greater brokerage expenses and larger amounts of short-term capital gains allocable to interestholders of a Master Portfolio and shareholders of a corresponding Fund.

BROKERAGE COMMISSIONS. The table below sets forth the brokerage commissions paid by each Master Portfolio for the periods noted. Any differences in brokerage commissions paid by the Master Portfolios from year to year are due to changes in market conditions and the frequency and size of interestholder transactions. None of these brokerage commissions were paid to affiliated brokers:

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                                   FISCAL YEAR ENDED   FISCAL YEAR ENDED    FISCAL YEAR ENDED
MASTER PORTFOLIO                      12/31/2007           12/31/2008           12/31/2009
--------------------------------  ------------------  -------------------  -------------------
Bond Index Master Portfolio              N/A                 N/A                  N/A
S&P 500 Stock Master Portfolio          $43,298             $113,013             $14,788

BROKERAGE COMMISSIONS PAID TO AFFILIATES. During the past three fiscal years, the Master Portfolios paid no brokerage commissions to affiliated brokers.

SECURITIES OF REGULAR BROKERS-DEALERS. As of December 31, 2009, the Master Portfolios owned securities of their "regular brokers or dealers" (as defined in the 1940 Act) or their parents, as follows:

MASTER PORTFOLIO                       BROKER-DEALER OR PARENT           AMOUNT
--------------------------------  --------------------------------  ---------------
Bond Index Master Portfolio       Citigroup Inc.                     $    781,585
                                  Morgan Stanley                     $    698,099
                                  Goldman Sachs Group Inc. (The)     $    676,702
                                  JP Morgan Chase & Co.              $    373,769
                                  Deutsche Bank AG                   $    107,956
S&P 500 Stock Master Portfolio    JP Morgan Chase & Co               $ 33,200,656
                                  Goldman Sachs Group Inc. (The)     $ 17,553,788
                                  Citigroup Inc.                     $ 13,026,191
                                  Morgan Stanley                     $  8,142,575

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Distributions and Taxes

The following information supplements, and should be read in conjunction with, the section in each Prospectus entitled "Account Information - Taxes." The Prospectus generally describes the U.S. federal income tax treatment of distributions by the Funds. This section of the SAI provides additional information concerning U.S. federal income taxes. It is based on the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), applicable Treasury Regulations, judicial authority, and administrative rulings and practice, all as of the date of this SAI and all of which are subject to change, including changes with retroactive effect. The following discussion does not address any state, local or foreign tax matters.

A shareholder's tax treatment may vary depending upon his or her particular situation. This discussion only applies to shareholders who are U.S. persons, I.E., U.S. citizens or residents or U.S. corporations, partnerships, trusts or estates, and who are subject to U.S. federal income tax and hold Fund shares as capital assets within the meaning of the Internal Revenue Code. Except as otherwise noted, it may not apply to certain types of shareholders who may be subject to special rules, such as insurance companies, tax-exempt organizations, shareholders holding Fund shares through tax-advantaged accounts (such as 401(k) plan accounts or individual retirement accounts ("IRAs")), financial institutions, broker-dealers, entities that are not organized under the laws of the United States or a political subdivision thereof, persons who are neither citizens nor residents of the United States, shareholders holding Fund shares as part of a hedge, straddle or conversion transaction, and shareholders who are subject to the U.S. federal alternative minimum tax.

The Trust has not requested and will not request an advance ruling from the Internal Revenue Service (the "IRS") as to the U.S. federal income tax matters described below. The IRS could adopt positions contrary to those discussed below and such positions could be sustained. In addition, the foregoing discussion and the discussions in the Prospectus applicable to each shareholder address only some of the U.S. federal income tax considerations generally affecting investments in the Funds. Prospective shareholders are urged to consult with their own tax advisers and financial planners as to the particular U.S. federal tax consequences to them of an investment in the Funds, as well as the applicability and effect of any state, local or foreign laws, and the effect of possible changes in applicable tax laws.

QUALIFICATION AS A REGULATED INVESTMENT COMPANY. Each Fund has elected to be treated, has qualified and intends to continue to qualify each year as a "regulated investment company" under Subchapter M of the Internal Revenue Code, as long as such qualification is in the best interests of the Fund's shareholders. Each Fund will be treated as a separate entity for U.S. federal income tax purposes. Thus, the provisions of the Internal Revenue Code applicable to regulated investment companies generally will apply separately to each Fund, rather than to the Trust as a whole. Furthermore, each Fund will separately determine its income, gains, losses and expenses for U.S. federal income tax purposes.

In order to qualify as a regulated investment company under the Internal Revenue Code, each Fund must, among other things, derive at least 90% of its annual gross income from dividends, interest, certain payments with respect to securities loans, gains from the sale or other disposition of stock, securities or foreign currencies, or other income attributable to its business of investing in such stock, securities or foreign currencies (including, but not limited to, gains from options, futures or forward contracts) and net income derived from an interest in a qualified publicly-traded partnership as defined in section 851(h) of the Internal Revenue Code. Pursuant to regulations that may be promulgated in the future, the IRS may limit qualifying income from foreign currency gains to the amount of such currency gains which are directly related to a Fund's principal business of investing in stock or securities. Each Fund must also diversify its holdings so that, at the end of each quarter of the taxable year: (i) at least 50% of the value of its assets consists of (A) cash and cash items (including receivables), U.S. government securities and securities of other regulated investment companies, and (B) other securities, with such other securities limited, in respect to any one issuer, to an amount not greater than 5% of the value of the regulated investment company's total assets and to not more than 10% of the outstanding voting securities of such issuer, and (ii) not more than 25% of the value of the regulated investment company's total assets is invested in (A) the securities (other than U.S. government securities and securities of other regulated investment companies) of any one issuer, (B) the securities (other than the securities of other regulated investment companies) of two or more issuers that the regulated investment company controls and that are engaged in the same, similar, or related trades or businesses, or (C) the securities

53

of one or more qualified publicly-traded partnerships. The qualifying income and diversification requirements applicable to a Fund may limit the extent to which it can engage in transactions in options, futures contracts, forward contracts and swap agreements.

In addition, each Fund generally must distribute to its shareholders an amount equal to or exceeding the sum of (i) 90% of its "investment company taxable income," as that term is defined in the Internal Revenue Code (which generally includes, among other things, dividends, taxable interest, and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses) without regard to the deduction for dividends paid and (ii) 90% of its net tax-exempt income earned in each taxable year. A Fund generally will not be subject to U.S. federal income tax on the investment company taxable income and net capital gain (I.E., the excess of net long-term capital gain over net short-term capital loss) it distributes to its shareholders. However, if a Fund meets such distribution requirements, but chooses to retain some portion of its investment company taxable income or net capital gain, it generally will be subject to U.S. federal income tax at regular corporate rates on the amount retained. Although dividends generally will be treated as distributed when paid, if a Fund declares a distribution to shareholders of record in October, November or December of one year and pays the distribution by January 31 of the following year, the Fund and its shareholders will be treated as if the Fund paid the distribution by December 31 of the calendar year in which it is declared. Each Fund intends to distribute its net income and gain in a timely manner to maintain its status as a regulated investment company and eliminate Fund-level U.S. federal income taxation of such income and gain. However, no assurance can be given that a Fund will not be subject to U.S. federal income taxation.

If, in any taxable year, a Fund fails to qualify as a regulated investment company under the Internal Revenue Code or fails to meet the distribution requirements, such Fund would be taxed in the same manner as an ordinary corporation without any deduction for distributions to shareholders, and all distributions from the Fund's earnings and profits (including any distributions of net tax-exempt income and net capital gain) to its shareholders also would be taxable as ordinary income at the shareholder level. To qualify again to be taxed as a regulated investment company in a subsequent year, the Fund may be required to pay an interest charge and penalty to the IRS as well as distribute to its shareholders its earnings and profits attributable to non-regulated investment company years. In addition, if the Fund failed to qualify as a regulated investment company for a period greater than two taxable years, the Fund may be required to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the Fund had been liquidated) or, alternatively, to be subject to taxation on such built-in gain recognized for a period of ten years, in order to qualify as a regulated investment company in a subsequent year.

EXCISE TAX. A 4% non-deductible excise tax will be imposed on each Fund's capital gain net income (generally the excess of capital gains over capital losses as adjusted for ordinary losses) to the extent it fails to distribute during each calendar year (i) at least 98% of its ordinary income (excluding capital gains and losses) for the calendar year, (ii) at least 98% of its capital gain net income for the 12 month period ending on October 31, and (iii) all of its ordinary capital gain net income from previous years that was not distributed or subject to tax during such years. Each Fund intends to distribute substantially all of its net income and gains, if any, by the end of each calendar year and, thus, expects not to be subject to the excise tax. However, no assurance can be given that a Fund will not be subject to the excise tax.

CAPITAL LOSS CARRY-FORWARDS. A Fund is permitted to carry forward a net capital loss from any year to offset its capital gains, if any, realized during the eight years following the year of the loss. A Fund's capital loss carry-forward is treated as a short-term capital loss in the year to which it is carried. If future capital gains are offset by carried-forward capital losses, such future capital gains are not subject to Fund-level U.S. federal income taxation, regardless of whether they are distributed to shareholders. Accordingly, the Funds do not expect to distribute any such capital gains. The Funds cannot carry back or carry forward any net operating losses. As of December 31, 2009, the Funds had capital loss carry-forwards approximating the amount indicated for U.S. federal income tax purposes, expiring in the years indicated:

                       EXPIRING     EXPIRING     EXPIRING      EXPIRING      EXPIRING      EXPIRING      EXPIRING      EXPIRING
FUND                  12/31/2010   12/31/2011   12/31/2012    12/31/2013    12/31/2014    12/31/2015    12/31/2016    12/31/2017
------------------- ------------- ------------ ------------ ------------- ------------- ------------- ------------- -------------
BlackRock Bond       $         -     $36,738    $        -   $ 1,501,172   $ 2,280,081   $   450,134   $   291,035   $         -
 Index Fund
BlackRock S&P 500     72,553,461           -     1,601,227    21,068,838    31,394,394    18,209,354    55,579,531    21,080,621
 Stock Fund

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EQUALIZATION ACCOUNTING. Under the Internal Revenue Code, a Fund may use the so-called "equalization method" of accounting to allocate a portion of its "earnings and profits," which generally equals a Fund's undistributed net investment income and realized capital gains, with certain adjustments, to redemption proceeds. This method permits a Fund to achieve more balanced distributions for both continuing and redeeming shareholders. Although using this method generally will not affect a Fund's total returns, it may reduce the amount that the Fund would otherwise distribute to continuing shareholders by reducing the Fund's required distributions amounts by a portion of the redemption proceeds paid to redeeming shareholders. However, the IRS has not expressly sanctioned the equalization accounting method used by the Funds, and thus the use of this method may be subject to IRS scrutiny.

INVESTMENT THROUGH MASTER PORTFOLIOS. Each Fund seeks to continue to qualify as a regulated investment company by investing its assets in a Master Portfolio. Each Master Portfolio is treated as a non-publicly traded partnership (or, in the event that a Fund is the sole investor in a Master Portfolio, as disregarded from the Fund) for U.S. federal income tax purposes rather than as a regulated investment company or a corporation under the Internal Revenue Code. Under the rules applicable to a non-publicly traded partnership (or disregarded entity), a proportionate share of any interest, dividends, gains and losses of a Master Portfolio will be deemed to have been realized by (I.E., "passed-through" to) its investors, including the Fund, regardless of whether any amounts are actually distributed by the Master Portfolio. Each investor in a Master Portfolio will be taxable on such share, as determined in accordance with the governing instruments of the particular Master Portfolio, the Internal Revenue Code and Treasury Regulations. Therefore, to the extent that a Master Portfolio were to accrue but not distribute any income or gains, a Fund would be deemed to have realized its proportionate share of such income or gains without receipt of any corresponding distribution. However, each Master Portfolio will seek to minimize recognition by its investors (such as a Fund) of income and gains without a corresponding distribution. Furthermore, each Master Portfolio's assets, income and distributions will be managed in such a way that an investor in a Master Portfolio will be able to continue to qualify as a regulated investment company by investing its assets through the Master Portfolio.

TAXATION OF FUND INVESTMENTS. In general, if a Fund realizes gains or losses on the sale of portfolio securities by the Master Portfolio, such gains or losses are capital gains or losses, and if the Master Portfolio has held the disposed securities for more than one year at the time of disposition, such gains and losses generally are treated as long-term capital gains or losses.

If a Fund purchases a debt obligation with original issue discount ("OID"), generally at a price less than its principal amount, such as a zero-coupon bond, the Fund may be required to annually include in its taxable income a portion of the OID as ordinary income, even though the Fund will not receive cash payments for such discount until maturity or disposition of the obligation. A portion of the OID includible in income with respect to certain high-yield corporate debt securities may be treated as a dividend for U.S. federal income tax purposes. Gains recognized on the disposition of a debt obligation (including a municipal obligation) purchased by a Fund at a market discount, usually at a price less than its principal amount, generally will be treated as ordinary income to the extent of the portion of market discount which accrued, but was not previously recognized pursuant to an available election, during the term that the Fund held the debt obligation. A Fund generally will be required to make distributions to shareholders representing the OID on debt securities that is currently includible in income, even though the cash representing such income may not have been received by the Fund. Cash to pay such distributions may be obtained from borrowing or from sales proceeds of securities held by a Fund which the Fund otherwise might have continued to hold.

If an option granted by a Fund lapses or is terminated through a closing transaction, such as a repurchase by the Fund of the option from its holder, the Fund generally will realize a short-term capital gain or loss, depending on whether the premium income is greater or less than the amount paid by the Fund in the closing transaction. Some capital losses may be deferred if they result from a position that is part of a "straddle," discussed below. If securities are sold by a Fund pursuant to the exercise of a call option granted by it, the Fund will add the premium received to the sale price of the securities delivered in determining the amount of gain or loss on the sale. If securities are purchased by a Fund pursuant to the exercise of a put option written by it, the Fund will subtract the premium received from its cost basis in the securities purchased.

Some regulated futures contracts, certain foreign currency contracts, and non-equity listed options used by a Fund will be deemed "Section 1256 contracts." A Fund will be required to "mark-to-market" any such contracts held at the end of the taxable year by treating them as if they had been sold on the last day of that year at fair market value. Sixty percent of any net gain or loss realized on all dispositions of Section 1256 contracts, including deemed dispositions under the "mark-to-market" rule, generally will be treated as long-term capital gain or loss, and the remaining 40% will be treated as short-term capital gain or loss. Transactions that qualify as designated "hedging transactions," as defined in Section 1221(b)(2) of the Internal Revenue Code, are excepted from the mark-to-market rule and the "60%/40%" rule.

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Foreign exchange gains and losses realized by a Fund in connection with certain transactions involving foreign currency-denominated debt securities, certain options and futures contracts relating to foreign currency, foreign currency forward contracts, foreign currencies, or payables or receivables denominated in a foreign currency are subject to Section 988 of the IRC, which generally causes such gains and losses to be treated as ordinary income and losses and may affect the amount and timing of recognition of the Fund's income. Under Treasury Regulations that may be promulgated in the future, any such transactions that are not directly related to a Fund's investments in stock or securities (or its options contracts or futures contracts with respect to stock or securities) may have to be limited in order to enable the Fund to satisfy the 90% income test described above. If the net foreign exchange loss for a year exceeds a Fund's investment company taxable income (computed without regard to such loss), the resulting ordinary loss for such year will not be deductible by the Fund or its shareholders in future years.

Offsetting positions held by a Fund involving certain financial forward, futures or options contracts may be considered, for U.S. federal income tax purposes, to constitute "straddles." "Straddles" are defined to include "offsetting positions" in actively traded personal property. The tax treatment of "straddles" is governed by Section 1092 of the Internal Revenue Code which, in certain circumstances, overrides or modifies the provisions of Section 1256. If a Fund is treated as entering into "straddles" by engaging in certain financial forward, futures or option contracts, such straddles could be characterized as "mixed straddles" if one or more (but not all) of the futures, forward, or option contracts or other positions comprising a part of such straddles are governed by Section 1256 of the Internal Revenue Code, described above. A Fund may make one or more elections with respect to "mixed straddles." Depending upon which election is made, if any, the results with respect to a Fund may differ. Generally, to the extent the straddle rules apply to positions established by a Fund, losses realized by the Fund may be deferred to the extent of unrealized gain in any offsetting positions. Moreover, as a result of the straddle and the conversion transaction rules, short-term capital loss on straddle positions may be recharacterized as long-term capital loss, and long-term capital gain may be characterized as short-term capital gain or ordinary income. Further, the Fund may be required to capitalize, rather than deduct currently, any interest expense on indebtedness incurred or continued to purchase or carry any positions that are part of a straddle. Because the application of the straddle rules may affect the character of gains and losses, defer losses, and/or accelerate the recognition of gains or losses from affected straddle positions, the amount which must be distributed to shareholders, and which will be taxed to shareholders as ordinary income of long-term capital gain, may be increased or decreased substantially as compared to a Fund that had not engaged in such transactions.

If a Fund enters into a "constructive sale" of any appreciated financial position in stock, a partnership interest, or certain debt instruments, the Fund will be treated as if it had sold and immediately repurchased the property and must recognize gain (but not loss) with respect to that position. A constructive sale occurs when a Fund enters into one of the following transactions with respect to the same or substantially identical property: (i) a short sale; (ii) an offsetting notional principal contract; (iii) a futures or forward contract; or (iv) other transactions identified in Treasury Regulations that may be promulgated in the future. The character of the gain from constructive sales will depend upon a Fund's holding period in the property. Losses from a constructive sale of property will be recognized when the property is subsequently disposed of. The character of such losses will depend upon a Fund's holding period in the property and the application of various loss deferral provisions in the Internal Revenue Code. Constructive sale treatment does not apply to a transaction if such transaction is closed before the end of the 30th day after the close of the Fund's taxable year, the Fund holds the appreciated financial position throughout the 60-day period beginning with the day such transaction was closed, and the Fund's risk of loss with respect to such position is not reduced at any time during such 60-day period.

The amount of long-term capital gain a Fund may recognize from derivative transactions is limited with respect to certain pass-through entities. The amount of long-term capital gain is limited to the amount of such gain a Fund would have had if the Fund directly invested in the pass-through entity during the term of the derivative contract. Any gain in excess of this amount is treated as ordinary income. An interest charge is imposed on the amount of gain that is treated as ordinary income.

"Passive foreign investment corporations" ("PFICs") are generally defined as foreign corporations that receive at least 75% of their annual gross income from passive sources (such as interest, dividends, certain rents and royalties, or capital gains) or that hold at least 50% of their assets in investments producing such passive income. If a Fund acquires any equity interest (which generally includes not only stock, but may also include an option to acquire stock such as is inherent in a convertible bond under Treasury Regulations that may be promulgated in the future) in a PFIC, the Fund could be subject to U.S. federal income tax and IRS interest charges on "excess distributions" received from the PFIC or on gain from the sale of stock in the PFIC, even if all income or gain actually received by the Fund is timely distributed to its shareholders. Excess distributions will

56

be characterized as ordinary income even though, absent the application of PFIC rules, some excess distributions would have been classified as capital gain.

A Fund will not be permitted to pass through to its shareholders any credit or deduction for taxes and interest charges incurred with respect to PFICs. Elections may be available that would ameliorate these adverse tax consequences, but such elections could require a Fund to recognize taxable income or gain without the concurrent receipt of cash. Investments in PFICs could also result in the treatment of associated capital gains as ordinary income. The Funds may limit and/or manage their holdings in PFICs to minimize their tax liability or maximize their returns from these investments. Because it is not always possible to identify a foreign corporation as a PFIC in advance of acquiring shares in the corporation, however, a Fund may incur the tax and interest charges described above in some instances.

Rules governing the U.S. federal income tax aspects of swap agreements are in a developing stage and are not entirely clear in certain respects. Accordingly, while each Fund intends to account for such transactions in a manner it deems to be appropriate, the IRS might not accept such treatment. If it did not, the status of a Fund as a regulated investment company might be jeopardized. The Funds intend to monitor developments in this area. Certain requirements that must be met under the Internal Revenue Code in order for each Fund to qualify as a regulated investment company may limit the extent to which a Fund will be able to engage in swap agreements.

In addition to the investments described above, prospective shareholders should be aware that other investments made by the Funds may involve sophisticated tax rules that may result in income or gain recognition by the Funds without corresponding current cash receipts. Although the Funds seek to avoid significant non-cash income, such non-cash income could be recognized by the Funds, in which case the Funds may distribute cash derived from other sources in order to meet the minimum distribution requirements described above. In this regard, the Funds could be required at times to liquidate investments prematurely in order to satisfy their minimum distribution requirements.

TAXATION OF DISTRIBUTIONS. For U.S. federal income tax purposes, a Fund's earnings and profits, described above, are determined at the end of the Fund's taxable year and are allocated PRO RATA to distributions made throughout the entire year. All distributions paid out of a Fund's earnings and profits (as determined at the end of the year), whether paid in cash or reinvested in the Fund, generally are deemed to be taxable distributions and must generally be reported on each Fund shareholder's U.S. federal income tax return. Distributions in excess of a Fund's earnings and profits will first be treated as a return of capital up to the amount of a shareholder's tax basis in the shareholder's Fund shares and any such amount in excess of that basis as capital gain from the sale of shares, as discussed below. A Fund may make distributions in excess of earnings and profits to a limited extent, from time to time.

In general, assuming that each Fund has sufficient earnings and profits, distributions from investment company taxable income either are taxable as ordinary income or, if so designated by a Fund and certain other conditions are met, as "qualified dividend income" taxable at a reduced U.S. federal income tax rate to individual shareholders.

Dividend income distributed to individual shareholders will qualify as "qualified dividend income" as that term is defined in Section 1(h)(11)(B) of the Internal Revenue Code to the extent such distributions are attributable to income from the Fund's investments in common and preferred stock of U.S. companies and stock of certain qualified foreign corporations provided that certain holding period and other requirements are met by both the Fund and the shareholders. Since the income of BlackRock Bond Index Fund is not generally from sources that pay qualified dividend income, none of the distributions to shareholders of that Fund are expected to be taxable as qualified dividend income.

A distribution that is attributable to qualified dividend income of a Fund that is paid by the Fund to an individual shareholder will not be taxable as qualified dividend income to such shareholder if (i) the dividend is received with respect to any share of the Fund held for fewer than 61 days during the 121 day-period beginning on the date which is 60 days before the date on which such share became ex-dividend with respect to such dividend, (ii) to the extent that the shareholder is under an obligation (whether pursuant to a short sale or otherwise) to make related payments with respect to positions in substantially similar or related property, or (iii) the shareholder elects to have the dividend treated as investment income for purposes of the limitation on deductibility of investment interest. The "ex-dividend" date is the date on which the owner of the share at the commencement of such date is entitled to receive the next issued dividend payment for such share even if the share is sold by the owner on that date or thereafter.

Distributions designated by a Fund as a capital gain dividend will be taxed to shareholders as long-term capital gain (to the extent such distributions do not exceed the Fund's actual net capital gain for the taxable year), regardless of how long a

57

shareholder has held Fund shares. Each Fund will designate capital gain dividends, if any, in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year. The U.S. federal income tax status of all distributions will be reported to shareholders annually.

Some states will not tax distributions made to individual shareholders that are attributable to interest a Fund earned on direct obligations of the U.S. government if the Fund meets the state's minimum investment or reporting requirements, if any. Investments in Ginnie Mae or Fannie Mae securities, bankers' acceptances, commercial paper and repurchase agreements collateralized by U.S. government securities generally do not qualify for tax-free treatment. This exemption may not apply to corporate shareholders.

SALES OF FUND SHARES. Redemptions generally are taxable events for shareholders that are subject to tax. Shareholders should consult their own tax advisers with reference to their individual circumstances to determine whether any particular transaction in Fund shares is properly treated as a sale for tax purposes, as the following discussion assumes, and the tax treatment of any gains or losses recognized in such transaction. In general, if Fund shares are sold, a shareholder will recognize gain or loss equal to the difference between the amount realized on the sale and the shareholder's adjusted tax basis in the shares. This gain or loss will be long-term capital gain or loss if the shareholder has held such Fund shares for more than one year at the time of the sale.

If a shareholder receives a capital gain dividend with respect to any Fund share and such Fund share is held for six months or less, then (unless otherwise disallowed) any loss on the sale or exchange of that Fund share will be treated as a long-term capital loss to the extent of the capital gain dividend. If a shareholder realizes a loss on a disposition of Fund shares, the loss will be disallowed to the extent that the shareholder purchases substantially identical shares within the 61-day period beginning 30 days before and ending 30 days after the disposition.

Under Treasury regulations, if a shareholder recognizes a loss with respect to shares of a Fund of $2 million or more for an individual shareholder, or $10 million or more for a corporate shareholder, in any single taxable year (or greater amounts over a combination of years), the shareholder must file with the IRS a disclosure statement on Form 8886. Shareholders who own portfolio securities directly are in many cases excepted from this requirement but, under current guidance, shareholders of regulated investment companies are not excepted. A shareholder who fails to make the required disclosure to the IRS may be subject to substantial penalties. The fact that a loss is reportable under these regulations does not affect the legal determination of whether or not the taxpayer's treatment of the loss is proper. Shareholders should consult with their tax advisers to determine the applicability of these regulations in light of their individual circumstances.

FOREIGN TAXES. Amounts realized by a Fund on foreign securities may be subject to withholding and other taxes imposed by such countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a Fund's total assets at the close of its taxable year were to consist of securities of non-U.S. corporations, the Fund would be eligible to file an annual election with the IRS pursuant to which the Fund could pass-FOREIGN TAXES. Amounts realized by a Fund on foreign securities may be subject to withholding and other taxes imposed by such countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a Fund's total assets at the close of its taxable year were to consist of securities of non-U.S. corporations, the Fund would be eligible to file an annual election with the IRS pursuant to which the Fund could pass-through to its shareholders on a PRO RATA basis foreign income and similar taxes paid by the Fund, which could be claimed, subject to certain limitations, either as a tax credit or deduction by shareholders. However, neither of the Funds expects to qualify for this election.

FEDERAL INCOME TAX RATES. As of the printing of this SAI, the maximum stated individual U.S. federal income tax rate applicable to (i) ordinary income generally is 35%; (ii) qualified dividend income is 15%; (iii) capital gain dividend is 15%; and (iv) long-term capital gains is 15%.

An individual shareholder also should be aware that the benefits of the favorable tax rates applicable to capital gain dividends, long-term capital gains, and qualified dividend income may be impacted by the application of the alternative minimum tax. Under current law, the maximum 35% U.S. federal income tax rate on ordinary income and the maximum 15% U.S. federal income tax rate on capital gain dividends, long-term capital gains and qualified dividend income will cease to apply to taxable years beginning after December 31, 2010.

The maximum stated corporate U.S. federal income tax rate applicable to ordinary income, qualified dividend income, capital gain dividends and long-term capital gain is generally 35%. Actual marginal tax rates may be higher for some shareholders, for example, through reductions in deductions. Naturally, the amount of tax payable by any taxpayer will be affected by a combination of tax laws covering, for example, deductions, credits, deferrals, exemptions, sources of income and other matters.

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BACK-UP WITHHOLDING. The Trust may be required to withhold, subject to certain exemptions, at a rate of 28% ("back-up withholding") on all distributions and redemption proceeds (including proceeds from exchanges and redemptions in-kind) paid or credited to a Fund shareholder, unless the shareholder generally certifies under penalties of perjury that the shareholder's social security or other "taxpayer identification number" ("TIN") provided is correct and that the shareholder is not subject to back-up withholding, or the IRS notifies the Fund that the shareholder's TIN is incorrect or that the shareholder is subject to back-up withholding. This tax is not an additional U.S. federal income tax imposed on the shareholder, and the shareholder may claim the tax withheld as a tax payment on his or her U.S. federal income tax return, provided that the required information is furnished to the IRS. An investor must provide a valid TIN upon opening or reopening an account. If a shareholder fails to furnish a valid TIN upon request, the shareholder can also be subject to IRS penalties. The rate of back-up withholding is set to increase for taxable years beginning after December 31, 2010.

TAX-DEFERRED PLANS. The shares of the Funds may be available for a variety of tax-deferred retirement and other tax-advantaged plans and accounts, including IRAs, Simplified Employee Pension Plans, Savings Incentive Match Plans for Employees, Roth IRAs, and Coverdell Education Savings Accounts. Prospective investors should contact their tax advisers and financial planners regarding the tax consequences to them of holding Fund shares through a tax-advantaged plan or account.

CORPORATE SHAREHOLDERS. Subject to limitations and other rules, a corporate shareholder of BlackRock S&P 500 Stock Fund may be eligible for the dividends-received deduction on Fund distributions to the extent that such distributions are attributable to dividends from domestic corporations, which, if received directly by the corporate shareholder, would qualify for such deduction. In general, a distribution by a Fund attributable to dividends of a domestic corporation will only be eligible for the deduction if: (i) the corporate shareholder holds the Fund shares upon which the distribution is made for at least 46 days during the 91-day period beginning 45 days prior to the date upon which the shareholder becomes entitled to the distribution; and (ii) the Fund holds the shares of the domestic corporation producing the dividend income in an unleveraged position for at least 46 days during the 91-day period beginning 45 days prior to the date upon which the Fund becomes entitled to such dividend income. A longer holding period applies to investments in preferred stock.

FOREIGN SHAREHOLDERS. With respect to taxable years of a Fund beginning before January 1, 2010, certain distributions, if designated by a Fund as "interest-related dividends," generally attributable to the Fund's net interest income earned on certain debt obligations paid to a non-resident alien individual, foreign trust (I.E., a trust other than a trust which a U.S. court is able to exercise primary supervision over administration of that trust and one or more U.S. persons have authority to control substantial decisions of that trust), foreign estate (I.E., the income of which is not subject to U.S. tax regardless of source) or a foreign corporation (each, a "foreign shareholder") generally will be exempt from U.S. federal income tax withholding tax, provided the Fund obtains a properly completed and signed certificate of foreign status from such foreign shareholder ("exempt foreign shareholder"). If applicable, each Fund may choose to designate any interest-related dividends in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year. All other distributions made to exempt foreign shareholders attributable to net investment income, such as dividends received by a Fund, generally will be subject to non-refundable U.S. federal income tax withholding at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Notwithstanding the foregoing, if a distribution described above is "effectively connected" with a U.S. trade or business (or, if an income tax treaty applies, is attributable to a permanent establishment) of the recipient foreign shareholder, U.S. federal income tax withholding and exemptions attributable to foreign persons will not apply and the distribution will be subject to the tax, reporting and withholding requirements generally applicable to U.S. persons.

In general, a foreign shareholder's capital gains realized on the disposition of Fund shares, capital gain distributions and, with respect to taxable years of a Fund beginning before January 1, 2010, "short-term capital gain distributions" (defined below) are not subject to U.S. federal income tax withholding, provided that the Fund obtains a properly completed and signed certificate of foreign status, unless: (i) such gains or distributions are effectively connected with a U.S. trade or business (or, if an income tax treaty applies, are attributable to a permanent establishment) of the foreign shareholder; (ii) in the case of an individual foreign shareholder, the shareholder is present in the United States for a period or periods aggregating 183 days or more during the year of the sale and certain other conditions are met; or (iii) with respect to taxable years of a Fund beginning before January 1, 2010, such gains or distributions are attributable to gain from the sale or exchange of a U.S. real property interest. If such gains or distributions are effectively connected with a U.S. trade or business or are attributable to a U.S. permanent establishment of the foreign shareholder pursuant to an income tax treaty, the tax, reporting and withholding requirements applicable to U.S. persons generally apply. If such gains or distributions are not effectively connected for this purpose, but the foreign shareholder meets the requirements of clause (ii) described above, such gains and distributions will

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be subject to U.S. federal income tax withholding tax at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Gains or distributions attributable to gain from sales or exchanges of U.S. real property interests are taxed to a foreign shareholder as if that gain were effectively connected with the shareholder's conduct of a U.S. trade or business, and therefore such gains or distributions may be required to be reported by a foreign shareholder on a U.S. federal income tax return. Such gains or distributions also will be subject to U.S. income tax at the rates applicable to U.S. holders and/or may be subject to U.S. federal income tax withholding. While the Funds do not expect Fund shares to constitute U.S. real property interests, a portion of a Fund's distributions may be attributable to gain from the sale or exchange of U.S. real property interests. Foreign shareholders should contact their tax advisers and financial planners regarding the tax consequences to them of such distributions. "Short-term capital gain distributions" are certain distributions that a Fund may choose to designate as such in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year generally attributable to its net short-term capital gain.

If a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the U.S. at the time of the shareholder's death, Fund shares will be deemed to be property situated in the U.S. and will be subject to federal estate taxes (at current graduated rates of 18% to 45% of the total value, less allowable deductions and credits). With respect to estates of decedents dying before January 1, 2010, if a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, Fund shares are not deemed to be property situated in the United States in the proportion that, at the end of the quarter of the Fund's taxable year immediately preceding the shareholder's date of death, the assets of the Fund that are "qualifying assets" (I.E., bank deposits, debt obligations or property not within the United States) with respect to the decedent bear to the total assets of the Fund. In general, no federal gift tax will be imposed on gifts of Fund shares made by foreign shareholders.

The availability of reduced U.S. taxes pursuant to the 1972 Convention or the applicable estate tax convention depends upon compliance with established procedures for claiming the benefits thereof, and may, under certain circumstances, depend upon the foreign shareholder making a satisfactory demonstration to U.S. tax authorities that the shareholder qualifies as a foreign person under federal income tax laws and the 1972 Convention.

Special rules apply to foreign partnerships and those holding Fund shares through foreign partnerships.

RECENTLY ENACTED LEGISLATION. Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012, to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code) unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

Capital Stock

As of the date of this SAI, the beneficial interests in the Trust are divided into transferable shares of 11 separate and distinct series authorized and established by the Board of Trustees. The number of shares of each series, and class thereof, is unlimited and each share has no par value. The Board of Trustees may, in the future, authorize the issuance of other series representing shares of additional investment portfolios or funds. Except to the extent the 1940 Act expressly grants to shareholders the power to vote on such termination(s), the Trust, or any series (or class) thereof, may be terminated at any time by the Trustees with written notice to the shareholders.

Although the Trust is not required to hold regular annual shareholder meetings, occasional annual or special meetings may be required for purposes such as electing and removing Trustees, approving advisory contracts, and changing a Fund's fundamental investment policies.

VOTING. All shares of the Trust will be voted separately by individual series, except: (i) when required by the 1940 Act, shares will be voted in the aggregate and not by individual series; and (ii) when the Trustees have determined that the matter affects the interests of more than one series, then the shareholders of all such affected series will be entitled to vote thereon in the aggregate and not by individual series. The Trustees also may determine that a matter affects only the interests of one or

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more classes of a series, in which case any such matter will be voted on separately by such class or classes. For example, a change in a Fund's fundamental investment policy would be voted upon only by shareholders of that Fund. Additionally, approval of a Master Portfolio's Advisory Contract is a matter to be determined separately by each Master Portfolio. Approval by the shareholders of a Fund is effective as to that Fund whether or not sufficient votes are received from the shareholders of the other investment portfolios to approve the proposal as to those investment portfolios. As used in the Prospectus of each Fund and in this SAI, the term "1940 Act majority," when referring to approvals to be obtained from shareholders of a Fund, means the vote of the lesser of (i) 67% of the shares of the Fund represented at a meeting if the holders of more than 50% of the outstanding shares of the Fund are present in person or by proxy, or (ii) more than 50% of the outstanding shares of the Fund. The term "majority," when referring to the approvals to be obtained from shareholders of the Trust as a whole, means the vote of the lesser of (i) 67% of the Trust's shares represented at a meeting if the holders of more than 50% of the Trust's outstanding shares are present in person or by proxy, or (ii) more than 50% of the Trust's outstanding shares.

Each share will entitle the holder thereof to one vote for each dollar (and each fractional dollar thereof) of NAV (number of shares owned times NAV per share) of shares outstanding in such holder's name on the books of the Trust. There shall be no cumulative voting in the election of Trustees. Depending on the terms of a particular benefit plan and the matter being submitted to a vote, a sponsor may request direction from individual participants regarding a shareholder vote. For additional voting information and a discussion of the possible effects of changes to a Master Portfolio's investment objective or policies on a Fund, as an interestholder in the Master Portfolio, or the Fund's shareholders, see "Management - Master/Feeder Structure."

The Trust may dispense with an annual meeting of shareholders in any year in which it is not required to elect Trustees under the 1940 Act. However, the Trust will hold a special meeting of its shareholders for the purpose of voting on the question of removal of a Trustee or Trustees if requested in writing by the holders of at least 10% of the Trust's outstanding voting securities, and to assist in communicating with other shareholders as required by Section 16(c) of the 1940 Act.

DIVIDENDS AND DISTRIBUTIONS. Each share of a Fund represents an equal proportional interest in the Fund with each other share and is entitled to such dividends and distributions out of the income earned on the assets belonging to the Fund as are declared in the discretion of the Trustees. In the event of the liquidation or dissolution of the Trust, shareholders of a Fund are entitled to receive the assets attributable to the Fund that are available for distribution, and a distribution of any general assets not attributable to a particular investment portfolio that are available for distribution in such manner and on such basis as the Trustees in their sole discretion may determine. Shareholders are not entitled to any preemptive rights. All shares, when issued, will be fully paid and non-assessable by the Trust.

MASTER PORTFOLIOS. MIP is an open-end, series management investment company organized as a Delaware statutory trust on October 20, 1993. MIP's Declaration of Trust provides that obligations of MIP are not binding upon its Trustees individually but only upon the property of MIP and that the Trustees will not be liable for any action or failure to act, but nothing in the Declaration of Trust protects a Trustee against any liability to which the Trustee would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of the Trustee's office.

Interests in each Master Portfolio of MIP have voting and other rights generally corresponding to those rights enumerated above for shares of the Funds. MIP also intends to dispense with annual meetings, but is required by
Section 16(c) of the 1940 Act to hold a special meeting and assist investor communications under the circumstances described above with respect to the Trust. Whenever a Fund is requested to vote on a matter with respect to its Master Portfolio, the Fund will follow its voting procedures, as described in "Voting."

Additional Information on the Funds

The Trust provides annual and semi-annual reports to all shareholders. The annual reports contain audited financial statements and other information about the Funds, including additional information on performance. Shareholders may obtain a copy of the Trust's most recent annual or semi-annual reports without charge by calling 1-800-441-7762 (toll-free).

The registration statement, including the Prospectus, this SAI and the exhibits filed therewith, may be examined at the office of the SEC in Washington, D.C. Statements contained in the Prospectus or this SAI as to the contents of any contract or other document referred to herein or in the Prospectus are not necessarily complete and, in each instance, reference is made to the

61

copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference.

No person has been authorized to give any information or to make any representations other than those contained in the Prospectus, this SAI and in the Trust's official sales literature in connection with the offer of the Trust's shares and, if given or made, such other information or representations must not be relied upon as having been authorized by the Trust. This SAI does not constitute an offer in any state in which, or to any person to whom, such offering may not lawfully be made.

Financial Statements

The audited financial statements, including the schedule of investments, financial highlights and independent registered public accounting firm's reports for the fiscal year ended December 31, 2009 for each Fund and related Master Portfolio are hereby incorporated by reference to the Trust's annual report, as filed with the SEC on March 10, 2010. The annual report, which contains the referenced audited financial statements, is available upon request and without charge.

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APPENDIX A

DESCRIPTION OF CORPORATE BOND RATINGS

Ratings are generally given to securities at the time of issuance. While the rating agencies may from time to time revise such ratings, they undertake no obligation to do so, and the ratings given to securities at issuance do not necessarily represent ratings which would be given to these securities on a particular subsequent date.

Bonds which are unrated expose the investor to risks with respect to capacity to pay interest or repay principal which are similar to the risks of lower-rated speculative bonds. Evaluation of these securities is dependent on the investment adviser's judgment, analysis and experience in the evaluation of such bonds.

Investors should note that the assignment of a rating to a bond by a rating service may not reflect the effect of recent developments on the issuer's ability to make interest and principal payments.

The descriptions below relate to corporate bonds and are not applicable to the other types of securities.

MOODY'S INVESTORS SERVICE, INC.

AAA: Bonds which are rated Aaa are judged to be of the best quality. They carry the smallest degree of investment risk and are generally referred to as "gilt edged." Interest payments are protected by a large or by an exceptionally stable margin and principal is secure. While the various protective elements are likely to change, such changes as can be visualized are most unlikely to impair the fundamentally strong position of such issues.

AA: Bonds which are rated Aa are judged to be of high quality by all standards. Together with the Aaa group they comprise what are generally known as high grade bonds. They are rated lower than the best bonds because margins of protection may not be as large as in Aaa securities or fluctuation of protective elements may be of greater amplitude or there may be other elements present which make the long term risk appear somewhat larger than the Aaa securities.

A: Bonds which are rated A possess many favorable investment attributes and are to be considered as upper-medium-grade obligations. Factors giving security to principal and interest are considered adequate, but elements may be present which suggest a susceptibility to impairment sometime in the future.

BAA: Bonds which are rated Baa are considered as medium-grade obligations (I.E., they are neither highly protected nor poorly secured). Interest payments and principal security appear adequate for the present but certain protective elements may be lacking or may be characteristically unreliable over any great length of time. Such bonds lack outstanding investment characteristics and in fact have speculative characteristics as well.

BA: Bonds which are rated Ba are judged to have speculative elements; their future cannot be considered as well-assured. Often the protection of interest and principal payments may be very moderate and thereby not well safeguarded during other good and bad times over the future. Uncertainty of position characterizes bonds in this class.

B: Bonds which are rated B generally lack characteristics of the desirable investment. Assurance of interest and principal payments or of maintenance of other terms of the contract over any long period of time may be small.

CAA: Bonds which are rated Caa are of poor standing. Such issues may be in default or there may be present elements of danger with respect to principal or interest.

CA: Bonds which are rated Ca represent obligations which are speculative in a high degree. Such issues are often in default or have other marked shortcomings.

C: Bonds which are rated C are the lowest rated class of bonds, and issues so rated can be regarded as having extremely poor prospects of ever attaining any real investment standing.

ABSENCE OF RATING: Where no rating has been assigned or where a rating has been suspended or withdrawn, it may be for reasons unrelated to the quality of the issue.

Should no rating be assigned, the reason may be one of the following:

1. An application for rating was not received or accepted.

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2. The issue or issuer belongs to a group of securities or companies that are not rated as a matter of policy.

3. There is a lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed, in which case the rating is not published in Moody's publications.

Suspension or withdrawal may occur if new and material circumstances arise, the effects of which preclude satisfactory analysis; if there is no longer available reasonable up-to-date data to permit a judgment to be formed; if a bond is called for redemption; or for other reasons.

NOTE: Moody's applies numerical modifiers, 1, 2, and 3 in each generic rating classification from Aa through Caa. The modifier 1 indicates that the security ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates that the issue ranks in the lower end of its generic rating category.

STANDARD & POOR'S

AAA: An obligation rated AAA has the highest rating assigned by S&P. The obligor's capacity to meet its financial commitment on the obligation is extremely strong.

AA: An obligation rated AA differs from the highest rated obligations only to a small degree. The obligor's capacity to meet its financial commitment is very strong.

A: An obligation rated A is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rated categories. However, the obligor's capacity to meet its financial commitment on the obligation is still strong.

BBB: An obligation rated BBB exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitment on the obligation.

Obligations rated BB, B, CCC, CC, and C are regarded as having significant speculative characteristics. BB indicates the least degree of speculation and C the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposures to adverse conditions.

BB: An obligation rated BB is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions that could lead to the obligor's inadequate capacity to meet its financial commitment on the obligation.

B: An obligation rated B is more vulnerable to nonpayment than obligations rated BB, but the obligor currently has the capacity to meet its financial commitment on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitment on the obligation.

CCC: An obligation rated CCC is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitment on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitment on the obligation.

CC: An obligation rated CC is currently highly vulnerable to nonpayment.

C: A 'C' rating is assigned to obligations that are currently highly vulnerable to nonpayment, obligations that have payment arrearages allowed by the terms of the documents, or obligations of an issuer that is the subject of a bankruptcy petition or similar action which have not experienced a payment default. Among others, the 'C' rating may be assigned to subordinated debt, preferred stock or other obligations on which cash payments have been suspended in accordance with the instrument's terms or when preferred stock is the subject of a distressed exchange offer, whereby some or all of the issue is either repurchased for an amount of cash or replaced by other instruments having a total value that is less than par.

D: An obligation rated 'D' is in payment default. The 'D' rating category is used when payments on an obligation, including a regulatory capital instrument, are not made on the date due even if the applicable grace period has not expired, unless S&P believes that such payments will be made during such grace period. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of similar action if payments on an obligation are jeopardized. An obligation's rating is

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lowered to 'D' upon completion of a distressed exchange offer, whereby some or all of the issue is either repurchased for an amount of cash or replaced by other instruments having a total value that is less than par.

PLUS (+) OR MINUS (-): The ratings from AA to CCC may be modified by the addition of a plus or minus sign to show relative standing within the major rating categories.

NR: NR indicates no rating has been requested, that there is insufficient information on which to base a rating, or that S&P does not rate a particular type of obligation as a matter of policy.

COMMERCIAL PAPER

S&P's commercial paper rating is a current assessment of the likelihood of timely payment of debt considered short-term in the relevant market.

A-1: This highest category indicates that the degree of safety regarding timely payment is strong. Those issues determined to possess extremely strong safety characteristics are denoted with a plus (+) sign designation.

A-2: Capacity for timely payment on issues with this designation is satisfactory. However, the relative degree of safety is not as high as for issues designated "A-1."

A-3: Issues carrying this designation have adequate capacity for timely payment. They are, however, more vulnerable to the adverse effects of changes in circumstances than obligations carrying the higher designations.

FITCH RATINGS

INVESTMENT-GRADE BOND RATINGS

AAA: Highest credit quality. "AAA" ratings denote the lowest expectation of credit risk. They are assigned only in case of exceptionally strong capacity for timely payment of financial commitments. This capacity is highly unlikely to be adversely affected by foreseeable events.

AA: Very high credit quality. "AA" ratings denote a very low expectation of credit risk. They indicate very strong capacity for timely payment of financial commitments. This capacity is not significantly vulnerable to foreseeable events.

A: High credit quality. "A" ratings denote a low expectation of credit risk. The capacity for timely payment of financial commitments is considered strong. This capacity may, nevertheless, be more vulnerable to changes in circumstances or in economic conditions than is the case for higher ratings.

BBB: Good credit quality. "BBB" ratings indicate that there is currently a low expectation of credit risk. The capacity for timely payment of financial commitments is considered adequate, but adverse changes in circumstances and in economic conditions are more likely to impair this capacity. This is the lowest investment-grade category.

HIGH YIELD BOND RATINGS

BB: Speculative. "BB" ratings indicate that there is a possibility of credit risk developing, particularly as the result of adverse economic change over time; however, business or financial alternatives may be available to allow financial commitments to be met. Securities rated in this category are not investment-grade.

B: Highly speculative. "B" ratings indicate that significant credit risk is present, but a limited margin of safety remains. Financial commitments are currently being met; however, capacity for continued payment is contingent upon a sustained, favorable business and economic environment.

CCC, CC, AND C: High default risk. Default is a real possibility. Capacity for meeting financial commitments is solely reliant upon sustained, favorable business or economic developments. A "CC" rating indicates that default of some kind appears probable. "C" ratings signal imminent default.

Defaulted obligations typically are not assigned "D" ratings, but are instead rated in the "B" to "C" rating categories, depending upon their recovery prospects and other relevant characteristics. This approach better aligns obligations that have comparable overall expected loss but varying vulnerability to default and loss.

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NOTES TO RATINGS

"+" or "-" may be appended to a rating to denote relative status within major rating categories. Such suffixes are not added to the "AAA" long-term rating category, to categories below "B," or to short-term ratings other than "F-l."

"NR" indicates that Fitch does not rate the issuer or issue in question.

"Withdrawn": A rating is withdrawn when Fitch deems the amount of information available to be inadequate for rating purposes, or when an obligation matures, is called, or refinanced.

SAI-BR3-BDSP-0510

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APPENDIX B

Proxy Voting Policies

For The BlackRock-Advised Funds

December, 2009

Copyright (C) 2009 BlackRock, Inc.
All rights reserved.


Table of Contents

Page

I. INTRODUCTION............................................................1
II. PROXY VOTING POLICIES...................................................2

   A.  Boards of Directors....................................................2
   B.  Auditors...............................................................2
   C.  Compensation and Benefits..............................................2
   D.  Capital Structure......................................................2
   E.  Corporate Charter and By-Laws..........................................3
   F.  Environmental and Social Issues........................................3
IV.    REPORTS TO THE BOARD...................................................3

I.   INTRODUCTION

     The Trustees/Directors ("Directors") of the BlackRock-Advised Funds (the
     "Funds") have the responsibility for voting proxies relating to portfolio
     securities of the Funds, and have determined that it is in the best
     interests of the Funds and their shareholders to delegate that
     responsibility to BlackRock Advisors, LLC and its affiliated U.S.
     registered investment advisers ("BlackRock"), the investment adviser to the
     Funds, as part of BlackRock's authority to manage, acquire and dispose of
     account assets. The Directors hereby direct BlackRock to vote such proxies
     in accordance with this Policy, and any proxy voting guidelines that the

Adviser determines are appropriate and in the best interests of the Funds' shareholders and which are consistent with the principles outlined in this Policy. The Directors have authorized BlackRock to utilize an unaffiliated third-party as its agent to vote portfolio proxies in accordance with this Policy and to maintain records of such portfolio proxy voting.

Rule 206(4)-6 under the Investment Advisers Act of 1940 requires, among other things, that an investment adviser that exercises voting authority over clients' proxy voting adopt policies and procedures reasonably designed to ensure that the adviser votes proxies in the best interests of clients, discloses to its clients information about those policies and procedures and also discloses to clients how they may obtain information on how the adviser has voted their proxies.

BlackRock has adopted separate but substantially similar guidelines and procedures that are consistent with the principles of this Policy. BlackRock's Corporate Governance Committee (the "Committee"), addresses proxy voting issues on behalf of BlackRock and its clients, including the Funds. The Committee is comprised of senior members of BlackRock's Portfolio Management and Administration Groups and is advised by BlackRock's Legal and Compliance Department.

BlackRock votes (or refrains from voting) proxies for each Fund in a manner that BlackRock, in the exercise of its independent business judgment, concludes are in the best economic interests of such Fund. In some cases, BlackRock may determine that it is in the best economic interests of a Fund to refrain from exercising the Fund's proxy voting rights (such as, for example, proxies on certain non-U.S. securities that might impose costly or time-consuming in-person voting requirements). With regard to the relationship between securities lending and proxy voting, BlackRock's approach is also driven by our clients' economic interests. The evaluation of the economic desirability of recalling loans involves balancing the revenue producing value of loans against the likely economic value of casting votes. Based on our evaluation of this relationship, BlackRock believes that the likely economic value of casting a vote generally is less than the securities lending income, either because the votes will not have significant economic consequences or because the outcome of the vote would not be affected by BlackRock recalling loaned securities in order to ensure they are voted. Periodically, BlackRock analyzes the process and benefits of voting proxies for securities on loan, and will consider whether any modification of its proxy voting policies or procedures are necessary in light of any regulatory changes.

BlackRock will normally vote on specific proxy issues in accordance with BlackRock's proxy voting guidelines. BlackRock's proxy voting guidelines provide detailed guidance as to how to vote proxies on certain important or commonly raised issues. BlackRock may, in the exercise of its business judgment, conclude that the proxy voting guidelines do not cover the specific matter upon which a proxy vote is requested, or that an exception to the proxy voting guidelines would be in the best economic interests of a Fund. BlackRock

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votes (or refrains from voting) proxies without regard to the relationship of the issuer of the proxy (or any shareholder of such issuer) to the Fund, the Fund's affiliates (if any), BlackRock or BlackRock's affiliates. When voting proxies, BlackRock attempts to encourage companies to follow practices that enhance shareholder value and increase transparency and allow the market to place a proper value on their assets.

II. PROXY VOTING POLICIES

A. BOARDS OF DIRECTORS

The Funds generally support the board's nominees in the election of directors and generally supports proposals that strengthen the independence of boards of directors. As a general matter, the Funds believe that a company's board of directors (rather than shareholders) is most likely to have access to important, nonpublic information regarding a company's business and prospects, and is therefore best-positioned to set corporate policy and oversee management. The Funds therefore believe that the foundation of good corporate governance is the election of responsible, qualified, independent corporate directors who are likely to diligently represent the interests of shareholders and oversee management of the corporation in a manner that will seek to maximize shareholder value over time. In individual cases, consideration may be given to a director nominee's history of representing shareholder interests as a director of the company issuing the proxy or other companies, or other factors to the extent deemed relevant by the Committee.

B. AUDITORS

These proposals concern those issues submitted to shareholders related to the selection of auditors. As a general matter, the Funds believe that corporate auditors have a responsibility to represent the interests of shareholders and provide an independent view on the propriety of financial reporting decisions of corporate management. While the Funds anticipate that BlackRock will generally defer to a corporation's choice of auditor, in individual cases, consideration may be given to an auditors' history of representing shareholder interests as auditor of the company issuing the proxy or other companies, to the extent deemed relevant.

C. COMPENSATION AND BENEFITS

These proposals concern those issues submitted to shareholders related to management compensation and employee benefits. As a general matter, the Funds favor disclosure of a company's compensation and benefit policies and oppose excessive compensation, but believe that compensation matters are normally best determined by a corporation's board of directors, rather than shareholders. Proposals to "micro-manage" a company's compensation practices or to set arbitrary restrictions on compensation or benefits should therefore generally not be supported.

D. CAPITAL STRUCTURE

These proposals relate to various requests, principally from management, for approval of amendments that would alter the capital structure of a company, such as an increase in authorized shares. As a general matter, the Funds expect that BlackRock will support requests that it believes enhance the rights of common shareholders and oppose requests that appear to be unreasonably dilutive.

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E. CORPORATE CHARTER AND BY-LAWS

These proposals relate to various requests for approval of amendments to a corporation's charter or by-laws. As a general matter, the Funds generally vote against anti-takeover proposals and proposals that would create additional barriers or costs to corporate transactions that are likely to deliver a premium to shareholders.

F. ENVIRONMENTAL AND SOCIAL ISSUES

These are shareholder proposals addressing either corporate social and environmental policies or requesting specific reporting on these issues. The Funds generally do not support proposals on social issues that lack a demonstrable economic benefit to the issuer and the Fund investing in such issuer. BlackRock seeks to make proxy voting decisions in the manner most likely to protect and promote the long-term economic value of the securities held in client accounts. We intend to support economically advantageous corporate practices while leaving direct oversight of company management and strategy to boards of directors. We seek to avoid micromanagement of companies, as we believe that a company's board of directors is best positioned to represent shareholders and oversee management on shareholders behalf. Issues of corporate social and environmental responsibility are evaluated on a case-by-case basis within this framework.

III. CONFLICTS MANAGEMENT

BlackRock maintains policies and procedures that are designed to prevent any relationship between the issuer of the proxy (or any shareholder of the issuer) and a Fund, a Fund's affiliates (if any), BlackRock or BlackRock's affiliates, from having undue influence on BlackRock's proxy voting activity. In certain instances, BlackRock may determine to engage an independent fiduciary to vote proxies as a further safeguard against potential conflicts of interest or as otherwise required by applicable law. The independent fiduciary may either vote such proxies or provide BlackRock with instructions as to how to vote such proxies. In the latter case, BlackRock votes the proxy in accordance with the independent fiduciary's determination.

IV. REPORTS TO THE BOARD

BlackRock will report to the Directors on proxy votes it has made on behalf of the Funds at least annually.

3

BLACKROCK FUNDS III

Statement of Additional Information

Dated May 1, 2010

PORTFOLIO/SHARE CLASS                                                     TICKER
-----------------------------------------------------------------------  -------
LIFEPATH(Reg. TM) RETIREMENT PORTFOLIO
 Investor A Shares                                                        LPRAX
 Investor C Shares                                                        LPCRX
 Institutional Shares                                                     STLAX
 Class K Shares                                                           LPSAX
 Class R Shares                                                           LPRRX
LIFEPATH 2020 PORTFOLIO(Reg. TM)
 Investor A Shares                                                        LPRCX
 Investor C Shares                                                        LPCMX
 Institutional Shares                                                     STLCX
 Class K Shares                                                           LPSCX
 Class R Shares                                                           LPRMX
LIFEPATH 2030 PORTFOLIO(Reg. TM)
 Investor A Shares                                                        LPRDX
 Investor C Shares                                                        LPCNX
 Institutional Shares                                                     STLDX
 Class K Shares                                                           LPSDX
 Class R Shares                                                           LPRNX
LIFEPATH 2040 PORTFOLIO(Reg. TM)
 Investor A Shares                                                        LPREX
 Investor C Shares                                                        LPCKX
 Institutional Shares                                                     STLEX
 Class K Shares                                                           LPSFX
 Class R Shares                                                           LPRKX
LIFEPATH(Reg. TM) 2050 PORTFOLIO
 Investor A Shares                                                        LPRFX
 Investor C Shares                                                        LPCPX
 Institutional Shares                                                     STLFX
 Class K Shares                                                           LPSGX
 Class R Shares                                                           LPRPX

BlackRock Funds III (the "Trust") is an open-end, series management investment company. This combined Statement of Additional Information ("SAI") contains additional information about Investor A Shares, Investor C Shares, Institutional Shares, Class K Shares and Class R Shares of the Trust's LifePath Retirement Portfolio, LifePath 2020 Portfolio, LifePath 2030 Portfolio, LifePath 2040 Portfolio and LifePath 2050 Portfolio (each, a "LifePath Portfolio" and collectively, the "LifePath Portfolios"). The LifePath Portfolios were formerly named the LifePath Funds.

Each LifePath Portfolio invests substantially all of its assets in a separate portfolio (each, a "Master Portfolio" and collectively, the "Master Portfolios") of Master Investment Portfolio ("MIP") that has the same investment objective as the corresponding LifePath Portfolio. Each Master Portfolio, in turn, invests in a combination of stock, bond and money market funds (the "Underlying Funds"). MIP is an open-end, series management investment company. BlackRock Fund Advisors ("BFA" or the "Investment Adviser") (formerly, Barclays Global Fund Advisors) serves as investment adviser to the Master Portfolios and also serves as investment adviser to each of the Underlying Funds, except for the BlackRock Cash Funds: Institutional, a series of the Trust, which invests all of its assets in a master portfolio of MIP advised by BFA. References to the investments, investment policies and risks of a LifePath Portfolio, unless otherwise indicated, should be understood to include references to the investments, investment policies and risks of such Master Portfolio.

This SAI is not a prospectus and should be read in conjunction with the current prospectuses for Investor A Shares, Investor C Shares, Institutional Shares, Class K Shares and Class R Shares of the LifePath Portfolios, each dated May 1, 2010, (each, a "Prospectus" and collectively, the "Prospectuses"). All terms used in this SAI that are defined in the Prospectuses have the meanings assigned in the Prospectuses. The audited financial statements for the LifePath Portfolios, which include the schedule of investments and report of the independent registered public accounting firm for the fiscal year ended December


31, 2009, are hereby incorporated by reference to the LifePath Portfolios' annual reports and semi-annual reports. Copies of the Prospectuses, annual reports, and semi-annual reports may be obtained without charge by calling 1-800-441-7762 (toll-free).

LifePath(Reg. TM) is a registered service mark of BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) and the LifePath products are covered by U.S. Patents 5,812,987 and 6,336,102.


TABLE OF CONTENTS

                                                                                    PAGE
                                                                                   -----
History of the Trust                                                                  1
Description of the LifePath Portfolios and their Investments and Risks                1
   Investment Objective and Policies                                                  1
   Investment Restrictions                                                            2
   Fundamental Investment Restrictions                                                2
   Non-Fundamental Investment Restrictions                                            2
   Fundamental Investment Restrictions of the Master Portfolios                       3
   Non-Fundamental Investment Restrictions of the Master Portfolios                   4
Investments and Risks of the Master Portfolios                                        4
   Borrowing                                                                          4
   Investments in Underlying Funds                                                    4
   Loans of Portfolio Securities                                                      4
   Short-Term Instruments                                                             5
   U.S. Government Obligations                                                        5
Investments and Risks of the Underlying Funds                                         5
   Asset-Backed and Commercial Mortgage-Backed Securities                             5
   Bonds                                                                              6
   Borrowing                                                                          6
   Brady Bonds                                                                        6
   Collateralized Debt Obligations                                                    6
   Convertible Securities                                                             7
   Corporate Bonds                                                                    7
   Credit-Linked Securities                                                           7
   Currency Transactions                                                              8
   Diversification and Concentration                                                  8
   Equity Securities                                                                  9
   Floating-Rate and Variable-Rate Obligations                                        9
   Forward Commitments, When-Issued Purchases and Delayed-Delivery Transactions      10
   Funding Agreements                                                                10
   Futures Contracts, Options Transactions, and Swap Transactions                    10
   High-Yield Securities                                                             11
   Hybrid ARM Securities                                                             12
   Illiquid Securities                                                               12
   Inflation-Protected Obligations                                                   12
   iShares Funds                                                                     13
   Investment Companies                                                              13

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                                                                                    PAGE
                                                                                   -----
   Letters of Credit                                                                 14
   Loan Participations and Assignments                                               14
   Loans of Portfolio Securities                                                     15
   Mortgage Pass-Through Securities                                                  15
   Mortgage Securities                                                               16
   Municipal Securities                                                              16
   Non-U.S. Securities and Emerging Markets Securities                               17
   Participation Interests                                                           18
   Ratings                                                                           18
   Repurchase Agreements                                                             18
   Restricted Securities                                                             19
   Reverse Repurchase Agreements                                                     19
   Short-Term Instruments                                                            19
   Stock Index Futures and Options on Stock Index Futures                            19
   Unrated Investments                                                               20
   U.S. Government Obligations                                                       20
   Warrants                                                                          20
Portfolio Holdings Information                                                       20
   Service Providers                                                                 21
   Third-Party Feeder LifePath Portfolios                                            21
   Securities and Exchange Commission Filings                                        22
   Other Public Disclosure                                                           22
   Approved Recipients                                                               22
Management                                                                           22
   Share Ownership Information                                                       32
   Ownership of Securities of Certain Entities                                       33
   Compensation of Trustees                                                          33
   Master/Feeder Structure                                                           34
   Codes of Ethics                                                                   35
   Proxy Voting Policies of the Master Portfolios                                    35
   Shareholder Communication to the Board of Trustees                                36
Control Persons and Principal Holders of Securities                                  36
Investment Adviser and Other Service Providers                                       46
   Investment Adviser                                                                46
   Advisory Fees                                                                     46
   Underlying Funds                                                                  47
   Administrator                                                                     48

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                                                                                    PAGE
                                                                                   -----
   Shareholder Servicing Agents                                                      49
   Distributor                                                                       51
   Investor A, Investor C and Class R Shares Distribution and Service Plan           51
   MIP Distribution Plan                                                             53
   Custodian                                                                         53
   Transfer and Dividend Disbursing Agent                                            53
   Independent Registered Public Accounting Firm                                     53
   Legal Counsel                                                                     53
Portfolio Managers                                                                   53
Determination of Net Asset Value                                                     57
Purchase, Redemption and Pricing of Shares                                           59
   Terms of Purchase and Redemption                                                  59
   In-Kind Purchases                                                                 60
   Suspension of Redemption Rights or Payment of Redemption Proceeds                 60
   Declaration of Trust Provisions Regarding Redemptions at Option of Trust          60
Portfolio Transactions                                                               60
   General                                                                           60
   Portfolio Turnover                                                                61
   Brokerage Commissions                                                             62
   Brokerage Commissions Paid to Affiliates                                          62
   Securities of Regular Broker-Dealers                                              62
   Frequent Trading in Portfolio Shares                                              62
Distributions and Taxes                                                              63
   Qualification as a Regulated Investment Company                                   63
   Excise Tax                                                                        64
   Capital Loss Carry-Forwards                                                       64
   Equalization Accounting                                                           65
   Investment Through Master Portfolios                                              65
   Taxation of Underlying Fund Investments                                           65
   Taxation of Distributions                                                         67
   Sales of LifePath Portfolio Shares                                                68
   Foreign Taxes                                                                     68
   Federal Income Tax Rates                                                          68
   Back-Up Withholding                                                               69
   Tax-Deferred Plans                                                                69
   Corporate Shareholders                                                            69
   Foreign Shareholders                                                              69

iii

                                                                                    PAGE
                                                                                   -----
   Recently Enacted Legislation                                                      70
Capital Stock                                                                        71
   Voting                                                                            71
   Dividends and Distributions                                                       72
   Master Portfolios                                                                 72
Additional Information on the LifePath Portfolios                                    72
Financial Statements                                                                 72
Disclaimers                                                                          72
APPENDIX A                                                                          A-1

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History of the Trust

The Trust was organized on December 4, 2001 as a statutory trust under the laws of the State of Delaware. On August 21, 2001, the Board of Directors of Barclays Global Investors Funds, Inc. (the "Company") approved a proposal to redomicile the Company from a Maryland corporation to a Delaware statutory trust (the "Redomiciling"). Shareholders of the Company approved the Redomiciling on November 16, 2001. The Trust was established with multiple series, including the LifePath Portfolios, corresponding to, and having identical designations as, the Company's series. The Redomiciling was effected on January 11, 2002, at which time the Trust assumed the operations of the Company and adopted the Company's registration statement. Shortly thereafter, the Company was dissolved.

The Trust consists of multiple series, including the LifePath Portfolios. The Trust's principal office is located at 400 Howard Street, San Francisco, CA 94105. Each LifePath Portfolio invests all of its assets in a Master Portfolio of MIP (as shown below), which has substantially the same investment objective, policies and restrictions as the related LifePath Portfolio. Each Master Portfolio, in turn, invests in a combination of Underlying Funds and may also invest in U.S. government securities and short-term paper. BTC, the parent company of BFA, has granted the Trust a non-exclusive license to use the name "LifePath." If the license agreement is terminated, the Trust, at BTC's request, will cease using the "LifePath" name.

LIFEPATH PORTFOLIO                      MASTER PORTFOLIO IN WHICH THE LIFEPATH PORTFOLIO INVESTS
--------------------------------------  ---------------------------------------------------------
       LifePath Retirement Portfolio    LifePath(Reg. TM) Retirement Master Portfolio
       LifePath 2020 Portfolio          LifePath 2020 Master Portfolio(Reg. TM)
       LifePath 2030 Portfolio          LifePath 2030 Master Portfolio(Reg. TM)
       LifePath 2040 Portfolio          LifePath 2040 Master Portfolio(Reg. TM)
       LifePath 2050 Portfolio          LifePath(Reg. TM) 2050 Master Portfolio

On April 30, 2001, Class R of the LifePath Portfolios commenced operations and the existing unnamed class of shares was named "Class I." On July 1, 2001, the Company's LifePath Income, LifePath 2020, LifePath 2030 and LifePath 2040 Funds were renamed the LifePath Income, LifePath 2020, LifePath 2030 and LifePath 2040 Portfolios, respectively. On February 12, 2003, the Trust's LifePath Income Portfolio was renamed LifePath Retirement Portfolio. On November 20, 2009, LifePath 2010 Portfolio merged into LifePath Retirement Portfolio. Effective as of the date of this SAI, Class R Shares are renamed Investor A Shares, Class R-1 Shares are renamed Class R Shares and Class S Shares are renamed Class K Shares. Investor C Shares of the LifePath Portfolios are expected to commence operations on or shortly after the date of this SAI.

On December 1, 2009, the Trust was renamed BlackRock Funds III.

Description of the LifePath Portfolios and their Investments and Risks

INVESTMENT OBJECTIVE AND POLICIES. The Trust is an open-end, series management investment company. There are five Master Portfolios in which the LifePath Portfolios invest, each of which is a series of MIP. The Master Portfolios in which the LifePath Portfolios invest are diversified funds as defined in the Investment Company Act of 1940, as amended (the "1940 Act"). Organizations and other entities such as the LifePath Portfolios that hold beneficial interests in a Master Portfolio may be referred to herein as "feeder funds."

Each LifePath Portfolio has adopted a non-fundamental investment objective, and investment policies that may be fundamental or non-fundamental. Fundamental policies cannot be changed without approval by the holders of a majority (as defined in the 1940 Act) of the outstanding voting securities of such LifePath Portfolio. Non-fundamental policies may be changed without shareholder approval by vote of a majority of the trustees of the Trust (the "Trustees") at any time.

Each LifePath Portfolio has adopted a non-fundamental investment objective that is set forth in the Prospectus. The investment objective and policies of a LifePath Portfolio determine the allocation of assets to the Underlying Funds, the

1

degree of risk to which the LifePath Portfolio is subject and, ultimately, its performance. As with all investment companies, there can be no assurance that the investment objective of any LifePath Portfolio will be achieved.

INVESTMENT RESTRICTIONS.

FUNDAMENTAL INVESTMENT RESTRICTIONS. The LifePath Portfolios are subject to the following investment restrictions, all of which are fundamental policies. Each LifePath Portfolio may not:

(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of a LifePath Portfolio's investments in that industry would equal or exceed 25% of the current value of the LifePath Portfolio's total assets, provided that this restriction does not limit a LifePath Portfolio's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities;.

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of a LifePath Portfolio's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the LifePath Portfolio's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit a LifePath Portfolio's cash or cash items, investments in securities issued or guaranteed by the U.S. government, its agencies and instrumentalities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with a LifePath Portfolio's investment program may be deemed to be an underwriting; and provided further, that the purchase by the LifePath Portfolio of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the LifePath Portfolio shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the LifePath Portfolio from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business); and

(7) Purchase or sell commodities, provided that (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments.

With respect to paragraph (3) above, the 1940 Act currently allows a LifePath Portfolio to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of a LifePath Portfolio's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL INVESTMENT RESTRICTIONS. The LifePath Portfolios are subject to the following investment restrictions, all of which are non-fundamental policies and may be changed without shareholder approval by vote of a majority of the Trustees at any time.

As a matter of non-fundamental policy:

(1) Each LifePath Portfolio may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder. Other investment companies in which the LifePath Portfolios invest can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by a LifePath Portfolio;

2

(2) Each LifePath Portfolio may not invest more than 15% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others, (i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale,
(ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each LifePath Portfolio may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of a LifePath Portfolio's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked-to-market daily; and

(4) Each LifePath Portfolio may not purchase securities on margin, but each LifePath Portfolio may make margin deposits in connection with transactions in options, forward contracts, futures contracts, including those relating to indexes, and options on futures contracts or indexes.

Notwithstanding any other investment policy or restriction (whether or not fundamental), each LifePath Portfolio may and does invest all of its assets in the securities of a single open-end management investment company with substantially the same fundamental investment objective, policies and limitations as the LifePath Portfolio. See "Management - Master/Feeder Structure." In addition, the Underlying Funds in which the LifePath Portfolios may invest have adopted certain investment restrictions that may be different from those listed above, thereby permitting the LifePath Portfolios to engage indirectly in investment strategies that are prohibited under the restrictions listed above. The investment restrictions of each Underlying Fund are set forth in its respective statement of additional information.

FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE MASTER PORTFOLIOS. The Master Portfolios have adopted the following investment restrictions as fundamental policies. These restrictions cannot be changed, as to a Master Portfolio, without approval by the holders of a majority (as defined in the 1940 Act) of the Master Portfolio's outstanding voting interests. The Master Portfolios may not:

(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of a Master Portfolio's investments in that industry would equal or exceed 25% of the current value of the Master Portfolio's total assets, provided that this restriction does not limit a Master Portfolio's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities;

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of a Master Portfolio's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the Master Portfolio's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit a Master Portfolio's cash or cash items, investments in securities issued or guaranteed by the U.S. government, its agencies and instrumentalities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with a Master Portfolio's investment program may be deemed to be an underwriting; and provided further, that the purchase by the Master Portfolio of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Master Portfolio shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the Master Portfolio from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business); and

(7) Purchase or sell commodities, provided that (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments.

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With respect to paragraph (3) above, the 1940 Act currently allows a Master Portfolio to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of a Master Portfolio's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE MASTER PORTFOLIOS. The Master
Portfolios have adopted the following investment restrictions as non-fundamental policies. These restrictions may be changed without interestholder approval by vote of a majority of the Trustees of MIP at any time. The Master Portfolios are subject to the following investment restrictions, all of which are non-fundamental policies:

(1) Each Master Portfolio may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder. Other investment companies in which a Master Portfolio invests can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by such Master Portfolio;

(2) Each Master Portfolio may not invest more than 15% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others, (i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale,
(ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each Master Portfolio may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of the Master Portfolio's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked-to-market daily; and

(4) Each Master Portfolio may not purchase securities on margin, but each Master Portfolio may make margin deposits in connection with transactions in options, forward contracts, futures contracts, including those related to indexes, and options on futures contracts or indexes.

Investments and Risks of the Master Portfolios

BORROWING. The Master Portfolios may borrow money for temporary or emergency purposes, including the meeting of redemption requests. Borrowing involves special risk considerations. Interest costs on borrowings may fluctuate with changing market rates of interest and may partially offset or exceed the return earned on borrowed funds (or on the assets that were retained rather than sold to meet the needs for which funds were borrowed). Under adverse market conditions, a Master Portfolio might have to sell portfolio securities to meet interest or principal payments at a time when investment considerations would not favor such sales. Reverse repurchase agreements, short sales not against the box, dollar roll transactions and other similar investments that involve a form of leverage (I.E., risk of gain or loss higher than the amount invested) have characteristics similar to borrowings. The Master Portfolios maintain liquid assets in connection with those types of transactions.

INVESTMENTS IN UNDERLYING FUNDS. To implement its asset allocation strategy, each Master Portfolio invests its assets in a combination of Underlying Funds. Each Underlying Fund invests directly in portfolio securities, except that BlackRock Cash Funds: Institutional invests all of its assets in a related master portfolio of MIP.

LOANS OF PORTFOLIO SECURITIES. Each Master Portfolio may lend portfolio securities to certain creditworthy borrowers, including borrowers affiliated with BFA. The borrowers provide collateral that is maintained in an amount at least equal to the current market value of the securities loaned. A Master Portfolio may terminate a loan at any time and obtain the return of the securities loaned. Each Master Portfolio receives the value of any interest or cash or non-cash distributions paid on the loaned securities.

With respect to loans that are collateralized by cash, the borrower will be entitled to receive a fee based on the amount of cash collateral. The Master Portfolio is compensated by the difference between the amount earned on the reinvestment of cash collateral and the fee paid to the borrower. In the case of collateral other than cash, the Master Portfolio is compensated by a fee paid by the borrower equal to a percentage of the market value of the loaned securities. Any cash collateral may be reinvested in certain short-term instruments either directly on behalf of each lending Master Portfolio or through one or more joint accounts or money market funds, including those managed by BFA; such reinvestments are subject to investment risk.

4

Securities lending involves exposure to certain risks, including operational risk (I.E., the risk of losses resulting from problems in the settlement and accounting process), "gap" risk (I.E., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Master Portfolio has agreed to pay a borrower), and credit, legal, counterparty and market risk. In the event a borrower does not return a Master Portfolio's securities as agreed, the Master Portfolio may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated plus the transaction costs incurred in purchasing replacement securities.

A Master Portfolio may pay a portion of the interest or fees earned from securities lending to a borrower as described above, and to a securities lending agent who administers the lending program in accordance with guidelines approved by MIP's Board of Trustees. BTC acts as securities lending agent for the Master Portfolios, subject to the overall supervision of BFA. BTC receives a portion of the revenues generated by securities lending activities as compensation for its services in this regard.

SHORT-TERM INSTRUMENTS. The Master Portfolios may invest in various money market instruments. Money market instruments are generally short-term investments that may include but are not limited to: (i) obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities (including government-sponsored enterprises); (ii) negotiable certificates of deposit ("CDs"), bankers' acceptances, fixed time deposits and other obligations of domestic banks (including non-U.S. branches); (iii) commercial paper; (iv) non-convertible corporate debt securities (E.G., bonds and debentures); (v) repurchase agreements; and (vi) U.S. dollar-denominated obligations of non-U.S. banks (including U.S. branches) that, in the opinion of BFA, are of comparable quality to obligations of U.S. banks which may be purchased by the Master Portfolio. Any of these instruments may be purchased on a current or a forward-settled basis. Money market instruments also include shares of money market mutual funds, including those managed by BFA. See "Investments in Underlying Funds" above.

U.S. GOVERNMENT OBLIGATIONS. The Master Portfolios may invest in various types of U.S. government obligations. A U.S. government obligation is a type of bond. U.S. government obligations include securities issued or guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities. Payment of principal and interest on U.S. government obligations (i) may be backed by the full faith and credit of the United States (as with U.S. Treasury obligations and Government National Mortgage Association ("Ginnie Mae") certificates) or (ii) may be backed solely by the issuing or guaranteeing agency or instrumentality itself (as with Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac"), or Federal Home Loan Bank ("FHLB") notes). In the latter case, the investor must look principally to the agency or instrumentality issuing or guaranteeing the obligation for ultimate repayment, which agency or instrumentality may be privately owned. There can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. As a general matter, the value of debt instruments, including U.S. government obligations, declines when market interest rates increase and rises when market interest rates decrease. Certain types of U.S. government obligations are subject to fluctuations in yield or value due to their structure or contract terms.

Investments and Risks of the Underlying Funds

Set forth below is more detailed information regarding types of instruments in which the Underlying Funds may invest, strategies BFA may employ in pursuit of an Underlying Fund's investment objective, and related risks.

ASSET-BACKED AND COMMERCIAL MORTGAGE-BACKED SECURITIES. Certain of the Underlying Funds may invest in asset-backed and commercial mortgage-backed securities. Asset-backed securities are securities backed by installment contracts, credit-card receivables or other assets. Commercial mortgage-backed

securities are securities backed by commercial real estate properties. Both asset-backed and commercial mortgage-backed securities represent interests in "pools" of assets in which payments of both interest and principal on the securities are made on a regular basis. The payments are, in effect, "passed through" to the holder of the securities (net of any fees paid to the issuer or guarantor of the securities). The average life of asset-backed and commercial mortgage-backed securities varies with the maturities of the underlying instruments and, as a result of prepayments, can often be less than the original maturity of the assets underlying the securities. For this and other reasons, an asset-backed and commercial mortgage-backed security's stated maturity may be shortened or extended, and the security's total return may be difficult to predict precisely. BlackRock Cash Funds: Institutional may invest in such securities up to the limits prescribed by Rule 2a-7 and other provisions of the 1940 Act. Changes in liquidity may result in significant, rapid and unpredictable changes in the prices for credit-linked securities. Also see "Mortgage Pass-Through Securities" and "Mortgage Securities."

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Beginning in the second half of 2007, through 2008 and continuing into 2009, the market for asset-backed and mortgage-backed securities experienced substantially, often dramatically, lower valuations and reduced liquidity. These instruments continue to be subject to liquidity constraints, price volatility, credit downgrades and increases in default rates and, therefore, may be more difficult to value and more difficult to dispose of than previously.

BONDS. A bond is an interest-bearing security issued by a company or a governmental unit or a non-U.S. entity. The issuer of a bond has a contractual obligation to pay interest at a stated rate on specific dates and to repay principal (the bond's face value) periodically or on a specified maturity date. Bonds are generally used by corporations and governments to borrow money from investors.

An issuer may have the right to redeem or "call" a bond before maturity, in which case the investor may have to reinvest the proceeds at lower market rates. Similarly, an Underlying Fund may have to reinvest interest income or payments received when bonds mature, sometimes at lower market rates. Most bonds bear interest income at a "coupon" rate that is fixed for the life of the bond. The value of a fixed-rate bond usually rises when market interest rates fall, and falls when market interest rates rise. Accordingly, a fixed-rate bond's yield (income as a percent of the bond's current value) may differ from its coupon rate as its value rises or falls. When an investor purchases a fixed-rate bond at a price that is greater than its face value, the investor is purchasing the bond at a premium. Conversely, when an investor purchases a fixed-rate bond at a price that is less than its face value, the investor is purchasing the bond at a discount. Fixed-rate bonds that are purchased at a discount pay less current income than securities with comparable yields that are purchased at face value, with the result that prices for such fixed-rate securities can be more volatile than prices for such securities that are purchased at face value. Other types of bonds bear income at an interest rate that is adjusted periodically. Because of their adjustable interest rates, the value of "floating-rate" or "variable-rate" bonds fluctuates much less in response to market interest rate movements than the value of fixed-rate bonds. See "Floating-Rate and Variable-Rate Obligations" below. Generally, prices of higher quality issues tend to fluctuate less with changes in market interest rates than prices of lower quality issues and prices of longer maturity issues tend to fluctuate more than prices of shorter maturity issues. An Underlying Fund may treat a bond as having a shorter maturity for purposes of calculating the weighted average maturity of its investment portfolio. Bonds may be senior or subordinated obligations. Senior obligations generally have the first claim on a corporation's earnings and assets and, in the event of liquidation, are paid before subordinated obligations. Bonds may be unsecured (backed only by the issuer's general creditworthiness) or secured (backed by specified collateral).

BORROWING. Each Underlying Fund may borrow in the same manner as the Master Portfolios, as described above.

BRADY BONDS. Each Underlying Fund may invest in Brady bonds. Brady bonds are securities created through the exchange of existing commercial bank loans to public and private entities in certain emerging markets for new bonds in connection with debt restructurings. Brady bonds have been issued since 1989. In light of the history of defaults of countries issuing Brady bonds on their commercial bank loans, investments in Brady bonds may be viewed as speculative and subject to the same risks as emerging market securities. Brady bonds may be fully or partially collateralized or uncollateralized, are issued in various currencies (but primarily the U.S. dollar) and are actively traded in over-the-counter ("OTC") secondary markets. Incomplete collateralization of interest or principal payment obligations results in increased credit risk. Dollar-denominated collateralized Brady bonds, which may be either fixed-rate or floating-rate bonds, are generally collateralized by U.S. Treasury securities.

COLLATERALIZED DEBT OBLIGATIONS. A Master Portfolio may invest in collateralized debt obligations ("CDOs"), which include collateralized bond obligations ("CBOs"), collateralized loan obligations ("CLOs") and other similarly structured securities. CBOs and CLOs are types of asset-backed securities. A CBO is a trust which is backed by a diversified pool of fixed income securities. A CLO is a trust typically collateralized by a pool of loans, which may include, among others, domestic and foreign senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment-grade or equivalent unrated loans. CDOs may charge management fees and administrative expenses.

CDO cash flows are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the subordinate "equity" tranche which bears the bulk of defaults from the bonds, loans or other underlying collateral and serves to protect the other, more senior tranches from default in all but the most severe circumstances. Because it is partially protected from defaults, a senior tranche from a CDO typically has higher ratings and lower yields than its underlying collateral, and can be rated investment-grade. Despite the protection provided by the equity tranche, senior CDO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults in the event of collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as market aversion to CDOs as a class.

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Additionally, tranches that are senior to the equity tranche are often subordinate to other, more senior tranches, which may have a variety of preferences, including the authority to compel early redemption of subordinate tranches.

In addition to the risks generally associated with fixed income securities (E.G., interest rate risk and default risk), CDOs carry additional risks including, but not limited to: (i) concentrated portfolios with heightened exposure to movements in a particular segment of the market; (ii) significant leverage that could magnify the affect of adverse events; (iii) distributions from the collateral may not be adequate to make interest or other payments;
(iv) the quality of the collateral may decline in value or default; (v) a Master Portfolio may invest in CDOs that are subordinate to other classes; (vi) the market for a CDO, or the fixed income markets more generally, may become illiquid; and (vii) the complex structure of the CDO may not be fully understood at the time of investment and may give rise to disputes with the issuer or unexpected investment results.

These risks have recently led to actual defaults and market losses on certain CDOs.

CONVERTIBLE SECURITIES. Certain of the Underlying Funds may purchase fixed income convertible securities, such as bonds or preferred stock, which may be converted at a stated price within a specified period of time into a specified number of shares of common stock of the same or a different issuer. Convertible securities are senior to common stock in a corporation's capital structure, but usually are subordinated to non-convertible debt securities. While providing a fixed income stream (generally higher in yield than the income from a common stock but lower than that afforded by a non-convertible debt security), a convertible security also affords an investor the opportunity, through its conversion feature, to participate in the capital appreciation of the common stock into which it is convertible.

In general, the market value of a convertible security is the higher of its "investment value" (I.E., its value as a fixed income security) or its "conversion value" (I.E., the value of the underlying shares of common stock if the security is converted). As a fixed income security, the market value of a convertible security generally increases when interest rates decline and generally decreases when interest rates rise. However, the price of a convertible security also is influenced by the market value of the security's underlying common stock. Thus, the price of a convertible security generally increases as the market value of the underlying stock increases and generally decreases as the market value of the underlying stock declines. Investments in convertible securities generally entail less risk than investments in the common stock of the same issuer.

CORPORATE BONDS. Certain of the Underlying Funds may invest in investment-grade corporate bonds. The investment return of corporate bonds reflects interest on the security and changes in the market value of the security. The market value of a corporate bond may be affected by changes in the market rate of interest, the credit rating of the corporation, the corporation's performance and perceptions of the corporation in the market place. There is a risk that the issuers of the securities may not be able to meet their obligations on interest or principal payments at the time called for by an instrument.

CREDIT-LINKED SECURITIES. Certain of the Underlying Funds may invest in credit-linked securities. Credit-linked securities are securities that are collateralized usually by one or more credit default swaps on corporate credits and, in some instances, by government securities or similar low-risk assets. As an investor in credit-linked securities, an Underlying Fund has the right to receive periodic interest payments from the issuer of the credit-linked security at an agreed-upon interest rate and, subject to certain conditions, a return of principal at the maturity date.

Credit-linked securities are typically privately negotiated transactions between two or more parties. The issuer of the credit-linked security will usually be a financial institution or a special purpose vehicle established by a financial institution. An Underlying Fund bears the risk that the issuer of the credit-linked security will default or become bankrupt. An Underlying Fund bears the risk of loss of its principal investment and the periodic interest payments expected to be received for the duration of its investment in the credit-linked security.

Credit-linked securities are also subject to the credit risk of the corporate issuers underlying the credit default swaps. If one or more of the credit events agreed upon in the credit default swap occurs with respect to one or more of the underlying corporate issuers and the credit default swap is physically settled, an Underlying Fund may receive physical delivery of the security or loan that is subject to the relevant credit event, and the Underlying Fund's principal investment would be reduced by the corresponding face value of the security or loan that is the subject of the credit event. In instances where the underlying credit default swap is cash-settled on the occurrence of a credit event, an Underlying Fund's principal investment would be reduced, typically by the face value of the security or loan in respect of which the applicable credit event has occurred, and the Underlying Fund would not receive physical delivery of the loan or security that was the subject of the relevant credit event.

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The market for credit-linked securities may be, or suddenly can become, illiquid. Indeed, often credit-linked securities are subject to significant restrictions on transfer, thereby enhancing the illiquidity of such securities. Changes in liquidity may result in significant, rapid and unpredictable changes in the prices for credit-linked securities. In certain cases, a market price for a credit-linked security may not be available. The value of a credit-linked security will typically increase or decrease with any change in value of the underlying collateral, if any, held by the issuer of the credit default swap. Further, in cases where the credit-linked security is structured such that the payments to an Underlying Fund are based on amounts received in respect of, or the value or performance of, any reference obligation specified in the terms of the relevant credit default swap, fluctuations in the value of such reference obligation or the performance of the related reference entity may affect the value of the credit-linked security.

An investment in credit-linked securities involves reliance on the counterparty to the swap entered into with the issuer to make periodic payments to the issuer under the terms of the credit default swap. Any delay or cessation in the making of such payments may be expected in certain instances to result in delays or reductions in payments to an Underlying Fund as an investor in such credit-linked securities. Additionally, credit-linked securities are typically structured as limited recourse obligations of the issuer of the securities, such that the securities issued will usually be obligations solely of the issuer and will not be obligations or responsibilities of any other person.

CURRENCY TRANSACTIONS. Those Underlying Funds that may engage in currency transactions do not expect to engage in currency transactions for the purpose of hedging against declines in the value of the Underlying Funds' assets that are denominated in a non-U.S. currency. The Underlying Funds may enter into non-U.S. currency forward and non-U.S. currency futures contracts to facilitate local securities settlements or to protect against currency exposure in connection with their distributions to shareholders, but may not enter into such contracts for speculative purposes.

A forward currency contract is an obligation to purchase or sell a specific currency at a future date, which may be any fixed number of days from the date of the contract agreed upon by the parties, at a price set at the time of the contract. A currency futures contract is a contract involving an obligation to deliver or acquire the specified amount of a specific currency, at a specified price and at a specified future time. Currency futures contracts may be settled on a net cash payment basis rather than by the sale and delivery of the underlying currency. To the extent required by law, liquid assets committed to futures contracts will be maintained.

Foreign exchange transactions involve a significant degree of risk and the markets in which foreign exchange transactions are effected are highly volatile, highly specialized and highly technical. Significant changes, including changes in liquidity and prices, can occur in such markets within very short periods of time, often within minutes. Foreign exchange trading risks include, but are not limited to, exchange rate risk, counterparty risk, maturity gap, interest rate risk, and potential interference by foreign governments through regulation of local exchange markets, foreign investment or particular transactions in foreign currency. If BFA utilizes foreign exchange transactions at an inappropriate time or judges market conditions, trends or correlations incorrectly, foreign exchange transactions may not serve their intended purpose of improving the correlation of an Underlying Fund's return with the performance of its underlying index and may lower the Underlying Fund's return. An Underlying Fund could experience losses if the value of its currency forwards, options and futures positions were poorly correlated with its other investments or if it could not close out its positions because of an illiquid market. In addition, an Underlying Fund could incur transaction costs, including trading commissions, in connection with certain foreign currency transactions.

DIVERSIFICATION AND CONCENTRATION. Certain of the Underlying Funds are "diversified funds." A diversified fund is one that, with respect to 75% of its total assets is limited by the 1940 Act such that it does not invest more than 5% of its total assets in securities of any one issuer and does not acquire more than 10% of the outstanding voting securities of any one issuer (excluding cash and cash items, U.S. government securities, and securities of other investment companies). The remaining 25% of a diversified fund's assets may be invested in any manner.

Other Underlying Funds are classified as "non-diversified" for purposes of the 1940 Act. A "non-diversified" classification means that an Underlying Fund is not limited by the 1940 Act with regard to the percentage of its assets that may be invested in the securities of a single issuer. The securities of a particular issuer (or securities of issuers in particular industries) may dominate the Underlying Fund's underlying index and, consequently, the Underlying Fund's investment portfolio. This may adversely affect the Underlying Fund's performance or subject the Underlying Fund's shares to greater price volatility than that experienced by more diversified investment companies.

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In addition, an Underlying Fund may concentrate its investments in a particular industry or group of industries. The securities of issuers in particular industries may dominate an Underlying Fund's underlying index and consequently the Underlying Fund's investment portfolio. This may adversely affect the Underlying Fund's performance or subject the Underlying Fund's shares to greater price volatility than that experienced by less concentrated investment companies.

Each Underlying Fund intends to maintain the required level of diversification and otherwise conduct its operations so as to qualify as a "regulated investment company" for purposes of the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), and to relieve the Underlying Fund of any liability for U.S. federal income tax to the extent that its earnings are distributed to shareholders, provided that the Underlying Fund satisfies a minimum distribution requirement. Compliance with the diversification requirements of the Internal Revenue Code may limit the investment flexibility of an Underlying Fund and make it less likely that the Underlying Fund will meet its investment objective.

EQUITY SECURITIES. An investment in an Underlying Fund should be made with an understanding of the risks inherent in an investment in equity securities, including the risk that the financial condition of issuers may become impaired or that the general condition of the stock market may deteriorate (either of which may cause a decrease in the value of the portfolio securities and thus in the value of shares of an Underlying Fund). Common stocks are susceptible to general stock market fluctuations and to volatile increases and decreases in value as market confidence and perceptions of their issuers change. These investor perceptions are based on various and unpredictable factors, including expectations regarding government, economic, monetary and fiscal policies, inflation and interest rates, economic expansion or contraction, and global or regional political, economic or banking crises. Holders of common stocks incur more risks than holders of preferred stocks and debt obligations because common stockholders generally have rights to receive payments from stock issuers inferior to the rights of creditors, or holders of debt obligations or preferred stocks. Further, unlike debt securities, which typically have a stated principal amount payable at maturity (the value of which, however, is subject to market fluctuations prior to maturity), or preferred stocks, which typically have a liquidation preference and which may have stated optional or mandatory redemption provisions, common stocks have neither a fixed principal amount nor a maturity.

Although most of the securities in each Underlying Index are listed on a national securities exchange, the principal trading market for some may be in the over-the-counter market. The existence of a liquid trading market for certain securities may depend on whether dealers will make a market in such securities. There can be no assurance that a market will be made or maintained or that any such market will be or remain liquid. The price at which securities may be sold and the value of an Underlying Fund's shares will be adversely affected if trading markets for an Underlying Fund's portfolio securities are limited or absent, or if bid/ask spreads are wide.

FLOATING-RATE AND VARIABLE-RATE OBLIGATIONS. The Underlying Funds may purchase debt instruments with interest rates that are periodically adjusted at specified intervals or whenever a benchmark rate or index changes. The floating-rate and variable-rate instruments that the Underlying Funds may purchase include certificates of participation in such instruments. The interest rate adjustments generally limit the increase or decrease in the amount of interest received on the debt instruments. Floating-rate and variable-rate instruments are subject to interest rate risk and credit risk. The interest rate on an inverse floating-rate security resets in the opposite direction from the market rate of interest to which the security is benchmarked. An inverse floating rate security may exhibit greater price volatility than a fixed-rate security of similar credit quality.

The Underlying Funds may purchase floating-rate and variable-rate demand notes and bonds, which are obligations ordinarily having stated maturities in excess of thirteen months, but which permit the holder to demand payment of principal at any time, or at specified intervals not exceeding 397 days, as defined in Rule 2a-7 of the 1940 Act. Variable-rate demand notes including master demand notes are demand obligations that permit an Underlying Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between an Underlying Fund, as lender, and the borrower. The interest rates on these notes fluctuate from time to time. The issuer of such obligations ordinarily has a corresponding right, after a given period, to prepay in its discretion the outstanding principal amount of the obligations plus accrued interest upon a specified number of days' notice to the holders of such obligations. The interest rate on a floating-rate demand obligation is based on a known lending rate, such as a bank's prime rate, and is adjusted automatically each time such rate is adjusted. The interest rate on a variable-rate demand obligation is adjusted automatically at specified intervals. Frequently, such obligations are secured by letters of credit or other credit support arrangements provided by banks.

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These obligations are direct lending arrangements between the lender and borrower. There may not be an established secondary market for these obligations, although they are redeemable at face value. Accordingly, where these obligations are not secured by letters of credit or other credit support arrangements, an Underlying Fund's right to redeem is dependent on the ability of the borrower to pay principal and interest on demand. Such obligations frequently are not rated by credit rating agencies and an Underlying Fund may invest in obligations that are not so rated only if BFA determines that at the time of investment the obligations are of comparable quality to the other obligations in which an Underlying Fund may invest. BFA considers on an ongoing basis the creditworthiness of the issuers of the floating-rate and variable-rate demand obligations in an Underlying Fund's portfolio.

FORWARD COMMITMENTS, WHEN-ISSUED PURCHASES AND DELAYED-DELIVERY TRANSACTIONS. Certain of the Underlying Funds may purchase or sell securities on a when-issued or delayed-delivery basis and make contracts to purchase or sell securities for a fixed price at a future date beyond customary settlement time. Securities purchased or sold on a when-issued, delayed-delivery or forward commitment basis involve a risk of loss if the value of the security to be purchased declines, or the value of the security to be sold increases, before the settlement date. Although an Underlying Fund will generally purchase securities with the intention of acquiring them, the Underlying Fund may dispose of securities purchased on a when-issued, delayed-delivery or a forward commitment basis before settlement when deemed appropriate by BFA.

FUNDING AGREEMENTS. Certain of the Underlying Funds may invest in short-term funding agreements. A funding agreement is a contract between an issuer and a purchaser that obligates the issuer to pay a guaranteed rate of interest on a principal sum deposited by the purchaser. Funding agreements will also guarantee the return of principal and may guarantee a stream of payments over time. A funding agreement has a fixed maturity and may have either a fixed-, variable- or floating-interest rate that is based on an index and guaranteed for a fixed time period. An Underlying Fund will purchase short-term funding agreements only from banks and insurance companies that, at the time of purchase, are rated in one of the three highest rating categories by a nationally recognized statistical ratings organization ("NRSRO").

The secondary market, if any, for these funding agreements is limited; thus, such investments purchased by an Underlying Fund may be treated as illiquid. If a funding agreement is determined to be illiquid it will be valued at its fair market value as determined by procedures approved by the Underlying Fund's Board of Trustees.

FUTURES CONTRACTS, OPTIONS TRANSACTIONS, AND SWAP TRANSACTIONS.

FUTURES CONTRACTS. Each Underlying Fund may enter into futures contracts and options. These futures contracts and options will be used to simulate investment in the respective underlying index that the Underlying Fund is tracking, to facilitate trading or to reduce transaction costs. Each Underlying Fund will enter into futures contracts and options that are traded on a U.S. or non-U.S. exchange. No Underlying Fund will use futures or options for speculative purposes. Each Underlying Fund intends to use futures and options in accordance with Rule 4.5 of the Commodity Exchange Act ("CEA"). The Trust, on behalf of each Underlying Fund, has claimed an exclusion from the definition of the term "commodity pool operator" in accordance with Rule 4.5 so that each Underlying Fund is not subject to registration or regulation as a commodity pool operator under the CEA.

Futures contracts provide for the future sale by one party and purchase by another party of a specified amount of a specific instrument or index at a specified future time and at a specified price. Each Underlying Fund may enter into futures contracts to purchase securities indexes when BFA anticipates purchasing the underlying securities and believes prices will rise before the purchase will be made. To the extent required by law, liquid assets committed to futures contracts will be maintained.

A call option gives a holder the right to purchase a specific security at a specified price ("exercise price") within a specified period of time. A put option gives a holder the right to sell a specific security at a specified exercise price within a specified period of time. The initial purchaser of a call option pays the "writer" a premium, which is paid at the time of purchase and is retained by the writer whether or not such option is exercised. Each Underlying Fund may purchase put options to hedge its portfolio against the risk of a decline in the market value of securities held and may purchase call options to hedge against an increase in the price of securities it is committed to purchase. Each Underlying Fund may write put and call options along with a long position in options to increase its ability to hedge against a change in the market value of the securities it holds or is committed to purchase. Investments in futures contracts and other investments that contain leverage may require each Underlying Fund to maintain liquid assets. Generally, each Underlying Fund maintains an amount of liquid assets equal to its obligations relative to the position involved, adjusted daily on a marked-to-market basis. With respect to futures contracts that are contractually required to "cash-settle," each Underlying Fund maintains liquid assets in an amount at least equal to each Underlying Fund's daily marked-to-market obligation (I.E., each Underlying Fund's daily net liability, if any), rather than

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the contracts' notional value (I.E., the value of the underlying asset). By maintaining assets equal to its net obligation under cash-settled futures contracts, the Underlying Fund may employ leverage to a greater extent than if each Underlying Fund set aside assets equal to the futures contracts' full notional value. Each Underlying Fund bases its asset maintenance policies on methods permitted by the staff of the SEC and may modify these policies in the future to comply with any changes in the guidance articulated from time to time by the SEC or its staff.

OPTIONS TRANSACTIONS. Each Underlying Fund may invest in options on futures contracts. An option on a futures contract, as contrasted with the direct investment in such a contract, gives the purchaser the right, in return for the premium paid, to assume a position in the underlying futures contract at a specified exercise price at any time prior to the expiration date of the option. Upon exercise of an option, the delivery of the futures position by the writer of the option to the holder of the option will be accompanied by delivery of the accumulated balance in the writer's futures margin account that represents the amount by which the market price of the futures contract exceeds (in the case of a call) or is less than (in the case of a put) the exercise price of the option on the futures contract. The potential for loss related to the purchase of an option on a futures contract is limited to the premium paid for the option plus transaction costs. Because the value of the option is fixed at the point of sale, there are no daily cash payments by the purchaser to reflect changes in the value of the underlying contract; however, the value of the option changes daily and that change would be reflected in the NAV of the Underlying Fund. The potential for loss related to writing call options is unlimited. The potential for loss related to writing put options is limited to the agreed upon price per share times the number of shares minus the premium received from writing the put.

Each Underlying Fund may purchase and write put and call options on futures contracts that are traded on a U.S. exchange as a hedge against changes in value of its portfolio securities, or in anticipation of the purchase of securities, and may enter into closing transactions with respect to such options to terminate existing positions. There is no guarantee that such closing transactions can be effected.

Upon entering into a futures contract, the Underlying Fund will be required to deposit with the broker an amount of cash or cash equivalents known as "initial margin," which is in the nature of a performance bond or good faith deposit on the contract and is returned to the Underlying Fund upon termination of the futures contract, assuming all contractual obligations have been satisfied. Subsequent payments, known as "variation margin," to and from the broker will be made daily as the price of the index underlying the futures contract fluctuates, making the long and short positions in the futures contract more or less valuable, a process known as "marking-to-market." At any time prior to the expiration of a futures contract, the Underlying Fund may elect to close the position by taking an opposite position, which will operate to terminate the Underlying Fund's existing position in the contract.

SWAP TRANSACTIONS. Swap transactions are contracts between parties in which one party agrees to make periodic payments to the other party based on the change in market value or level of a specified rate, index or asset. In return, the other party agrees to make periodic payments to the first party based on the return of a different specified rate, index or asset. Swap agreements will usually be performed on a net basis, with each Underlying Fund receiving or paying only the net amount of the two payments. The net amount of the excess, if any, of each Underlying Fund's obligations over its entitlements with respect to each swap is accrued on a daily basis and an amount of liquid assets having an aggregate value at least equal to the accrued excess will be maintained by each Underlying Fund.

The use of interest-rate and index swaps is a highly specialized activity that involves investment techniques and risks different from those associated with ordinary portfolio security transactions. These transactions generally do not involve the delivery of securities or other underlying assets or principal.

HIGH-YIELD SECURITIES. Certain of the Underlying Funds may invest in high-yield debt securities. Investment in high yield securities generally provides greater income and increased opportunity for capital appreciation than investments in higher quality securities, but they also typically entail greater price volatility and credit risk. These high yield securities are regarded as predominantly speculative with respect to the issuer's continuing ability to meet principal and interest payments. Analysis of the creditworthiness of issuers of debt securities that are high yield may be more complex than for issuers of higher quality debt securities. In addition, high yield securities are often issued by smaller, less creditworthy issuers or by highly leveraged (indebted) firms, which are generally less able than more financially stable firms to make scheduled payments of interest and principal. The risks posed by securities issued under such circumstances are substantial. Investing in high-yield debt securities involves risks that are greater than the risks of investing in higher quality debt securities. These risks include:
(i) changes in credit status, including weaker overall credit conditions of issuers and risks of default; (ii) industry, market and

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economic risk; and (iii) greater price variability and credit risks of certain high-yield securities such as zero coupon and payment-in-kind securities. While these risks provide the opportunity for maximizing return over time, they may result in greater volatility of the value of an Underlying Fund's portfolio.

Furthermore, the value of high-yield securities may be more susceptible to real or perceived adverse economic, company or industry conditions than is the case for higher quality securities. The market values of certain of these lower-rated and unrated debt securities tend to reflect individual corporate developments to a greater extent than do higher-rated securities, and tend to be more sensitive to economic conditions than are higher-rated securities. Adverse market, credit or economic conditions could make it difficult at certain times to sell certain high-yield securities held by an Underlying Fund.

The secondary market on which high yield securities are traded may be less liquid than the market for higher grade securities. Less liquidity in the secondary trading market could adversely affect the price at which the Underlying Funds could sell a high yield security, and could adversely affect the daily net asset value per share of the Underlying Funds. When secondary markets for high yield securities are less liquid than the market for higher grade securities, it may be more difficult to value the securities because there is less reliable, objective data available.

The use of credit ratings as a principal method of selecting high yield securities can involve certain risks. For example, credit ratings evaluate the safety of principal and interest payments, not the market value risk of high yield securities. Also, credit rating agencies may fail to change credit ratings in a timely fashion to reflect events since the security was last rated.

HYBRID ARM SECURITIES. Hybrid ARM securities are interests in pools of hybrid adjustable-rate mortgages (hybrid ARMs). A hybrid ARM is a mortgage in which the interest rate is fixed for a specified period and then resets periodically, or floats, for the remaining mortgage term. After the initial fixed interest rate period, the interest rate on a hybrid ARM can be reset by a maximum specified amount to an adjustable rate based on a margin over an identified index. As with other adjustable rate mortgages, the adjustable interest rates on hybrid ARMs are subject to periodic and lifetime caps on the increased rates that mortgagors are required to pay.

Hybrid ARM securities are subject to a combination of the risks associated with fixed-rate and adjustable-rate mortgage-backed securities. If a greater percentage of the mortgage pool backing a hybrid ARM security consists of hybrid ARMS in their initial fixed-rate mode, the hybrid ARM securities will be more susceptible to the risks associated with fixed-rate bonds and mortgage-backed securities. These risks would include possible reductions in market value (i) during periods of rising interest rates and (ii) due to the unanticipated shortening or extension of the security's average life resulting from unforeseen mortgage prepayment patterns. If a greater percentage of the underlying mortgage pool consists of hybrid ARMS in their adjustable-rate mode, the hybrid ARM securities will be more susceptible to the risks associated with capped adjustable-rate securities. These risks include (i) the possibility of reduced yields during periods of falling interest rates, (ii) possible reductions in market value if market interest rates rise above the interest rate caps on the underlying hybrid ARMs, and (iii) possible increases in mortgage default rates to the extent that mortgagors are unable to afford higher adjustable mortgage rates.

Because hybrid ARM securities are more complex than conventional fixed-rate and adjustable-rate mortgage-backed securities, it may be more difficult for investors to analyze and predict how the values of hybrid ARM securities will change in response to market interest rate and credit conditions. As a result of this uncertainty, a hybrid ARM security could suffer from a disproportionate reduction in value or loss of market liquidity during periods of volatile interest rates or credit market disruptions.

ILLIQUID SECURITIES. Certain of the Underlying Funds may invest up to 15% (except that BlackRock Cash Funds: Institutional may invest only up to 10%) of the value of their respective net assets in securities as to which a liquid trading market does not exist, provided such investments are consistent with their respective investment objectives. Such securities may include securities that are not readily marketable, such as privately issued securities and other securities that are subject to legal or contractual restrictions on resale, floating-rate and variable-rate demand obligations as to which an Underlying Fund cannot exercise a demand feature on not more than seven days' notice and as to which there is no secondary market, and repurchase agreements providing for settlement more than seven days after notice.

INFLATION-PROTECTED OBLIGATIONS. Certain of the Underlying Funds invest almost exclusively in inflation-protected public obligations of the U.S. Treasury, commonly known as "TIPS." TIPS are a type of U.S. government obligation issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS are income-generating instruments whose interest and principal payments are adjusted for inflation - a sustained increase in prices that erodes the purchasing power of

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money. The inflation adjustment, which is typically applied monthly to the principal of the bond, follows a designated inflation index, such as the consumer price index. A fixed coupon rate is applied to the inflation-adjusted principal so that as inflation rises, both the principal value and the interest payments increase. This can provide investors with a hedge against inflation, as it helps preserve the purchasing power of an investment. Because of this inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds.

ISHARES FUNDS. The iShares Funds (the "Underlying iShares Funds") and the other Underlying Funds in which the Master Portfolios were invested as of March 31, 2010 are listed below under "Investment Adviser and Other Service Providers." Each iShares Fund is a type of investment company referred to as an exchange-traded fund ("ETF"). Each iShares Fund is designed to track a particular index and is advised by BFA. Shares of the Underlying iShares Funds are listed for trading on the national securities exchanges and trade throughout the day on those exchanges and other secondary markets. There can be no assurance that the requirements of the national securities exchanges necessary to maintain the listing of shares of the Underlying iShares Funds will continue to be met. A national securities exchange may, but is not required to, remove the shares of the Underlying iShares Funds from listing if
(1) following the initial 12-month period beginning upon the commencement of trading of an Underlying iShares Fund, there are fewer than 50 beneficial holders of the shares for 30 or more consecutive trading days, (2) the value of the Underlying iShares Fund's underlying index is no longer calculated or available, or (3) any other event shall occur or condition exist that, in the opinion of the national securities exchange, makes further dealings on the national securities exchange inadvisable. A national securities exchange will remove the shares of an Underlying iShares Fund from listing and trading upon termination of the Underlying iShares Fund. As in the case of other publicly-traded securities, brokers' commissions on transactions will be based on negotiated commission rates at customary levels. An investment in an ETF generally presents the same primary risks as an investment in an open-end investment company that is not exchange-traded and that has the same investment objectives, strategies, and policies. The price of an ETF can fluctuate within a wide range, and an Underlying Fund could lose money investing in an ETF if the prices of the securities held by the ETF go down. In addition, ETFs are subject to the following risks that do not apply to an open-end investment company that is not exchange-traded: (i) the market price of the ETF's shares may trade at a discount to their net asset value; (ii) an active trading market for an ETF's shares may not develop or be maintained; or (iii) trading of an ETF's shares may be halted if the listing exchange's officials deem such action appropriate, the shares are delisted from the exchange, or the activation of market-wide "circuit breakers" (which are tied to large decreases in stock prices) halts stock trading generally.

INVESTMENT COMPANIES. The Underlying Funds may invest in the securities of other investment companies (including money market funds) to the extent allowed by law. Under the 1940 Act, an Underlying Fund's investment in investment companies is limited to, subject to certain exceptions, (i) 3% of the total outstanding voting stock of any one investment company, (ii) 5% of the Underlying Fund's total assets with respect to any one investment company and
(iii) 10% of the Underlying Fund's total assets invested in investment companies in the aggregate. To the extent allowed by law or regulation, each Underlying Fund may invest its assets in securities of investment companies that are money market funds, including those advised by BFA or otherwise affiliated with BFA, in excess of the limits discussed above. Other investment companies in which an Underlying Fund invests can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Underlying Fund.

An Underlying Fund may purchase shares of ETFs. An Underlying Fund may purchase ETF shares for the same reason it would purchase (and as an alternative to purchasing) futures contracts - to obtain relatively low-cost exposure to the stock market while maintaining flexibility to meet the liquidity needs of the Underlying Fund. ETF shares enjoy several advantages over futures. Depending on the market, the holding period, and other factors, ETF shares can be less costly than futures. In addition, ETF shares can be purchased for smaller sums and offer exposure to market sectors and styles for which there is no suitable or liquid futures contract. An Underlying Fund may also purchase ETF shares for other purposes, including improving its ability to track its underlying index. An Underlying Fund may invest in shares of ETFs that are advised by BFA.

The iShares MSCI Emerging Markets Index Fund, in order to improve its portfolio liquidity and its ability to track the MSCI Emerging Markets Index, may invest up to 10% of its assets in shares of other iShares Funds that invest in securities in the iShares MSCI Emerging Markets Index Fund. BFA will not charge advisory fees on that portion of the iShares MSCI Emerging Market Index Fund's assets invested in shares of other iShares Funds.

An investment in an iShares Fund that invests in foreign countries involves risks similar to those of investing in a broad-based portfolio of equity securities traded on exchanges in the respective countries covered by the individual iShares Fund. These risks include market fluctuations caused by such factors as economic and political developments, changes in interest rates

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and perceived trends in stock prices. Investing in securities issued by companies domiciled in countries other than the domicile of the investor and denominated in currencies other than an investor's local currency entails certain considerations and risks not typically encountered by the investor in making investments in its home country and in that country's currency. See "Non-U.S. Securities and Emerging Markets Securities" below.

LETTERS OF CREDIT. Certain of the debt obligations (including municipal securities, certificates of participation, commercial paper and other short-term obligations) that certain of the Underlying Funds may purchase may be backed by an unconditional and irrevocable letter of credit of a bank, savings and loan association or insurance company that assumes the obligation for payment of principal and interest in the event of default by the issuer. Only banks, savings and loan associations and insurance companies that, in the opinion of BFA, are of comparable quality to issuers of other permitted investments of an Underlying Fund may be used for letter of credit-backed investments.

LOAN PARTICIPATIONS AND ASSIGNMENTS. An Underlying Fund may purchase interests in loan participations that typically represent direct participation in loans to corporate borrowers, and generally are offered by an intermediary bank or other financial institution or lending syndicate. Under these loan participation arrangements, an Underlying Fund will have the right to receive payments of principal, interest and any fees to which it is entitled from the bank selling the loan participation upon receipt by the bank of the payments from the borrower. The borrower in the underlying loan will be deemed to be the issuer of the participation interest except to the extent an Underlying Fund derives its rights from the intermediary bank that sold the loan participation. Interests in loan participations in which an Underlying Fund may invest may not be rated by any NRSRO. An Underlying Fund will invest in loan participations that are not so rated only if BFA determines that at the time of the investment the interests in loan participations are of comparable quality to the other instruments in which the Underlying Fund may invest.

Because the bank issuing the loan participation does not guarantee the participation in any way, the participation is subject to the credit risks associated with the underlying corporate borrower. In addition, it may be necessary, under the terms of the loan participation, for an Underlying Fund to assert its rights against the underlying corporate borrower in the event that the underlying corporate borrower should fail to pay principal and interest when due. Thus, an Underlying Fund could be subject to delays, expenses, and risks that are greater than those that would have been involved if the Underlying Fund had purchased a direct obligation of the borrower.

An Underlying Fund may also assume the credit risk associated with an interposed bank or other financial intermediary. In the case of a loan that is administered by an agent bank acting as agent for all holders, the agent bank administers the terms of the loan, as specified in the loan agreement. In addition, the agent bank is normally responsible for the collection of principal and interest payments from the corporate borrower and the apportionment of these payments to the credit of all institutions that are parties to the loan agreement. Unless, under the terms of the loan or other indebtedness, an Underlying Fund has direct recourse against the corporate borrower, the Underlying Fund may have to rely on the agent bank or other financial intermediary to apply appropriate credit remedies against a corporate borrower.

A financial institution's employment as agent bank might be terminated in the event that it fails to observe a requisite standard of care or becomes insolvent. A successor agent bank would generally be appointed to replace the terminated agent bank, and assets held by the agent bank under the loan agreement should remain available to holders of such indebtedness. However, if assets held by the agent bank for the benefit of an Underlying Fund were determined to be subject to the claims of the agent bank's general creditors, the Underlying Fund might incur certain costs and delays in realizing payment on a loan or loan participation and could suffer a loss of principal and/or interest. In situations involving other interposed financial institutions (E.G., an insurance company or governmental agency) similar risks may arise.

Moreover, under the terms of the loan participation, an Underlying Fund may be regarded as a creditor of the issuing bank (rather than of the underlying corporate borrower), so that the Underlying Fund also may be subject to the risk that the issuing bank may become insolvent. Further, in the event of the bankruptcy or insolvency of the corporate borrower, the loan participation might be subject to certain defenses that can be asserted by the borrower as a result of improper conduct by the issuing bank. If an Underlying Fund does not receive scheduled interest or principal payments on such indebtedness, the Underlying Fund's net asset value and yield could be adversely affected. Loans that are fully secured offer an Underlying Fund more protection than an unsecured loan in the event of non-payment of scheduled interest or principal. However, there is no assurance that the liquidation of collateral from a secured loan would satisfy the corporate borrower's obligation, or that the collateral could be liquidated.

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An Underlying Fund may invest in loan participations of below investment-grade quality. Indebtedness of companies whose creditworthiness is poor involves substantially greater risks, and may be highly speculative. Some companies may never pay off their indebtedness, or may pay only a small fraction of the amount owed. Consequently, when investing in indebtedness of companies with poor credit, an Underlying Fund bears a substantial risk of losing the entire amount invested.

Loans and other types of direct indebtedness may be subject to restrictions on resale. In addition, the secondary market, if any, for loans and other types of direct indebtedness may be limited; thus, loans and other types of direct indebtedness purchased by an Underlying Fund may be treated as illiquid.

Investments in loans through a direct assignment of the financial institution's interests with respect to the loan may involve additional risks to an Underlying Fund. For example, if a loan is foreclosed, an Underlying Fund could become part owner of any collateral, and would bear the costs and liabilities associated with owning and disposing of the collateral. In addition, it is conceivable that under emerging legal theories of lender liability, an Underlying Fund could be held liable as co-lender. It is unclear whether loans and other forms of direct indebtedness offer securities law protections against fraud and misrepresentation. In the absence of definitive regulatory guidance, an Underlying Fund relies on BFA's research in an attempt to avoid situations where fraud or misrepresentation could adversely affect the Underlying Fund.

LOANS OF PORTFOLIO SECURITIES. Each Underlying Fund may lend portfolio securities in the same manner as the Master Portfolios, as described above.

MORTGAGE PASS-THROUGH SECURITIES. A significant portion of the Barclays Capital U.S. Aggregate Bond Index and the entire Barclays Capital U.S. MBS Index represent the U.S. agency mortgage pass-through segment of the U.S. investment grade bond market. Therefore, a substantial portion of each of the iShares Barclays Aggregate Bond Fund and iShares Barclays MBS Bond Fund is invested to seek exposure to a representative sample of U.S. agency mortgage pass-through securities included in such indexes. The term "U.S. agency mortgage pass-through security" refers to a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. government-sponsored enterprises, such as the Government Natioinal Mortgage Association, Federal National Mortgage Association or the Federal Home Lome Mortgage Corporation. In the basic mortgage pass-through structure, mortgages with similar issuer, term and coupon characteristics are collected and aggregated into a "pool" consisting of multiple mortgage loans. The pool is assigned a CUSIP number and undivided interests in the pool are traded and sold as pass-through securities. The holder of the security is entitled to a PRO RATA share of principal and interest payments (including unscheduled prepayments) from the pool of mortgage loans. The portion of the Barclays Capital U.S. Aggregate Bond Index and Barclays Capital U.S. MBS Index representing the mortgage pass-through segment of the U.S. investment grade bond market is comprised of multiple pools of fixed-rate and hybrid ARMs mortgage pass-through securities. A hybrid ARM is a mortgage in which the homeowner pays a fixed interest rate for a fixed period of time (typically 3, 5, 7, or 10 years) and a floating rate after that period, combining the features of fixed-rate and adjustable-rate mortgage securities.

An investment in a specific pool of pass-through securities requires an analysis of the specific prepayment risk of mortgages within the covered pool (since mortgagors typically have the option to prepay their loans). The level of prepayments on a pool of mortgage securities is difficult to predict and can impact the subsequent cash flows, value and yield of the mortgage pool. In addition, when trading specific mortgage pools, precise execution, delivery and settlement arrangements must be negotiated for each transaction. These factors combine to make trading in mortgage pools somewhat cumbersome.

For these and other reasons, the iShares Barclays Aggregate Bond Fund and iShares Barclays MBS Bond Fund seek to obtain exposure to the fixed-rate portion of the U.S. agency mortgage pass-through securities, which represent a significant portion of their respective underlying indexes, primarily through the use of "to-be-announced" or "TBA transactions." "TBA" refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Most transactions in fixed-rate mortgage pass-through securities occur through the use of TBA transactions. TBA transactions generally are conducted in accordance with widely-accepted guidelines which establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined two days prior to settlement date. Each Underlying Fund intends to use TBA transactions in several ways. For example, each Underlying Fund expects that it will regularly enter into TBA agreements and "roll over" such agreements prior to the settlement date stipulated in such agreements. This type of TBA transaction is sometimes known as a "TBA roll." In a "TBA roll," each Underlying Fund generally will sell the obligation to purchase the pools stipulated in the TBA agreement prior to the stipulated settlement date and will enter into a new TBA agreement for future delivery of

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pools of mortgage pass-through securities. In addition, each Underlying Fund may enter into TBA agreements and settle such transactions on the stipulated settlement date by accepting actual receipt or delivery of the pools of mortgage pass-through securities stipulated in the TBA agreement. Default by or bankruptcy of a counterparty to a TBA transaction would expose the Underlying Fund to possible loss because of adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction. To minimize this risk, each Underlying Fund will enter into TBA transactions only with established counterparties (such as major broker-dealers) and BFA will monitor the creditworthiness of such counterparties. Each Underlying Fund's use of "TBA rolls" may cause the Underlying Fund to experience higher portfolio turnover, higher transaction costs and to pay higher capital gain distributions to shareholders (which may be taxable).

The iShares Barclays Aggregate Bond Fund and iShares Barclays MBS Bond Fund intend to invest cash pending settlement of any TBA transactions in money market instruments, repurchase agreements or other high-quality, liquid short-term instruments, including money market funds advised by BFA. Each Underlying Fund will assume its pro rata share of fees and expenses of any money market fund that it may invest in, in addition to each Underlying Fund's own fees and expenses.

MORTGAGE SECURITIES. Mortgage securities are issued by government and non-government entities such as banks, mortgage lenders, or other institutions. A mortgage security is an obligation of the issuer that is backed by a mortgage or pool of mortgages or a direct interest in an underlying pool of mortgages. Some mortgage securities, such as collateralized mortgage obligations, make payments of both principal and interest at a range of specified intervals; others make semi-annual interest payments at a pre-determined rate and repay principal at maturity (like a typical bond). Mortgage securities are based on different types of mortgages, including those on commercial real estate or residential properties. Stripped mortgage securities are created when the interest and principal components of a mortgage security are separated and sold as individual securities. In the case of a stripped mortgage security, the holder of the "principal-only" security (PO) receives the principal payments made by the underlying mortgage, while the holder of the "interest-only" security (IO) receives interest payments from the same underlying mortgage.

The value of mortgage securities may change due to shifts in the market's perception of the creditworthiness of issuers and changes in interest rates or liquidity. The value of some mortgage-backed securities may be particularly sensitive to changes in prevailing interest rates. In addition, regulatory or tax changes may adversely affect the mortgage securities market as a whole. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information required to evaluate the practices of these mortgage originators. In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate.

Non-government mortgage securities may be subject to greater price changes than government issues. Mortgage securities are subject to prepayment risk. Prepayment risk is the risk that early principal payments made on the underlying mortgages, usually in response to a reduction in interest rates, will result in the return of principal to the investor, causing the investor to be invested subsequently at a lower current interest rate. Alternatively, in a rising interest rate environment, mortgage security values may be adversely affected when prepayments on underlying mortgages do not occur as anticipated, resulting in the extension of the security's effective maturity and the related increase in interest rate sensitivity of a longer-term instrument. The prices of stripped mortgage securities tend to be more volatile in response to changes in interest rates than those of non-stripped mortgage securities. In addition, although mortgages and mortgage-related securities are generally supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Also see "Asset-Backed and Commercial Mortgage-Backed Securities," "Hybrid ARM Securities" and "Mortgage Pass-Through Securities."

MUNICIPAL SECURITIES. Certain of the Underlying Funds may invest in municipal securities. Municipal securities are generally issued by states and local governments and their agencies, authorities and other instrumentalities. Municipal bonds are subject to interest rate, credit and market risk. The ability of a municipal security issuer to make payments on that security

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could be affected by litigation, legislation or other political events or the bankruptcy of the issuer. Lower-rated municipal bonds are subject to greater credit and market risk than higher quality municipal bonds. Municipal securities in which the Underlying Funds may invest include, but are not limited to, municipal lease obligations and securities issued by entities whose underlying assets are municipal bonds. There is no guarantee that income from municipal securities will be exempt from federal or state taxes. Changes in federal or state tax treatment of municipal securities may make municipal securities less attractive as investments or cause them to lose value.

In addition, certain of the Underlying Funds may invest in residual interest bonds, which are created by depositing municipal securities in a trust and dividing the income stream of an underlying municipal bond in two parts, one, a variable-rate security and the other, a residual interest bond. The interest rate for the variable-rate security is determined by an index or an auction process held approximately every seven to 35 days, while the residual interest bond holder receives the balance of the income from the underlying municipal bond less an auction fee. The market prices of residual interest bonds may be highly sensitive to changes in market rates and may decrease significantly when market rates increase.

BlackRock Cash Funds: Institutional may invest in high-quality long-term municipal bonds, municipal notes and short-term commercial paper, with remaining maturities not exceeding 397 calendar days.

NON-U.S. SECURITIES AND EMERGING MARKETS SECURITIES. Certain of the Underlying Funds may invest in certain securities of non-U.S. issuers. Investing in the securities of non-U.S. issuers involves special risks and considerations not typically associated with investing in U.S. issuers. These include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or potentially confiscatory taxation or war, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, potential restrictions of the flow of international capital, generally less liquid and less efficient securities markets, generally greater price volatility, less publicly available information about issuers, the imposition of withholding or other taxes, higher transaction and custody costs, delays and risks attendant in settlement procedures, difficulties in enforcing contractual obligations, lesser liquidity and significantly smaller market capitalization of most non-U.S. securities markets, more substantial government interference with the economy and transaction costs of foreign currency conversions. Non-U.S. issuers may be subject to less governmental regulation than U.S. issuers. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy with respect to growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions. In addition, changes in foreign exchange rates also will affect the value of securities denominated or quoted in currencies other than the U.S. dollar. Certain foreign markets have specific geographical risks such as a heightened likelihood of earthquakes, tsunamis, or volcanoes. Certain foreign markets also experience acts of terrorism, territorial disputes or other defense concerns. These situations may have a significant impact on the economies of, and investments in, these geographic areas.

Securities issued by certain companies organized outside the United States may not be deemed to be foreign securities (but rather deemed to be U.S. securities) if the company's principal operations are conducted from the U.S., the company's equity securities trade principally on a U.S. stock exchange, or the company does a substantial amount of business in the U.S.

OBLIGATIONS OF FOREIGN GOVERNMENTS, SUPRANATIONAL ENTITIES AND BANKS. Certain of the Underlying Funds may invest in U.S. dollar-denominated short-term obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions, agencies or instrumentalities that are determined by BFA to be of comparable quality to the other obligations in which the Underlying Funds may invest. Certain foreign governments, specifically foreign governments in emerging markets, historically have encountered difficulties in servicing their debt obligations, withheld payments of principal and interest, and declared moratoria on the payment of principal and interest on their sovereign debts. Certain of the Underlying Funds may also invest in debt obligations of supranational entities. Supranational entities include international organizations designated or supported by governmental entities to promote economic reconstruction or development and international banking institutions and related government agencies. Examples include the International Bank for Reconstruction and Development (the World Bank), the Asian Development Bank and the InterAmerican Development Bank. The percentage of an Underlying Fund's assets invested in obligations of foreign governments and supranational entities will vary depending on the relative yields of such securities, the economic and financial markets of the countries in which the investments are made and the interest rate climate of such countries.

Certain of the Underlying Funds may invest a portion of their total assets in debt obligations of foreign branches of U.S. banks or U.S. branches of foreign banks that are denominated in and pay interest in U.S. dollars.

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Certain of the Underlying Funds may purchase publicly-traded common stocks of foreign corporations. To the extent an Underlying Fund invests in securities of foreign issuers, the Underlying Fund's investment in such securities may also be in the form of American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs") and European Depositary Receipts ("EDRs") (collectively, "Depositary Receipts"). Depositary Receipts are receipts, typically issued by a bank or trust company, that evidence ownership of underlying securities issued by a foreign corporation. For ADRs, the depositary is typically a U.S. financial institution and the underlying securities are issued by a foreign issuer. For other Depositary Receipts, the depositary may be a foreign or a U.S. entity, and the underlying securities may have a foreign or a U.S. issuer. Depositary Receipts will not necessarily be denominated in the same currency as their underlying securities. Generally, ADRs, in registered form, are designed for use in the U.S. securities markets, and EDRs, in bearer form, are designed for use in European securities markets. GDRs are tradable both in the United States and in Europe and are designed for use throughout the world. An Underlying Fund may invest in Depositary Receipts through "sponsored" or "unsponsored" facilities. A sponsored facility is established jointly by the issuer of the underlying security and a depositary, whereas a depositary may establish an unsponsored facility without participation by the issuer of the deposited security. Holders of unsponsored Depositary Receipts generally bear all the costs of such facilities and the depositary of an unsponsored facility frequently is under no obligation to distribute interestholder communications received from the issuer of the deposited security or to pass through voting rights to the holders of such receipts in respect of the deposited securities. The issuers of unsponsored Depositary Receipts are not obligated to disclose material information in the United States and, therefore, there may be less information available regarding such issuers and there may not be a correlation between such information and the market value of the Depositary Receipts.

EMERGING MARKETS. Some foreign markets in which the Underlying Funds invest are considered to be emerging markets. Investment in these emerging markets subjects an Underlying Fund to a greater risk of loss than investments in developed markets. This is due to, among other things, greater market volatility, lower trading volume, political and economic instability, greater risk of market shut down and more governmental limitations on foreign investment policy than those typically found in developed markets.

PARTICIPATION INTERESTS. An Underlying Fund may invest in participation interests in any type of security in which the Underlying Fund may invest. A participation interest gives an Underlying Fund an undivided interest in the underlying securities in the proportion that the Underlying Fund's participation interest bears to the total principal amount of the underlying securities.

RATINGS. An investment-grade rating means the security or issuer is rated investment-grade by Moody's(Reg. TM) Investors Service, Inc. ("Moody's"), Standard & Poor's(Reg. TM), a division of The McGraw-Hill Companies, Inc. ("S&P"), Fitch Inc. ("Fitch"), Dominion Bond Rating Service Limited, or another credit rating agency designated as a NRSRO by the Securities and Exchange Commission ("SEC"), or is unrated but considered to be of equivalent quality by BFA. Bonds rated Baa by Moody's or BBB by S&P or above are considered "investment-grade" securities; bonds rated Baa are considered medium-grade obligations which lack outstanding investment characteristics and have speculative characteristics, while bonds rated BBB are regarded as having adequate capacity to pay principal and interest.

Subsequent to purchase by the applicable Underlying Funds, a rated security may cease to be rated or its rating may be reduced below an investment-grade rating. Bonds rated lower than Baa3 by Moody's or BBB- by S&P are below investment-grade quality and are obligations of issuers that are considered predominantly speculative with respect to the issuer's capacity to pay interest and repay principal according to the terms of the obligation and, therefore, carry greater investment risk, including the possibility of issuer default and bankruptcy and increased market price volatility. Such securities ("lower-rated securities") are commonly referred to as "junk bonds" and are subject to a substantial degree of credit risk. Lower-rated securities are often issued by smaller, less creditworthy companies or by highly leveraged (indebted) firms, which are generally less able than more financially stable firms to make scheduled payments of interest and principal. The risks posed by securities issued under such circumstances are substantial. Bonds rated below investment-grade tend to be less marketable than higher-quality bonds because the market for them is less broad. The market for unrated bonds is even narrower.

REPURCHASE AGREEMENTS. The Underlying Funds may enter into repurchase agreements. A repurchase agreement is an instrument under which the purchaser (I.E., the Underlying Fund) acquires the security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price, thereby determining the yield during the purchaser's holding period. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the

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underlying securities will not be considered to be owned by each Underlying Fund but only to constitute collateral for the seller's obligation to pay the repurchase price, and, in the event of a default by the seller, each Underlying Fund may suffer time delays and incur costs or losses in connection with the disposition of the collateral.

In any repurchase transaction, the collateral for a repurchase agreement may include (i) cash items; (ii) obligations issued by the U.S. government or its agencies or instrumentalities; or (iii) obligations that, at the time the repurchase agreement is entered into, are rated in the highest rating category generally by at least two NRSROs, or, if unrated, determined to be of comparable quality by BFA. Collateral, however, is not limited to the foregoing and may include for example obligations rated below the highest category by NRSROs. Collateral for a repurchase agreement may also include securities that an Underlying Fund could not hold directly without the repurchase obligation. Irrespective of the type of collateral underlying the repurchase agreement, in the case of a repurchase agreement entered into by a non-money market fund, the repurchase obligation of a seller must be of comparable credit quality to securities which are rated in one of the two highest rating categories by any NRSRO.

Repurchase agreements pose certain risks for an Underlying Fund that utilizes them. Such risks are not unique to the Underlying Fund but are inherent in repurchase agreements. The Underlying Funds seek to minimize such risks but because of the inherent legal uncertainties involved in repurchase agreements, such risks cannot be eliminated. Lower quality collateral and collateral with longer maturities may be subject to greater price fluctuations than higher quality collateral and collateral with shorter maturities. If the repurchase agreement counterparty were to default, lower quality collateral may be more difficult to liquidate than higher quality collateral. Should the counterparty default and the amount of collateral not be sufficient to cover the counterparty's repurchase obligation, the Underlying Fund would retain the status of an unsecured creditor of the counterparty (I.E., the position the Underlying Fund would normally be in if it were to hold, pursuant to its investment policies, other unsecured debt securities of the defaulting counterparty) with respect to the amount of the shortfall. As an unsecured creditor, an Underlying Fund would be at risk of losing some or all of the principal and income involved in the transaction.

RESTRICTED SECURITIES. Restricted securities are subject to legal restrictions on their sale. Difficulty in selling restricted securities may result in a loss or be costly to an Underlying Fund. Restricted securities generally can be sold in privately negotiated transactions, pursuant to an exemption from registration under the Securities Act of 1933, as amended, or in a registered public offering. Where registration is required, the restricted security's holder may be obligated to pay all or part of the registration expense and a considerable period may elapse between the time the holder decides to seek registration and the time the holder may be permitted to sell the security under an effective registration statement. If, during that period, adverse market conditions were to develop, the holder might obtain a less favorable price than prevailed when it decided to seek registration of the security.

REVERSE REPURCHASE AGREEMENTS. Certain of the Underlying Funds may enter into reverse repurchase agreements, which involve the sale of securities with an agreement to repurchase the securities at an agreed-upon price, date and interest payment and have the characteristics of borrowing. Generally the effect of such transactions is that an Underlying Fund can recover all or most of the cash invested in the portfolio securities involved during the term of the reverse repurchase agreement, while in many cases the Underlying Fund is able to keep some of the interest income associated with those securities. Such transactions are only advantageous if an Underlying Fund has an opportunity to earn a greater rate of interest on the cash derived from these transactions than the interest cost of obtaining the same amount of cash. Opportunities to realize earnings from the use of the proceeds equal to or greater than the interest required to be paid may not always be available and an Underlying Fund intends to use the reverse repurchase technique only when BFA believes it will be advantageous to the Underlying Fund. The use of reverse repurchase agreements may exaggerate any interim increase or decrease in the value of an Underlying Fund's assets. The Underlying Fund's exposure to reverse repurchase agreements will be covered by assets having a value equal to or greater than such committments. Each Underlying Fund maintains liquid assets having a value equal to or greater than reverse repurchase agreement commitments. Under the 1940 Act, reverse repurchase agreements are considered borrowings.

SHORT-TERM INSTRUMENTS. Each Underlying Fund may invest in short-term instruments in the same manner as the Master Portfolios, as described above.

STOCK INDEX FUTURES AND OPTIONS ON STOCK INDEX FUTURES. Certain of the Underlying Funds may invest in stock index futures and options on stock index futures as a substitute for a comparable market position in the underlying securities. An index futures contract is a standardized agreement between two parties that commits one party to buy and the other party to sell a

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stipulated quantity of a market index at a set price on or before a given date in the future. The seller never actually delivers "shares" of the index or shares of all the stocks in the index. Instead, the buyer and the seller settle the difference between the contract price and the market price in cash on the agreed-upon date - the buyer paying the difference if the actual price is lower than the contract price and the seller paying the difference if the actual price is higher. An Underlying Fund intends to purchase and sell futures contracts on the stock index for which it can obtain the best price with consideration also given to liquidity.

An option on a stock index is similar to an option on a stock except that expiration cycles vary either monthly or quarterly and the delivery requirements are different. Instead of giving the right to take or make delivery of stock at a specified price, an option on a stock index gives the holder the right to receive a cash "exercise settlement amount" equal to (i) the amount, if any, by which the fixed exercise price of the option exceeds (in the case of a put) or is less than (in the case of a call) the closing value of the underlying index on the date of exercise, multiplied by (ii) a fixed "index multiplier." Receipt of this cash amount depends upon the closing level of the stock index upon which the option is based being greater than (in the case of a call) or less than (in the case of a put) the exercise price of the option. The amount of cash received is equal to such difference between the closing price of the index and the exercise price of the option expressed in dollars multiplied by a specified multiplier. The writer of the option is obligated, in return for the premium received, to make delivery of this amount. The writer may offset a position in stock index options prior to expiration by entering into a closing transaction on an exchange or the writer may let the option expire unexercised. The Underlying Funds maintain liquid assets in connection with these types of futures contracts.

UNRATED INVESTMENTS. BlackRock Cash Funds: Institutional may purchase instruments that are not rated if, in the opinion of BFA, such obligations are of an investment quality that is comparable to other rated investments that are permitted for purchase by BlackRock Cash Funds: Institutional, if they are purchased in accordance with BlackRock Cash Funds: Institutional's procedures adopted by the Trust's Board of Trustees in accordance with Rule 2a-7 under the 1940 Act. Such procedures require approval or ratification by the Board of Trustees of the purchase of unrated securities. After purchase by BlackRock Cash Funds: Institutional, a security may cease to be rated or its rating may be reduced below the minimum required for purchase by BlackRock Cash Funds:
Institutional. Neither event will require an immediate sale of such security by BlackRock Cash Funds: Institutional provided that, when a security ceases to be rated, BFA determines that such security presents minimal credit risks and, provided further that, when a security rating is downgraded below the eligible quality for investment or no longer presents minimal credit risks, BFA finds that the sale of such security would not be in BlackRock Cash Funds:
Institutional's shareholders' best interest.

To the extent the ratings given by a NRSRO may change as a result of changes in such organization or its rating systems, BlackRock Cash Funds: Institutional will attempt to use comparable ratings as standards for investments in accordance with the investment policies contained in its registration statement.

U.S. GOVERNMENT OBLIGATIONS. Certain of the Underlying Funds may invest a portion of their assets in U.S. government obligations and may make such investments in the same manner as the Master Portfolios, as described above.

WARRANTS. A warrant is an instrument issued by a corporation that gives the holder the right to subscribe to a specified amount of the corporation's capital stock at a set price for a specified period of time. The prices of warrants do not necessarily correlate with the prices of the underlying securities.

SELECTIVE DISCLOSURE OF PORTFOLIO HOLDINGS

Pursuant to policies and procedures adopted by the Trust, MIP and BFA, the Trust, MIP and BFA may, under certain circumstances as set forth below, make selective disclosure with respect to a Fund's or Master Portfolio's portfolio holdings. The Boards of Trustees of the Trust and MIP have approved the adoption by the Trust and MIP of the policies and procedures set forth below, and have delegated to BFA the responsibility for ongoing monitoring and supervision to ensure compliance with these policies and procedures. The Boards of Trustees provide ongoing oversight of the Trust's, MIP's and BFA's compliance with the policies and procedures. As part of this oversight function, the Trustees receive from the Trust's and MIP's Chief Compliance Officer at least quarterly and more often, as necessary, reports on compliance with these policies and procedures, including reports on any violations of these policies and procedures that may occur. In addition, the Trustees receive an annual assessment of the adequacy and effectiveness of the policies and procedures with respect to the Trust and MIP, and any changes thereto, and an annual review of the operation of the policies and procedures.

Examples of the information that may be disclosed pursuant to the Trust's and MIP's policies and procedures would include (but is not limited to) specific portfolio holdings -- including the number of shares held, weightings of particular holdings, specific sector and industry weightings, trading details, and the portfolio manager's discussion of Fund or Master Portfolio performance and reasoning for significant changes in portfolio composition. This information may be both material non-public information ("Confidential Information") and proprietary information of the firm. The Trust or MIP may disclose such information to individual investors, institutional investors, financial advisers and other financial intermediaries that sell the Trust's shares, affiliates of the Trust or MIP, third party service providers to the Trust or MIP, lenders to the Trust or MIP, and independent rating agencies and ranking organizations. The Trust, MIP, BFA and its affiliates receive no compensation or other consideration with respect to such disclosures.

Subject to the exceptions set forth below, Confidential Information relating to a Fund or Master Portfolio may not be disclosed to persons not employed by BFA or its affiliates unless such information has been publicly disclosed via a filing with the Commission (e.g., Trust annual report), a press release or placement on a publicly-available internet website. If the Confidential Information has not been publicly disclosed, an employee of BFA who wishes to distribute Confidential Information relating to the Trust or MIP must first do the following: (i) require the person or company receiving the Confidential Information to sign, before BFA will provide disclosure of any such information, a confidentiality agreement approved by an attorney in BFA's Legal Department in which the person or company (a) agrees to use the Confidential Information solely in connection with a legitimate business use (i.e., due diligence, etc.) and (b) agrees not to trade on the basis of the information so provided; (ii) obtain the authorization of an attorney in BFA's Legal Department prior to disclosure; and (iii) only distribute Confidential Information that is at least thirty (30) calendar days old unless a shorter period has specifically been approved by an attorney in BFA's Legal Department.

20

Prior to providing any authorization for such disclosure of Confidential Information, an attorney in BFA's Legal Department must review the proposed arrangement and make a determination that it is in the best interests of the Trust's shareholders. In connection with day-to-day portfolio management, the Trust or MIP may disclose Confidential Information to executing broker-dealers that is less than 30 days old in order to facilitate the purchase and sale of portfolio holdings. The Trust and MIP have adopted policies and procedures, including a Code of Ethics, Code of Conduct, and various policies regarding securities trading and trade allocations, to address potential conflicts of interest that may arise in connection with disclosure of Confidential Information. These procedures are designed, among other things, to prohibit personal trading based on Confidential Information, to ensure that portfolio transactions are conducted in the best interests of the Trust and its shareholders and to prevent portfolio management from using Confidential Information for the benefit of one Fund, Master Portfolio or account at the expense of another. In addition, as noted, an attorney in BFA's Legal Department must determine that disclosure of Confidential Information is for a legitimate business purpose and is in the best interests of the Trust's shareholders, and that any conflicts of interest created by release of the Confidential Information have been addressed by BFA's existing policies and procedures. For more information with respect to potential conflicts of interest, see the section entitled "Management-- Potential Conflicts of Interest" in this Statement of Additional Information.

Confidential Information -- whether or not publicly disclosed -- may be disclosed to Trust Trustees, the independent Trustees' counsel, the Trust's outside counsel, accounting services provider and independent registered public accounting firm without meeting the conditions outlined above. Confidential Information may, with the prior approval of the Trust's Chief Compliance Officer or BFA's General Counsel, also be disclosed to any auditor of the parties to a service agreement involving the Trust or MIP, or as required by judicial or administrative process or otherwise by applicable law or regulation. If Confidential Information is disclosed to such persons, each such person will be subject to restrictions on trading in the subject securities under either the Trust's, MIP's and BFA's Code of Ethics or an applicable confidentiality agreement, or under applicable laws or regulations or court order.

BFA has entered into ongoing arrangements to provide monthly and quarterly selective disclosure of Trust and MIP portfolio holdings to the following persons or entities:

Trust's and MIP's Boards of Trustees and, if necessary independent Trustees' counsel and Trust counsel

Trust's Transfer Agent

Trust's and MIP's independent registered public accounting firm

Trust's and MIP's accounting services provider

MIP Custodian

MIP's pricing services - Interactive Data Corp. and Reuters, Inc.

Independent rating agencies -- Morningstar, Inc., Lipper Inc., Moody's Investors Service, Inc. and Standard & Poor's

Information aggregators -- Wall Street on Demand, Thomson Financial, eVestment Alliance, informa PSN investment solutions, Micropal, iMoneyNet and Bloomberg

Sponsors of 401(k) plans that include BlackRock-advised Funds -- E.I. Dupont de Nemours and Company, Inc.

Consultants for pension plans that invest in BlackRock-advised Funds -- Rocaton Investment Advisors, LLC; Mercer Investment Consulting; Watson Wyatt Investment Consulting; Towers Perrin HR Services; Pinnacle West; Callan Associates; Brockhouse & Cooper; Cambridge Associates; Mercer; Morningstar/Investorforce; Russell Investments (Mellon Analytical Solutions); and Wilshire Associates

Portfolio Compliance Consultants -- i-Flex Solutions, Inc.

Third-party feeder funds---Hewitt Money Market Fund, Hewitt Series Trust, Hewitt Financial Services LLC, PayPal Money Market Fund, PayPal Funds, PayPal Asset Management, Inc. Homestead, Inc., Transamerica and State Farm Mutual Fund Trust, and their respective boards, sponsors, administrators and other service providers

Affiliated feeder funds---BlackRock Cayman Prime Money Market Fund, Ltd. And BlackRock Cayman Treasury Money Market Fund Ltd., and their respective boards, sponsors, administrators and other service providers

21

Other --- Chicago Mercantile Exchange, Inc., Be Creative, Inc. and Investment Company Institute

Other than with respect to the Board of Trustees, each of the persons or entities set forth above is subject to an agreement to keep the information disclosed confidential and to use it only for legitimate business purposes. Each Trustee has a fiduciary duty as a trustee to act in the best interests of the Trust and its shareholders. Selective disclosure is made to the Board of Trustees and independent registered public accounting firm at least quarterly and otherwise as frequently as necessary to enable such persons or entities to provide services to the Trust. Selective disclosure is made to the Trust's Transfer Agent, accounting services provider, and Custodian as frequently as necessary to enable such persons or entities to provide services to the Trust, typically on a daily basis. Disclosure is made to Lipper Inc. and Wall Street on Demand on a monthly basis and to Morningstar and Thomson Financial on a quarterly basis, and to each such firm upon specific request with the approval of BFA's Legal Department. Disclosure is made to 401(k) plan sponsors on a yearly basis and pension plan consultants on a quarterly basis.

The Trust and BFA monitor, to the extent possible, the use of Confidential Information by the individuals or firms to which it has been disclosed. To do so, in addition to the requirements of any applicable confidentiality agreement and/or the terms and conditions of the Trust's and BFA's Code of Ethics and Code of Conduct -- all of which require persons or entities in possession of Confidential Information to keep such information confidential and not to trade on such information for their own benefit -- BFA's compliance personnel under the supervision of the Trust's Chief Compliance Officer, monitor BFA's securities trading desks to determine whether individuals or firms who have received Confidential Information have made any trades on the basis of that information. In addition, BFA maintains an internal restricted list to prevent trading by the personnel of BFA or its affiliates in securities -- including securities held by the Trust or MIP -- about which BFA has Confidential Information. There can be no assurance, however, that the Trust's policies and procedures with respect to the selective disclosure of Trust portfolio holdings will prevent the misuse of such information by individuals or firms that receive such information

Management

The Board of Trustees of the Trust, consists of thirteen individuals (each, a "Trustee"), eleven of whom are Independent Trustees. The same individuals serve on the Board of Trustees of MIP. The registered investment companies advised by BFA or its affiliates (the "BlackRock-advised Funds") are organized into one complex of closed-end funds, two complexes of open-end funds (the Equity-Liquidity Complex and the Equity-Bond Complex) and one complex of ETFs (each, a "BlackRock Fund Complex"). The Trust and MIP are included in the BlackRock Fund Complex referred to as the Equity-Liquidity Complex. The Trustees also oversee as board members the operations of the other open-end registered investment companies included in the Equity-Liquidity Complex. The address for each Trustee and officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055.

The Board of Trustees has overall responsibility for the oversight of the Trust and the LifePath Portfolios. The Co-Chairs of the Board are Independent Trustees, and the Chair of each Board committee (each, a "Committee") is an Independent Trustee. The Board has five standing Committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight and Contract Committee and an Executive Committee. The Board also has one ad hoc committee, the Joint Product Pricing Committee. The role of the Co-Chairs of the Board is to preside at all meetings of the Board and to act as a liaison with service providers, officers, attorneys, and other Trustees generally between meetings. The Chair of each Committee performs a similar role with respect to the Committee. The Co-Chairs of the Board or the Chair of a Committee may also perform such other functions as may be delegated by the Board or the Committee from time to time. The Independent Trustees meet regularly outside the presence of Trust management, in executive session or with other service providers to the Trust and the LifePath Portfolios. The Board has regular meetings five times a year, and may hold special meetings if required before its next regular meeting. Each Committee meets regularly to conduct the oversight functions delegated to that Committee by the Board and reports its findings to the Board. The Board and each standing Committee conduct annual assessments of their oversight function and structure. The Board has determined that the

22

Board's leadership structure is appropriate because it allows the Board to exercise independent judgment over management and to allocate areas of responsibility among Committees and the full Board to enhance effective oversight.

The Board has engaged BFA to manage the LifePath Portfolios on a day-to-day basis. The Board is responsible for overseeing BFA, other service providers, the operations of the LifePath Portfolios and associated risk in accordance with the provisions of the 1940 Act, state law, other applicable laws, the Trust's charter, and the LifePath Portfolios' investment objectives and strategies. The Board reviews, on an ongoing basis, the LifePath Portfolios' performance, operations, and investment strategies and techniques. The Board also conducts reviews of BFA and its role in running the operations of the LifePath Portfolios.

Day-to-day risk management with respect to the LifePath Portfolios is the responsibility of BFA or of sub-advisers or other service providers (depending on the nature of the risk), subject to the supervision of BFA. The LifePath Portfolios are subject to a number of risks, including investment, compliance, operational and valuation risks, among others. While there are a number of risk management functions performed by BFA and the sub-advisers or other service providers, as applicable, it is not possible to eliminate all of the risks applicable to the LifePath Portfolios. Risk oversight forms part of the Board's general oversight of the LifePath Portfolios and is addressed as part of various Board and Committee activities. The Board, directly or through a Committee, also reviews reports from, among others, management, the independent registered public accounting firm for the LifePath Portfolios, sub-advisers, and internal auditors for the investment adviser or its affiliates, as appropriate, regarding risks faced by the LifePath Portfolios and management's or the service provider's risk functions. The Committee system facilitates the timely and efficient consideration of matters by the Trustees, and facilitates effective oversight of compliance with legal and regulatory requirements and of the LifePath Portfolios' activities and associated risks. The Board has appointed a Chief Compliance Officer, who oversees the implementation and testing of the LifePath Portfolios' compliance program and reports to the Board regarding compliance matters for the LifePath Portfolios and their service providers. The Independent Trustees have engaged independent legal counsel to assist them in performing their oversight responsibilities.

The members of the Audit Committee are Kenneth L. Urish (Chair), Herbert I. London and Frederick W. Winter, all of whom are Independent Trustees. The principal responsibilities of the Audit Committee are to approve the selection, retention, termination and compensation of the Trust's independent registered public accounting firm (the "independent auditors") and to oversee the independent auditors' work. The Audit Committee's responsibilities include, without limitation, to (1) evaluate the qualifications and independence of the independent auditors; (2) approve all audit engagement terms and fees for each LifePath Portfolio; (3) review the conduct and results of each independent audit of each LifePath Portfolio's financial statements; (4) review any issues raised by the independent auditors or Trust management regarding the accounting or financial reporting policies and practices of each LifePath Portfolio and the internal controls of each LifePath Portfolio and certain service providers;
(5) oversee the performance of each LifePath Portfolio's internal audit function provided by its investment adviser, administrator, pricing agent or other service provider; (6) discuss with Trust management its policies regarding risk assessment and risk management and (7) resolve any disagreements between Trust management and the independent auditors regarding financial reporting. The Board has adopted a written charter for the Audit Committee. During the period December 1, 2009 through December 31, 2009, the Audit Committee met one time.

The members of the Governance and Nominating Committee (the "Governance Committee") are Dr. Matina Horner (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The principal responsibilities of the Governance Committee are to (1) identify individuals qualified to serve as Independent Trustees of the Trust and recommend Independent Trustee nominees for election by shareholders or appointment by the Board; (2) advise the Board with respect to Board composition, procedures and committees (other than the Audit Committee); (3) oversee periodic self-assessments of the Board and committees of the Board (other than the Audit Committee); (4) review and make recommendations regarding Independent Trustee compensation; and (5) monitor corporate governance matters and develop appropriate recommendations to the Board. The Governance Committee may consider nominations for the office of Trustee made by LifePath Portfolio shareholders as it deems appropriate. LifePath Portfolio shareholders who wish to recommend a nominee should send nominations to the Secretary of the Trust that include biographical information and set forth the qualifications of the proposed nominee. The Board has adopted a written charter for the Governance Committee. During the period December 1, 2009 through December 31, 2009, the Governance Committee met one time.

The members of the Compliance Committee are Joseph P. Platt, Jr. (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The Compliance Committee's purpose is to assist the Board in fulfilling its responsibility to oversee regulatory and fiduciary compliance matters involving the Trust, the LifePath Portfolio-related activities of BFA and

23

the Trust's third party service providers. The Compliance Committee's responsibilities include, without limitation, to (1) oversee the compliance policies and procedures of the Trust and its service providers and recommend changes or additions to such policies and procedures; (2) review information on and, where appropriate recommend policies concerning, the Trust's compliance with applicable law; and (3) review reports from, oversee the annual performance review of, and make certain recommendations regarding the Trust's Chief Compliance Officer. The Board has adopted a written charter for the Compliance Committee. During the period December 1, 2009 through December 31, 2009, the Compliance Committee met two times.

The members of the Performance Oversight and Contract Committee (the "Performance Oversight Committee") are David O. Beim (Chair), Toby Rosenblatt (Vice Chair), Ronald W. Forbes and Rodney D. Johnson, all of whom are Independent Trustees. The Performance Oversight Committee's purpose is to assist the Board in fulfilling its responsibility to oversee each LifePath Portfolio's investment performance relative to its agreed-upon performance objectives and to assist the Independent Trustees in their consideration of investment advisory agreements. The Performance Oversight Committee's responsibilities include, without limitation, to (1) review each LifePath Portfolio's investment objectives, policies and practices and each LifePath Portfolio's investment performance; (2) review personnel and resources devoted to management of each LifePath Portfolio and evaluate the nature and quality of information furnished to the Performance Oversight Committee; (3) recommend any required action regarding change in fundamental and non-fundamental investment policies and restrictions, fund mergers or liquidations; (4) request and review information on the nature, extent and quality of services provided to the shareholders; and (5) make recommendations to the Board concerning the approval or renewal of investment advisory agreements. The Board has adopted a written charter for the Performance Oversight Committee. During the period December 1, 2009 through December 31, 2009, the Performance Oversight Committee met one time.

The Boards of the Equity-Liquidity Complex, the Equity-Bond Complex and the closed-end BlackRock Fund Complex, established the ad hoc Joint Product Pricing Committee (the "Product Pricing Committee") comprised of eight members drawn from the independent board members serving on the boards of these BlackRock Fund Complexes. Ronald W. Forbes and Rodney D. Johnson are members of the Product Pricing Committee representing the Equity-Liquidity Complex. One independent board member representing the closed-end BlackRock Fund Complex and five independent board members representing the Equity-Bond Complex serve on the Product Pricing Committee. The Product Pricing Committee is chaired by an independent board member from the Equity-Bond Complex. The purpose of the Product Pricing Committee is to review the components and pricing structure of the non-money market funds in the BlackRock Fund Complexes. During the period from December 1, 2009 through December 31, 2009, the Product Pricing Committee did not meet.

The members of the Executive Committee are Ronald W. Forbes and Rodney D. Johnson, both of whom are Independent Trustees, and Richard S. Davis, who serves as an interested Trustee. The principal responsibilities of the Executive Committee are to (1) act on routine matters between meetings of the Board; (2) act on such matters as may require urgent action between meetings of the Board; and (3) exercise such other authority as may from time to time be delegated to the Executive Committee by the Board. The Board has adopted a written charter for the Executive Committee. During the period December 1, 2009 through December 31, 2009, the Executive Committee met one time.

The Governance Committee has adopted a statement of policy that describes the experience, qualifications, skills and attributes that are necessary and desirable for potential Independent Trustee candidates (the "Statement of Policy"). The Board believes that each Independent Trustee satisfied, at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. Furthermore, in determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, skills, attributes and qualifications, which allow the Board to operate effectively in governing the Trust and protecting the interests of shareholders. Among the attributes common to all Trustees are their ability to review critically, evaluate, question and discuss information provided to them, to interact effectively with the Trust's investment adviser, sub-advisers, other service providers, counsel and independent auditors, and to exercise effective business judgment in the performance of their duties as Trustees. Each Trustee's ability to perform his or her duties effectively is evidenced by his or her educational background or professional training; business, consulting, public service or academic positions; experience from service as a board member of the Trust and the other funds in the BlackRock Fund Complex (and any predecessor funds), other investment funds, public companies, or non-profit entities or other organizations; ongoing commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout the years; or other relevant life

24

experiences. Information about the specific experience, skills, attributes and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a Trustee of the Trust, is provided below.

Certain biographical and other information relating to the Trustees of the Trust is set forth below, including their ages, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                 NUMBER OF
                                                                                                BLACKROCK-
                                                                                                  ADVISED
                                                                                                REGISTERED
                                                                                                INVESTMENT
                                                                                                 COMPANIES
                                                                                                 ("RICS")
                                                                                               CONSISTING OF
                                                                                                INVESTMENT
                             POSITION(S)        LENGTH OF                                       PORTFOLIOS
           NAME               HELD WITH            TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
         AND AGE              THE TRUST         SERVED/2/         DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ----------------- ----------------- ------------------------------ ---------------- -----------------
INDEPENDENT TRUSTEES/1/
David O. Beim/3/          Trustee           2009 to present   Professor of Finance and       36 RICs          None
(69)                                                          Economics at the Columbia      consisting of
                                                              University Graduate School     104 Portfolios
                                                              of Business since 1991;
                                                              Trustee, Phillips Exeter
                                                              Academy since 2002;
                                                              Chairman, Wave Hill, Inc.
                                                              (public garden and cultural
                                                              center) from 1990 to 2006.

Ronald W. Forbes/4/       Trustee           2009 to present   Professor Emeritus of          36 RICs          None
(69)                                                          Finance, School of Business,   consisting of
                                                              State University of New York   104 Portfolios
                                                              at Albany since 2000.

Dr. Matina S. Horner/5/   Trustee           2009 to present   Executive Vice President of    36 RICs          NSTAR
(70)                                                          Teachers Insurance and         consisting of    (electric and
                                                              Annuity Association and        104 Portfolios   gas utility)
                                                              College Retirement Equities
                                                              Fund from 1989 to 2003.

Rodney D. Johnson/4/      Trustee           2009 to present   President, Fairmont Capital    36 RICs          None
(68)                                                          Advisors, Inc. since 1987;     consisting of
                                                              Director, Fox Chase Cancer     104 Portfolios
                                                              Center since 2004; Member
                                                              of Archdiocesan Investment
                                                              Committee of the
                                                              Archdiocese of Philadelphia
                                                              since 2004; Director, The
                                                              Committee of Seventy (civic)
                                                              since 2006.

25

                                                                                                 NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                             POSITION(S)         LENGTH OF                                       PORTFOLIOS
           NAME               HELD WITH             TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
         AND AGE              THE TRUST          SERVED/2/          DURING PAST FIVE YEARS        OVERSEEN     DIRECTORSHIPS
------------------------- ----------------- ----------------- ------------------------------ ---------------- -----------------
Herbert I. London         Trustee           2009 to present   Professor Emeritus, New        36 RICs          AIMS
(71)                                                          York University since 2005;    consisting of    Worldwide,
                                                              John M. Olin Professor of      104 Portfolios   Inc.
                                                              Humanities, New York                            (marketing)
                                                              University from 1993 to 2005
                                                              and Professor thereof from
                                                              1980 to 2005; President,
                                                              Hudson Institute (policy
                                                              research organization) since
                                                              1997 and Trustee thereof
                                                              since 1980; Chairman of the
                                                              Board of Trustees for
                                                              Grantham University since
                                                              2006; Director, InnoCentive,
                                                              Inc. (strategic solutions
                                                              company) since 2005;
                                                              Director of Cerego, LLC
                                                              (software development and
                                                              design) since 2005.

Cynthia A.                Trustee           2009 to present   Professor, Harvard Business    36 RICs          Newell
Montgomery                                                    School since 1989; Director,   consisting of    Rubbermaid,
(57)                                                          Harvard Business School        104 Portfolios   Inc.
                                                              Publishing since 2005;                          (manufacturing)
                                                              Director, McLean Hospital
                                                              since 2005.

Joseph P. Platt, Jr./6/   Trustee           2009 to present   Director, The West Penn        36 RICs          Greenlight
(62)                                                          Allegheny Health System (a     consisting of    Capital Re,
                                                              not-for-profit health system)  104 Portfolios   Ltd
                                                              since 2008; Director, Jones                     (reinsurance
                                                              and Brown (Canadian                             company);
                                                              insurance broker) since                         WQED Multi-
                                                              1998; General Partner, Thorn                    Media (public
                                                              Partner, LP (private                            broadcasting
                                                              investment) since 1998;                         not-for-
                                                              Partner Amarna Corporation,                     profit)
                                                              LLC (private investment
                                                              company) from 2002 to
                                                              2008.

Robert C. Robb, Jr.       Trustee           2009 to present   Partner, Lewis, Eckert, Robb   36 RICs          None
(64)                                                          and Company (management        consisting of
                                                              and financial consulting       104 Portfolios
                                                              firm) since 1981.

26

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                             POSITION(S)        LENGTH OF                                        PORTFOLIOS
         NAME                 HELD WITH            TIME            PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
       AND AGE                THE TRUST         SERVED(2)           DURING PAST FIVE YEARS        OVERSEEN     DIRECTORSHIPS
------------------------- ----------------- ----------------- ------------------------------ ---------------- -----------------
Toby Rosenblatt/7/        Trustee           2009 to present   President, Founders            36 RICs          A.P. Pharma
(71)                                                          Investments Ltd. (private      consisting of    Inc. (specialty
                                                              investments) since 1999;       104 Portfolios   pharmaceuticals)
                                                              Director, College Access
                                                              Foundation of California
                                                              (philanthropic foundation)
                                                              since 2009; Director, Forward
                                                              Management, LLC since
                                                              2007; Director, the James
                                                              Irvine Foundation
                                                              (philanthropic foundation)
                                                              from 1998 to 2008.

Kenneth L. Urish/8/       Trustee           2009 to present   Managing Partner, Urish        36 RICs          None
(59)                                                          Popeck & Co., LLC (certified   consisting of
                                                              public accountants and         104 Portfolios
                                                              consultants) since 1976;
                                                              Member of External Advisory
                                                              Board, the Pennsylvania
                                                              State University Accounting
                                                              Department since 2001;
                                                              Trustee, The Holy Family
                                                              Foundation since 2001;
                                                              Committee Member,
                                                              Professional Ethics
                                                              Committee of the
                                                              Pennsylvania Institute of
                                                              Certified Public Accountants
                                                              from 2007 to 2010; President
                                                              and Trustee, Pittsburgh
                                                              Catholic Publishing
                                                              Associates from 2003 to
                                                              2008; Director, Inter-Tel from
                                                              2006 to 2007.

Frederick W. Winter       Trustee           2009 to present   Professor and Dean Emeritus    36 RICs          None
(65)                                                          of the Joseph M. Katz School   consisting of
                                                              of Business, University of     104 Portfolios
                                                              Pittsburgh since 2005 and
                                                              dean thereof from 1997 to
                                                              2005; Director, Alkon
                                                              Corporation (pneumatics)
                                                              since 1992; Director
                                                              Tippman Sports (recreation)
                                                              since 2005; Director,
                                                              Indotronix International (IT
                                                              services) from 2004 to 2008.

27

                                                                                                 NUMBER OF
                                                                                                BLACKROCK-
                                                                                                  ADVISED
                                                                                                REGISTERED
                                                                                                INVESTMENT
                                                                                                 COMPANIES
                                                                                                 ("RICS")
                                                                                               CONSISTING OF
                                                                                                INVESTMENT
                             POSITION(S)        LENGTH OF                                       PORTFOLIOS
        NAME                  HELD WITH            TIME            PRINCIPAL OCCUPATION(S)    ("PORTFOLIOS")      PUBLIC
       AND AGE                THE TRUST         SERVED/2/          DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ----------------- ----------------- ------------------------------ ---------------- -----------------
INTERESTED TRUSTEES/1/,/9/
Richard S. Davis          Trustee           2009 to present   Managing Director,             169 RICs         None
(64)                                                          BlackRock, Inc. since 2005;    consisting of
                                                              Chief Executive Officer, State 298 Portfolios
                                                              Street Research &
                                                              Management Company from
                                                              2000 to 2005; Chairman of
                                                              the Board of Trustees, State
                                                              Street Research Mutual
                                                              Funds from 2000 to 2005;
                                                              Chairman, SSR Realty from
                                                              2000 to 2004.

Henry Gabbay              Trustee           2009 to present   Consultant, BlackRock, Inc.    169 RICs         None
(62)                                                          from 2007 to 2008;             consisting of
                                                              Managing Director,             298 Portfolios
                                                              BlackRock, Inc. from 1989 to
                                                              2007; Chief Administrative
                                                              Officer, BlackRock Advisors,
                                                              LLC from 1998 to 2007;
                                                              President of BlackRock
                                                              Funds and BlackRock Bond
                                                              Allocation Target Shares
                                                              from 2005 to 2007 and
                                                              Treasurer of certain closed-
                                                              end funds in the BlackRock
                                                              fund complex from 1989 to
                                                              2006.


/1/ Trustees serve until their resignation, removal or death, or until December 31 of the year in which they turn 72. The Board of Trustees has approved one-year extensions in the terms of Trustees who turn 72 prior to December 31, 2013.
/2/ In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, the Trustees were elected to the Trust's Board. As a result, although the chart shows the Trustees as joining the Trust's Board in 2009, each Trustee first became a member of the boards of other funds advised by BlackRock Advisors, LLC or its affiliates as follows: David O. Beim, 1998; Ronald W. Forbes, 1977; Dr. Matina Horner, 2004; Rodney D. Johnson, 1995; Herbert I. London, 1987; Cynthia A. Montgomery, 1994; Joseph P. Platt, Jr., 1999; Robert C. Robb, Jr., 1999; Toby Rosenblatt, 2005; Kenneth L. Urish, 1999; and Frederick W. Winter, 1999.
/3/ Chair of the Performance Oversight Committee. /4/ Co-Chair of the Board of Trustees. /5/ Chair of the Governance Committee. /6/ Chair of the Compliance Committee.
/7/ Vice Chair of the Performance Oversight Committee. /8/ Chair of the Audit Committee.
/9/ Mr. Davis is an "interested person," as defined in the 1940 Act, of the Trust based on his position with BlackRock, Inc. and its affiliates. Mr. Gabbay is an "interested person" of the Trust based on his former positions with BlackRock, Inc. and its affiliates as well as his ownership of BlackRock, Inc. and The PNC Financial Services Group, Inc. securities.

28

Certain biographical and other information relating to the officers of the Trust is set forth below, including their year of birth, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                 NUMBER OF
                                                                                                BLACKROCK-
                                                                                                  ADVISED
                                                                                                REGISTERED
                                                                                                INVESTMENT
                                                                                                 COMPANIES
                                                                                                  ("RICS"
                                                                                               CONSISTING OF
                                                                                                INVESTMENT
                                                                                                PORTFOLIOS
          NAME             POSITION(S) HELD     LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST     TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- ----------------
Trust Officers(1)
----------------------

Anne F. Ackerley          President and      2009 to present   Managing Director of           169 RICs         None
1962                      Chief Executive                      BlackRock, Inc. since 2000;    consisting of
                          Officer                              Vice President of the          298 Portfolios
                                                               BlackRock-advised Funds
                                                               from 2007 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's Global Client
                                                               Group (GCG) since 2009;
                                                               Chief Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               from 2006 to 2009; Head of
                                                               BlackRock's Mutual Fund
                                                               Group from 2000 to 2006.

Richard Hoerner, CFA      Vice President     2009 to present   Managing Director of           24 RICs          None
1958                                                           BlackRock, Inc. since 2000;    consisting of
                                                               Co-head of BlackRock's Cash    73 Portfolios
                                                               Management Portfolio
                                                               Management Group since
                                                               2002; Member of the Cash
                                                               Management Group
                                                               Executive Committee since
                                                               2005.

Jeffrey Holland, CFA      Vice President     2009 to present   Managing Director of           70 RICs          None
1971                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    201 Portfolios
                                                               from 2006 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               since 2009; Co-head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group from 2007
                                                               to 2009; Product Manager of
                                                               Raymond James &
                                                               Associates from 2003 to
                                                               2006.

29

                                                                                                 NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
           NAME            POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- ----------------
Brendan Kyne              Vice President     2009 to present   Managing Director of           169 RICs         None
1977                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    298 Portfolios
                                                               from 2008 to 2009; Head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group since 2009,
                                                               co-head thereof from 2007
                                                               to 2009; Vice President of
                                                               BlackRock, Inc. from 2005 to
                                                               2008.

Simon Mendelson           Vice President     2009 to present   Managing Director of           24 RICs          None
1964                                                           BlackRock, Inc. since 2005;    consisting of
                                                               Chief Operating Officer and    73 Portfolios
                                                               head of the Global Client
                                                               Group for BlackRock's Global
                                                               Cash Management Business
                                                               since 2007; Head of
                                                               BlackRock's Strategy and
                                                               Development Group from
                                                               2005 to 2007.

Brian Schmidt             Vice President     2009 to present   Managing Director of           70 RICs          None
1958                                                           BlackRock, Inc. since 2004;    consisting of
                                                               Various positions with U.S.    201 Portfolios
                                                               Trust Company from 1991 to
                                                               2003: Director from 2001 to
                                                               2003, Senior Vice President
                                                               from 1998 to 2003; Vice
                                                               President, Chief Financial
                                                               Officer and Treasurer of
                                                               Excelsior Funds, Inc.,
                                                               Excelsior Tax-Exempt Funds,
                                                               Inc. and Excelsior Funds
                                                               Trust from 2001 to 2003.

30

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
          NAME             POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST      TIME SERVED         DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- ----------------
Christopher Stavrakos,    Vice President     2009 to present   Managing Director of           24 RICs          None
CFA                                                            BlackRock, Inc. since 2006;    consisting of
1959                                                           Co-head of BlackRock's Cash    73 Portfolios
                                                               Management Portfolio
                                                               Management Group since
                                                               2006; Senior Vice President,
                                                               CIO, and Director of Liability
                                                               Management for the
                                                               Securities Lending Group at
                                                               Mellon Bank from 1999 to
                                                               2006.

Neal J. Andrews           Chief Financial    2009 to present   Managing Director of           169 RICs         None
1966                      Officer and                          BlackRock, Inc. since 2006;    consisting of
                          Assistant                            Senior Vice President and      298 Portfolios
                          Treasurer                            Line of Business Head of
                                                               Fund Accounting and
                                                               Administration at PNC
                                                               Global Investment Servicing
                                                               (U.S.) Inc. from 1992 to
                                                               2006.

Jay M. Fife               Treasurer          2009 to present   Managing Director of           169 RICs         None
1970                                                           BlackRock, Inc. since 2007     consisting of
                                                               and Director in 2006;          298 Portfolios
                                                               Assistant Treasurer of the
                                                               Merrill Lynch Investment
                                                               Managers, L.P. ("MLIM") and
                                                               Fund Asset Management,
                                                               L.P. advised funds from 2005
                                                               to 2006; Director of MLIM
                                                               Fund Services Group from
                                                               2001 to 2006.

Brian P. Kindelan         Chief              2009 to present   Chief Compliance Officer of    169 RICs         None
1959                      Compliance                           the BlackRock-advised funds    consisting of
                          Officer and                          since 2007; Managing           298 Portfolios
                          Anti-Money                           Director and Senior Counsel
                          Laundering                           of BlackRock, Inc. since
                          Compliance                           2005.
                          Officer

31

                                                                                                 NUMBER OF
                                                                                                BLACKROCK-
                                                                                                  ADVISED
                                                                                                REGISTERED
                                                                                                INVESTMENT
                                                                                                 COMPANIES
                                                                                                  ("RICS"
                                                                                               CONSISTING OF
                                                                                                INVESTMENT
                                                                                                PORTFOLIOS
          NAME             POSITION(S) HELD      LENGTH OF        PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
   AND YEAR OF BIRTH        WITH THE TRUST      TIME SERVED       DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ----------------------------- ---------------- -----------------
Howard B. Surloff         Secretary          2009 to present   Managing Director and         169 RICs         None

1965                                                           General Counsel of U.S.       consisting of
                                                               Funds at BlackRock, Inc.      298 Portfolios
                                                               since 2006; General Counsel
                                                               (U.S.) of Goldman Sachs
                                                               Asset Management, L.P.
                                                               from 1993 to 2006.


(1) Officers of the Trust serve at the pleasure of the Board of Trustees.

SHARE OWNERSHIP INFORMATION. Information relating to each Trustee's share ownership in the LifePath Portfolios and in all BlackRock-advised Funds that are overseen by the respective Trustee ("Supervised Funds") as of December 31, 2009 is set forth in the chart below:

                                     DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------------------
Interested Trustees     LifePath     LifePath    LifePath    LifePath    LifePath    Aggregate
                        Retirement   2020        2030        2040        2050        Dollar Range
                        Portfolio    Portfolio   Portfolio   Portfolio   Portfolio   of Securities
                                                                                     in the Supervised Funds
Richard S. Davis        None         None        None        None        None        over $100,000
Henry Gabbay            None         None        None        None        None        over $100,000

                                     DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------------------
Independent Trustees    LifePath     LifePath    LifePath    LifePath    LifePath    Aggregate
                        Retirement   2020        2030        2040        2050        Dollar Range
                        Portfolio    Portfolio   Portfolio   Portfolio   Portfolio   of Securities
                                                                                     in the Supervised Funds
David O. Beim           None         None        None        None        None        over $100,000
Ronald W. Forbes        None         None        None        None        None        over $100,000
Dr. Matina S. Horner    None         None        None        None        None        over $100,000
Rodney D. Johnson       None         None        None        None        None        over $100,000
Herbert I. London       None         None        None        None        None        $50,001
                                                                                     - $100,000
Cynthia A. Montgomery   None         None        None        None        None        over $100,000
Joseph P. Platt, Jr.    None         None        None        None        None        over $100,000
Robert C. Robb, Jr.     None         None        None        None        None        over $100,000
Toby Rosenblatt         None         None        None        None        None        over $100,000

32

                                     DOLLAR RANGE OF EQUITY SECURITIES
                        ------------------------------------------------------------
Kenneth L. Urish        None         None        None        None        None        $50,001
                                                                                     - $100,000
Frederick W. Winter     None         None        None        None        None        over $100,000

OWNERSHIP OF SECURITIES OF CERTAIN ENTITIES. As of March 31, 2010, the Trustees and officers of the Trust as a group owned an aggregate of less than 1% of the outstanding shares of any LifePath Portfolio. As of March 31, 2010, none of the Independent Trustees or their immediate family members owned beneficially or of record any securities of affiliates of the Investment Adviser.

COMPENSATION OF TRUSTEES. Each current Trustee who is an Independent Trustee is paid as compensation an annual retainer of $250,000 per year for his or her services as a Board member to the BlackRock-advised Funds in the Equity-Liquidity Complex, including the Trust and MIP, and a $5,000 Board meeting fee to be paid for each in-person Board meeting attended (a $2,500 Board meeting fee for telephonic attendance at regular Board meetings), for up to five Board meetings held in a calendar year (compensation for meetings in excess of this number to be determined on a case by case basis), together with out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. The Co-Chairs of the Boards of Trustees are each paid an additional annual retainer of $45,000. The Chairs of the Audit Committees, Compliance Committees, Governance Committees and Performance Oversight Committees and the Vice-Chair of the Performance Oversight Committees are each paid an additional annual retainer of $25,000. The Chair of the Product Pricing Committee, who oversees funds in the Equity-Bond Complex, is paid an annual retainer of $25,000 that is allocated among all of the non-money market funds in the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes.

Mr. Gabbay is an interested Trustee of the Trust and serves as an interested board member of the other funds which comprise the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes. Mr. Gabbay receives as compensation for his services as a board member of each of these three BlackRock Fund Complexes, (i) an annual retainer of $487,500, paid quarterly in arrears, allocated to the BlackRock-advised Funds in these three BlackRock Fund Complexes, including the Trust and MIP, and (ii) with respect to each of the two open-end BlackRock Fund Complexes, a board meeting fee of $3,750 (with respect to meetings of the Equity-Liquidity Complex) and $18,750 (with respect to meetings of the Equity-Bond Complex) to be paid for attendance at each board meeting up to five board meetings held in a calendar year by each such Complex (compensation for meetings in excess of this number to be determined on a case by case basis). Mr. Gabbay will also be reimbursed for out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. Mr. Gabbay's compensation for serving on the boards of funds in these three BlackRock Fund Complexes (including the Trust and MIP) is equal to 75% of each retainer and, as applicable, of each meeting fee (without regard to additional fees paid to Board and Committee chairs) received by the independent board members serving on such boards. The Board or any other BlackRock-advised Fund may modify the board members' compensation from time to time depending on market conditions and Mr. Gabbay's compensation would be impacted by those modifications.

Each of the Independent Trustees and Mr. Gabbay agreed to a 10% reduction in their compensation described above for the period December 1, 2009 through December 31, 2009.

From January 1, 2009 through November 30, 2009, the Trust paid each Independent Trustee then in office the Trust's allocable share of the following Independent Trustee fees and expenses: (i) an annual base fee of $60,000; (ii) a per meeting fee of $6,000 for meetings of the Board attended by the Trustee; (iii) a committee meeting fee of $2,500 for each Audit Committee meeting attended by the Trustee; and (iv) a committee meeting fee of $2,000 for each Nominating and Governance Committee meeting attended by the Trustee. The Chairperson of the Audit Committee was paid the Trust's allocable share of an annual fee of $10,000 and the Chairperson of the Nominating and Governance Committee was paid the Trust's allocable share of an annual fee of $5,000. The Lead Independent Trustee was paid the Trust's allocable share of an additional annual base fee of $17,500. These Independent Trustee fees and expenses were allocated between the Trust and MIP, based on their respective assets under management.

The Trust reimburses each Trustee for travel and other out-of-pocket expenses incurred by him/her in connection with attending Board and committee meetings. Currently, the Trustees do not receive any retirement benefits or deferred compensation from the fund complex, as defined in Form N-1A under the 1940 Act.

33

As of December 1, 2009, the members of the Board of Trustees of the Trust listed below resigned (each, a "Previous Trustee"). The table below indicates the amount of compensation each Previous Trustee was paid as of December 31, 2009. Compensation is not shown for the New Trustees because they did not serve as Trustees of the Trust until December 1, 2009, and the New Trustees did not receive compensation from the Trust in 2009.

COMPENSATION
FOR THE FISCAL YEAR ENDED DECEMBER 31, 2009

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INTERESTED TRUSTEE          FROM THE TRUST        FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Lee T. Kranefuss                           $0                       $0
H. Michael Williams                        $0                       $0

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INDEPENDENT TRUSTEES        FROM THE TRUST        FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Mary G. F. Bitterman/2/         $78,394                          $157,000
A. John Gambs/3/                $72,310                          $157,500
Hayne E. Leland                 $60,640                          $132,000
Jeffrey M. Lyons                $67,078                          $146,000
Wendy Paskin-Jordan             $64,552                          $140,500
Leo Soong/4/                    $72,584                          $158,000


/1/ Includes compensation for serving on the Board of Trustees of MIP. /2/ Previously the Nominating and Governance Committee Chair. /3/ Previously the Audit Committee Chair. /4/ Previously the Lead Independent Trustee.

MASTER/FEEDER STRUCTURE. Each LifePath Portfolio seeks to achieve its investment objective by investing all of its assets in the corresponding Master Portfolio of MIP, which in turn invests in a combination of Underlying Funds. In other words, the LifePath Portfolios are "Feeder Funds" into the Master Portfolios, and the Master Portfolios in turn are "Funds of Funds." The Trust's Board of Trustees believes that neither a LifePath Portfolio nor its shareholders will be adversely affected by investing its assets in a Master Portfolio. However, if another feeder fund or other investor withdraws its investment from such Master Portfolio, the economic efficiencies (E.G., spreading fixed expenses among a larger asset base) that the Trust's Board of Trustees believes may be available through investment in the Master Portfolio may not be fully achieved. In addition, although it is unlikely, the master/feeder structure may give rise to accounting or operational difficulties.

A LifePath Portfolio may withdraw its investment in the corresponding Master Portfolio only if the Trust's Board of Trustees determines that such action is in the best interests of such LifePath Portfolio and its shareholders. Prior to any such withdrawal, the Board of Trustees would consider alternative investments, including investing all of the LifePath Portfolio's assets in another investment company with substantially the same investment objective as the LifePath Portfolio or hiring an investment adviser to manage the LifePath Portfolio's assets in accordance with the investment policies described above with respect to the LifePath Portfolio and its Master Portfolios.

Whenever a LifePath Portfolio, as an interestholder of a related Master Portfolio, is requested to vote on any matter submitted to interestholders of the Master Portfolio, the LifePath Portfolio will either hold a meeting of its shareholders to consider such matters and cast its votes in proportion to the votes received from its shareholders (shares for which a LifePath Portfolio receives no voting instructions will be voted in the same proportion as the votes received from the other LifePath Portfolio shareholders) or cast its votes, as an interestholder of the Master Portfolio, in proportion to the votes received by the Master Portfolio from all other interestholders of the Master Portfolios.

Certain policies of the Master Portfolios that are non-fundamental may be changed by the vote of a majority of MIP's Trustees without interestholder approval. If a Master Portfolio's investment objective or fundamental or non-fundamental policies are changed, the corresponding LifePath Portfolio may elect to change its investment objective or policies to correspond to those of the Master Portfolio.

34

A LifePath Portfolio also may elect to redeem its interests from its Master Portfolio and either seek a new investment company with a matching investment objective in which to invest or retain its own investment adviser to manage its portfolio in accordance with its investment objective. In the latter case, a LifePath Portfolio's inability to find a substitute investment company in which to invest or equivalent management services could adversely affect shareholders' investments in the LifePath Portfolio. Each LifePath Portfolio will provide its shareholders with written notice 30 days prior to the implementation of any change in the investment objective of the LifePath Portfolio or the corresponding Master Portfolio, to the extent possible.

CODES OF ETHICS. The Trust, BFA and BRIL have adopted Codes of Ethics pursuant to Rule 17j-1 under the 1940 Act. The Codes of Ethics permit personnel subject to the Codes of Ethics to invest in securities, subject to certain limitations, including securities that may be purchased or held by the LifePath Portfolios. The Codes of Ethics are on public file with, and are available from, the SEC.

PROXY VOTING POLICIES OF THE MASTER PORTFOLIOS.

The Board of Trustees of MIP has delegated the voting of proxies for each Master Portfolio's securities to BFA pursuant to MIP's proxy voting guidelines. Under these guidelines, BFA will vote proxies related to the securities held by each Master Portfolio in the best interests of the Master Portfolio and its stockholders. From time to time, a vote may present a conflict between the interests of the Master Portfolio's stockholders, on the one hand, and those of BFA, or any affiliated person of MIP or BFA, on the other. In such event, provided that Blackrock's Equity Investment Policy Oversight Committee, or a sub-committee thereof (the "Committee") is aware of the real or potential conflict or material non-routine matter and if the Committee does not reasonably believe it is able to follow its general voting guidelines (or if the particular proxy matter is not addressed in the guidelines) and vote impartially, the Committee may retain an independent fiduciary to advise the Committee on how to vote or to cast votes on behalf of BFA's clients. If BFA determines not to retain an independent fiduciary, or does not desire to follow the advice of such independent fiduciary, the Committee shall determine how to vote the proxy after consulting with BlackRock's Portfolio Management Group and/or BlackRock's Legal and Compliance Department and concluding that the vote cast is in its client's best interest notwithstanding the conflict. A copy of MIP's Proxy Voting Policies is attached as Appendix B.

Information on how a Master Portfolio voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available without charge, (i) at www.blackrock.com and (ii) on the SEC's website at http://www.sec.gov.

35

Control Persons and Principal Holders of Securities

As of March 31, 2010, the shareholders identified below were known by the Trust to own 5% or more of each LifePath Portfolio's outstanding Investor A, Institutional, Class K or Class R Shares in the listed capacity. As of such date, Investor C Shares had not commenced operations.

                                                                            PERCENTAGE     NATURE OF
      INSTITUTIONAL SHARES           NAME AND ADDRESS OF SHAREHOLDER       OF PORTFOLIO    OWNERSHIP
-------------------------------  ---------------------------------------  --------------  ----------
LifePath Retirement Portfolio    Merrill Lynch, Pierce, Fenner & Smith           6%         Record
                                 4800 Deer Lake Drive East
                                 3rd Floor
                                 Jacksonville, FL 32246
                                 Charles Schwab & Co., Inc.                     17%         Record
                                 101 Montgomery Street
                                 San Francisco, CA 94104
                                 New York Life Trust Company                    19%         Record
                                 169 Lackawanna Avenue
                                 Parsippany, NJ 07054
                                 NFS LLC                                        23%         Record
                                 4 Manhattanville Road
                                 Purchase, NY 10577
LifePath 2020 Portfolio          Mac & Co.                                       6%         Record
                                 P.O. Box 3198
                                 525 William Penn Place
                                 Pittsburgh, PA 15230
                                 New York Life Trust Company                    18%         Record
                                 169 Lackawanna Avenue
                                 Parsippany, NJ 07054
                                 Charles Schwab & Co., Inc.                     20%         Record
                                 101 Montgomery Street
                                 San Francisco, CA 94104
                                 NFS LLC                                        31%         Record
                                 4 Manhattanville Road
                                 Purchase, NY 10577
LifePath 2030 Portfolio          Fifth Third Bank                                6%         Record
                                 P.O. Box 630074
                                 Cincinnati, OH 45263

36

                                                                            PERCENTAGE     NATURE OF
      INSTITUTIONAL SHARES           NAME AND ADDRESS OF SHAREHOLDER       OF PORTFOLIO    OWNERSHIP
-------------------------------  ---------------------------------------  --------------  ----------
                                 Mac & Co.                                       7%         Record
                                 P.O. Box 3198
                                 525 William Penn Place
                                 Pittsburgh, PA 15230
                                 Charles Schwab & Co., Inc.                     18%         Record
                                 101 Montgomery Street
                                 San Francisco, CA 94104
                                 NFS LLC                                        21%         Record
                                 4 Manhattanville Road
                                 Purchase, NY 10577
                                 New York Life Trust Company                    23%         Record
                                 169 Lackawanna Avenue
                                 Parsippany, NJ 07054
LifePath 2040 Portfolio          Fifth Third Bank                                7%         Record
                                 P.O. Box 630074
                                 Cincinnati, OH 45263
                                 Mac & Co.                                       7%         Record
                                 P.O. Box 3198
                                 525 William Penn Place
                                 Pittsburgh, PA 15230
                                 NFS LLC                                        17%         Record
                                 4 Manhattanville Road
                                 Purchase, NY 10577
                                 New York Life Trust Company                    20%         Record
                                 169 Lackawanna Avenue
                                 Parsippany, NJ 07054
                                 Charles Schwab & Co., Inc.                     23%         Record
                                 101 Montgomery Street
                                 San Francisco, CA 94104
LifePath 2050 Portfolio          Mac & Co.                                       6%         Record
                                 P.O. Box 3198
                                 525 William Penn Place
                                 Pittsburgh, PA 15230
                                 Charles Schwab & Co., Inc.                     10%         Record
                                 101 Montgomery Street
                                 San Francisco, CA 94104
                                 Wachovia Bank                                  16%         Record
                                 1525 West W.T. Harris Blvd.
                                 Charlotte, NC 28288
                                 Fifth Third Bank                               19%         Record
                                 P.O. Box 630074
                                 Cincinnati, OH 45263
                                 NFS LLC                                        40%         Record
                                 4 Manhattanville Road
                                 Purchase, NY 10577

37

                                                                            PERCENTAGE     NATURE OF
       INVESTOR A SHARES             NAME AND ADDRESS OF SHAREHOLDER       OF PORTFOLIO    OWNERSHIP
-------------------------------  ---------------------------------------  --------------  -----------
LifePath Retirement Portfolio    National Financial Services                     5%         Record
                                 200 Liberty Street
                                 New York, NY 10281
                                 State Street Bank and Trust Company             6%         Record
                                 One Heritage Drive
                                 Quincy, MA 02171
                                 Merrill Lynch, Pierce, Fenner & Smith           7%         Record
                                 4800 Deer Lake Drive East
                                 3rd Floor
                                 Jacksonville, FL 32246
                                 Hartford Life Insurance Company                59%         Record
                                 P.O. Box 2999
                                 Hartford, CT 06104
LifePath 2020 Portfolio          State Street Bank and Trust Company             6%         Record
                                 One Heritage Drive
                                 Quincy, MA 02171
                                 National Financial Services                     8%         Record
                                 200 Liberty Street
                                 New York, NY 10281
                                 Hartford Life Insurance Company                66%         Record
                                 P.O. Box 2999
                                 Hartford, CT 06104
LifePath 2030 Portfolio          State Street Bank and Trust Company             6%         Record
                                 One Heritage Drive
                                 Quincy, MA 02171
                                 National Financial Services                     9%         Record
                                 200 Liberty Street
                                 New York, NY 10281
                                 Hartford Life Insurance Company                68%         Record
                                 P.O. Box 2999
                                 Hartford, CT 06104
LifePath 2040 Portfolio          State Street Bank and Trust Company             6%         Record
                                 One Heritage Drive
                                 Quincy, MA 02171
                                 National Financial Services                     8%         Record
                                 200 Liberty Street
                                 New York, NY 10281
                                 Hartford Life Insurance Company                68%         Record
                                 P.O. Box 2999
                                 Hartford, CT 06104
LifePath 2050 Portfolio          National Financial Services                    45%         Record
                                 200 Liberty Street
                                 New York, NY 10281
                                 Hartford Life Insurance Company                46%         Record
                                 P.O. Box 2999
                                 Hartford, CT 06104

38

         CLASS K SHARES           NAME AND ADDRESS OF SHAREHOLDER
-------------------------------  ---------------------------------------   OF PORTFOLIO    OWNERSHIP
LifePath Retirement Portfolio    Mercer Trust Company                            50%        Record
                                 One Investors Way
                                 Norwood, MA 02062
                                 NFS LLC                                         50%        Record
                                 100 Magellan Way # KW1C
                                 Covington, KY 41015
LifePath 2020 Portfolio          Mercer Trust Company                            17%        Record
                                 One Investors Way
                                 Norwood, MA 02062
                                 NFS LLC                                         51%        Record
                                 100 Magellan Way # KW1C
                                 Covington, KY 41015
                                 Wilmington Trust Company                        33%        Record
                                 P.O. Box 8971
                                 Wilmington, DE 19899
LifePath 2030 Portfolio          Mercer Trust Company                            12%        Record
                                 One Investors Way
                                 Norwood, MA 02062
                                 NFS LLC                                         33%        Record
                                 100 Magellan Way # KW1C
                                 Covington, KY 41015
                                 Wilmington Trust Company                        50%        Record
                                 P.O. Box 8971
                                 Wilmington, DE 19899
LifePath 2040 Portfolio          Wilmington Trust Company                        98%        Record
                                 P.O. Box 8971
                                 Wilmington, DE 19899
LifePath 2050 Portfolio          Barclays California Corporation                 16%        Record
                                 45 Fremont Street
                                 San Francisco, CA 94105
                                 Mercer Trust Company                            84%        Record
                                 One Investors Way
                                 Norwood, MA 02062

For purposes of the 1940 Act, any person who owns directly or through one or more controlled companies more than 25% of the voting securities of a company is presumed to "control" such company. Accordingly, to the extent that a shareholder identified in the foregoing table is identified as the beneficial holder of more than 25% of a LifePath Portfolio, or is identified as the holder of record of more than 25% of a LifePath Portfolio and has voting and/or investment powers, it may be presumed to control such LifePath Portfolio.

As of March 31, 2010, Trustees and officers of the Trust, as a group, beneficially owned less than 1% of the outstanding shares of the Trust.

POTENTIAL CONFLICTS OF INTEREST. The Bank of America Corporation ("BAC"), through its subsidiary Merrill Lynch & Co., Inc. ("Merrill Lynch"), Barclays PLC ("Barclays"), and The PNC Financial Services Group, Inc. ("PNC"), each have a significant economic interest in BlackRock, Inc., the parent of BFA, the LifePath Portfolios' investment adviser. PNC is considered to be an affiliate of BlackRock, Inc., under the 1940 Act. Certain activities of BFA, BlackRock Advisors, LLC, BlackRock, Inc. and their

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affiliates (collectively, "BlackRock") and PNC and its affiliates (collectively, "PNC" and together with BlackRock, "Affiliates"), and those of BAC, Merrill Lynch and their affiliates (collectively, the "BAC Entities") and Barclays and its affiliates (collectively, the "Barclays Entities") (BAC Entities and Barclays Entities, collectively, the "BAC/Barclays Entities"), with respect to the LifePath Portfolios and/or other accounts managed by BlackRock, PNC or BAC/Barclays Entities, may give rise to actual or perceived conflicts of interest such as those described below.

BlackRock is one of the world's largest asset management firms. BAC is a national banking corporation which through its affiliates and subsidiaries, including Merrill Lynch, provides a full range of financial services. Merrill Lynch is a full service investment banking, broker-dealer, asset management and financial services organization. PNC is a diversified financial services organization spanning the retail, business and corporate markets. Barclays is a major global financial services provider engaged in a range of activities including retail and commercial banking, credit cards, investment banking, and wealth management. BlackRock, BAC, Merrill Lynch, PNC, Barclays and their respective affiliates (including, for these purposes, their directors, partners, trustees, managing members, officers and employees), including the entities and personnel who may be involved in the investment activities and business operations of a LifePath Portfolio, are engaged worldwide in businesses, including equity, fixed income, cash management and alternative investments, and have interests other than those of managing the LifePath Portfolios. These are considerations of which investors in a LifePath Portfolio should be aware, and which may cause conflicts of interest that could disadvantage the LifePath Portfolio and its shareholders. These activities and interests include potential multiple advisory, transactional, financial and other interests in securities and other instruments, and companies that may be purchased or sold by a LifePath Portfolio.

BlackRock and its Affiliates, as well as the BAC/Barclays Entities, have proprietary interests in, and may manage or advise with respect to, accounts or funds (including separate accounts and other funds and collective investment vehicles) that have investment objectives similar to those of a LifePath Portfolio and/or that engage in transactions in the same types of securities, currencies and instruments as the LifePath Portfolio. One or more Affiliates and BAC/Barclays Entities are also major participants in the global currency, equities, swap and fixed income markets, in each case both on a proprietary basis and for the accounts of customers. As such, one or more Affiliates or BAC/Barclays Entities are or may be actively engaged in transactions in the same securities, currencies, and instruments in which a LifePath Portfolio invests. Such activities could affect the prices and availability of the securities, currencies, and instruments in which a LifePath Portfolio invests, which could have an adverse impact on the LifePath Portfolio's performance. Such transactions, particularly in respect of most proprietary accounts or customer accounts, will be executed independently of a LifePath Portfolio's transactions and thus at prices or rates that may be more or less favorable than those obtained by the LifePath Portfolio. When BlackRock and its Affiliates or the BAC/Barclays Entities seek to purchase or sell the same assets for their managed accounts, including a LifePath Portfolio, the assets actually purchased or sold may be allocated among the accounts on a basis determined in their good faith discretion to be equitable. In some cases, this system may adversely affect the size or price of the assets purchased or sold for a LifePath Portfolio. In addition, transactions in investments by one or more other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of a LifePath Portfolio, particularly, but not limited to, with respect to small capitalization, emerging market or less liquid strategies. This may occur when investment decisions regarding a LifePath Portfolio are based on research or other information that is also used to support decisions for other accounts. When BlackRock or its Affiliates or a BAC/Barclays Entity implements a portfolio decision or strategy on behalf of another account ahead of, or contemporaneously with, similar decisions or strategies for a LifePath Portfolio, market impact, liquidity constraints, or other factors could result in the LifePath Portfolio receiving less favorable trading results and the costs of implementing such decisions or strategies could be increased or the LifePath Portfolio could otherwise be disadvantaged. BlackRock or it Affiliates or a BAC/Barclays Entity may, in certain cases, elect to implement internal policies and procedures designed to limit such consequences, which may cause a LifePath Portfolio to be unable to engage in certain activities, including purchasing or disposing of securities, when it might otherwise be desirable for it to do so.

Conflicts may also arise because portfolio decisions regarding a LifePath Portfolio may benefit other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity. For example, the sale of a long position or establishment of a short position by a LifePath Portfolio may impair the price of the same security sold short by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts, and the purchase of a security or covering of a short position in a security by a LifePath Portfolio may increase the price of the same security held by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts.

BlackRock and its Affiliates or a BAC/Barclays Entity and their clients may pursue or enforce rights with respect to an issuer in which a LifePath Portfolio has invested, and those activities may have an adverse effect on the LifePath Portfolio. As a result,

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prices, availability, liquidity and terms of the LifePath Portfolio's investments may be negatively impacted by the activities of BlackRock or its Affiliates or a BAC/Barclays Entity or their clients, and transactions for the LifePath Portfolio may be impaired or effected at prices or terms that may be less favorable than would otherwise have been the case.

The results of a LifePath Portfolio's investment activities may differ significantly from the results achieved by BlackRock and its Affiliates or the BAC/Barclays Entities for their proprietary accounts or other accounts (including investment companies or collective investment vehicles) managed or advised by them. It is possible that one or more Affiliate- or BAC/Barclays Entity-managed accounts and such other accounts will achieve investment results that are substantially more or less favorable than the results achieved by a LifePath Portfolio. Moreover, it is possible that a LifePath Portfolio will sustain losses during periods in which one or more Affiliates or BAC/Barclays Entity-managed accounts achieve significant profits on their trading for proprietary or other accounts. The opposite result is also possible. The investment activities of one or more Affiliates or BAC/Barclays Entities for their proprietary accounts and accounts under their management may also limit the investment opportunities for a LifePath Portfolio in certain emerging and other markets in which limitations are imposed upon the amount of investment, in the aggregate or in individual issuers, by affiliated foreign investors.

From time to time, a LifePath Portfolio's activities may also be restricted because of regulatory restrictions applicable to one or more Affiliates or BAC/Barclays Entities, and/or their internal policies designed to comply with such restrictions. As a result, there may be periods, for example, when BlackRock, and/or one or more Affiliates or BAC/Barclays Entities, will not initiate or recommend certain types of transactions in certain securities or instruments with respect to which BlackRock and/or one or more Affiliates or BAC/Barclays Entities are performing services or when position limits have been reached.

In connection with its management of a LifePath Portfolio, BlackRock may have access to certain fundamental analysis and proprietary technical models developed by one or more Affiliates or BAC/Barclays Entities. BlackRock will not be under any obligation, however, to effect transactions on behalf of a LifePath Portfolio in accordance with such analysis and models. In addition, neither BlackRock nor any of its Affiliates, nor any BAC/Barclays Entity, will have any obligation to make available any information regarding their proprietary activities or strategies, or the activities or strategies used for other accounts managed by them, for the benefit of the management of a LifePath Portfolio and it is not anticipated that BlackRock will have access to such information for the purpose of managing the LifePath Portfolio. The proprietary activities or portfolio strategies of BlackRock and its Affiliates and the BAC/Barclays Entities, or the activities or strategies used for accounts managed by them or other customer accounts could conflict with the transactions and strategies employed by BlackRock in managing a LifePath Portfolio.

In addition, certain principals and certain employees of BlackRock are also principals or employees of BlackRock or another Affiliate. As a result, the performance by these principals and employees of their obligations to such other entities may be a consideration of which investors in a LifePath Portfolio should be aware.

BlackRock may enter into transactions and invest in securities, instruments and currencies on behalf of a LifePath Portfolio in which customers of BlackRock or its Affiliates or a BAC/Barclays Entity, or, to the extent permitted by the SEC, BlackRock or another Affiliate or a BAC/Barclays Entity, serves as the counterparty, principal or issuer. In such cases, such party's interests in the transaction will be adverse to the interests of the LifePath Portfolio, and such party may have no incentive to assure that the LifePath Portfolio obtains the best possible prices or terms in connection with the transactions. In addition, the purchase, holding and sale of such investments by a LifePath Portfolio may enhance the profitability of BlackRock or its Affiliates or a BAC/Barclays Entity. One or more Affiliates or BAC/Barclays Entities may also create, write or issue derivatives for their customers, the underlying securities, currencies or instruments of which may be those in which a LifePath Portfolio
invests or which may be based on the performance of the LifePath Portfolio. A LifePath Portfolio may, subject to applicable law, purchase investments that are the subject of an underwriting or other distribution by one or more Affiliates or BAC/Barclays Entities and may also enter into transactions with other clients of an Affiliate or BAC/Barclays Entity where such other clients have interests adverse to those of the LifePath Portfolio.

At times, these activities may cause departments of BlackRock or its Affiliates or a BAC/Barclays Entity to give advice to clients that may cause these clients to take actions adverse to the interests of the LifePath Portfolio. To the extent affiliated transactions are permitted, a LifePath Portfolio will deal with BlackRock and its Affiliates or BAC/Barclays Entities on an arms-length basis. BlackRock or its Affiliates or a BAC/Barclays Entity may also have an ownership interest in certain trading or information systems used by a LifePath Portfolio. A LifePath Portfolio's use of such trading or information systems may enhance the profitability of BlackRock and its Affiliates or BAC/Barclays Entities.

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One or more Affiliates or one of the BAC/Barclays Entities may act as broker, dealer, agent, lender or adviser or in other commercial capacities for a LifePath Portfolio. It is anticipated that the commissions, mark-ups, mark-downs, financial advisory fees, underwriting and placement fees, sales fees, financing and commitment fees, brokerage fees, other fees, compensation or profits, rates, terms and conditions charged by an Affiliate or BAC/Barclays Entity will be in its view commercially reasonable, although each Affiliate or BAC/Barclays Entity, including its sales personnel, will have an interest in obtaining fees and other amounts that are favorable to the Affiliate or BAC/Barclays Entity and such sales personnel.

Subject to applicable law, the Affiliates and BAC/Barclays Entities (and their personnel and other distributors) will be entitled to retain fees and other amounts that they receive in connection with their service to the LifePath Portfolios as broker, dealer, agent, lender, adviser or in other commercial capacities and no accounting to the LifePath Portfolios or their shareholders will be required, and no fees or other compensation payable by the LifePath Portfolios or their shareholders will be reduced by reason of receipt by an Affiliate or BAC/Barclays Entity of any such fees or other amounts.

When an Affiliate or BAC/Barclays Entity acts as broker, dealer, agent, adviser or in other commercial capacities in relation to the LifePath Portfolios, the Affiliate or BAC/Barclays Entity may take commercial steps in its own interests, which may have an
adverse effect on the LifePath Portfolios. A LifePath Portfolio will be required to establish business relationships with its counterparties based on the LifePath Portfolio's own credit standing. Neither BlackRock nor any of the Affiliates, nor any BAC/Barclays Entity, will have any obligation to allow their credit to be used in connection with a LifePath Portfolio's establishment of its business relationships, nor is it expected that the LifePath Portfolio's counterparties will rely on the credit of BlackRock or any of the Affiliates or BAC/Barclays Entities in evaluating the LifePath Portfolio's creditworthiness.

Purchases and sales of securities for a LifePath Portfolio may be bunched or aggregated with orders for other BlackRock client accounts. BlackRock and its Affiliates and the BAC/Barclays Entities, however, are not required to bunch or aggregate orders if portfolio management decisions for different accounts are made separately, or if they determine that bunching or aggregating is not practicable, required or with cases involving client direction.

Prevailing trading activity frequently may make impossible the receipt of the same price or execution on the entire volume of securities purchased or sold. When this occurs, the various prices may be averaged, and the LifePath Portfolios will be charged or credited with the average price. Thus, the effect of the aggregation may operate on some occasions to the disadvantage of the LifePath Portfolios. In addition, under certain circumstances, the LifePath Portfolios will not be charged the same commission or commission equivalent rates in connection with a bunched or aggregated order.

BlackRock may select brokers (including, without limitation, Affiliates or BAC/Barclays Entities) that furnish BlackRock, the LifePath Portfolios, other BlackRock client accounts or other Affiliates or BAC/Barclays Entities or personnel, directly or through correspondent relationships, with research or other appropriate services which provide, in BlackRock's view, appropriate assistance to BlackRock in the investment decision-making process (including with respect to futures, fixed-price offerings and over-the-counter transactions). Such research or other services may include, to the extent permitted by law, research reports on companies, industries and securities; economic and financial data; financial publications; proxy analysis; trade industry seminars; computer data bases; research-oriented software and other services and products. Research or other services obtained in this manner may be used in servicing any or all of the LifePath Portfolios and other BlackRock client accounts, including in connection with BlackRock client accounts other than those that pay commissions to the broker relating to the research or other service arrangements. Such products and services may disproportionately benefit other BlackRock client accounts relative to the LifePath Portfolios based on the amount of brokerage commissions paid by the LifePath Portfolios and such other BlackRock client accounts. For example, research or other services that are paid for through one client's commissions may not be used in managing that client's account. In addition, other BlackRock client accounts may receive the benefit, including disproportionate benefits, of economies of scale or price discounts in connection with products and services that may be provided to the LifePath Portfolios and to such other BlackRock client accounts. To the extent that BlackRock uses soft dollars, it will not have to pay for those products and services itself.

BlackRock may receive research that is bundled with the trade execution, clearing, and/or settlement services provided by a particular broker-dealer. To the extent that BlackRock receives research on this basis, many of the same conflicts related to traditional soft dollars may exist. For example, the research effectively will be paid by client commissions that also will be used to pay for the execution, clearing, and settlement services provided by the broker-dealer and will not be paid by BlackRock.

BlackRock may endeavor to execute trades through brokers who, pursuant to such arrangements, provide research or other services in order to ensure the continued receipt of research or other services BlackRock believes are useful in its investment

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decision-making process. BlackRock may from time to time choose not to engage in the above described arrangements to varying degrees. BlackRock may also enter into commission sharing arrangements under which BlackRock may execute transactions through a broker-dealer, including, where permitted, an Affiliate or BAC/Barclays Entity, and request that the broker-dealer allocate a portion of the commissions or commission credits to another firm that provides research to BlackRock. To the extent that BlackRock engages in commission sharing arrangements, many of the same conflicts related to traditional soft dollars may exist.

BlackRock may utilize certain electronic crossing networks ("ECNs") in executing client securities transactions for certain types of securities. These ECNs may charge fees for their services, including access fees and transaction fees. The transaction fees, which are similar to commissions or markups/markdowns, will generally be charged to clients and, like commissions and markups/markdowns, would generally be included in the cost of the securities purchased. Access fees may be paid by BlackRock even though incurred in connection with executing transactions on behalf of clients, including the LifePath Portfolios. In certain circumstances, ECNs may offer volume discounts that will reduce the access fees typically paid by BlackRock. This would have the effect of reducing the access fees paid by BlackRock. BlackRock will only utilize ECNs consistent with its obligation to seek to obtain best execution in client transactions.

BlackRock has adopted policies and procedures designed to prevent conflicts of interest from influencing proxy voting decisions that it makes on behalf of advisory clients, including the LifePath Portfolios, and to help ensure that such decisions are made in accordance with BlackRock's fiduciary obligations to its clients. Nevertheless, notwithstanding such proxy voting policies and procedures, actual proxy voting decisions of BlackRock may have the effect of favoring the interests of other clients or businesses of other divisions or units of BlackRock and/or its Affiliates or a BAC/Barclays Entity, provided that BlackRock believes such voting decisions to be in accordance with its fiduciary obligations. For a more detailed discussion of these policies and procedures, see "Proxy Voting Policies of the Master Portfolios."

It is also possible that, from time to time, BlackRock or its Affiliates or a BAC/Barclays Entity may, although they are not required to, purchase and hold shares of a LifePath Portfolio. Increasing a LifePath Portfolio's assets may enhance investment flexibility and diversification and may contribute to economies of scale that tend to reduce the LifePath Portfolio's expense ratio. BlackRock and its Affiliates or BAC/Barclays Entities reserve the right to redeem at any time some or all of the shares of a LifePath Portfolio acquired for their own accounts. A large redemption of shares of a LifePath Portfolio by BlackRock or its Affiliates or by a BAC/Barclays Entity could significantly reduce the asset size of the LifePath Portfolio, which might have an adverse effect on the LifePath Portfolio's investment flexibility, portfolio diversification and expense ratio. BlackRock will consider the effect of redemptions on a LifePath Portfolio and other shareholders in deciding whether to redeem its shares.

It is possible that a LifePath Portfolio may invest in securities of companies with which an Affiliate or a BAC/Barclays Entity has or is trying to develop investment banking relationships as well as securities of entities in which BlackRock or its Affiliates or a BAC/Barclays Entity has significant debt or equity investments or in which an Affiliate or BAC/Barclays Entity makes a market. A LifePath Portfolio also may invest in securities of companies to which an Affiliate or a BAC/Barclays Entity provides or may some day provide research coverage. Such investments could cause conflicts between the interests of a LifePath Portfolio and the interests of other clients of BlackRock or its Affiliates or a BAC/Barclays Entity. In making investment decisions for a LifePath Portfolio, BlackRock is not permitted to obtain or use material non-public information acquired by any division, department or Affiliate of BlackRock or of a BAC/Barclays Entity in the course of these activities. In addition, from time to time, the activities of an Affiliate or a BAC/Barclays Entity may limit a LifePath Portfolio's flexibility in purchases and sales of securities. When an Affiliate is engaged in an underwriting or other distribution of securities of an entity, BlackRock may be prohibited from purchasing or recommending the purchase of certain securities of that entity for a LifePath Portfolio.

BlackRock and its Affiliates and the BAC/Barclays Entities, their personnel and other financial service providers have interests in promoting sales of the LifePath Portfolios. With respect to BlackRock and its Affiliates and BAC/Barclays Entities and their personnel, the remuneration and profitability relating to services to and sales of the LifePath Portfolios or other products may be greater than remuneration and profitability relating to services to and sales of certain funds or other products that might be provided or offered. BlackRock and its Affiliates or BAC/Barclays Entities and their sales personnel may directly or indirectly receive a portion of the fees and commissions charged to the LifePath Portfolios or their shareholders. BlackRock and its advisory or other personnel may also benefit from increased amounts of assets under management. Fees and commissions may also be higher than for other products or services, and the remuneration and profitability to BlackRock or its Affiliates or a BAC/Barclays Entity and such personnel resulting from transactions on behalf of or management of the LifePath Portfolios may be greater than the remuneration and profitability resulting from other funds or products.

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BlackRock and its Affiliates or a BAC/Barclays Entity and their personnel may receive greater compensation or greater profit in connection with an account for which BlackRock serves as an adviser than with an account advised by an unaffiliated investment adviser. Differentials in compensation may be related to the fact that BlackRock may pay a portion of its management fee to its Affiliate or to a BAC/Barclays Entity, or relate to compensation arrangements, including for portfolio management, brokerage transactions or account servicing. Any differential in compensation may create a financial incentive on the part of BlackRock or its Affiliates or BAC/Barclays Entities and their personnel to recommend BlackRock over unaffiliated investment advisers or to effect transactions differently in one account over another.

BlackRock and its Affiliates or a BAC/Barclays Entity may provide valuation assistance to certain clients with respect to certain securities or other investments and the valuation recommendations made for their clients' accounts may differ from the valuations for the same securities or investments assigned by a LifePath Portfolio's pricing vendors, especially if such valuations are based on broker-dealer quotes or other data sources unavailable to the LifePath Portfolio's pricing vendors. While BlackRock will generally communicate its valuation information or determinations to a LifePath Portfolio's pricing vendors and/or fund accountants, there may be instances where the LifePath Portfolio's pricing vendors or fund accountants assign a different valuation to a security or other investment than the valuation for such security or investment determined or recommended by BlackRock.

As disclosed in more detail in "Determination of Net Asset Value" in this SAI, when market quotations are not readily available or are believed by BlackRock to be unreliable, a LifePath Portfolio's investments may be valued at fair value by BlackRock, pursuant to procedures adopted by the Trust's Board of Trustees. When determining an asset's "fair value," BlackRock seeks to determine the price that a LifePath Portfolio might reasonably expect to receive from the current sale of that asset in an arm's-length transaction. The price generally may not be determined based on what a LifePath Portfolio might reasonably expect to receive for selling an asset at a later time or if it holds the asset to maturity. While fair value determinations will be based upon all available factors that BlackRock deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models, fair value represents only a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value. As a result, a LifePath Portfolio's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued by BlackRock (pursuant to Board-adopted procedures) at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

To the extent permitted by applicable law, a LifePath Portfolio may invest all or some of its short term cash investments in any money market fund or similarly-managed private fund advised or managed by BlackRock. In connection with any such investments, a LifePath Portfolio, to the extent permitted by the 1940 Act, may pay its share of expenses of a money market fund in which it invests, which may result in a LifePath Portfolio bearing some additional expenses.

BlackRock and its Affiliates or a BAC/Barclays Entity and their directors, officers and employees, may buy and sell securities or other investments for their own accounts, and may have conflicts of interest with respect to investments made on behalf of a LifePath Portfolio. As a result of differing trading and investment strategies or constraints, positions may be taken by directors, officers, employees and Affiliates of BlackRock or by BAC/Barclays Entities that are the same, different from or made at different times than positions taken for a LifePath Portfolio. To lessen the possibility that a LifePath Portfolio will be adversely affected by this personal trading, the LifePath Portfolios, BRIL and BFA each have adopted a Code of Ethics in compliance with Section 17(j) of the 1940 Act that restricts securities trading in the personal accounts of investment professionals and others who normally come into possession of information regarding the LifePath Portfolio's portfolio transactions. Each Code of Ethics can be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling the SEC at (202) 551-8090. Each Code of Ethics is also available on the EDGAR Database on the SEC's Internet site at http://www.sec.gov, and copies may be obtained, after paying a duplicating fee, by e-mail at publicinfo@sec.gov or by writing the SEC's Public Reference Section, Washington, DC 20549-1520.

BlackRock and its Affiliates will not purchase securities or other property from, or sell securities or other property to, a LifePath Portfolio, except that the LifePath Portfolio may in accordance with rules adopted under the 1940 Act engage in transactions with accounts that are affiliated with the LifePath Portfolio as a result of common officers, directors, or investment advisers or pursuant to exemptive orders granted to the LifePath Portfolios and/or BlackRock by the SEC. These transactions would be affected in circumstances in which BlackRock determined that it would be appropriate for a LifePath Portfolio to purchase and another client of BlackRock to sell, or a LifePath Portfolio to sell and another client of BlackRock to

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purchase, the same security or instrument on the same day. From time to time, the activities of a LifePath Portfolio may be restricted because of regulatory requirements applicable to BlackRock or its Affiliates or a BAC/Barclays Entity and/or BlackRock's internal policies designed to comply with, limit the applicability of, or otherwise relate to such requirements. A client not advised by BlackRock would not be subject to some of those considerations. There may be periods when BlackRock may not initiate or recommend certain types of transactions, or may otherwise restrict or limit their advice in certain securities or instruments issued by or related to companies for which an Affiliate or a BAC/Barclays Entity is performing investment banking, market making, advisory or other services or has proprietary positions. For example, when an Affiliate is engaged in an underwriting or other distribution of securities of, or advisory services for, a company, the LifePath Portfolios may be prohibited from or limited in purchasing or selling securities of that company. In addition, when BlackRock is engaged to provide advisory or risk management services for a company, BlackRock may be prohibited from or limited in purchasing or selling securities of that company on behalf of a LifePath Portfolio, particularly where such services result in BlackRock obtaining material non-public information about the company. Similar situations could arise if personnel of BlackRock or its Affiliates or a BAC/Barclays Entity serve as directors of companies the securities of which the LifePath Portfolios wish to purchase or sell. However, if permitted by applicable law, and where consistent with BlackRock's policies and procedures (including the necessary implementation of appropriate information barriers), the LifePath Portfolios may purchase securities or instruments that are issued by such companies, are the subject of an underwriting, distribution, or advisory assignment by an Affiliate or a BAC/Barclays Entity or are the subject of an advisory or risk management assignment by BlackRock, or where personnel of BlackRock or its Affiliates or of BAC/Barclays Entities are directors or officers of the issuer.

In certain circumstances where the LifePath Portfolios invest in securities issued by companies that operate in certain regulated industries, in certain emerging or international markets, or are subject to corporate or regulatory ownership definitions, there may be limits on the aggregate amount invested by Affiliates (including BlackRock) or BAC/Barclays Entities for their proprietary accounts and for client accounts (including the LifePath Portfolios) that may not be exceeded without the grant of a license or other regulatory or corporate consent, or, if exceeded, may cause BlackRock, the LifePath Portfolios or other client accounts to suffer disadvantages or business restrictions. As a result, BlackRock on behalf of its clients (including the LifePath Portfolios) may limit purchases, sell existing investments, or otherwise restrict or limit the exercise of rights (including voting rights) when BlackRock, in its sole discretion, deems it appropriate in light of potential regulatory or other restrictions on ownership or other consequences resulting from reaching investment thresholds.

In those circumstances where ownership thresholds or limitations must be observed, BlackRock seeks to equitably allocate limited investment opportunities among clients (including the LifePath Portfolios), taking into consideration benchmark weight and investment strategy. When ownership in certain securities nears an applicable threshold, BlackRock may limit purchases in such securities to the issuer's weighting in the applicable benchmark used by BlackRock to manage the LifePath Portfolio. If client (including LifePath Portfolio) holdings of an issuer exceed an applicable threshold and BlackRock is unable to obtain relief to enable the continued holding of such investments, it may be necessary to sell down these positions to meet the applicable limitations. In these cases, benchmark overweight positions will be sold prior to benchmark positions being reduced to meet applicable limitations.

In addition to the foregoing, other ownership thresholds may trigger reporting requirements to governmental and regulatory authorities, and such reports may entail the disclosure of the identity of a client or BlackRock's intended strategy with respect to such security or asset.

BlackRock and its Affiliates and BAC/Barclays Entities may maintain securities indexes as part of their product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including BlackRock and its Affiliates and BAC/Barclays Entities may be paid licensing fees for use of their index or index name. BlackRock and its Affiliates and BAC/Barclays Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with BlackRock and its Affiliates and BAC/Barclays Entities will be as favorable as those terms offered to other index licensees.

BlackRock and its Affiliates and BAC/Barclays Entities may serve as authorized participants in the creation and redemption of ETFs, including funds advised by affiliates of BlackRock. BlackRock and its Affiliates and BAC/Barclays Entities may therefore be deemed to be participants in a distribution of such ETFs, which could render them statutory underwriters.

Present and future activities of BlackRock and its Affiliates and BAC/Barclays Entities, including BlackRock Advisors, LLC, in addition to those described in this section, may give rise to additional conflicts of interest.

Present and future activities of BlackRock and its Affiliates and BAC/Barclays Entities, including BlackRock Advisors, LLC, in addition to those described in this section, may give rise to additional conflicts of interest.

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Investment Adviser and Other Service Providers

INVESTMENT ADVISER. BFA provides investment advisory services to each Master Portfolio pursuant to an investment advisory contract (each, an "Advisory Contract") with MIP. Pursuant to the Advisory Contracts, BFA furnishes to MIP's Board of Trustees periodic reports on the investment strategy and performance of each Master Portfolio.

BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc.

The corresponding Advisory Contract is subject to annual approval by (i) MIP's Board of Trustees or (ii) vote of a majority (as defined in the 1940 Act) of the outstanding voting interests of such Master Portfolio, provided that in either event the continuance also is approved by a majority of Independent Trustees of MIP, by a vote cast in person at a meeting called for the purpose of voting on such approval. The corresponding Advisory Contract is terminable without penalty on 60 days' written notice by either party. The corresponding Advisory Contract will terminate automatically, as to the relevant Master Portfolio, in the event of its assignment (as defined in the 1940 Act).

ADVISORY FEES. BFA is entitled to receive monthly fees at the annual rate of 0.35% of the average daily net assets of each Master Portfolio. BFA has contractually agreed, for the period May 1, 2006 through close of business on November 30, 2011, to waive management fees charged to the Master Portfolios in an amount equal to the management fees charged by BFA to the Underlying Funds in order to avoid duplication of such fees. In addition, BTC may receive fees as Administrator of certain

46

of the Underlying Funds; however, BFA has contractually agreed, through close of business on November 30, 2011, to waive from management fees charged to the Master Portfolios an amount equal to the administration fees charged by BTC to those Underlying Funds. Any such waiver will reduce the expenses of a Master Portfolio and, accordingly, have a favorable impact on its performance.

For the fiscal years shown below, the related Master Portfolio of each LifePath Portfolio paid, with respect to the LifePath Portfolios, the following management fees to BFA, net of waivers and/or offsetting credits:

                                  FISCAL YEAR ENDED       FISCAL YEAR        FISCAL YEAR
LIFEPATH PORTFOLIO                    12/31/2007       ENDED 12/31/2008    ENDED 12/31/2009
-------------------------------  -------------------  ------------------  -----------------
LifePath Retirement Portfolio          $ 18,223            $ 18,301           $ 34,699
LifePath 2020 Portfolio                $157,437            $ 99,817           $114,482
LifePath 2030 Portfolio                $ 98,295            $ 58,864           $ 68,396
LifePath 2040 Portfolio                $ 57,883            $ 30,501           $ 40,293
LifePath 2050 Portfolio(1)               N/A                ($1,314)           ($2,166)


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

For the fiscal years shown below, BFA waived the following management fees with respect to the LifePath Portfolios:

                                  FISCAL YEAR ENDED    FISCAL YEAR ENDED     FISCAL YEAR
LIFEPATH PORTFOLIO                    12/31/2007           12/31/2008      ENDED 12/31/2009
-------------------------------  -------------------  ------------------  -----------------
LifePath Retirement Portfolio         $  424,199           $  473,654         $  601,228
LifePath 2020 Portfolio               $2,872,147           $2,722,162         $2,417,919
LifePath 2030 Portfolio               $2,034,762           $2,013,088         $1,872,914
LifePath 2040 Portfolio               $1,466,380           $1,480,212         $1,509,621
LifePath 2050 Portfolio(1)               N/A               $      361         $   20,699


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

The fees and expenses of the Independent Trustees of MIP, counsel to the Independent Trustees of MIP and the independent registered public accounting firm that provides audit services in connection with the Master Portfolios (collectively referred to as the "MIP Independent Expenses") are paid directly by the Master Portfolios. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to each Master Portfolio for such MIP Independent Expenses.

For the fiscal years shown below, BFA provided an offsetting credit for MIP Independent Expenses, in the amounts shown, against mangement fees paid by the Master Portfolios in which the LifePath Portfolios invest:

                                  FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
LIFEPATH PORTFOLIO                    12/31/2007           12/31/2008          12/31/2009
-------------------------------  -------------------  -------------------  ------------------
LifePath Retirement Portfolio          $12,052              $ 7,796              $ 8,435
LifePath 2020 Portfolio                $21,013              $16,283              $14,874
LifePath 2030 Portfolio                $17,912              $13,511              $12,615
LifePath 2040 Portfolio                $15,986              $11,495              $11,434
LifePath 2050 Portfolio(1)               N/A                $ 1,329              $ 2,892


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

UNDERLYING FUNDS. BFA serves as investment adviser to each of the Underlying Funds, with the exception of BlackRock Cash Funds: Institutional, which invests in a master portfolio of MIP advised by BFA. Each Master Portfolio, as a shareholder of the Underlying Funds, bears a PRO RATA share of the Underlying Funds' management fees, which are based on aggregate net assets, as listed in the chart below. Please note that the list of Underlying Funds below is as of March 31, 2010 but BFA may add, eliminate or replace Underlying Funds at any time.

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UNDERLYING FUND                                                   ADVISORY FEE /1/
---------------------------------------------------------------  -----------------
           Active Stock Master Portfolio                                0.25%
           CoreAlpha Bond Master Portfolio                              0.25%
           iShares S&P MidCap 400 Index Fund                            0.20%
           iShares S&P SmallCap 600 Index Fund                          0.20%
           iShares Cohen & Steers Realty Majors Index Fund              0.35%
           iShares MSCI Canada Index Fund                               0.55%/2/
           iShares MSCI EAFE Index Fund                                 0.35%/3/
           iShares MSCI EAFE Small Cap Index Fund                       0.40%
           iShares MSCI Emerging Markets Index Fund                     0.72%/4/
           iShares FTSE EPRA/NAREIT Developed Real Estate ex-           0.48%
            U.S. Index Fund
           iShares Barclays TIPS Bond Fund                              0.20%
           BlackRock Cash Funds: Institutional                          0.07%/5/


/1/ BFA has contractually agreed through close of business on November 30, 2011, to waive management fees and administration fees, if any, charged to each Master Portfolio in an amount equal to the management fees charged by BFA to the Underlying Fund.

/2/ For its management services to the iShares MSCI Canada Index Fund, BFA is entitled to receive a management fee based on the Fund's allocable portion of the aggregate of the average daily net assets of the Fund and certain other iShares funds (iShares MSCI Australia Index Fund, iShares MSCI Austria Investable Market Index Fund, iShares MSCI Belgium Investable Market Index Fund, iShares MSCI EMU Index Fund, iShares MSCI France Index Fund, iShares MSCI Germany Index Fund, iShares MSCI Hong Kong Index Fund, iShares MSCI Italy Index Fund, iShares MSCI Japan Index Fund, iShares MSCI Japan Small Cap Index Fund, iShares MSCI Malaysia Index Fund, iShares MSCI Mexico Investable Market Index Fund, iShares MSCI Netherlands Investable Market Index Fund, iShares MSCI Singapore Index Fund, iShares MSCI Spain Index Fund, iShares MSCI Sweden Index Fund, iShares MSCI Switzerland Index Fund and iShares MSCI United Kingdom Index Fund) as follows: 0.59% per annum of the aggregate net assets less than or equal to $7.0 billion, plus 0.54% per annum of the aggregate net assets over $7.0 billion, up to and including $11.0 billion, plus 0.49% per annum of the aggregate net assets over $11.0 billion, up to and including $24.0 billion, plus 0.44% per annum of the aggregate net assets over $24.0 billion, up to and including $48.0 billion, plus 0.40% per annum of the aggregate net assets in excess of $48.0 billion.

/3/ For its management services to the iShares MSCI EAFE Index Fund, BFA is entitled to receive a management fee based on the Fund's allocable portion of the aggregate of the average daily net assets of the Fund and certain other iShares funds (iShares MSCI ACWI ex US Index Fund and iShares MSCI ACWI Index Fund) as follows: 0.35% per annum of the aggregate net assets less than or equal to $30 billion, plus 0.32% per annum of the aggregate net assets between $30.0 billion and $60.0 billion, plus 0.28% per annum of the aggregate net assets in excess of $60 billion.

/4/ For its management services to the iShares MSCI Emerging Markets Index Fund, BFA is entitled to receive a management fee based on the Fund's allocable portion of the aggregate of the average daily net assets of the Fund and certain other iShares funds (iShares MSCI All Country Asia ex Japan Index Fund, iShares MSCI BRIC Index Fund, iShares MSCI Emerging Markets Eastern Europe Index Fund, iShares MSCI Emerging Markets Financials Sector Index Fund and iShares MSCI Emerging Markets Materials Sector Index Fund) as follows: 0.75% per annum of the aggregate net assets less than or equal to $14.0 billion, plus 0.68% per annum of the aggregate net assets over $14.0 billion, up to and including $28.0 billion, plus 0.61% per annum of the aggregate net assets in excess of $28.0 billion.

/5/ The management fee for the BlackRock Cash Funds: Institutional is 0.10%, however BFA has contractually agreed to waive a portion of its management fee through close of business on November 30, 2011. After giving effect to such contractual waiver, the management fee will be 0.07%.

ADMINISTRATOR. The Trust has engaged BTC to provide certain administration services to the LifePath Portfolios. BTC and its affiliates provide the LifePath Portfolios with administration services, including provision of management reporting and treasury administration services, financial reporting, legal and tax services, and supervision of the LifePath Portfolios' administrative operations, preparation of proxy statements and shareholder reports. BTC and its affiliates also furnish office space and certain facilities to conduct the LifePath Portfolios' business and compensate the Trust's Trustees, officers and employees who are affiliated with BTC. BTC is entitled to receive an annual administration fee of 0.50% of average daily net assets of Investor A, Investor C, Institutional and Class R Shares and 0.15% of average daily net assets of Class K Shares of each LifePath Portfolio for providing administrative services.

BTC also may engage and supervise Shareholder Servicing Agents, as defined in "Shareholder Servicing Agents" below, on behalf of Investor A, Investor C, Institutional and Class R Shares of the LifePath Portfolios.

BTC has engaged the Transfer Agent to provide certain sub-administrative services to the LifePath Portfolios. BTC, not the LifePath Portfolios, is responsible for providing compensation to the Transfer Agent for such services.

BTC has also agreed to bear all costs of the LifePath Portfolios' operations, including shareholder servicing and shareholder servicing and processing fees described below, other than brokerage expenses, management fees, distribution plan expenses, certain fees and expenses related to the Trust's Independent Trustees and their counsel, auditing fees, litigation expenses,

48

taxes or other extraordinary expenses. BTC has contracted with the Transfer Agent to provide certain sub-administration services for the LifePath Portfolios, and BTC pays the Transfer Agent for these services.

For the fiscal years shown below, the LifePath Portfolios paid the following administration fees to BTC, net of waivers and/or offsetting credits:

                                  FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
LIFEPATH PORTFOLIO                    12/31/2007           12/31/2008          12/31/2009
-------------------------------  -------------------  -------------------  ------------------
LifePath Retirement Portfolio         $  630,077          $  700,635           $  906,314
LifePath 2020 Portfolio               $4,328,921          $4,033,359           $3,615,234
LifePath 2030 Portfolio               $3,046,288          $2,960,478           $2,771,534
LifePath 2040 Portfolio               $2,177,674          $2,156,984           $2,212,707
LifePath 2050 Portfolio(1)               N/A              $  (10,768)          $   19,353


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

The fees and expenses of the Independent Trustees of the Trust, counsel to the Independent Trustees of the Trust and the Independent registered public accounting firm that provides audit services in connection with the LifePath Portfolios (collectively referred to as the "Independent Expenses") are paid directly by the LifePath Portfolios. For the fiscal year ended December 31, 2007, BTC voluntarily agreed to provide an offsetting credit against the administration fees paid by the LifePath Portfolios in an amount equal to the Independent Expenses. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to the LifePath Portfolios for such Independent Expenses.

For the fiscal years shown below, BTC provided an offsetting credit, in the amounts shown, against administration fees paid with respect to the LifePath Portfolios:

                                  FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
LIFEPATH PORTFOLIO                    12/31/2007           12/31/2008          12/31/2009
-------------------------------  -------------------  -------------------  ------------------
LifePath Retirement Portfolio          $18,027              $13,030              $13,105
LifePath 2020 Portfolio                $24,961              $21,114              $19,127
LifePath 2030 Portfolio                $22,467              $18,530              $17,130
LifePath 2040 Portfolio                $20,862              $16,496              $15,809
LifePath 2050 Portfolio(1)               N/A                $11,282              $10,981


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

SHAREHOLDER SERVICING AGENTS. The Board of Trustees has adopted a Shareholder Servicing Plan pursuant to which the LifePath Portfolios have entered or may enter into Shareholder Servicing Agreements with BTC and other entities, and BTC may also enter into such Agreements with such other entities (including BlackRock, BRIL, BAC, Merrill Lynch, PNC, Barclays and their affiliates) (collectively, "Shareholder Servicing Agents") for the provision of certain services to holders of Investor A, Investor C, Institutional and Class R Shares. No such agreements are contemplated in respect of Class K Shares. The shareholder services and processing services provided by BTC or Shareholder Servicing Agents may include serving as an agent of the LifePath Portfolios for purposes of accepting orders for purchases and redemptions of LifePath Portfolio shares, providing administrative support and account service such as processing purchases and redemptions of shares on behalf of individual and omnibus LifePath Portfolio accounts, keeping records, transmitting reports and communications from the LifePath Portfolios, and providing reports on the status of individual and omnibus accounts. Shareholder Servicing Agents may provide these services, in whole or in part, by operating electronic transaction systems or websites through which shareholders may obtain information or engage in purchase or redemption transactions of LifePath Portfolio shares. By operating these systems or providing other services described above, the Shareholder Servicing Agents make the LifePath Portfolios available to their clients.

A Shareholder Servicing Agent may make decisions about which investment options it will service and make available to its clients based on the payments the Shareholder Servicing Agent may be eligible to receive for its services. Therefore,

49

payments to a Shareholder Servicing Agent may create potential conflicts of interest between the Shareholder Servicing Agent and its clients where the Shareholder Servicing Agent determines which investment options it will make available to those clients.

Pursuant to its Administration Agreement with the Trust, as described in the section entitled "Administrator," BTC pays shareholder servicing fees to certain Shareholder Servicing Agents in amounts not exceeding maximum fee rates approved by the Trust's Board of Trustees for those shareholder servicing, sub-administration, recordkeeping, sub-transfer agency and processing services that the Shareholder Servicing Agents perform for their clients that would otherwise be performed by BTC or the LifePath Portfolios' other service providers. For providing some or all of these services, each Shareholder Servicing Agent is entitled to receive a monthly fee at the annual rate of up to 0.25% of the average daily net assets of the Institutional, Investor A, Class R and Investor C Shares of each LifePath Portfolio represented by shares owned during the period for which payment is being made by investors with whom the Shareholder Servicing Agent maintains a servicing relationship, or an amount that equals the maximum amount payable to the Shareholder Servicing Agent under applicable laws, regulations or rules, including the Conduct Rules of the Financial Industry Regulatory Authority, Inc. ("FINRA" and f/k/a the National Association of Securities Dealers, Inc. ("NASD")), whichever is less. For providing some or all of these processing services for investors of Class R Shares of each LifePath Portfolio, each Shareholder Servicing Agent is also entitled to receive a monthly fee at an annual rate of up to 0.25% of the average daily net assets of Class R Shares of each LifePath Portfolio represented by shares owned during the period for which payment is being made by investors with whom the Shareholder Servicing Agent maintains a servicing relationship.

For the fiscal years shown below, BTC paid shareholder servicing fees on behalf of the Institutional and Investor A Shares (previously designated Class R) of the LifePath Portfolios in the following aggregate amounts. As of such date, Class R and Investor C Shares of the LifePath Portfolios had not commenced operations:

                                  FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
LIFEPATH PORTFOLIO                    12/31/2007           12/31/2008          12/31/2009
-------------------------------  -------------------  -------------------  ------------------
LifePath Retirement Portfolio         $  502,393           $  645,733          $  520,128
LifePath 2020 Portfolio               $3,552,372           $3,849,665          $2,761,476
LifePath 2030 Portfolio               $2,484,967           $2,835,502          $2,122,282
LifePath 2040 Portfolio               $1,836,254           $2,071,492          $1,698,402
LifePath 2050 Portfolio(1)               N/A                  N/A              $   26,007


(1) LifePath 2050 Portfolio commenced operations on June 30, 2008.

A Shareholder Servicing Agent also may impose certain conditions on its customers, subject to the terms of the LifePath Portfolios' Prospectuses and this SAI, that are in addition to or different from those imposed by the Trust, such as requiring a minimum initial investment or payment of a separate fee for additional services.

Shareholder Servicing Agents may charge their clients additional fees for account-related services. Shareholder Servicing Agents may charge their customers a service fee in connection with the purchase or redemption of LifePath Portfolio shares. The amount and applicability of such a fee is determined and disclosed to its customers by each individual Shareholder Servicing Agent. Service fees typically are fixed, nominal dollar amounts and are in addition to the sales and other charges described in the Prospectuses and this SAI. Your Shareholder Servicing Agent will provide you with specific information about any service fees you will be charged.

NON-PLAN PAYMENTS. BlackRock may make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to the LifePath Portfolio). From time to time, BlackRock or its affiliates may compensate affiliated and unaffiliated entities (including BlackRock, BRIL, BAC, Merrill Lynch, PNC, Barclays and their affiliates, and entities that may also be serving as distribution agents or Shareholder Servicing Agents of the LifePath Portfolio) (collectively, "Service Organizations") for the sale and distribution of shares of a LifePath Portfolio or for services to a LifePath Portfolio and its shareholders. These payments that are not associated with the Shareholder Servicing Plan or Distribution Plan (described below) and are therefore referred to as "non-Plan payments". The non-Plan payments would be in addition to a LifePath Portfolio's payments described in this SAI for distribution (if the LifePath Portfolio has adopted a distribution plan pursuant to Rule 12b-1) and shareholder servicing. These non-Plan payments may take the form of, among other things, "due diligence" payments for a dealer's examination of the LifePath Portfolios and payments for providing extra employee training and information relating to LifePath Portfolios; "listing" fees for the placement of the

50

LifePath Portfolios on a dealer's list of mutual funds available for purchase by its customers; "finders" fees for directing investors to the LifePath Portfolio; "distribution and marketing support" fees or "revenue sharing" for providing assistance in promoting the sale of the LifePath Portfolios' shares; payments for the sale of shares and/or the maintenance of share balances; CUSIP fees; maintenance fees; and set-up fees regarding the establishment of new accounts. The payments made by BlackRock and its affiliates may be a fixed dollar amount or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization involved, and may be different for different Service Organizations. The payments described above are made from BlackRock's or its affiliates' own assets pursuant to agreements with Service Organizations and do not change the price paid by investors for the purchase of the LifePath Portfolio's shares or the amount the LifePath Portfolio will receive as proceeds from such sales.

The payments described above may be made, at the discretion of BlackRock or its affiliates, to Service Organizations in connection with the sale and distribution of LifePath Portfolio shares. Pursuant to applicable FINRA regulations, the details of certain of these payments, including the Service Organizations receiving such payments in connection with the sale and distribution of LifePath Portfolio shares, are required to be disclosed. The level of payments made to these Service Organizations in any year will vary and normally will not exceed the sum of (a) 0.25% of such year's LifePath Portfolio sales by that Service Organization, and (b) 0.21% of the assets attributable to that Service Organization invested in a LifePath Portfolio. As of the date of this SAI, as amended or supplemented from time to time, the following Service Organizations are receiving such payments in association with sale and distribution of products other than the LifePath Portfolios, that are advised or offered by BlackRock or its affiliates: Ameriprise Financial Services, Inc., AXA Advisors, LLC, Banc of America Investment Services, Inc., Citigroup, LPL Financial Corporation, Financial Network Investment Coporation, Merrill Lynch, MetLife Securities, Inc., Morgan Stanley, Multi-Financial Securities Corporation, New England Securities Corporation, Oppenheimer & Co. Inc., PrimeVest Financial Services, Raymond James & Associates, Inc., Raymond James Financial Services, Inc., RBC Capital Markets, Tower Square Securities Inc., UBS, Wachovia Securities, Walnut Street Securities Inc., Commonwealth Equity Services, LLP (Commonwealth Financial Network), Wells Fargo and/or broker-dealers and other financial services firms under common control with the above organizations (or their assignees).

OTHER DISTRIBUTION ARRANGEMENTS. If investment advisers, distributors or affiliates of mutual funds pay bonuses and incentives in differing amounts, financial firms and their financial consultants may have financial incentives for recommending a particular mutual fund over other mutual funds. In addition, depending on the arrangements in place at any particular time, a financial firm and its financial consultants may also have a financial incentive for recommending a particular share class over other share classes. You should consult your financial adviser and review carefully any disclosure by the financial firm as to compensation received by your financial adviser for more information about the payments described above.

Furthermore, BlackRock and its affiliates may contribute to various non-cash and cash incentive arrangements to promote the sale of shares, and may sponsor various contests and promotions subject to applicable FINRA regulations in which participants may receive prizes such as travel awards, merchandise and cash. Subject to applicable FINRA regulations, BlackRock and its affiliates may also: (i) pay for the travel expenses, meals, lodging and entertainment of broker/dealers, financial institutions and their salespersons in connection with educational and sales promotional programs, (ii) sponsor speakers, educational seminars and charitable events and (iii) provide other sales and marketing conferences and other resources to broker-dealers, financial institutions and their salespersons.

DISTRIBUTOR. BlackRock Investments, LLC is the distributor for the LifePath Portfolios' shares. The Distributor is a registered broker-dealer located at 40 East 52nd Street, New York, New York 10022.

Each LifePath Portfolio has entered into a distribution agreement with the Distributor in connection with the continuous offering of shares of the LifePath Portfolio (the "Distribution Agreement"). The Distribution Agreement obligates the Distributor to pay certain expenses in connection with the offering of shares of the LifePath Portfolios. After the prospectuses, statements of additional information and periodic reports have been prepared, set in type and mailed to shareholders, the Distributor pays for the printing and distribution of these documents used in connection with the offering to dealers and investors. The Distributor also pays for other supplementary sales literature and advertising costs.

INVESTOR A, INVESTOR C AND CLASS R SHARES DISTRIBUTION AND SERVICE PLAN. The Trust has adopted on behalf of Investor A, Investor C and Class R Shares of the LifePath Portfolios a Distribution and Service Plan that authorizes, under
Section 12(b) of the 1940 Act and Rule 12b-1 thereunder (the "Rule"), payment for distribution-related expenses and compensation for distribution-related services, including ongoing compensation to selling agents, in connection with Investor A, Investor C and

51

Class R Shares (the "Distribution Plan"). Each LifePath Portfolio may participate in joint distribution activities with other funds within the Trust. The cost of these activities is generally allocated among the LifePath Portfolios, with the LifePath Portfolios with higher asset levels paying a higher proportion of these costs.

The Distribution Plan was adopted by the Trust's Board of Trustees, including a majority of the Independent Trustees who had no direct or indirect financial interest in the operation of the Distribution Plan or in any agreement related to the Distribution Plan. The Distribution Plan was adopted because of its anticipated benefits to the LifePath Portfolios. The anticipated benefits include: easier and more effective management as a result of steady inflows of cash from the sale of new shares, a reduction in the expense ratio as a result of achieving economies of scale, lower transaction costs or better prices as a result of the ability to purchase larger blocks of securities, and avoidance of the forced sale of securities to meet redemptions that might adversely affect the performance of the LifePath Portfolios. Under the Distribution Plan and pursuant to the related Distribution Agreement with BRIL, the LifePath Portfolios may pay the Distributor, as compensation for distribution-related services, monthly fees at the annual rate of up to 0.25% of the average daily net assets of Class R Shares and up to 0.75% of the average daily net assets of Investor C Shares of the LifePath Portfolios offering such shares.

The actual fee payable to the Distributor is determined, within such limit, from time to time by mutual agreement between the Trust and the Distributor and will not exceed the maximum sales charges payable by mutual funds sold by members of FINRA, under the NASD Conduct Rules. The Distributor may enter into selling agreements with one or more selling agents (which may include BTC and its affiliates) under which such agents may receive compensation for distribution-related services from the Distributor, including, but not limited to, commissions or other payments to such agents based on the average daily net assets of LifePath Portfolio shares attributable to their customers. The Distributor may retain any portion of the total distribution fee payable thereunder to compensate it for distribution-related services provided by it or to reimburse it for other distribution-related expenses.

The Trust currently does not have a distribution plan in place for the Institutional or Class K Shares. Institutional and Class K shareholders do not pay any fees for distribution services. The Distribution Plan will continue in effect from year to year if such continuance is approved by a majority vote of the Board of Trustees, including a majority of the Independent Trustees. Any Distribution Agreement related to the Distribution Plan also must be approved by such vote of the Board of Trustees, including a majority of the Independent Trustees. The Distribution Agreement will terminate automatically if assigned and may be terminated at any time, without payment of any penalty, by a vote of a majority of the outstanding voting securities of the Trust or by vote of a majority of the Independent Trustees on not more than 60 days' written notice. The Distribution Plan may not be amended to increase materially the amounts payable thereunder without the approval of a majority of the outstanding voting securities of the LifePath Portfolios involved, and no material amendments to the Distribution Plan may be made except by a majority of both the Board of Trustees and the Independent Trustees. The Distribution Plan requires that the Treasurer of the Trust shall provide to the Trustees, and the Trustees shall review, at least quarterly, a written report of the amounts expended (and purposes therefor) under the Distribution Plan. The Rule also requires that the selection and nomination of Trustees who are not "interested persons" of the Trust be made by Independent Trustees.

For the fiscal year ended December 31, 2009, the LifePath Portfolios paid the following fees for distribution-related services under the Distribution Plan with respect to Investor A Shares. As of such date, Class R and Investor C Shares of the Trust had not commenced operations:

                                        FISCAL YEAR ENDED
LIFEPATH PORTFOLIO                         12/31/2009
-------------------------------------  ------------------
      LifePath Retirement Portfolio         $101,847
      LifePath 2020 Portfolio               $511,559
      LifePath 2030 Portfolio               $397,581
      LifePath 2040 Portfolio               $288,410
      LifePath 2050 Portfolio               $  1,697

Payments are made by the LifePath Portfolios pursuant to each Plan regardless of expenses incurred by the Distributor. In addition to payments received from the LifePath Portfolios, selling or servicing agents may receive significant additional payments directly from BTC, BFA, BRIL or their affiliates in connection with the sale of LifePath Portfolio shares.

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MIP DISTRIBUTION PLAN. MIP's Board of Trustees has adopted, on behalf of each LifePath Master Portfolio, a "defensive" distribution plan under Section 12(b) of the 1940 Act and Rule 12b-1 thereunder (the "MIP Plan"). The MIP Plan was adopted by a majority of MIP's Board of Trustees, including a majority of those Trustees who are not "interested persons" (as defined in the 1940 Act) of MIP, on October 10, 1995 and approved annually in the same manner. The MIP Plan provides that if any portion of a LifePath Master Portfolio's advisory fees (up to 0.25% of the average daily net assets of each LifePath Master Portfolio on an annual basis) were deemed to constitute an indirect payment for activities that are primarily intended to result in the sale of interests in a LifePath Master Portfolio, such payment would be authorized pursuant to the MIP Plan.

CUSTODIAN. State Street is the custodian for each LifePath Portfolio and Master Portfolio and is located at 200 Clarendon Street, Boston, MA 02116. The custodian, among other things, maintains a custody account or accounts in the name of the LifePath Portfolios and Master Portfolios; receives and delivers all assets for the LifePath Portfolios and Master Portfolios upon purchase and upon sale or maturity; collects and receives all income and other payments and distributions on account of the assets of the LifePath Portfolios and Master Portfolios; and pays all expenses of the LifePath Portfolios. State Street is not entitled to receive compensation for its services as custodian so long as it receives fees from BTC for providing sub-administration services to the LifePath Portfolios.

TRANSFER AND DIVIDEND DISBURSING AGENT. PNC Global Investment Servicing (U.S.) Inc., a subsidiary of PNC, acts as each LifePath Portfolio's transfer agent pursuant to a Transfer Agency, Dividend Disbursing Agency and Shareholder Servicing Agency Agreement (the "Transfer Agency Agreement") with the LifePath Portfolios. Pursuant to the Transfer Agency Agreement, the Transfer Agent is responsible for the issuance, transfer and redemption of shares and the opening and maintenance of shareholder accounts. PNC GIS is paid fees for the services it provides based on the type of account and the level of services provided. PNC GIS is also entitled to be reimbursed for its reasonable out-of-pocket expenses. BTC has agreed to pay these fees and expenses pursuant to its Administration Agreement with the Trust. PNC GIS may be paid fees for certain accounts that participate in certain fee-based programs sponsored by BFA or its affiliates. For purposes of the Transfer Agency Agreement, the term "account" includes a shareholder account maintained directly by the Transfer Agent and any other account representing the beneficial interest of a person in the relevant share class on a recordkeeping system.

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM. PricewaterhouseCoopers LLP, located at Three Embarcadero Center, San Francisco, CA 94111, serves as the independent registered public accounting firm for the Trust.

LEGAL COUNSEL. Sidley Austin LLP, located at 787 Seventh Avenue, New York, NY 10019, serves as legal counsel to the Trust, MIP and BFA.

Portfolio Managers

As of December 31, 2009, the individuals named as Portfolio Managers of the Master Portfolios in the Prospectuses were primarily responsible for the day-to-day management of certain types of other portfolios and/or accounts, as indicated in the table below:

                       REGISTERED                                              ACCOUNTS WITH
                       INVESTMENT        OTHER POOLED                         INCENTIVE-BASED
                        COMPANIES    INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
DAGMAR NIKLES         ------------  ---------------------  ----------------  -----------------
Number of Accounts        N/A                31                   3                 N/A
Net Assets                N/A          $15,140,406,393         $300,541             N/A

                       REGISTERED                                              ACCOUNTS WITH
                       INVESTMENT        OTHER POOLED                         INCENTIVE-BASED
                        COMPANIES    INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
LESLIE GAMBON         ------------  ---------------------  ----------------  -----------------
Number of Accounts        N/A                31                   3                 N/A
Net Assets                N/A          $15,140,406,393         $501,218             N/A

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                       REGISTERED                                              ACCOUNTS WITH
                       INVESTMENT        OTHER POOLED                         INCENTIVE-BASED
                        COMPANIES    INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
ALAN MASON            ------------  ---------------------  ----------------  -----------------
Number of Accounts        N/A               N/A                   4                 N/A
Net Assets                N/A               N/A                $231,863             N/A

                       REGISTERED                                              ACCOUNTS WITH
                       INVESTMENT        OTHER POOLED                         INCENTIVE-BASED
                        COMPANIES    INVESTMENT VEHICLES    OTHER ACCOUNTS    FEE ARRANGEMENTS
AMY WHITELAW(1)       ------------  ---------------------  ----------------  -----------------
Number of Accounts        N/A                86                   2                 N/A
Net Assets                N/A          $25,993,680,327         $908,190             N/A


(1) Ms. Whitelaw was appointed as a Portfolio Manager of the Master Portfolios effective April 30, 2010. Her information in the table above is as of December 31, 2009.

Certain of the portfolios or accounts for which the Portfolio Managers are primarily responsible for the day-to-day management are composed of securities the identity and amount of which are selected by a computer model that is based on prescribed, objective criteria using independent third-party data to replicate independently maintained indexes. The Portfolio Managers are required to manage each portfolio or account to meet those objectives. Pursuant to BTC and BFA policy, investment opportunities are allocated equitably among the Master Portfolios and other portfolios and accounts. For example, under certain circumstances, an investment opportunity may be restricted due to limited supply on the market, legal constraints or other factors, in which event the investment opportunity will be allocated equitably among those portfolios and accounts, including the Master Portfolios, seeking such investment opportunity. As a consequence, from time to time the Master Portfolios may receive a smaller allocation of an investment opportunity than they would have if the Portfolio Managers and BFA and its affiliates did not manage other portfolios or accounts.

Like the Master Portfolios, the other portfolios or accounts for which the Portfolio Managers are primarily responsible for the day-to-day portfolio management generally pay an asset-based fee to BFA or BTC, as applicable, for its advisory services. One or more of those other portfolios or accounts, however, may pay BTC an incentive-based fee in lieu of, or in addition to, an asset-based fee for its advisory services. A portfolio or account with an incentive-based fee would pay BTC a portion of that portfolio's or account's gains, or would pay BTC more for its services than would otherwise be the case if BTC meets or exceeds specified performance targets. By their very nature, incentive-based fee arrangements could present an incentive for BTC to devote greater resources, and allocate more investment opportunities, to the portfolios or accounts that have those fee arrangements, relative to other portfolios or accounts, in order to earn larger fees. Although BTC has an obligation to allocate resources and opportunities equitably among portfolios and accounts and intends to do so, interestholders of the Master Portfolios should be aware that, as with any group of portfolios and accounts managed by an investment adviser and/or its affiliates pursuant to varying fee arrangements, including incentive-based fee arrangements, there is the potential for a conflict-of-interest, that may result in the Portfolio Managers' favoring those portfolios or accounts with incentive-based fee arrangements.

The below table reflects, for each Portfolio Manager, the number of portfolios or accounts of the types enumerated in the above table and the aggregate of total assets in those portfolios or accounts with respect to which the investment management fees for those portfolios or accounts are based on the performance of those portfolios or accounts, as of December 31, 2009.

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES
                                     MANAGED BY PORTFOLIO MANAGER    AGGREGATE OF TOTAL ASSETS
DAGMAR NIKLES                       ------------------------------  --------------------------
Registered Investment Companies                  N/A                           N/A
Other Pooled Investment Vehicles                 N/A                           N/A
Other Accounts                                   N/A                           N/A

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                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES
                                     MANAGED BY PORTFOLIO MANAGER    AGGREGATE OF TOTAL ASSETS
LESLIE GAMBON                       ------------------------------  --------------------------
Registered Investment Companies                  N/A                           N/A
Other Pooled Investment Vehicles                 N/A                           N/A
Other Accounts                                   N/A                           N/A

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES
                                     MANAGED BY PORTFOLIO MANAGER    AGGREGATE OF TOTAL ASSETS
ALAN MASON                          ------------------------------  --------------------------
Registered Investment Companies                  N/A                           N/A
Other Pooled Investment Vehicles                 N/A                           N/A
Other Accounts                                   N/A                           N/A

                                     NUMBER OF OTHER ACCOUNTS WITH
                                        PERFORMANCE-BASED FEES
                                     MANAGED BY PORTFOLIO MANAGER    AGGREGATE OF TOTAL ASSETS
AMY WHITELAW(1)                     ------------------------------  --------------------------
Registered Investment Companies                  N/A                           N/A
Other Pooled Investment Vehicles                 N/A                           N/A
Other Accounts                                   N/A                           N/A


(1) Ms. Whitelaw was appointed as a Portfolio Manager of the Master Portfolios effective April 30, 2010. Her information in the table above is as of December 31, 2009.

The discussion below describes the Portfolio Managers' compensation as of December 1, 2009.

PORTFOLIO MANAGER COMPENSATION OVERVIEW. BFA's financial arrangements with its portfolio managers, its competitive compensation and its career path emphasis at all levels reflect the value senior management places on key resources. Compensation may include a variety of components and may vary from year to year based on a number of factors. The principal components of compensation include a base salary, a performance-based discretionary bonus, and participation in various benefits programs. In addition, a Portfolio Manager may have been paid a signing bonus or awarded sign-on equity in connection with initiation of employment with BlackRock.

BASE COMPENSATION. Generally, portfolio managers receive base compensation based on their seniority and/or their position with the firm. Senior portfolio managers who perform additional management functions within the portfolio management group or within BlackRock may receive additional compensation for serving in these other capacities.

DISCRETIONARY INCENTIVE COMPENSATION. Discretionary incentive compensation is a function of several components: the performance of BlackRock, the performance of the portfolio manager's group within BlackRock, the investment performance, including risk-adjusted returns, of the firm's assets under management or supervision by that portfolio manager relative to predetermined benchmarks, and the individual's seniority, role within the portfolio management team, teamwork and contribution to the overall performance of these portfolios and BlackRock.

DISTRIBUTION OF DISCRETIONARY INCENTIVE COMPENSATION. Discretionary incentive compensation is distributed to portfolio managers in a combination of cash and BlackRock, Inc. restricted stock units which vest ratably over a number of years. The BlackRock, Inc. restricted stock units, if properly vested, will be settled in BlackRock common stock. Typically, the cash bonus, when combined with base salary, represents more than 60% of total compensation for the portfolio managers. Paying a portion of annual bonuses in stock puts compensation earned by a portfolio manager for a given year "at risk" based on BlackRock's ability to sustain and improve its performance over future periods.

From time to time long-term incentive equity awards are granted to certain key employees to aid in retention, align their interests with long-term shareholder interests and motivate performance. Equity awards are generally granted in the form of BlackRock, Inc. restricted stock units that, once vested, settle in BlackRock common stock.

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As of December 31, 2009, the Portfolio Managers beneficially owned interests in each of the LifePath Portfolios that invest in Master Portfolios for which they are primarily responsible for the day-to-day management in amounts reflected in the following table:

LIFEPATH RETIREMENT PORTFOLIO
                                                        $10,001     $50,001    $100,001    $500,001    OVER
                                  NONE    $1 TO $10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                                 ------  ------------  ---------  ----------  ----------  ----------  -----
Dagmar Nikles                    X
Leslie Gambon                    X
Alan Mason                       X
Amy Whitelaw(1)                  X

LIFEPATH 2020 PORTFOLIO
                                                  $10,001     $50,001    $100,001    $500,001    OVER
                            NONE    $1 TO $10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                           ------  ------------  ---------  ----------  ----------  ----------  -----
Dagmar Nikles              X
Leslie Gambon              X
Alan Mason                 X
Amy Whitelaw(1)            X

LIFEPATH 2030 PORTFOLIO
                                                  $10,001     $50,001    $100,001    $500,001    OVER
                            NONE    $1 TO $10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                           ------  ------------  ---------  ----------  ----------  ----------  -----
Dagmar Nikles              X
Leslie Gambon              X
Alan Mason                 X
Amy Whitelaw(1)            X

LIFEPATH 2040 PORTFOLIO
                                                  $10,001     $50,001    $100,001    $500,001    OVER
                            NONE    $1 TO $10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                           ------  ------------  ---------  ----------  ----------  ----------  -----
Dagmar Nikles              X
Leslie Gambon              X
Alan Mason                 X
Amy Whitelaw(1)            X

LIFEPATH 2050 PORTFOLIO
                                                  $10,001     $50,001    $100,001    $500,001    OVER
                            NONE    $1 TO $10K    TO $50K    TO $100K    TO $500K     TO $1M     $1M
                           ------  ------------  ---------  ----------  ----------  ----------  -----
Dagmar Nikles              X
Leslie Gambon              X
Alan Mason                 X
Amy Whitelaw(1)            X

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(1) Ms. Whitelaw was appointed as a Portfolio Manager of the Master Portfolios effective April 30, 2010. Her information in the table above is as of December 31, 2009.

Determination of Net Asset Value

VALUATION OF SHARES. The aggregate net asset value of each LifePath Portfolio is calculated based on the net asset value of the corresponding Master Portfolio and is determined once daily Monday through Friday as of the close of business on the New York Stock Exchange (the "NYSE") on each day the NYSE is open for trading based upon prices at the time of closing. The NYSE generally closes at 4:00 p.m. Eastern time. The price at which a purchase or redemption is effected is based on the next calculation of net asset value after such an order is placed. Any assets or liabilities initially expressed in terms of non-U.S. dollar currencies are translated into U.S. dollars at the prevailing market rates as quoted by one or more banks or dealers on the day of valuation. The NYSE is not open for trading on New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.

The aggregate net asset value of the Master Portfolio is the value of the securities held by the Master Portfolio plus any cash or other assets (including interest and dividends accrued but not yet received) minus all liabilities (including accrued expenses). Expenses, including the fee payable to BlackRock, are accrued daily. Each investor in the Master Portfolio may add to or reduce its investment in the Master Portfolio on each day the NYSE is open for trading. The value of each investor's interest in the Master Portfolio will be determined after the close of business on the NYSE by multiplying the aggregate net asset value of the Master Portfolio by the percentage, effective for that day, that represents the investor's share of the aggregate interests in the Master Portfolio. Any additions or withdrawals to be effected on that day will then be effected. The investor's percentage of the aggregate interests in the Master Portfolio will then be recomputed as the percentage equal to the fraction (i) the numerator of which is the value of such investor's investment in the Master Portfolio as of the time of determination on such day plus or minus, as the case may be, the amount of any additions to or withdrawals from the investor's investment in the Master Portfolio effected on such day, and
(ii) the denominator of which is the aggregate net asset value of the Master Portfolio as of such time on such day plus or minus, as the case may be, the amount of the net additions to or withdrawals from the aggregate investments in the Master Portfolio by all investors in the Master Portfolio. The percentage so determined will then be applied to determine the value of the investor's interest in the Master Portfolio after the close of business on the NYSE or the next determination of the aggregate net asset value of the Master Portfolio.

Valuation of securities held by each LifePath Portfolio or Master Portfolio is as follows:

EQUITY INVESTMENTS. Equity securities traded on a recognized securities exchange (E.G., NYSE), separate trading boards of a securities exchange or through a market system that provides contemporaneous transaction pricing information (an "Exchange") are valued via independent pricing services generally at the Exchange closing price or if an Exchange closing price is not available, the last traded price on that Exchange prior to the time as of which the assets or liabilities are valued, however, under certain circumstances other means of determining current market value may be used. If an equity security is traded on more than one Exchange, the current market value of the security where it is primarily traded generally will be used. In the event that there are no sales involving an equity security held by a LifePath Portfolio on a day on which the LifePath Portfolio values such security, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such security. If a LifePath Portfolio holds both long and short positions in the same security, the last bid price will be applied to securities held long and the last ask price will be applied to securities sold short. If no bid or ask price is available on a day on which a LifePath Portfolio values such security, the prior day's price will be used, unless BlackRock determines that such prior day's price no longer reflects the fair value of the security, in which case such asset would be treated as a fair value asset.

FIXED-INCOME INVESTMENTS. Fixed-income securities for which market quotations are readily available are generally valued using such securities' most recent bid prices provided directly from one or more broker-dealers, market makers, or independent third-party pricing services which may use matrix pricing and valuation models to derive values, each in accordance with valuation procedures approved by the Trust's Board. The amortized cost method of valuation may be used with respect to debt obligations with 60 days or less remaining to maturity unless BFA determines such method does not represent fair value. Loan participation notes are generally valued at the mean of the last available bid prices from one or more brokers or dealers as obtained from independent third-party pricing services. Certain fixed-income investments including asset-backed and mortgage-related securities may be valued based on valuation models that consider the

57

estimated cash flows of each tranche of the entity, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche. Fixed-income securities for which market quotations are not readily available may be valued by third-party pricing services that make a valuation determination by securing transaction data (E.G., recent representative bids), credit quality information, perceived market movements, news, and other relevant information and by other methods, which may include consideration of: yields or prices of securities of comparable quality, coupon, maturity and type; indications as to values from dealers; and general market conditions.

OPTIONS, FUTURES, SWAPS AND OTHER DERIVATIVES. Exchange-traded equity options for which market quotations are readily available are valued at the mean of the last bid and ask prices as quoted on the Exchange or the board of trade on which such options are traded. In the event that there is no mean price available for an exchange traded equity option held by a LifePath Portfolio on a day on which the LifePath Portfolio values such option, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such option. If no bid or ask price is available on a day on which a LifePath Portfolio values such option, the prior day's price will be used, unless BlackRock determines that such prior day's price no longer reflects the fair value of the option in which case such option will be treated as a fair value asset. OTC options may be valued using a mathematical model which incorporates a number of market data factors. Financial futures contracts and options thereon, which are traded on exchanges, are valued at their last sale price or settle price as of the close of such exchanges. Swap agreements and other derivatives are generally valued daily based upon quotations from market makers or by a pricing service in accordance with the valuation procedures approved by the Board.

UNDERLYING FUNDS. Shares of underlying open-end funds are valued at net asset value. Shares of underlying exchange-traded closed-end funds or other ETFs will be valued at their most recent closing price.

GENERAL VALUATION INFORMATION

In determining the market value of portfolio investments, the LifePath Portfolio may employ independent third party pricing services, which may use, without limitation, a matrix or formula method that takes into consideration market indexes, matrices, yield curves and other specific adjustments. This may result in the securities being valued at a price different from the price that would have been determined had the matrix or formula method not been used. All cash, receivables and current payables are carried on each LifePath Portfolio's books at their face value.

Prices obtained from independent third party pricing services, broker-dealers or market makers to value each LifePath Portfolio's securities and other assets and liabilities are based on information available at the time the LifePath Portfolio values its assets and liabilities. In the event that a pricing service quotation is revised or updated subsequent to the day on which the LifePath Portfolio valued such security, the revised pricing service quotation generally will be applied prospectively. Such determination shall be made considering pertinent facts and circumstances surrounding such revision.

In the event that application of the methods of valuation discussed above result in a price for a security which is deemed not to be representative of the fair market value of such security, the security will be valued by, under the direction of or in accordance with a method specified by the Trust's Board as reflecting fair value. All other assets and liabilities (including securities for which market quotations are not readily available) held by a LifePath Portfolio (including restricted securities) are valued at fair value as determined in good faith by the Trust's Board or by BlackRock (its delegate). Any assets and liabilities which are denominated in a foreign currency are translated into U.S. dollars at the prevailing rates of exchange.

Certain of the securities acquired by the LifePath Portfolios may be traded on foreign exchanges or OTC markets on days on which a LifePath Portfolio's net asset value is not calculated. In such cases, the net asset value of a LifePath Portfolio's shares may be significantly affected on days when investors can neither purchase nor redeem shares of the LifePath Portfolio.

FAIR VALUE. When market quotations are not readily available or are believed by BlackRock to be unreliable, a LifePath Portfolio's investments are valued at fair value ("Fair Value Assets"). Fair Value Assets are valued by BlackRock in accordance with procedures approved by the Trust's Board. BlackRock may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its complete lack of trading, if BlackRock believes a market quotation from a broker-dealer or other source is unreliable (E.G., where it varies significantly from a recent trade, or no longer reflects the fair value of the security or other asset or liability subsequent to the most recent market quotation), where the security or other asset or liability is only thinly traded or due to the occurrence of a significant event subsequent to the most recent market quotation. For this purpose, a "significant event" is deemed to occur if BlackRock determines, in its business judgment prior to or at the time of pricing a LifePath Portfolio's assets or liabilities, that it is likely that the event will cause a material change to the last exchange closing price or closing market price of one or more assets or

58

liabilities held by the LifePath Portfolio. On any date the NYSE is open and the primary exchange on which a foreign asset or liability is traded is closed, such asset or liability will be valued using the prior day's price, provided that BlackRock is not aware of any significant event or other information that would cause such price to no longer reflect the fair value of the asset or liability, in which case such asset or liability would be treated as a Fair Value Asset. For certain foreign securities, a third-party vendor supplies evaluated, systematic fair value pricing based upon the movement of a proprietary multi-factor model after the relevant foreign markets have closed. This systematic fair value pricing methodology is designed to correlate the prices of foreign securities following the close of the local markets to the price that might have prevailed as of a LifePath Portfolio's pricing time.

BlackRock, with input from the BlackRock Portfolio Management Group, will submit its recommendations regarding the valuation and/or valuation methodologies for Fair Value Assets to BlackRock's Valuation Committee. The Valuation Committee may accept, modify or reject any recommendations. In addition, the LifePath Portfolios' accounting agent periodically endeavors to confirm the prices it receives from all third party pricing services, index providers and broker-dealers, and, with the assistance of BlackRock, to regularly evaluate the values assigned to the securities and other assets and liabilities held by the LifePath Portfolios. The pricing of all Fair Value Assets is subsequently reported to and ratified by the Board or a Committee thereof.

When determining the price for a Fair Value Asset, the BlackRock Valuation Committee (or the Pricing Group) shall seek to determine the price that a LifePath Portfolio might reasonably expect to receive from the current sale of that asset or liability in an arm's-length transaction. The price generally may not be determined based on what a LifePath Portfolio might reasonably expect to receive for selling an asset or liability at a later time or if it holds the asset or liability to maturity. Fair value determinations shall be based upon all available factors that the Valuation Committee (or Pricing Group) deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models.

Fair value represents a good faith approximation of the value of an asset or liability. The fair value of one or more assets or liabilities may not, in retrospect, be the price at which those assets or liabilities could have been sold during the period in which the particular fair values were used in determining a LifePath Portfolio's net asset value. As a result, a LifePath Portfolio's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

Each LifePath Portfolio's annual audited financial statements, which are prepared in accordance with generally accepted accounting principles ("GAAP"), follow the requirements for valuation set forth in Statement on Financial Accounting Standards No. 157, "Fair Value Measurements" ("FAS 157"), which defines and establishes a framework for measuring fair value under GAAP and expands financial statement disclosure requirements relating to fair value measurements.

Generally, FAS 157 and other accounting rules applicable to mutual funds and various assets in which they invest are evolving. Such changes may adversely affect a LifePath Portfolio. For example, the evolution of rules governing the determination of the fair market value of assets or liabilities to the extent such rules become more stringent would tend to increase the cost and/or reduce the availability of third-party determinations of fair market value. This may in turn increase the costs associated with selling assets or affect their liquidity due to the LifePath Portfolio's inability to obtain a third-party determination of fair market value.

Purchase, Redemption and Pricing of Shares

TERMS OF PURCHASE AND REDEMPTION. The LifePath Portfolios are generally open Monday through Friday and are closed on weekends and are generally closed on all other days on which the NYSE is closed for regular trading. The holidays on which the NYSE is closed currently are: New Year's Day, Martin Luther King, Jr.'s Day, Presidents' Day, Good Friday, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. Each LifePath Portfolio reserves the right to change the minimum amounts required for initial investment and subsequent investment, if any. On any day the LifePath Portfolios close early, purchase and redemption orders received after a LifePath Portfolio's closing time will be executed on the next business day. In addition, each LifePath Portfolio reserves the right to advance the time by which purchase and redemption orders must be received to be executed on the same business day as permitted by the SEC.

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IN-KIND PURCHASES. Payment for shares of a LifePath Portfolio may, at the discretion of BFA, be made in the form of securities that are permissible investments for the LifePath Portfolio and must meet the investment objective, policies and limitations of the LifePath Portfolio as described in the Prospectus and this SAI. In connection with an in-kind securities payment, a LifePath Portfolio may require, among other things, that the securities (i) be valued on the day of purchase in accordance with the pricing methods used by the LifePath Portfolio or its Master Portfolio or an Underlying Fund in which the Master Portfolio invests; (ii) are accompanied by satisfactory assurance that the LifePath Portfolio will have good and marketable title to such securities received by it; (iii) are not subject to any restrictions upon resale by the LifePath Portfolio; (iv) be in proper form for transfer to the LifePath Portfolio; and (v) are accompanied by adequate information concerning the basis and other tax matters relating to the securities. All dividends, interest, subscription or other rights pertaining to such securities shall become the property of the LifePath Portfolio engaged in the in-kind purchase transaction and must be delivered to such LifePath Portfolio by the investor upon receipt from the issuer. Securities acquired through an in-kind purchase will be
acquired for investment and not for immediate resale. Each LifePath Portfolio immediately will transfer to its Master Portfolio any and all securities received by it in connection with an in-kind purchase transaction, in exchange for interests in such Master Portfolio. Shares purchased in exchange for securities generally cannot be redeemed until the transfer has settled.

SUSPENSION OF REDEMPTION RIGHTS OR PAYMENT OF REDEMPTION PROCEEDS. The Trust may suspend the right of redemption or postpone redemption payments for any period during which (i) the NYSE is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Master Portfolio's investments is not reasonably practicable; or (iv) for such other periods as the SEC by order may permit. Each LifePath Portfolio reserves the right to suspend investors' rights of redemption and to delay delivery of redemption proceeds, as permitted under Section 22(e) of the 1940 Act, and other applicable laws.

DECLARATION OF TRUST PROVISIONS REGARDING REDEMPTIONS AT OPTION OF TRUST. As provided in the Trust's Declaration of Trust, the Trustees may require shareholders to redeem shares for any reason under terms set by the Trustees, including, but not limited to, the failure of a shareholder to supply a taxpayer identification number if required to do so, or to have the minimum investment required, or to pay when due for the purchase of shares issued to such shareholder.

Portfolio Transactions

Since each LifePath Portfolio invests all of its assets in a Master Portfolio, set forth below is a description of the Master Portfolios' policies governing portfolio securities transactions.

GENERAL. Subject to policies established by the Board of Trustees, BFA is primarily responsible for the execution of a Master Portfolio's portfolio transactions and the allocation of brokerage. BFA does not execute transactions through any particular broker or dealer, but seeks to obtain the best net results for the Master Portfolio, taking into account such factors as price (including the applicable brokerage commission or dealer spread), size of order, difficulty of execution, operational facilities of the firm and the firm's risk and skill in positioning blocks of securities. While BFA generally seeks reasonable trade execution costs, a Master Portfolio does not necessarily pay the lowest spread or commission available, and payment of the lowest commission or spread is not necessarily consistent with obtaining the best price and execution in particular transactions.

BFA does not consider the provision or value of research, products or services a broker or dealer may provide, if any, as a factor in the selection of a broker or dealer or the determination of the reasonableness of commissions paid in connection with portfolio transactions. BFA does not consider sales of shares of the mutual funds it advises as a factor in the selection of brokers or dealers to execute portfolio transactions for a Master Portfolio; however, whether or not a particular broker or dealer sells shares of the mutual funds advised by BFA neither qualifies nor disqualifies such broker or dealer to execute transactions for those mutual funds.

A Master Portfolio's purchase and sale orders for securities may be combined with those of other accounts that BFA manages or advises, and for which it has brokerage placement authority. If purchases or sales of portfolio securities of a Master Portfolio and one or more other accounts managed or advised by BFA are considered at or about the same time, transactions in such securities are allocated among the Master Portfolio and the other accounts in a manner deemed equitable to all by BFA. In some cases, this procedure could have a detrimental effect on the price or volume of the security as far as a Master Portfolio is concerned. However, in other cases, it is possible that the ability to participate in volume transactions and to negotiate lower brokerage commissions will be beneficial to a Master Portfolio.

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Payments of commissions to brokers who are affiliated persons of the Master Portfolio with respect to the LifePath Portfolio (or affiliated persons of such persons), will be made in accordance with Rule 17e-1 under the 1940 Act.

Each Master Portfolio anticipates that its brokerage transactions involving foreign securities generally will be conducted primarily on the principal stock exchanges of the applicable country. Foreign equity securities may be held by a Master Portfolio in the form of depositary receipts, or other securities convertible into foreign equity securities. Depositary receipts may be listed on stock exchanges, or traded in over-the-counter markets in the United States or Europe, as the case may be. American Depositary Receipts, like other securities traded in the United States, will be subject to negotiated commission rates. Because the shares of each LifePath Portfolio and interests of the Master Portfolios are redeemable on a daily basis in U.S. dollars, each Master Portfolio intends to manage its portfolio so as to give reasonable assurance that it will be able to obtain U.S. dollars to the extent necessary to meet anticipated redemptions. Under present conditions, it is not believed that these considerations will have a significant effect on a Master Portfolio's portfolio strategies.

Each Master Portfolio may invest in certain securities traded in the OTC market and intends to deal directly with the dealers who make a market in the particular securities, except in those circumstances in which better prices and execution are available elsewhere. Under the 1940 Act, persons affiliated with a Master Portfolio and persons who are affiliated with such affiliated persons are prohibited from dealing with the Master Portfolio as principal in the purchase and sale of securities unless a permissive order allowing such transactions is obtained from the SEC. Since transactions in the OTC market usually involve transactions with the dealers acting as principal for their own accounts, the Master Portfolios will not deal with affiliated persons, including PNC and its affiliates, in connection with such transactions. However, an affiliated person of a Master Portfolio may serve as its broker in OTC transactions conducted on an agency basis provided that, among other things, the fee or commission received by such affiliated broker is reasonable and fair compared to the fee or commission received by non-affiliated brokers in connection with comparable transactions. In addition, a Master Portfolio may not purchase securities during the existence of any underwriting syndicate for such securities of which PNC is a member or in a private placement in which PNC serves as placement agent except pursuant to procedures approved by the Board that either comply with rules adopted by the SEC or with interpretations of the SEC staff.

OTC issues, including most fixed-income securities such as corporate debt and U.S. government securities, are normally traded on a "net" basis without a stated commission, through dealers acting for their own account and not as brokers. The Master Portfolios will primarily engage in transactions with these dealers or deal directly with the issuer unless a better price or execution could be obtained by using a broker. Prices paid to a dealer with respect to both foreign and domestic securities will generally include a "spread," which is the difference between the prices at which the dealer is willing to purchase and sell the specific security at the time, and includes the dealer's normal profit.

Purchases of money market instruments by a Master Portfolio are made from dealers, underwriters and issuers. The Master Portfolios do not currently expect to incur any brokerage commission expense on such transactions because money market instruments are generally traded on a "net" basis with dealers acting as principal for their own accounts without a stated commission. The price of the security, however, usually includes a profit to the dealer.

A Master Portfolio will not purchase securities during the existence of any underwriting or selling group relating to such securities of which BFA, PNC or any affiliated person (as defined in the 1940 Act) thereof is a member except pursuant to procedures adopted by the Board in accordance with Rule 10f-3 under the 1940 Act. In no instance will portfolio securities be purchased from or sold to BFA, PNC or any affiliated person of the foregoing entities except as permitted by SEC exemptive order or by applicable law.

PORTFOLIO TURNOVER. Portfolio turnover may vary from year to year, as well as within a year. High portfolio turnover rates may result in comparatively greater brokerage expenses and larger amounts of short-term capital gains allocable to interestholders of a Master Portfolio and shareholders of the corresponding LifePath Portfolio.

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BROKERAGE COMMISSIONS. Each Master Portfolio purchases and sells those portfolio securities that are interests in Underlying Funds that are not iShares Funds by dealing directly with the issuer - the Underlying Funds. Each Master Portfolio purchases and sells those portfolio securities that are Underlying iShares Funds through brokers and will incur brokerage commissions on those transactions.

The table below sets forth the brokerage commissions paid by each Master Portfolio for the fiscal years noted:

                                         FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
MASTER PORTFOLIO                             12/31/2007           12/31/2008          12/31/2009
--------------------------------------  -------------------  -------------------  ------------------
LifePath Retirement Master Portfolio          $10,313              $ 24,659             $17,261
LifePath 2020 Master Portfolio                $80,576              $148,789             $89,676
LifePath 2030 Master Portfolio                $73,738              $130,637             $92,153
LifePath 2040 Master Portfolio                $62,630              $119,334             $76,825
LifePath 2050 Master Portfolio/1/               N/A                $  1,655             $ 7,713


/1/ LifePath 2050 Master Portfolio commenced operations on June 30, 2008.

BROKERAGE COMMISSIONS PAID TO AFFILIATES. During the past three fiscal years, the Master Portfolios paid no brokerage commissions to affiliated brokers.

SECURITIES OF REGULAR BROKER-DEALERS. As of December 31, 2009, none of the Master Portfolios in which each LifePath Portfolio invests owned securities of its "regular brokers or dealers" (as defined in the 1940 Act) or their parents.

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Distributions and Taxes

The following information supplements, and should be read in conjunction with, the section in each Prospectus entitled "Account Information - Taxes." The Prospectuses generally describe the U.S. federal income tax treatment of distributions by the LifePath Portfolios. This section of the SAI provides additional information concerning U.S. federal income taxes. It is based on the Internal Revenue Code, applicable Treasury Regulations, judicial authority, and administrative rulings and practice, all as of the date of this SAI and all of which are subject to change, including changes with retroactive effect. The following discussion does not address any state, local or foreign tax matters.

A shareholder's tax treatment may vary depending upon his or her particular situation. This discussion only applies to shareholders who are U.S. persons, I.E., U.S. citizens or residents or U.S. corporations, partnerships, trusts or estates, and who are subject to U.S. federal income tax and hold LifePath Portfolio shares as capital assets within the meaning of the Internal Revenue Code. Except as otherwise noted, it may not apply to certain types of shareholders who may be subject to special rules, such as insurance companies, tax-exempt organizations, shareholders holding LifePath Portfolio shares through tax-advantaged accounts (such as 401(k) plan accounts or individual retirement accounts), financial institutions, broker-dealers, entities that are not organized under the laws of the United States or a political subdivision thereof, persons who are neither citizens nor residents of the United States, shareholders holding LifePath Portfolio shares as part of a hedge, straddle or conversion transaction, and shareholders who are subject to the U.S. federal alternative minimum tax.

The Trust has not requested and will not request an advance ruling from the Internal Revenue Service (the "IRS") as to the U.S. federal income tax matters described below. The IRS could adopt positions contrary to those discussed below and such positions could be sustained. In addition, the foregoing discussion and the discussions in the Prospectuses applicable to each shareholder address only some of the U.S. federal income tax considerations generally affecting investments in the LifePath Portfolios. Prospective shareholders are urged to consult with their own tax advisers and financial planners as to the particular U.S. federal tax consequences to them of an investment in the LifePath Portfolios, as well as the applicability and effect of any state, local or foreign laws, and the effect of possible changes in applicable tax laws.

QUALIFICATION AS A REGULATED INVESTMENT COMPANY. Each LifePath Portfolio and Underlying Fund has elected to be treated, has qualified and intends to continue to qualify each year, as a "regulated investment company" under Subchapter M of the Internal Revenue Code as long as such qualification is in the best interests of the LifePath Portfolio's shareholders. Each LifePath Portfolio will be treated as a separate entity for U.S. federal income tax purposes. Thus, the provisions of the Internal Revenue Code applicable to regulated investment companies generally will apply separately to each LifePath Portfolio, even though each LifePath Portfolio is a series of a trust. Furthermore, each LifePath Portfolio separately determines its income, gains, losses and expenses for U.S. federal income tax purposes.

In order to qualify as a regulated investment company under the Internal Revenue Code, each LifePath Portfolio must, among other things, derive at least 90% of its annual gross income from dividends, interest, certain payments with respect to securities loans, gains from the sale or other disposition of stock, securities or foreign currencies, or other income attributable to its business of investing in such stock, securities or foreign currencies (including, but not limited to, gains from options, futures or forward contracts) and net income derived from an interest in a qualified publicly-traded partnership as defined in Section 851(h) of the Internal Revenue Code. Pursuant to regulations that may be promulgated in the future, the IRS may limit qualifying income from foreign currency gains to the amount of such currency gains that are directly related to a regulated investment company's principal business of investing in stock or securities. Each LifePath Portfolio must also diversify its holdings so that, at the end of each quarter of each taxable year: (i) at least 50% of the value of its assets consists of (A) cash and cash items (including receivables), U.S. government securities and securities of other regulated investment companies, and (B) other securities, with such other securities limited, in respect to any one issuer, to an amount not greater than 5% of the value of the LifePath Portfolio's total assets and to not more than 10% of the outstanding voting securities of such issuer and (ii) not more than 25% of the value of the LifePath Portfolio's total assets is invested in (A) the securities (other than U.S. government securities and securities of other regulated investment companies) of any one issuer, (B) the securities (other than the securities of other regulated investment companies) of two or more issuers that the LifePath Portfolio controls and that are engaged in the same, similar, or related trades or businesses, or (C) the securities of one or more qualified publicly-traded partnerships. The qualifying income and diversification requirements applicable to a LifePath Portfolio may limit the extent to which it can engage in transactions in options, futures contracts, forward contracts and swap agreements.

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In addition, each LifePath Portfolio generally must distribute to its shareholders an amount equal to or exceeding the sum of (i) 90% of its "investment company taxable income," as that term is defined in the Internal Revenue Code (which generally includes, among other things, dividends, taxable interest, and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses) without regard to the deduction for dividends paid and (ii) 90% of its net tax-exempt income earned in each taxable year. A LifePath Portfolio generally will not be subject to U.S. federal income tax on the investment company taxable income and "net capital gain" (I.E., the excess of net long-term capital gain over net short-term capital loss) it distributes to its shareholders. However, if a LifePath Portfolio meets such distribution requirements, but chooses to retain some portion of its investment company taxable income or net capital gain, it generally will be subject to U.S. federal income tax at regular corporate rates on the amount retained. Although dividends generally will be treated as distributed when paid, if a LifePath Portfolio declares a distribution to shareholders of record in October, November or December of one year and pays the distribution by January 31 of the following year, the LifePath Portfolio and its shareholders will be treated as if the LifePath Portfolio paid the distribution by December 31 of the calendar year in which it was declared. Each LifePath Portfolio intends to distribute its net income and gain in a timely manner to maintain its status as a regulated investment company and eliminate fund-level U.S. federal income taxation of such income and gain. However, no assurance can be given that a LifePath Portfolio will not be subject to U.S. federal income taxation.

If, in any taxable year, a LifePath Portfolio fails to qualify as a regulated investment company under the Internal Revenue Code or fails to meet the distribution requirements described above, the LifePath Portfolio would be taxed in the same manner as an ordinary U.S. corporation without any deduction for distributions to shareholders, and all distributions from the LifePath Portfolio's earnings and profits (including any distributions of net tax-exempt income and net capital gain) to its shareholders would also be taxable as ordinary income at the shareholder level. To qualify again to be taxed as a regulated investment company in a subsequent year, the LifePath Portfolio may be required to pay an interest charge and penalty to the IRS as well as distribute to its shareholders its earnings and profits attributable to non-regulated investment company years. In addition, if the LifePath Portfolio fails to qualify as a regulated investment company for a period greater than two taxable years, the LifePath Portfolio may be required to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the LifePath Portfolio had been liquidated) or, alternatively, to be subject to taxation on such built-in gain recognized for a period of ten years, in order to qualify as a regulated investment company in a subsequent year.

EXCISE TAX. A 4% non-deductible excise tax will be imposed on each LifePath Portfolio to the extent it fails to distribute during each calendar year (i) at least 98% of its ordinary income (excluding capital gains and losses) for the calendar year, (ii) at least 98% of its net capital gain income (generally the excess of capital gains over capital losses as adjusted for ordinary losses) for the 12 month period ending on October 31, and (iii) all of its ordinary income and net capital gain income from previous years that was not distributed or subject to tax during such years. Each LifePath Portfolio intends to distribute substantially all of its net income and gains, if any, by the end of each calendar year and, thus, expects not to be subject to the excise tax. However, no assurance can be given that a LifePath Portfolio will not be subject to the excise tax.

CAPITAL LOSS CARRY-FORWARDS. A LifePath Portfolio is permitted to carry forward a net capital loss from any year to offset its capital gains, if any, realized during the eight years following the year of the loss. A LifePath Portfolio's capital loss carry-forward is treated as a short-term capital loss in the year to which it is carried. If future capital gains are offset by carried-forward capital losses, such future capital gains are not subject to fund-level federal income taxation, regardless of whether they are distributed to shareholders. Accordingly, the LifePath Portfolios do not expect to distribute any such capital gains. The LifePath Portfolios cannot carry back or carry forward any net operating losses. As of December 31, 2009, the LifePath Portfolios had capital loss carry-forwards approximating the amount indicated for U.S. federal income tax purposes, expiring in the year indicated:

                                          EXPIRING               EXPIRING
LIFEPATH PORTFOLIO                       12/31/2016             12/31/2017
-------------------------------  -------------------------  -----------------
LifePath Retirement Portfolio         $  28,826,523(1)         $ 6,610,932
LifePath 2020 Portfolio               $   6,147,998            $56,526,213
LifePath 2030 Portfolio               $  12,392,101            $46,671,709
LifePath 2040 Portfolio               $  11,264,177            $37,111,457
LifePath 2050 Portfolio                    N/A                     N/A

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(1) The LifePath Retirement Portfolio had a capital loss carryforward of $27,945,792 that it acquired from the LifePath 2010 Portfolio which will expire on December 31, 2016. The capital loss carryforward of LifePath Retirement Portfolio may be subject to loss limitations.

EQUALIZATION ACCOUNTING. Each LifePath Portfolio may use the so-called "equalization method" of accounting to allocate a portion of its "earnings and profits," which generally equals a LifePath Portfolio's undistributed net investment income and realized capital gains, with certain adjustments, to redemption proceeds. This method permits a LifePath Portfolio to achieve more balanced distributions for both continuing and redeeming shareholders. Although using this method generally will not affect a LifePath Portfolio's total returns, it may reduce the amount that the LifePath Portfolio would otherwise distribute to continuing shareholders by reducing the LifePath Portfolio's required distribution amounts by a portion of the redemption proceeds paid to redeeming shareholders. However, the IRS has not expressly sanctioned the equalization accounting method used by the LifePath Portfolios, and thus the use of this method may be subject to IRS scrutiny.

INVESTMENT THROUGH MASTER PORTFOLIOS. Each LifePath Portfolio seeks to continue to qualify as a regulated investment company by investing its assets in a related Master Portfolio. Each Master Portfolio is treated as a non-publicly-traded partnership (or, in the event that a LifePath Portfolio is the sole investor in the related Master Portfolio, as disregarded from the LifePath Portfolio) for U.S. federal income tax purposes rather than as a regulated investment company or a corporation under the Internal Revenue Code. Under the rules applicable to a non-publicly-traded partnership (or disregarded entity), a proportionate share of any interest, dividends, gains and losses of a Master Portfolio will be deemed to have been realized by (I.E., "passed-through" to) its investors, including the corresponding LifePath Portfolio, regardless of whether any amounts are actually distributed by the Master Portfolio. Each investor in a Master Portfolio will be taxable on such share, as determined in accordance with the governing instruments of the particular Master Portfolio, the Internal Revenue Code and Treasury Regulations. Therefore, to the extent that a Master Portfolio were to accrue but not distribute any income or gains, the related LifePath Portfolio would be deemed to have realized its proportionate share of such income or gains without receipt of any corresponding distribution. However, each of the Master Portfolios will seek to minimize recognition by its investors (such as a corresponding LifePath Portfolio) of income and gains without a corresponding distribution. Furthermore, each Master Portfolio's assets, income and distributions will be managed in such a way that an investor in a Master Portfolio will be able to continue to qualify as a regulated investment company by investing its assets through the Master Portfolio.

TAXATION OF UNDERLYING FUND INVESTMENTS. In general, if an Underlying Fund realizes gains or losses on the sale of portfolio securities, such gains or losses are capital gains or losses, and if the Underlying Fund has held the disposed securities for more than one year at the time of disposition such gains and losses generally are treated as long-term capital gains or losses.

If an Underlying Fund purchases a debt obligation with original issue discount ("OID"), generally at a price less than its principal amount, such as a zero-coupon bond, the Underlying Fund may be required to annually include in its taxable income a portion of the OID as ordinary income, even though the Underlying Fund will not receive cash payments for such discount until maturity or disposition of the obligation. A portion of the OID includible in income with respect to certain high-yield corporate debt securities may be treated as a dividend for U.S. federal income tax purposes. Gains recognized on the disposition of a debt obligation (including a municipal obligation) purchased by an Underlying Fund at a market discount, usually at a price less than its principal amount, generally will be treated as ordinary income to the extent of the portion of market discount which accrued, but was not previously recognized pursuant to an available election, during the term that the Underlying Fund held the debt obligation. An Underlying Fund generally will be required to make distributions to shareholders representing the OID on debt securities that is currently includible in income, even though the cash representing such income may not have been received by the Underlying Fund. Cash to pay such distributions may be obtained from borrowing or from sales proceeds of securities held by an Underlying Fund which the Underlying Fund otherwise might have continued to hold.

If an option granted by an Underlying Fund lapses or is terminated through a closing transaction, such as a repurchase by the Underlying Fund of the option from its holder, the Underlying Fund generally will realize a short-term capital gain or loss, depending on whether the premium income is greater or less than the amount paid by the Underlying Fund in the closing transaction. Some capital losses may be deferred if they result from a position that is part of a "straddle," discussed below. If securities are sold by an Underlying Fund pursuant to the exercise of a call option granted by it, the Underlying Fund will add the premium received to the sale price of the securities delivered in determining the amount of gain or loss on the sale. If securities are purchased by an Underlying Fund pursuant to the exercise of a put option written by it, the Underlying Fund will subtract the premium received from its cost basis in the securities purchased.

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Some regulated futures contracts, certain foreign currency contracts, and non-equity listed options used by an Underlying Fund will be deemed "Section 1256 contracts." An Underlying Fund will be required to "mark to market" any such contracts held at the end of the taxable year by treating them as if they had been sold on the last day of that year at fair market value. Sixty percent of any net gain or loss realized on all dispositions of Section 1256 contracts, including deemed dispositions under the "mark-to-market" rule, generally will be treated as long-term capital gain or loss, and the remaining 40% will be treated as short-term capital gain or loss. Certain transactions that qualify as designated "hedging transactions," as defined in Section 1221(b)(2) of the Internal Revenue Code, are excepted from the mark-to-market rule and the "60%/40%" rule.

Foreign exchange gains and losses realized by an Underlying Fund in connection with certain transactions involving foreign currency-denominated debt securities, certain options and futures contracts relating to foreign currency, foreign currency forward contracts, foreign currencies, or payables or receivables denominated in a foreign currency are subject to Section 988 of the Internal Revenue Code, which generally causes such gains and losses to be treated as ordinary income and losses and may affect the amount and timing of recognition of the Underlying Fund's income. Under Treasury Regulations that may be promulgated in the future, any such transactions that are not directly related to an Underlying Fund's principal business of investing in stock or securities (or its options contracts or futures contracts with respect to stock or securities) may have to be limited in order to enable the Underlying Fund to satisfy the 90% income test described above. If the net foreign exchange loss for a year exceeds an Underlying Fund's investment company taxable income (computed without regard to such loss), the resulting ordinary loss for such year will not be deductible by the Underlying Fund or its shareholders in future years.

Offsetting positions held by an Underlying Fund involving certain financial forward, futures or options contracts may be considered, for U.S. federal income tax purposes, to constitute "straddles." "Straddles" are defined to include "offsetting positions" in actively traded personal property. The tax treatment of "straddles" is governed by Section 1092 of the Internal Revenue Code which, in certain circumstances, overrides or modifies the provisions of
Section 1256. If an Underlying Fund is treated as entering into "straddles" by engaging in certain financial forward, futures or option contracts, such straddles could be characterized as "mixed straddles" if one or more (but not all) of the futures, forward, or option contracts or other positions comprising a part of such straddles are governed by Section 1256 of the Internal Revenue Code, described above. An Underlying Fund may make one or more elections with respect to "mixed straddles." Depending upon which election is made, if any, the results with respect to an Underlying Fund may differ. Generally, to the extent the straddle rules apply to positions established by an Underlying Fund, losses realized by the Underlying Fund may be deferred to the extent of unrealized gain in any offsetting positions. Moreover, as a result of the straddle and the conversion transaction rules, short-term capital loss on straddle positions may be recharacterized as long-term capital loss, and long-term capital gain may be characterized as short-term capital gain or ordinary income. Further, the Underlying Fund may be required to capitalize, rather than deduct currently, any interest expense on indebtedness incurred or continued to purchase or carry any positions that are part of a straddle. Because the application of the straddle rules may affect the character of gains and losses, defer losses, and/or accelerate the recognition of gains or losses from affected straddle positions, the amount which must be distributed to Underlying Fund shareholders, and which will be taxed to Underlying Fund shareholders as ordinary income of long-term capital gain, may be increased or decreased substantially as compared to an Underlying Fund that had not engaged in such transactions.

If an Underlying Fund enters into a "constructive sale" of any appreciated financial position in stock, a partnership interest, or certain debt instruments, the Underlying Fund will be treated as if it had sold and immediately repurchased the property and must recognize gain (but not loss) with respect to that position. A constructive sale occurs when an Underlying Fund enters into one of the following transactions with respect to the same or substantially identical property: (i) a short sale; (ii) an offsetting notional principal contract; (iii) a futures or forward contract; or (iv) other transactions identified in Treasury Regulations that may be promulgated in the future. The character of the gain from constructive sales will depend upon an Underlying Fund's holding period in the property. Losses from a constructive sale of property will be recognized when the property is subsequently disposed of. The character of such losses will depend upon an Underlying Fund's holding period in the property and the application of various loss deferral provisions in the Internal Revenue Code. Constructive sale treatment does not apply to a transaction if such transaction is closed before the end of the 30th day after the close of the Underlying Fund's taxable year, the Underlying Fund holds the appreciated financial position throughout the 60-day period beginning with the day such transaction was closed, and the Underlying Fund's risk of loss with respect to such position is not reduced at any time during such 60-day period.

The amount of long-term capital gain an Underlying Fund may recognize from derivative transactions is limited with respect to certain pass-through entities. The amount of long-term capital gain is limited to the amount of such gain an Underlying Fund would have had if the Underlying Fund directly invested in the pass-through entity during the term of the derivative

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contract. Any gain in excess of this amount is treated as ordinary income. An interest charge is imposed on the amount of gain that is treated as ordinary income.

"Passive foreign investment corporations" ("PFICs") are generally defined as foreign corporations that receive at least 75% of their annual gross income from passive sources (such as interest, dividends, certain rents and royalties, or capital gains) or that hold at least 50% of their assets in investments producing such passive income. If an Underlying Fund acquires any equity interest (which generally includes not only stock but may also include an option to acquire stock such as is inherent in a convertible bond under Treasury Regulations that may be promulgated in the future) in a PFIC, the Underlying Fund could be subject to U.S. federal income tax and IRS interest charges on "excess distributions" received from the PFIC or on gain from the sale of stock in the PFIC, even if all income or gain actually received by the Underlying Fund is timely distributed to its shareholders. Excess distributions will be characterized as ordinary income even though, absent the application of PFIC rules, some excess distributions would have been classified as capital gain.

An Underlying Fund will not be permitted to pass through to its shareholders any credit or deduction for taxes and interest charges incurred with respect to PFICs. Elections may be available that would ameliorate these adverse tax consequences, but such elections could require an Underlying Fund to recognize taxable income or gain without the concurrent receipt of cash. Investments in PFICs could also result in the treatment of associated capital gains as ordinary income. The Underlying Fund may limit and/or manage their holdings in PFICs to minimize their tax liability or maximize their returns from these investments. Because it is not always possible to identify a foreign corporation as a PFIC in advance of acquiring shares in the corporation, however, an Underlying Fund may incur the tax and interest charges described above in some instances.

Rules governing the U.S. federal income tax aspects of swap agreements are in a developing stage and are not entirely clear in certain respects. Accordingly, while each Underlying Fund intends to account for such transactions in a manner it deems to be appropriate, the IRS might not accept such treatment. If it did not, the status of an Underlying Fund as a regulated investment company might be jeopardized. The Underlying Funds intend to monitor developments in this area. Certain requirements that must be met under the Internal Revenue Code in order for each Underlying Fund to qualify as a regulated investment company may limit the extent to which an Underlying Fund will be able to engage in swap agreements.

In addition to the investments described above, prospective shareholders should be aware that other investments made by the Underlying Fund may involve sophisticated tax rules that may result in income or gain recognition by the Underlying Fund without corresponding current cash receipts. Although the Underlying Fund seeks to avoid significant non-cash income, such non-cash income could be recognized by the Underlying Fund, in which case the Underlying Fund may distribute cash derived from other sources in order to meet the minimum distribution requirements described above. In this regard, the Underlying Fund could be required at times to liquidate investments prematurely in order to satisfy its minimum distribution requirements. In addition, payments received by the Underlying Funds in connection with securities lending and repurchase agreements will not qualify for recently enacted reductions in individual U.S. federal income tax on certain dividends and so may be taxable as ordinary income.

TAXATION OF DISTRIBUTIONS. For U.S. federal income tax purposes, a LifePath Portfolio's earnings and profits, described above, are determined at the end of the LifePath Portfolio's taxable year and are allocated PRO RATA to distributions made throughout the entire year. All distributions paid out of a LifePath Portfolio's earnings and profits (as determined at the end of the year), whether paid in cash or reinvested in the LifePath Portfolio, generally are deemed to be taxable distributions and must generally be reported on each LifePath Portfolio shareholder's U.S. federal income tax return. Distributions in excess of a LifePath Portfolio's earnings and profits will first be treated as a return of capital up to the amount of a shareholder's tax basis in the shareholder's LifePath Portfolio shares and any such amount in excess of that basis as capital gain from the sale of shares, as discussed below. A LifePath Portfolio may make distributions in excess of earnings and profits to a limited extent, from time to time.

In general, assuming that each LifePath Portfolio has sufficient earnings and profits, distributions from investment company taxable income either are taxable as ordinary income or, if so designated by a LifePath Portfolio and certain other conditions are met, as "qualified dividend income" taxable at a reduced U.S. federal income tax rate to individual shareholders. Dividend income distributed to individual shareholders will qualify as "qualified dividend income" as that term is defined in Section 1(h)(11)(B) of the Internal Revenue Code to the extent such distributions are attributable to income from the LifePath Portfolio's investments in common and preferred stock of U.S. companies and stock of certain qualified foreign corporations provided that certain holding period and other requirements are met by both the LifePath Portfolio and the shareholders.

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A distribution that is attributable to qualified dividend income of a LifePath Portfolio that is paid by the LifePath Portfolio to an individual shareholder will not be taxable as qualified dividend income to such shareholder if (i) the dividend is received with respect to any share of the LifePath Portfolio held for fewer than 61 days during the 121 day-period beginning on the date which is 60 days before the date on which such share became ex-dividend with respect to such dividend, (ii) to the extent that the shareholder is under an obligation (whether pursuant to a short sale or otherwise) to make related payments with respect to positions in substantially similar or related property, or (iii) the shareholder elects to have the dividend treated as investment income for purposes of the limitation on deductibility of investment interest. The "ex-dividend" date is the date on which the owner of the share at the commencement of such date is entitled to receive the next issued dividend payment for such share even if the share is sold by the owner on that date or thereafter.

Distributions designated by a LifePath Portfolio as a capital gain dividend will be taxed to its shareholders as long-term capital gain (to the extent such distributions do not exceed the LifePath Portfolio's actual net capital gain for the taxable year), regardless of how long a shareholder has held the LifePath Portfolio shares. Each LifePath Portfolio will designate capital gain dividends, if any, in a written notice mailed by the LifePath Portfolio to its shareholders no later than 60 days after the close of the LifePath Portfolio's taxable year. The U.S. federal income tax status of all distributions will be reported to shareholders annually.

SALES OF LIFEPATH PORTFOLIO SHARES. Redemptions generally are taxable events for shareholders that are subject to tax. Shareholders should consult their own tax advisers with reference to their individual circumstances to determine whether any particular transaction in LifePath Portfolio shares is properly treated as a sale for tax purposes, as the following discussion assumes, and the tax treatment of any gains or losses recognized in such transaction. In general, if LifePath Portfolio shares are sold, a shareholder will recognize gain or loss equal to the difference between the amount realized on the sale and the shareholder's adjusted tax basis in the shares. This gain or loss will be long-term capital gain or loss if the shareholder has held such LifePath Portfolio shares for more than one year at the time of the sale.

Also, if a shareholder realizes a loss on a disposition of LifePath Portfolio shares, the loss will be disallowed to the extent that he or she purchases substantially identical shares within the 61-day period beginning 30 days before and ending 30 days after the disposition. Any disallowed loss generally will be included in the tax basis of the purchased shares. If a shareholder receives a capital gain dividend with respect to any LifePath Portfolio share and such LifePath Portfolio share is held for six months or less, then (unless otherwise disallowed) any loss on the sale or exchange of that LifePath Portfolio share will be treated as a long-term capital loss to the extent of the capital gain dividend.

Under Treasury Regulations, if a shareholder recognizes a loss with respect to shares of a LifePath Portfolio of $2 million or more for an individual shareholder, or $10 million or more for a corporate shareholder, in any single taxable year (or greater amounts over a combination of years), the shareholder must file with the IRS a disclosure statement on Form 8886. Shareholders who own portfolio securities directly are in many cases exempt from this requirement but, under current guidance, shareholders of regulated investment companies are not exempt. A shareholder who fails to make the required disclosure to the IRS may be subject to substantial penalties. The fact that a loss is reportable under these regulations does not affect the legal determination of whether or not the taxpayer's treatment of the loss is proper. Shareholders should consult with their tax advisers to determine the applicability of these regulations in light of their individual circumstances.

FOREIGN TAXES. Amounts realized by a LifePath Portfolio on foreign securities may be subject to withholding and other taxes imposed by such foreign countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a LifePath Portfolio's total assets at the close of its taxable year were to consist of securities of non-U.S. corporations, the LifePath Portfolio would be eligible to file an annual election with the IRS pursuant to which the LifePath Portfolio could pass through to its shareholders on a PRO RATA basis foreign income and similar taxes paid by the LifePath Portfolio, which could be claimed, subject to certain limitations, either as a tax credit or deduction by shareholders. However, none of the LifePath Portfolios expects to qualify for this election.

FEDERAL INCOME TAX RATES. As of the date of this SAI, the maximum stated individual U.S. federal income tax rate applicable to (i) ordinary income generally is 35%; (ii) qualified dividend income is 15%; (iii) capital gain dividends is 15%; and (iv) long-term capital gains generally is 15%. An individual shareholder also should be aware that the benefits of the favorable tax rates applicable to capital gain dividends, long-term capital gains, and qualified dividend income may be impacted by the application of the alternative minimum tax. Under current law, the maximum 35% U.S. federal income tax rate on ordinary income and the maximum 15% U.S. federal income tax rate on capital gain dividends, long-term capital gains and qualified dividend income will cease to apply to taxable years beginning after December 31, 2010.

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The current maximum stated corporate U.S. federal income tax rate applicable to ordinary income, qualified dividend income, capital gain dividends, and long-term capital gains is generally 35%. Actual marginal tax rates may be higher for some shareholders, for example, through reductions in deductions. Naturally, the amount of tax payable by any taxpayer will be affected by a combination of tax laws covering, for example, deductions, credits, deferrals, exemptions, sources of income and other matters.

BACK-UP WITHHOLDING. The Trust may be required to withhold, subject to certain exemptions, at a rate of 28% ("back-up withholding") on all distributions and redemption proceeds (including proceeds from exchanges and redemptions in-kind) paid or credited to a LifePath Portfolio shareholder, unless the shareholder generally certifies under penalties of perjury that the shareholder's social security or other "taxpayer identification number" ("TIN") provided is correct and that the shareholder is not subject to back-up withholding, or the IRS notifies the LifePath Portfolio that the shareholder's TIN is incorrect or that the shareholder is subject to back-up withholding. This tax is not an additional U.S. federal income tax imposed on the shareholder, and the shareholder may claim the tax withheld as a tax payment on his or her U.S. federal income tax return, provided that the required information is furnished to the IRS. An investor must provide a valid TIN upon opening or reopening an account. If a shareholder fails to furnish a valid TIN upon request, the shareholder can also be subject to IRS penalties. The rate of back-up withholding is set to increase for taxable years beginning after December 31, 2010.

TAX-DEFERRED PLANS. Shareholders that are exempt from U.S. federal income tax, such as retirement plans that are qualified under Section 401 of the Internal Revenue Code, generally are not subject to U.S. federal income tax on LifePath Portfolio dividends or distributions or on sales of LifePath Portfolio shares unless the acquisition of the LifePath Portfolio shares was debt-financed. However, in the case of LifePath Portfolio shares held through a non-qualified deferred compensation plan, LifePath Portfolio dividends and distributions received by the plan and sales of LifePath Portfolio shares by the plan generally are taxable to the employer sponsoring such plan in accordance with the U.S. federal income tax laws governing deferred compensation plans.

A plan participant whose retirement plan invests in a LifePath Portfolio, whether such plan is qualified or not, generally is not taxed on fund dividends or distributions received by the plan or on sales of LifePath Portfolio shares by the plan for U.S. federal income tax purposes. However, distributions to plan participants from a retirement plan account generally are taxable as ordinary income and different tax treatment, including penalties on certain excess contributions and deferrals, certain pre-retirement and post-retirement distributions and certain prohibited transactions, may apply to accounts maintained as qualified retirement plans. All prospective investors should contact their tax advisers and financial planners regarding the tax consequences to them of holding LifePath Portfolio shares through a tax-advantaged plan or account.

CORPORATE SHAREHOLDERS. Subject to limitations and other rules, a corporate shareholder of a LifePath Portfolio may be eligible for the dividends-received deduction on the LifePath Portfolio's distributions to the extent that such distributions are attributable to dividends from domestic corporations, which, if received directly by the corporate shareholder, would qualify for such deduction. In general, a distribution by a LifePath Portfolio attributable to dividends of a domestic corporation will only be eligible for the deduction if certain holding period requirements are met. These requirements are complex and, therefore, corporate shareholders of the LifePath Portfolios are urged to consult their own tax advisers and financial planners.

FOREIGN SHAREHOLDERS. With respect to taxable years of a LifePath Portfolio beginning before January 1, 2010, certain distributions, if designated by a LifePath Portfolio as "interest-related dividends," that are generally attributable to the LifePath Portfolio's net interest income earned on certain debt obligations paid to a non-resident alien individual, foreign trust (I.E., a trust other than a trust which a U.S. court is able to exercise primary supervision over administration of that trust and one or more U.S. persons have authority to control substantial decisions of that trust), foreign estate (I.E., the income of which is not subject to U.S. tax regardless of source) or a foreign corporation (each, a "foreign shareholder") generally will be exempt from U.S. federal income tax withholding tax, provided the LifePath Portfolio obtains a properly completed and signed certificate of foreign status from such foreign shareholder ("exempt foreign shareholder"). If applicable, each LifePath Portfolio may choose to designate any interest-related dividends in a written notice mailed by the LifePath Portfolio to its shareholders no later than 60 days after the close of the LifePath Portfolio's taxable year. All other distributions made to exempt foreign shareholders attributable to net investment income, such as dividends received by a LifePath Portfolio, generally will be subject to non-refundable U.S. federal income tax withholding at a 30% rate (or a lower rate, if so provided under an applicable income tax treaty). Notwithstanding the foregoing, if a distribution described above is "effectively

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connected" with a U.S. trade or business (or, if an income tax treaty applies, is attributable to a permanent establishment) of the recipient foreign shareholder, U.S. federal income tax withholding and exemptions attributable to foreign persons will not apply and the distribution will be subject to the tax, reporting and withholding requirements generally applicable to U.S. persons.

In general, a foreign shareholder's capital gains realized on the disposition of LifePath Portfolio shares, capital gain distributions and, with respect to certain taxable years of a LifePath Portfolio before January 1, 2010, "short-term capital gain distributions" (defined below) are not subject to U.S. federal income tax withholding, provided that the LifePath Portfolio obtains a properly completed and signed certificate of foreign status, unless: (i) such gains or distributions are effectively connected with a U.S. trade or business (or, if an income tax treaty applies, are attributable to a permanent establishment) of the foreign shareholder; (ii) in the case of an individual foreign shareholder, the shareholder is present in the U.S. for a period or periods aggregating 183 days or more during the year of the sale and certain other conditions are met; or (iii) with respect to certain taxable years of a LifePath Portfolio before January 1, 2010, such gains or distributions are attributable to gain from the sale or exchange of a U.S. real property interest. If such gains or distributions are effectively connected with a U.S. trade or business or are attributable to a U.S. permanent establishment of the foreign shareholder pursuant to an income tax treaty, the tax, reporting and withholding requirements applicable to U.S. persons generally apply. If such gains or distributions are not effectively connected for this purpose, but the foreign shareholder meets the requirements of clause (ii) described above, such gains and distributions will be subject to U.S. federal income tax withholding tax at a 30% rate (or a lower rate, if so provided under an applicable income tax treaty). Gains or distributions attributable to gain from sales or exchanges of U.S. real property interests are taxed to a foreign shareholder as if that gain were effectively connected with the shareholder's conduct of a U.S. trade or business, and therefore such gains or distributions may be required to be reported by a foreign shareholder on a U.S. federal income tax return. Such gains or distributions also will be subject to U.S. federal income tax at the rates applicable to U.S. holders and/or may be subject to U.S. federal income tax withholding. While the LifePath Portfolios do not expect LifePath Portfolio shares to constitute U.S. real property interests, a portion of a LifePath Portfolio's distributions may be attributable to gain from the sale or exchange of U.S. real property interests. Foreign shareholders should contact their tax advisers and financial planners regarding the tax consequences to them of such distributions. "Short-term capital gain distributions" are certain distributions that a LifePath Portfolio may choose to designate as such in a written notice mailed by the LifePath Portfolio to its shareholders no later than 60 days after the close of the LifePath Portfolio's taxable year generally attributable to its net short-term capital gain.

If a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the U.S. at the time of the shareholder's death, LifePath Portfolio shares will be deemed to be property situated in the U.S. and will be subject to U.S. federal estate taxes (at current graduated rates of 18% to 45% of the total value, less allowable deductions and credits). With respect to estates of decedents dying before January 1, 2010, if a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, LifePath Portfolio shares are not deemed to be property situated in the United States in the proportion that, at the end of the quarter of the LifePath Portfolio's taxable year immediately preceding the shareholder's date of death, the assets of the LifePath Portfolio that are "qualifying assets" (I.E., bank deposits, debt obligations or property not within the United States) with respect to the decedent bear to the total assets of the LifePath Portfolio. In general, no U.S. federal gift tax will be imposed on gifts of LifePath Portfolio shares made by foreign shareholders.

The availability of reduced U.S. taxes pursuant to the 1972 Convention or the applicable estate tax convention depends upon compliance with established procedures for claiming the benefits thereof, and may, under certain circumstances, depend upon the foreign shareholder making a satisfactory demonstration to U.S. tax authorities that the shareholder qualifies as a foreign person under U.S. federal income tax laws and the 1972 Convention.

Special rules apply to foreign partnerships and those holding LifePath Portfolio shares through foreign partnerships.

RECENTLY ENACTED LEGISLATION. Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012, to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code) unless

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they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

Capital Stock

As of the date of this SAI, the beneficial interests in the Trust are divided into transferable shares of 11 separate and distinct series authorized and established by the Board of Trustees. The number of shares of each series, and class thereof, is unlimited and each share has no par value. The Board of Trustees may, in the future, authorize the issuance of other series representing shares of additional investment portfolios or funds. Except to the extent the 1940 Act expressly grants to shareholders the power to vote on such termination(s), the Trust, or any series (or class) thereof, may be terminated at any time by the Trustees with written notice to the shareholders.

Although the Trust is not required to hold regular annual shareholder meetings, occasional annual or special meetings may be required for purposes such as electing and removing Trustees, approving advisory contracts, and changing a LifePath Portfolio's fundamental investment policies.

VOTING. All shares of the Trust will be voted separately by individual series, except: (i) when required by the 1940 Act, shares will be voted in the aggregate and not by individual series; and (ii) when the Trustees have determined that the matter affects the interests of more than one series, then the shareholders of all such affected series will be entitled to vote thereon in the aggregate and not by individual series. The Trustees also may determine that a matter affects only the interests of one or more classes of a series, in which case any such matter will be voted on separately by such class or classes. For example, a change in a LifePath Portfolio's fundamental investment policy would be voted upon only by shareholders of that LifePath Portfolio. Additionally, approval of a Master Portfolio's Advisory Contract is a matter to be determined separately by each Master Portfolio. Approval by the shareholders of a LifePath Portfolio is effective as to that LifePath Portfolio whether or not sufficient votes are received from the shareholders of the other investment portfolios to approve the proposal as to those investment portfolios. As used in the Prospectuses of each LifePath Portfolio and in this SAI, the term "1940 Act majority," when referring to approvals to be obtained from shareholders of a LifePath Portfolio, means the vote of the lesser of (i) 67% of the shares of the LifePath Portfolio represented at a meeting if the holders of more than 50% of the outstanding shares of the LifePath Portfolio are present in person or by proxy, or (ii) more than 50% of the outstanding shares of the LifePath Portfolio. The term "majority," when referring to the approvals to be obtained from shareholders of the Trust as a whole, means the vote of the lesser of (i) 67% of the Trust's shares represented at a meeting if the holders of more than 50% of the Trust's outstanding shares are present in person or by proxy, or
(ii) more than 50% of the Trust's outstanding shares.

Each share will entitle the holder thereof to one vote for each dollar (and each fractional dollar thereof) of NAV (number of shares owned times NAV per share) of shares outstanding in such holder's name on the books of the Trust. There shall be no cumulative voting in the election of Trustees. Depending on the terms of a particular benefit plan and the matter being submitted to a vote, a sponsor may request direction from individual participants regarding a shareholder vote. For additional voting information and a discussion of the possible effects of changes to a Master Portfolio's investment objective or policies on a LifePath Portfolio, as an interestholder in the Master Portfolio, or the LifePath Portfolio's shareholders, see "Management - Master/Feeder Structure."

In accordance with the Trust's Declaration of Trust, the Board may, without shareholder approval (unless such shareholder approval is required by applicable law, including the 1940 Act), cause one or more Covered LifePath Portfolios (defined below) to merge, reorganize, consolidate, sell all or substantially all of their assets, or take other similar actions (collectively "merge") with, to or into another LifePath Portfolio. For example, as the target year of a Covered LifePath Portfolio (as set forth in its name) approaches, the Board of Trustees may authorize that Covered Portfolio to merge into or consolidate with LifePath Retirement Portfolio without shareholder approval of either constituent LifePath Portfolio. "Covered LifePath Portfolios" are LifePath 2020 Portfolio, LifePath 2030 Portfolio, LifePath 2040 Portfolio, LifePath 2050 Portfolio and any LifePath series commencing operations in the future.

The Trust may dispense with an annual meeting of shareholders in any year in which it is not required to elect Trustees under the 1940 Act. However, the Trust will hold a special meeting of its shareholders for the purpose of voting on the question of removal of a Trustee or Trustees if requested in writing by the holders of at least 10% of the Trust's outstanding voting securities, and to assist in communicating with other shareholders as required by Section 16(c) of the 1940 Act.

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DIVIDENDS AND DISTRIBUTIONS. Each share of a LifePath Portfolio represents an equal proportional interest in the LifePath Portfolio with each other share and is entitled to such dividends and distributions out of the income earned on the assets belonging to the LifePath Portfolio as are declared in the discretion of the Trustees. In the event of the liquidation or dissolution of the Trust, shareholders of a LifePath Portfolio are entitled to receive the assets attributable to the LifePath Portfolio that are available for distribution, and a distribution of any general assets not attributable to a particular investment portfolio that are available for distribution in such manner and on such basis as the Trustees in their sole discretion may determine. Shareholders are not entitled to any preemptive rights. All shares, when issued, will be fully paid and non-assessable by the Trust.

MASTER PORTFOLIOS. MIP is an open-end, series management investment company organized as a Delaware statutory trust on October 20, 1993. MIP's Declaration of Trust provides that obligations of MIP are not binding upon its Trustees individually but only upon the property of MIP and that the Trustees will not be liable for any action or failure to act, but nothing in the Declaration of Trust protects a Trustee against any liability to which the Trustee would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of the Trustee's office.

Interests in each Master Portfolio of MIP have voting and other rights generally corresponding to those rights enumerated above for shares of the LifePath Portfolios. MIP also intends to dispense with annual meetings, but is required by Section 16(c) of the 1940 Act to hold a special meeting and assist investor communications under the circumstances described above with respect to the Trust. Whenever a LifePath Portfolio is requested to vote on a matter with respect to its Master Portfolio, the LifePath Portfolio will follow its voting procedures, as described in "Voting."

Additional Information on the LifePath Portfolios

The Trust provides annual and semi-annual reports to all shareholders. The annual reports contain audited financial statements and other information about the LifePath Portfolios, including additional information on performance. Shareholders may obtain a copy of the Trust's most recent annual or semi-annual reports without charge by calling 1-800-441-7762 (toll-free).

The registration statement, including the Prospectuses, this SAI and the exhibits filed therewith, may be examined at the office of the SEC in Washington, D.C. Statements contained in the Prospectuses or this SAI as to the contents of any contract or other document referred to herein or in the Prospectuses are not necessarily complete and, in each instance, reference is made to the copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference.

No person has been authorized to give any information or to make any representations other than those contained in the Prospectuses, this SAI and in the Trust's official sales literature in connection with the offer of the LifePath Portfolios' shares and, if given or made, such other information or representations must not be relied upon as having been authorized by the Trust. This SAI does not constitute an offer in any state in which, or to any person to whom, such offering may not lawfully be made.

Financial Statements

The audited financial statements, including the schedule of investments, financial highlights and independent registered public accounting firm's reports for the fiscal year ended December 31, 2009 for each LifePath Portfolio and related Master Portfolio are hereby incorporated by reference to the Trust's annual report, as filed with the SEC on March 10, 2010. The annual report, which contains the referenced audited financial statements, is available upon request and without charge.

Disclaimers

The iShares S&P 500 Index Fund, iShares S&P MidCap 400 Index Fund, iShares S&P Small Cap 600 Index Fund, iShares S&P National AMT-Free Municipal Bond Fund and the iShares S&P North America Natural Resources Sector Index Fund (the "iShares S&P Funds") are not sponsored, endorsed, sold or promoted by Standard & Poor's or its affiliates. Standard & Poor's and its affiliates make no representation or warranty, express or implied, to the owners of shares of the iShares S&P Funds or

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any member of the public regarding the advisability of investing in securities generally or in iShares S&P Funds particularly or the ability of the Standard & Poor's Indexes to track general stock market performance. Standard & Poor's and its affiliates' only relationship to the iShares Trust (as used in these Disclaimers, the "Trust"), BTC and BFA is the licensing of certain trademarks and trade names of Standard & Poor's and its affiliates and of the Standard & Poor's Indexes, which are determined, composed and calculated by Standard & Poor's and its affiliates without regard to the Trust, BTC, BFA or the iShares S&P Funds. Standard & Poor's and its affiliates have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares S&P Funds into consideration in determining, composing or calculating the Standard & Poor's Indexes. Standard & Poor's and its affiliates are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares S&P Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares S&P Funds are to be converted into cash. Standard & Poor's and its affiliates have no obligation or liability in connection with the administration, marketing or trading of the iShares S&P Funds. Standard & Poor's and its affiliates do not guarantee the accuracy or the completeness of the Standard & Poor's Indexes or any data included therein and Standard & Poor's and its affiliates shall have no liability for any errors, omissions, or interruptions therein. Standard & Poor's and its affiliates make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares S&P Funds or any other person or entity from the use of the Standard & Poor's Indexes or any data included therein. Standard & Poor's and its affiliates make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the Standard & Poor's Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Standard & Poor's and its affiliates have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Standard & Poor's Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Russell Midcap Index Fund and the iShares Russell 2000 Index Fund (the "iShares Russell Funds") are not sponsored, endorsed, sold or promoted by Russell Investment Group. Russell Investment Group makes no representation or warranty, express or implied, to the owners of shares of the iShares Russell Funds or any member of the public regarding the advisability of investing in securities generally or in the iShares Russell Funds particularly or the ability of the Russell Indexes to track general stock market performance. Russell Investment Group's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Russell Investment Group's and of the Russell Indexes, which are determined, composed, and calculated by Russell Investment Group without regard to the Trust, BTC, BFA or the iShares Russell Funds. Russell Investment Group has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Russell Funds into consideration in determining, composing or calculating the Russell Indexes. Russell Investment Group is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares Russell Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Russell Funds are to be converted into cash. Russell Investment Group has no obligation or liability in connection with the administration, marketing or trading of the iShares Russell Funds. Russell Investment Group does not guarantee the accuracy or the completeness of the Russell Indexes or any data included therein and Russell Investment Group shall have no liability for any errors, omissions, or interruptions therein. Russell Investment Group makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Russell Funds or any other person or entity from the use of the Russell Indexes or any data included therein. Russell Investment Group makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Russell Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Russell Investment Group have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Russell Indexes or any data included therein, even if notified of the possibility of such damages.

The iShares Cohen & Steers Realty Majors Index Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers. Cohen & Steers makes no representation or warranty, express or implied, to the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares Cohen & Steers Realty Majors Index Fund particularly or the ability of the Cohen & Steers Realty Majors Index to track general stock market performance. Cohen & Steers' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Cohen & Steers and of the Cohen & Steers Realty Majors Index, which is determined, composed and calculated by Cohen & Steers without regard to the Trust, BTC, BFA or the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares Cohen & Steers Realty Majors Index Fund into consideration in determining, composing or calculating the Cohen & Steers Realty Majors Index. Cohen & Steers is not responsible for and has not participated in the determination of the prices and

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amount of shares of the iShares Cohen & Steers Realty Majors Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares Cohen & Steers Realty Majors Index Fund are to be converted into cash. Cohen & Steers has no obligation or liability in connection with the administration, marketing or trading of the iShares Cohen & Steers Realty Majors Index Fund. Cohen & Steers does not guarantee the accuracy or the completeness of the Cohen & Steers Realty Majors Index or any data included therein and Cohen & Steers shall have no liability for any errors, omissions, or interruptions therein. Cohen & Steers makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares Cohen & Steers Realty Majors Index Fund or any other person or entity from the use of the Cohen & Steers Realty Majors Index or any data included therein. Cohen & Steers makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Cohen & Steers Realty Majors Index or any data included therein. Without limiting any of the foregoing, in no event shall Cohen & Steers have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Cohen & Steers Realty Majors Index or any data included therein, even if notified of the possibility of such damages.

The iShares JPMorgan USD Emerging Markets Bond Fund is not sponsored, endorsed, sold or promoted by JPMorgan. JPMorgan makes no representation or warranty, express or implied, to the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares JPMorgan USD Emerging Markets Bond Fund particularly or the ability of the JPMorgan EMBI Global Core Index to track general bond market performance. JPMorgan's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of JPMorgan and of the JPMorgan EMBI Global Core Index which is determined, composed and calculated by JPMorgan without regard to the Trust, BTC, BFA or the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares JPMorgan USD Emerging Markets Bond Fund into consideration in determining, composing or calculating the JPMorgan EMBI Global Core Index. JPMorgan is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares JPMorgan USD Emerging Markets Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares JPMorgan USD Emerging Markets Bond Fund are to be converted into cash. JPMorgan has no obligation or liability in connection with the administration, marketing or trading of the iShares JPMorgan USD Emerging Markets Bond Fund. JPMorgan does not guarantee the accuracy or the completeness of the JPMorgan EMBI Global Core Index or any data included therein and JPMorgan shall have no liability for any errors, omissions, or interruptions therein. JPMorgan makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the JPMorgan USD Emerging Markets Bond Fund or any other person or entity from the use of the JPMorgan EMBI Global Core Index or any data included therein. JPMorgan makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the JPMorgan EMBI Global Core Index or any data included therein. Without limiting any of the foregoing, in no event shall JPMorgan have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the JPMorgan EMBI Global Core Index or any data included therein, even if notified of the possibility of such damages.

The iShares iBoxx $ High Yield Corporate Bond Fund is not sponsored, endorsed, sold or promoted by IIC. IIC makes no representation or warranty, express or implied, to the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any member of the public regarding the advisability of investing in securities generally or in the iShares iBoxx $ High Yield Corporate Bond Fund particularly or the ability of the iBoxx $ Liquid High Yield Index to track the general stock market performance. IIC's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of IIC and of the iBoxx $ Liquid High Yield Index which is determined, composed and calculated by IIC without regard to the Trust, BTC, BFA or the iShares iBoxx $ High Yield Corporate Bond Fund. IIC has no obligation to take the needs of BTC, BFA or the owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund into consideration in determining, composing or calculating the iBoxx $ Liquid High Yield Index. IIC is not responsible for and has not participated in the determination of the prices and amount of shares of the iShares iBoxx $ High Yield Corporate Bond Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares iBoxx $ High Yield Corporate Bond Fund are to be converted into cash. IIC has no obligation or liability in connection with the administration, marketing or trading of the iShares iBoxx $ High Yield Corporate Bond Fund. IIC does not guarantee the accuracy or the completeness of the iBoxx $ Liquid High Yield Index or any data included therein and IIC shall have no liability for any errors, omissions, or interruptions therein. IIC makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares iBoxx $ High Yield Corporate Bond Fund or any other person or entity from the use of the iBoxx $ Liquid High Yield Index or any data included therein. IIC makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the iBoxx $ Liquid High

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Yield Index or any data included therein. Without limiting any of the foregoing, in no event shall IIC have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the iBoxx $ Liquid High Yield Index or any data included therein, even if notified of the possibility of such damages.

The iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund is not sponsored, endorsed, sold or promoted by FTSE, the London Stock Exchange plc, Euronext N.V., the Financial Times Limited, EPRA or NAREIT (together, the "FTSE Licensor Parties"). None of the FTSE Licensor Parties makes any warranty or representation whatsoever, expressly or impliedly, either as to the results to be obtained from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index and/or the figure at which the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index stands at any particular time on any particular day or otherwise. The FTSE Licensor Parties' only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of the FTSE Licensor Parties and of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index, which is determined, composed and calculated by the FTSE Licensor Parties without regard to the Trust, BTC, BFA or the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties have no obligation to take the needs of BTC, BFA or the owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund into consideration in determining, composing or calculating the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index. The FTSE Licensor Parties are not responsible for and have not participated in the determination of the prices and amount of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund are to be converted into cash. The FTSE Licensor Parties have no obligation or liability in connection with the administration, marketing or trading of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund. The FTSE Licensor Parties do not guarantee the accuracy or the completeness of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein and the FTSE Licensor Parties shall have no liability for any errors, omissions, or interruptions therein. The FTSE Licensor Parties make no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund or any other person or entity from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. The FTSE Licensor Parties make no express or implied warranties and expressly disclaim all warranties of merchantability or fitness for a particular purpose or use with respect to the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein. Without limiting any of the foregoing, in no event shall the FTSE Licensor Parties have any liability for any special, punitive, indirect, or consequential damages (including lost profits) resulting from the use of the FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index or any data included therein, even if notified of the possibility of such damages.

The iShares MSCI Canada Index Fund, iShares MSCI EAFE Index Fund, iShares MSCI EAFE Small Cap Index Fund and iShares MSCI Emerging Markets Index Fund (the "iShares MSCI Index Funds") are not sponsored, endorsed, sold or promoted by MSCI or any affiliate of MSCI. Neither MSCI nor any other party makes any representation or warranty, express or implied, to the owners of the iShares MSCI Index Funds or any member of the public regarding the advisability of investing in funds generally or in the iShares MSCI Index Funds particularly or the ability of the MSCI Indexes to track general stock market performance. MSCI is the licensor of certain trademarks, servicemarks and trade names of MSCI and of the MSCI Indexes, which are determined, composed and calculated by MSCI without regard to the Trust, iShares, Inc., BTC, BFA or the iShares MSCI Index Funds. MSCI has no obligation to take the needs of BTC, BFA or the owners of the iShares MSCI Index Funds into consideration in determining, composing or calculating the MSCI Indexes. MSCI is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the iShares MSCI Index Funds to be issued or in the determination or calculation of the equation by which the iShares MSCI Index Funds are redeemable for cash. Neither MSCI nor any other party has any obligation or liability to owners of the iShares MSCI Index Funds in connection with the administration, marketing or trading of the iShares MSCI Index Funds. Although MSCI shall obtain information for inclusion in or for use in the calculation of the MSCI Indexes from sources which MSCI considers reliable, neither MSCI nor any other party guarantees the accuracy and/or the completeness of the MSCI Indexes or any data included therein. Neither MSCI nor any other party makes any warranty, express or implied, as to results to be obtained by a licensee, licensee's customers and counterparties, the owners of the iShares MSCI Index Funds or any other person or entity from the use of the MSCI Indexes or any data included hereunder or for any other use. Neither MSCI nor any other party makes any express or implied warranties, and MSCI hereby expressly disclaims all warranties of merchantability or fitness for a particular purpose with respect to the MSCI Indexes or any data included therein. Without limiting any of the foregoing, in no event shall MSCI or any other party have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

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The iShares Barclays 1-3 Year Credit Bond Fund, iShares Barclays 1-3 Year Treasury Bond Fund, iShares Barclays 3-7 Year Treasury Bond Fund, iShares Barclays 7-10 Year Treasury Bond Fund, iShares Barclays 10-20 Year Treasury Bond Fund, iShares Barclays 20+ Year Treasury Bond Fund, iShares Barclays Aggregate Bond Fund, iShares Barclays Credit Bond Fund, iShares Barclays Government/Credit Bond Fund, iShares Barclays Intermediate Credit Bond Fund, iShares Barclays Intermediate Government/Credit Bond Fund, iShares Barclays MBS Bond Fund, iShares Barclays Short Treasury Bond Fund and the iShares Barclays TIPS Bond Fund (collectively, the "Barclays Capital Funds") are not sponsored, endorsed, sold or promoted by Barclays Capital. Barclays Capital makes no representation or warranty, express or implied, to the owners of shares of the Barclays Capital Funds or any member of the public regarding the advisability of investing in securities generally or in the Barclays Capital Funds particularly or the ability of the Barclays Capital Funds' underlying indexes (the "Underlying Indexes") to track general bond market performance. Barclays Capital's only relationship to the Trust, BTC and BFA is the licensing of certain trademarks and trade names of Barclays Capital and of the Underlying Indexes, which are determined, composed and calculated by Barclays Capital without regard to the Trust, BTC, BFA or the Barclays Capital Funds. Barclays Capital has no obligation to take the needs of BTC, BFA or the owners of shares of the Barclays Capital Funds into consideration in determining, composing or calculating the Underlying Indexes. Barclays Capital is not responsible for and has not participated in the determination of the prices and amount of shares of the Barclays Capital Funds, or the timing of the issuance or sale of such shares or in the determination or calculation of the equation by which shares of the Barclays Capital Funds are to be converted into cash. Barclays Capital has no obligation or liability in connection with the administration, marketing or trading of the Barclays Capital Funds. Barclays Capital does not guarantee the accuracy or the completeness of the Underlying Indexes or any data included therein and Barclays Capital shall have no liability for any errors, omissions or interruptions therein. Barclays Capital makes no warranty, express or implied, as to results to be obtained by BTC, BFA, owners of shares of the Barclays Capital Funds or any other person or entity from the use of the Underlying Indexes or any data included therein. Barclays Capital makes no express or implied warranties and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Underlying Indexes or any data included therein. Without limiting any of the foregoing, in no event shall Barclays Capital have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) resulting from the use of the Underlying Indexes or any data included therein, even if notified of the possibility of such damages.

BFA does not guarantee the accuracy or the completeness of any underlying index or any data included therein and BFA shall have no liability for any errors, omissions, or interruptions therein.

BFA makes no warranty, express or implied, to the owners of shares of the iShares funds or to any other person or entity as to results to be obtained by the series of the Trust from the use of any underlying index or any data included therein. BFA makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to any underlying index or any data included therein. Without limiting any of the foregoing, in no event shall BFA have any liability for any special, punitive, direct, indirect, or consequential damages (including lost profits), even if notified of the possibility of such damages.

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APPENDIX A

DESCRIPTION OF CORPORATE BOND RATINGS

Ratings are generally given to securities at the time of issuance. While the rating agencies may from time to time revise such ratings, they undertake no obligation to do so, and the ratings given to securities at issuance do not necessarily represent ratings which would be given to these securities on a particular subsequent date.

Bonds which are unrated expose the investor to risks with respect to capacity to pay interest or repay principal which are similar to the risks of lower-rated speculative bonds. Evaluation of these securities is dependent on the investment adviser's judgment, analysis and experience in the evaluation of such bonds.

Investors should note that the assignment of a rating to a bond by a rating service may not reflect the effect of recent developments on the issuer's ability to make interest and principal payments.

The descriptions below relate to corporate bonds and are not applicable to the other types of securities.

MOODY'S INVESTORS SERVICE, INC.

AAA: Bonds which are rated Aaa are judged to be of the best quality. They carry the smallest degree of investment risk and are generally referred to as "gilt edged." Interest payments are protected by a large or by an exceptionally stable margin and principal is secure. While the various protective elements are likely to change, such changes as can be visualized are most unlikely to impair the fundamentally strong position of such issues.

AA: Bonds which are rated Aa are judged to be of high quality by all standards. Together with the Aaa group they comprise what are generally known as high grade bonds. They are rated lower than the best bonds because margins of protection may not be as large as in Aaa securities or fluctuation of protective elements may be of greater amplitude or there may be other elements present which make the long term risk appear somewhat larger than the Aaa securities.

A: Bonds which are rated A possess many favorable investment attributes and are to be considered as upper-medium-grade obligations. Factors giving security to principal and interest are considered adequate, but elements may be present which suggest a susceptibility to impairment sometime in the future.

BAA: Bonds which are rated Baa are considered as medium-grade obligations (I.E., they are neither highly protected nor poorly secured). Interest payments and principal security appear adequate for the present but certain protective elements may be lacking or may be characteristically unreliable over any great length of time. Such bonds lack outstanding investment characteristics and in fact have speculative characteristics as well.

BA: Bonds which are rated Ba are judged to have speculative elements; their future cannot be considered as well-assured. Often the protection of interest and principal payments may be very moderate and thereby not well safeguarded during other good and bad times over the future. Uncertainty of position characterizes bonds in this class.

B: Bonds which are rated B generally lack characteristics of the desirable investment. Assurance of interest and principal payments or of maintenance of other terms of the contract over any long period of time may be small.

CAA: Bonds which are rated Caa are of poor standing. Such issues may be in default or there may be present elements of danger with respect to principal or interest.

CA: Bonds which are rated Ca represent obligations which are speculative in a high degree. Such issues are often in default or have other marked shortcomings.

C: Bonds which are rated C are the lowest rated class of bonds, and issues so rated can be regarded as having extremely poor prospects of ever attaining any real investment standing.

ABSENCE OF RATING: Where no rating has been assigned or where a rating has been suspended or withdrawn, it may be for reasons unrelated to the quality of the issue.

Should no rating be assigned, the reason may be one of the following:

1. An application for rating was not received or accepted.

A-1

2. The issue or issuer belongs to a group of securities or companies that are not rated as a matter of policy.

3. There is a lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed, in which case the rating is not published in Moody's publications.

Suspension or withdrawal may occur if new and material circumstances arise, the effects of which preclude satisfactory analysis; if there is no longer available reasonable up-to-date data to permit a judgment to be formed; if a bond is called for redemption; or for other reasons.

NOTE: Moody's applies numerical modifiers, 1, 2, and 3 in each generic rating classification from Aa through Caa. The modifier 1 indicates that the security ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates that the issue ranks in the lower end of its generic rating category.

STANDARD & POOR'S

AAA: An obligation rated AAA has the highest rating assigned by S&P. The obligor's capacity to meet its financial commitment on the obligation is extremely strong.

AA: An obligation rated AA differs from the highest rated obligations only to a small degree. The obligor's capacity to meet its financial commitment is very strong.

A: An obligation rated A is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rated categories. However, the obligor's capacity to meet its financial commitment on the obligation is still strong.

BBB: An obligation rated BBB exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitment on the obligation.

Obligations rated BB, B, CCC, CC, and C are regarded as having significant speculative characteristics. BB indicates the least degree of speculation and C the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposures to adverse conditions.

BB: An obligation rated BB is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions that could lead to the obligor's inadequate capacity to meet its financial commitment on the obligation.

B: An obligation rated B is more vulnerable to nonpayment than obligations rated BB, but the obligor currently has the capacity to meet its financial commitment on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitment on the obligation.

CCC: An obligation rated CCC is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitment on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitment on the obligation.

CC: An obligation rated CC is currently highly vulnerable to nonpayment.

C: A 'C' rating is assigned to obligations that are currently highly vulnerable to nonpayment, obligations that have payment arrearages allowed by the terms of the documents, or obligations of an issuer that is the subject of a bankruptcy petition or similar action which have not experienced a payment default. Among others, the 'C' rating may be assigned to subordinated debt, preferred stock or other obligations on which cash payments have been suspended in accordance with the instrument's terms or when preferred stock is the subject of a distressed exchange offer, whereby some or all of the issue is either repurchased for an amount of cash or replaced by other instruments having a total value that is less than par.

D: An obligation rated 'D' is in payment default. The 'D' rating category is used when payments on an obligation, including a regulatory capital instrument, are not made on the date due even if the applicable grace period has not expired, unless S&P believes that such payments will be made during such grace period. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of similar action if payments on an obligation are jeopardized. An obligation's rating is

A-2

lowered to 'D' upon completion of a distressed exchange offer, whereby some or all of the issue is either repurchased for an amount of cash or replaced by other instruments having a total value that is less than par.

PLUS (+) OR MINUS (-): The ratings from AA to CCC may be modified by the addition of a plus or minus sign to show relative standing within the major rating categories.

NR: NR indicates no rating has been requested, that there is insufficient information on which to base a rating, or that S&P does not rate a particular type of obligation as a matter of policy.

COMMERCIAL PAPER

S&P's commercial paper rating is a current assessment of the likelihood of timely payment of debt considered short-term in the relevant market.

A-1: This highest category indicates that the degree of safety regarding timely payment is strong. Those issues determined to possess extremely strong safety characteristics are denoted with a plus (+) sign designation.

A-2: Capacity for timely payment on issues with this designation is satisfactory. However, the relative degree of safety is not as high as for issues designated "A-1."

A-3: Issues carrying this designation have adequate capacity for timely payment. They are, however, more vulnerable to the adverse effects of changes in circumstances than obligations carrying the higher designations.

FITCH RATINGS

INVESTMENT-GRADE BOND RATINGS

AAA: Highest credit quality. "AAA" ratings denote the lowest expectation of credit risk. They are assigned only in case of exceptionally strong capacity for timely payment of financial commitments. This capacity is highly unlikely to be adversely affected by foreseeable events.

AA: Very high credit quality. "AA" ratings denote a very low expectation of credit risk. They indicate very strong capacity for timely payment of financial commitments. This capacity is not significantly vulnerable to foreseeable events.

A: High credit quality. "A" ratings denote a low expectation of credit risk. The capacity for timely payment of financial commitments is considered strong. This capacity may, nevertheless, be more vulnerable to changes in circumstances or in economic conditions than is the case for higher ratings.

BBB: Good credit quality. "BBB" ratings indicate that there is currently a low expectation of credit risk. The capacity for timely payment of financial commitments is considered adequate, but adverse changes in circumstances and in economic conditions are more likely to impair this capacity. This is the lowest investment-grade category.

HIGH YIELD BOND RATINGS

BB: Speculative. "BB" ratings indicate that there is a possibility of credit risk developing, particularly as the result of adverse economic change over time; however, business or financial alternatives may be available to allow financial commitments to be met. Securities rated in this category are not investment-grade.

B: Highly speculative. "B" ratings indicate that significant credit risk is present, but a limited margin of safety remains. Financial commitments are currently being met; however, capacity for continued payment is contingent upon a sustained, favorable business and economic environment.

CCC, CC, AND C: High default risk. Default is a real possibility. Capacity for meeting financial commitments is solely reliant upon sustained, favorable business or economic developments. A "CC" rating indicates that default of some kind appears probable. "C" ratings signal imminent default.

Defaulted obligations typically are not assigned "D" ratings, but are instead rated in the "B" to "C" rating categories, depending upon their recovery prospects and other relevant characteristics. This approach better aligns obligations that have comparable overall expected loss but varying vulnerability to default and loss.

A-3

NOTES TO RATINGS

"+" or "-" may be appended to a rating to denote relative status within major rating categories. Such suffixes are not added to the "AAA" long-term rating category, to categories below "B," or to short-term ratings other than "F-l."

"NR" indicates that Fitch does not rate the issuer or issue in question.

"Withdrawn": A rating is withdrawn when Fitch deems the amount of information available to be inadequate for rating purposes, or when an obligation matures, is called, or refinanced.

A-4

APPENDIX B

Proxy Voting Policies

For The BlackRock-Advised Funds

December, 2009


Table of Contents

                                                                            Page
I.   INTRODUCTION                                                              1
II.  PROXY VOTING POLICIES...............................................      2
     A.  Boards of Directors.............................................      2
     B.  Auditors........................................................      2
     C.  Compensation and Benefits.......................................      2
     D.  Capital Structure...............................................      2
     E.  Corporate Charter and By-Laws...................................      3
     F.  Environmental and Social Issues.................................      3
IV.  REPORTS TO THE BOARD................................................      3


I. INTRODUCTION

The Trustees/Directors ("Directors") of the BlackRock-Advised Funds (the "Funds") have the responsibility for voting proxies relating to portfolio securities of the Funds, and have determined that it is in the best interests of the Funds and their shareholders to delegate that responsibility to BlackRock Advisors, LLC and its affiliated U.S. registered investment advisers ("BlackRock"), the investment adviser to the Funds, as part of BlackRock's authority to manage, acquire and dispose of account assets. The Directors hereby direct BlackRock to vote such proxies in accordance with this Policy, and any proxy voting guidelines that the Adviser determines are appropriate and in the best interests of the Funds' shareholders and which are consistent with the principles outlined in this Policy. The Directors have authorized BlackRock to utilize an unaffiliated third-party as its agent to vote portfolio proxies in accordance with this Policy and to maintain records of such portfolio proxy voting.

Rule 206(4)-6 under the Investment Advisers Act of 1940 requires, among other things, that an investment adviser that exercises voting authority over clients' proxy voting adopt policies and procedures reasonably designed to ensure that the adviser votes proxies in the best interests of clients, discloses to its clients information about those policies and procedures and also discloses to clients how they may obtain information on how the adviser has voted their proxies.

BlackRock has adopted separate but substantially similar guidelines and procedures that are consistent with the principles of this Policy. BlackRock's Corporate Governance Committee (the "Committee"), addresses proxy voting issues on behalf of BlackRock and its clients, including the Funds. The Committee is comprised of senior members of BlackRock's Portfolio Management and Administration Groups and is advised by BlackRock's Legal and Compliance Department.

BlackRock votes (or refrains from voting) proxies for each Fund in a manner that BlackRock, in the exercise of its independent business judgment, concludes are in the best economic interests of such Fund. In some cases, BlackRock may determine that it is in the best economic interests of a Fund to refrain from exercising the Fund's proxy voting rights (such as, for example, proxies on certain non-U.S. securities that might impose costly or time-consuming in-person voting requirements). With regard to the relationship between securities lending and proxy voting, BlackRock's approach is also driven by our clients' economic interests. The evaluation of the economic desirability of recalling loans involves balancing the revenue producing value of loans against the likely economic value of casting votes. Based on our evaluation of this relationship, BlackRock believes that the likely economic value of casting a vote generally is less than the securities lending income, either because the votes will not have significant economic consequences or because the outcome of the vote would not be affected by BlackRock recalling loaned securities in order to ensure they are voted. Periodically, BlackRock analyzes the process and benefits of voting proxies for securities on loan, and will consider whether any modification of its proxy voting policies or procedures are necessary in light of any regulatory changes.

BlackRock will normally vote on specific proxy issues in accordance with BlackRock's proxy voting guidelines. BlackRock's proxy voting guidelines provide detailed guidance as to how to vote proxies on certain important or commonly raised issues. BlackRock may, in the exercise of its business judgment, conclude that the proxy voting guidelines do not cover the specific matter upon which a proxy vote is requested, or that an exception to the proxy voting guidelines would be in the best economic interests of a Fund. BlackRock

1

votes (or refrains from voting) proxies without regard to the relationship of the issuer of the proxy (or any shareholder of such issuer) to the Fund, the Fund's affiliates (if any), BlackRock or BlackRock's affiliates. When voting proxies, BlackRock attempts to encourage companies to follow practices that enhance shareholder value and increase transparency and allow the market to place a proper value on their assets.

II. PROXY VOTING POLICIES

A. BOARDS OF DIRECTORS

The Funds generally support the board's nominees in the election of directors and generally supports proposals that strengthen the independence of boards of directors. As a general matter, the Funds believe that a company's board of directors (rather than shareholders) is most likely to have access to important, nonpublic information regarding a company's business and prospects, and is therefore best-positioned to set corporate policy and oversee management. The Funds therefore believe that the foundation of good corporate governance is the election of responsible, qualified, independent corporate directors who are likely to diligently represent the interests of shareholders and oversee management of the corporation in a manner that will seek to maximize shareholder value over time. In individual cases, consideration may be given to a director nominee's history of representing shareholder interests as a director of the company issuing the proxy or other companies, or other factors to the extent deemed relevant by the Committee.

B. AUDITORS

These proposals concern those issues submitted to shareholders related to the selection of auditors. As a general matter, the Funds believe that corporate auditors have a responsibility to represent the interests of shareholders and provide an independent view on the propriety of financial reporting decisions of corporate management. While the Funds anticipate that BlackRock will generally defer to a corporation's choice of auditor, in individual cases, consideration may be given to an auditors' history of representing shareholder interests as auditor of the company issuing the proxy or other companies, to the extent deemed relevant.

C. COMPENSATION AND BENEFITS

These proposals concern those issues submitted to shareholders related to management compensation and employee benefits. As a general matter, the Funds favor disclosure of a company's compensation and benefit policies and oppose excessive compensation, but believe that compensation matters are normally best determined by a corporation's board of directors, rather than shareholders. Proposals to "micro-manage" a company's compensation practices or to set arbitrary restrictions on compensation or benefits should therefore generally not be supported.

D. CAPITAL STRUCTURE

These proposals relate to various requests, principally from management, for approval of amendments that would alter the capital structure of a company, such as an increase in authorized shares. As a general matter, the Funds expect that BlackRock will support requests that it believes enhance the rights of common shareholders and oppose requests that appear to be unreasonably dilutive.

2

E. CORPORATE CHARTER AND BY-LAWS

These proposals relate to various requests for approval of amendments to a corporation's charter or by-laws. As a general matter, the Funds generally vote against anti-takeover proposals and proposals that would create additional barriers or costs to corporate transactions that are likely to deliver a premium to shareholders.

F. ENVIRONMENTAL AND SOCIAL ISSUES

These are shareholder proposals addressing either corporate social and environmental policies or requesting specific reporting on these issues. The Funds generally do not support proposals on social issues that lack a demonstrable economic benefit to the issuer and the Fund investing in such issuer. BlackRock seeks to make proxy voting decisions in the manner most likely to protect and promote the long-term economic value of the securities held in client accounts. We intend to support economically advantageous corporate practices while leaving direct oversight of company management and strategy to boards of directors. We seek to avoid micromanagement of companies, as we believe that a company's board of directors is best positioned to represent shareholders and oversee management on shareholders behalf. Issues of corporate social and environmental responsibility are evaluated on a case-by-case basis within this framework.

III. CONFLICTS MANAGEMENT

BlackRock maintains policies and procedures that are designed to prevent any relationship between the issuer of the proxy (or any shareholder of the issuer) and a Fund, a Fund's affiliates (if any), BlackRock or BlackRock's affiliates, from having undue influence on BlackRock's proxy voting activity. In certain instances, BlackRock may determine to engage an independent fiduciary to vote proxies as a further safeguard against potential conflicts of interest or as otherwise required by applicable law. The independent fiduciary may either vote such proxies or provide BlackRock with instructions as to how to vote such proxies. In the latter case, BlackRock votes the proxy in accordance with the independent fiduciary's determination.

IV. REPORTS TO THE BOARD

BlackRock will report to the Directors on proxy votes it has made on behalf of the Funds at least annually.

SAI-BR3-LP-0510


BLACKROCK FUNDS III

Statement of Additional Information

Dated May 1, 2010

FUND                                                                      TICKER
-----------------------------------------------------------------------  -------
BLACKROCK CASH FUNDS: INSTITUTIONAL
 Aon Captives Shares                                                      AOCXX
 Capital Shares                                                           BCIXX
 Institutional Shares                                                     BGIXX
 Premium Shares                                                           BSSXX
 Select Shares                                                            BGLXX
 Trust Shares                                                             BGTXX
BLACKROCK CASH FUNDS: PRIME
 Capital Shares                                                           BCPXX
 Institutional Shares                                                     BPIXX
 Premium Shares                                                           BPSXX
 Select Shares                                                            BPLXX
 Trust Shares                                                             BPEXX
BLACKROCK CASH FUNDS: GOVERNMENT
 Institutional Shares                                                     BVIXX
 Select Shares                                                            BVSXX
 Trust Shares                                                             BVTXX
BLACKROCK CASH FUNDS: TREASURY
 Capital Shares                                                           BCYXX
 Institutional Shares                                                     BRIXX
 Premium Shares                                                           BSPXX
 Select Shares                                                            BRSXX
 Trust Shares                                                             BYTXX

BlackRock Funds III (the "Trust") is an open-end, series management investment company. This combined Statement of Additional Information ("SAI") contains additional information about Premium, Capital, Institutional, Select and Trust Shares of the following series of the Trust - BlackRock Cash Funds: Prime, BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Treasury and Institutional, Select and Trust Shares of BlackRock Cash Funds: Government (each, a "Fund" and collectively, the "Funds"). This SAI also contains information about Aon Captives Shares of BlackRock Cash Funds: Institutional.

Each Fund seeks to achieve its investment objective by investing all of its assets in a master portfolio of Master Investment Portfolio ("MIP"). BlackRock Cash Funds: Institutional invests in Money Market Master Portfolio; BlackRock Cash Funds: Prime invests in Prime Money Market Master Portfolio; BlackRock Cash Funds: Government invests in Government Money Market Master Portfolio; and BlackRock Cash Funds: Treasury invests in Treasury Money Market Master Portfolio (each, a "Master Portfolio" and collectively, the "Master Portfolios"). MIP is an open-end, series management investment company. BlackRock Fund Advisors ("BFA" or the "Investment Adviser") (formerly, Barclays Global Fund Advisors) serves as investment adviser to each Master Portfolio. References to the investments, investment policies and risks of a Fund, unless otherwise indicated, should be understood to include references to the investments, investment policies and risks of such Fund's Master Portfolio.

This SAI is not a prospectus and should be read in conjunction with the current prospectuses for Premium, Capital, Institutional, Select and Trust Shares of the Funds, and Aon Captives Shares of BlackRock Cash Funds: Institutional, each dated May 1, 2010 (each, a "Prospectus" and collectively, the "Prospectuses"), and as amended from time to time. All terms used in this SAI that are defined in the Prospectuses have the meanings assigned in the Prospectuses. The audited financial statements for the Funds, which include the schedules of investments and report of the independent registered public accounting firm for the fiscal year ended December 31, 2009, are hereby incorporated by reference to the Funds' annual


reports, semi-annual reports and Prospectuses for Capital, Premium, Institutional, Select and Trust Shares of the Funds, and Aon Captives Shares of BlackRock Cash Funds: Institutional. Copies of the Prospectuses, annual reports and semi-annual reports may be obtained without charge by writing to BlackRock Funds III, c/o SEI Investments Distribution Co., One Freedom Valley Drive, Oaks, PA 19456, or by calling 1-800-768-2836 (toll-free).


TABLE OF CONTENTS

                                                                                    PAGE
                                                                                   -----
History of the Trust                                                                  1
Description of the Funds and their Investments and Risks                              1
   Investment Objectives and Policies                                                 1
   Master/Feeder Structure                                                            1
Investment Restrictions                                                               2
   Fundamental Investment Restrictions of the Funds                                   2
   Non-Fundamental Investment Restrictions of the Funds                               3
   Investments and Risks                                                              4
   Asset-Backed and Commercial Mortgage-Backed Securities                             5
   Bank Obligations                                                                   5
   Commercial Paper and Short-Term Corporate Debt Instruments                         6
   Floating-Rate and Variable-Rate Obligations                                        6
   Forward Commitments, When-Issued Purchases and Delayed-Delivery Transactions       7
   Funding Agreements                                                                 7
   Illiquid Securities                                                                7
   Investment Company Securities                                                      7
   Letters of Credit                                                                  7
   Loans of Portfolio Securities                                                      7
   Loan Participation Agreements                                                      8
   Medium-Term Notes                                                                  8
   Mortgage Pass-Through Securities                                                   8
   Mortgage Securities                                                                9
   Municipal Securities                                                              10
   Non-U.S. Obligations                                                              10
   Participation Interests                                                           11
   Repurchase Agreements                                                             11
   Restricted Securities                                                             11
   Unrated Investments                                                               11
   U.S. Government Obligations                                                       12
   U.S. Treasury Obligations                                                         12
Portfolio Holdings Information                                                       12
   Service Providers                                                                 12
   Third-Party Feeder Funds                                                          13
   Securities and Exchange Commission Filings                                        13
   Other Public Disclosure                                                           14
   Approved Recipients                                                               14

i

                                                                                    PAGE
                                                                                   -----
Management                                                                           14
   Share Ownership Information                                                       24
   Ownership of Securities of Certain Entities                                       25
   Compensation of Trustees                                                          25
   Master/Feeder Structure                                                           26
   Codes of Ethics                                                                   26
   Proxy Voting Policies of the Master Portfolios                                    26
   Shareholder Communication to the Board of Trustees                                27
Control Persons and Principal Holders of Securities                                  28
Investment Adviser and Other Service Providers                                       38
   Investment Adviser                                                                38
   Advisory Fees                                                                     38
   Administrator                                                                     39
   Distributor                                                                       40
   BlackRock Cash Funds: Institutional - Aon Captives Shares Distribution Plan       40
   Shareholder Servicing Agents                                                      41
   Custodian                                                                         43
   Transfer and Dividend Disbursing Agent                                            44
   Independent Registered Public Accounting Firm                                     44
   Legal Counsel                                                                     44
Determination of Net Asset Value                                                     44
Purchase, Redemption and Pricing of Shares                                           45
   Terms of Purchase and Redemption                                                  45
   In-Kind Purchases                                                                 45
   Suspension of Redemption Rights or Payment of Redemption Proceeds                 45
   Declaration of Trust Provisions Regarding Redemptions at Option of Trust          45
Portfolio Transactions                                                               45
   General                                                                           46
   Portfolio Turnover                                                                47
   Securities of Regular Broker-Dealers                                              47
Distributions and Taxes                                                              47
   Qualification as a Regulated Investment Company                                   48
   Excise Tax                                                                        49
   Capital Loss Carry-Forwards                                                       49
   Investment Through the Master Portfolios                                          49
   Taxation of Fund Investments                                                      50

ii

                                                                                    PAGE
                                                                                   -----
   Taxation of Distributions                                                         51
   Sales of Fund Shares                                                              51
   Foreign Taxes                                                                     51
   Federal Income Tax Rates                                                          52
   Back-Up Withholding                                                               52
   Tax-Deferred Plans                                                                52
   Foreign Shareholders                                                              52
   Recently Enacted Legislation                                                      53
Capital Stock                                                                        53
   Voting                                                                            54
   Dividends and Distributions                                                       54
   Master Portfolios                                                                 54
Additional Information on the Funds                                                  55
Financial Statements                                                                 55

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History of the Trust

The Trust was organized on December 4, 2001 as a statutory trust under the laws of the State of Delaware. On August 21, 2001, the Board of Directors of Barclays Global Investors Funds, Inc. (the "Company") approved a proposal to redomicile the Company from a Maryland corporation to a Delaware statutory trust (the "Redomiciling"). Shareholders of the Company approved the Redomiciling on November 16, 2001. The Trust was established with multiple series, including the Funds, corresponding to, and having identical designations as, the Company's series. The Redomiciling was effected on January 11, 2002, at which time the Trust assumed the operations of the Company and adopted the Company's registration statement. Shortly thereafter, the Company was dissolved.

The Trust's principal office is located at 400 Howard Street, San Francisco, CA 94105. Each Fund invests all of its assets in a Master Portfolio of MIP (as shown below), which has substantially the same investment objective, policies and restrictions as the related Fund.

FUND                                          MASTER PORTFOLIO IN WHICH THE FUND INVESTS
--------------------------------------------  -------------------------------------------
       BlackRock Cash Funds: Prime            Prime Money Market Master Portfolio
       BlackRock Cash Funds: Institutional    Money Market Master Portfolio
       BlackRock Cash Funds: Government       Government Money Market Master Portfolio
       BlackRock Cash Funds: Treasury         Treasury Money Market Master Portfolio

The Trust consists of multiple series, including the Funds. Each Fund issues shares in multiple classes, currently including SL Agency, Premium, Capital, Institutional, Select and Trust Shares, and with respect only to BlackRock Cash Funds: Institutional, Aon Captives Shares. SL Agency Shares are discussed in a separate Statement of Additional Information. On August 14, 2002, the Trust's board of trustees (the "Board of Trustees" or the "Board") approved changing the name of BlackRock Cash Funds: Institutional Distributor Shares to the "Aon Captives Shares."

On December 1, 2009, the Trust was renamed BlackRock Funds III and certain of its series were also renamed. Prime Money Market Fund was renamed BlackRock Cash Funds: Prime. Institutional Money Market Fund was renamed BlackRock Cash Funds: Institutional. Government Money Market Fund was renamed BlackRock Cash Funds: Government. Treasury Money Market Fund was renamed BlackRock Cash Funds:
Treasury.

On April 30, 2010, Capital and Premium Shares of BlackRock Cash Funds:
Government were closed.

Description of the Funds and their Investments and Risks

INVESTMENT OBJECTIVES AND POLICIES. The Trust is an open-end, series management investment company. Each Fund and Master Portfolio has adopted an investment objective and investment policies that may be fundamental or non-fundamental. Fundamental policies cannot be changed without approval by the holders of a majority (as defined in the Investment Company Act of 1940, as amended (the "1940 Act")) of the outstanding voting securities of such Fund or Master Portfolio, as the case may be. Non-fundamental policies may be changed without shareholder approval by the vote of a majority of the trustees of the Trust or of MIP (the "Trustees"), as the case may be, at any time.

The Funds and the Master Portfolios in which they invest are diversified funds as defined in the 1940 Act. Each Fund's investment objective is set forth in its Prospectuses. Each Fund's investment objective is non-fundamental and can be changed by the Trust's Board of Trustees without shareholder approval. The investment objective and investment policies of a Fund determine the types of portfolio securities in which the Fund invests, the degree of risk to which the Fund is subject and, ultimately, the Fund's performance. There can be no assurance that the investment objective of any Fund will be achieved.

MASTER/FEEDER STRUCTURE. Each Fund seeks to achieve its investment objective by investing all of its assets in the corresponding Master Portfolio of MIP. The Trust's Board of Trustees believes that under normal circumstances, none of the Funds or their shareholders will be adversely affected by investing Fund assets in a Master Portfolio. However, if a mutual

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fund or other investor redeems its interests from a Master Portfolio, the economic efficiencies (E.G., spreading fixed expenses over a larger asset base) that the Trust's Board of Trustees believes may be available through a Fund's investment in such Master Portfolio may not be fully achieved. In addition, although unlikely, the master/feeder structure may give rise to accounting or operational difficulties.

The fundamental policies of each Master Portfolio cannot be changed without approval by the holders of a majority (as defined in the 1940 Act) of a Master Portfolio's outstanding interests. Whenever a Fund, as an interestholder of a Master Portfolio, is requested to vote on any matter submitted to interestholders of the Master Portfolio, a Fund will either hold a meeting of its shareholders to consider such matters and cast its votes in proportion to the votes received from its shareholders (shares for which a Fund receives no voting instructions will be voted in the same proportion as the votes received from the other Fund shareholders) or cast its votes, as an interestholder of the Master Portfolio, in proportion to the votes received by the Master Portfolio from all other interestholders of the Master Portfolio.

Certain policies of the Master Portfolios that are non-fundamental may be changed by vote of a majority of MIP's Trustees without interestholder approval. If a Master Portfolio's investment objective or fundamental or non-fundamental policies are changed, a Fund may elect to change its objective or policies to correspond to those of the related Master Portfolio. Each Fund may redeem its interests from its Master Portfolio only if the Trust's Board of Trustees determines that such action is in the best interests of the Fund and its shareholders, for this or any other reason. Prior to such redemption, the Trust's Board of Trustees would consider alternatives, including whether to seek a new investment company with a matching investment objective in which to invest or retain its own investment adviser to manage the Fund's portfolio in accordance with its investment objective. In the latter case, a Fund's inability to find a substitute investment company in which to invest or equivalent management services could adversely affect shareholders' investments in the Fund.

Investment Restrictions

FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds are subject to the following investment restrictions, all of which are fundamental policies. Each Fund may not:

(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of the Fund's investments in that industry would equal or exceed 25% of the current value of the Fund's total assets, provided that this restriction does not limit the Fund's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities; and further provided that, with respect to BlackRock Cash Funds: Prime and BlackRock Cash Funds:
Institutional, the Fund reserves the right to concentrate in the obligations of domestic banks (as such term is interpreted by the Securities and Exchange Commission ("SEC") or its staff);

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of the Fund's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the Fund's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit the Fund's cash or cash items, investments in U.S. government securities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with the Fund's investment program may be deemed to be an underwriting; and provided further, that the purchase by the Fund of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Fund shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the Fund from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business); and

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(7) Purchase or sell commodities, provided that: (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments.

With respect to the fundamental policy relating to concentration set forth in paragraph (1) above, the 1940 Act does not define what constitutes "concentration" in an industry and it is possible that interpretations of concentration could change in the future. Accordingly, the policy in paragraph
(1) above will be interpreted to refer to concentration as that term may be interpreted from time to time. In this respect, and in accordance with SEC staff interpretations, the ability of BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional to concentrate in the obligations of domestic banks means that these Funds are permitted to invest, without limit, in bankers' acceptances, certificates of deposit and other short-term obligations issued by
(a) U.S. banks, (b) U.S. branches of foreign banks (in circumstances in which the U.S. branches of foreign banks are subject to the same regulation as U.S. banks), and (c) foreign branches of U.S. banks (in circumstances in which the Funds will have recourse to the U.S. bank for the obligations of the foreign branch).

The Trust has delegated to BFA the ability to determine the methodology used by the Master Portfolios to classify issuers by industry. BFA defines industries and classifies each issuer according to the industry in which the issuer conducts its principal business activity pursuant to its proprietary industry classification system. In classifying companies by industry, BFA may draw on its credit, research and investment resources and those of BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) or its other affiliates, and BFA may (but need not) consider classifications by third-party industry classification systems. BFA believes that its system is reasonably designed so that issuers with primary economic characteristics that are materially the same are classified in the same industry. For example, asset-backed commercial paper may be classified in an industry based on the nature of the assets backing the commercial paper, and foreign banks may be classified in an industry based on the region in which they do business if BFA has determined that the foreign banks within that industry have primary economic characteristics that are materially the same.

A fund that invests a significant percentage of its total assets in a single industry may be particularly susceptible to adverse events affecting that industry and may be more risky than a fund that does not concentrate in an industry. To the extent BFA's classification system results in broad categories, concentration risk may be decreased. On the other hand, to the extent it results in narrow categories, concentration risk may be increased.

With respect to paragraph (3) above, the 1940 Act currently allows each Fund to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of each Fund's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds have adopted the following investment restrictions as non-fundamental policies. These restrictions may be changed without shareholder approval by a majority of the Trustees of the Trust at any time.

(1) Each Fund may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder;

(2) Each Fund may not invest more than 10% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others,
(i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale, (ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each Fund may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of a Fund's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked-to-market daily; and

(4) Each Fund may not make investments for the purpose of exercising control or management; provided that a Fund may invest all of its assets in a diversified, open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Fund, without regard to the limitations set forth in this paragraph.

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BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury have adopted the following investment restriction as an additional non-fundamental policy:

Each Fund will provide shareholders with at least 60 days' notice of any change to the Fund's non-fundamental policy to invest at least 80% of the Fund's assets in the types of securities described in the Fund's principal investment strategies. The notice will be provided in plain English in a separate written document, and will contain the following prominent statement or similar statement in bold-face type: "Important Notice Regarding Change in Investment Policy." This statement will appear on both the notice and the envelope in which it is delivered, unless it is delivered separately from other communications to investors, in which case the statement will appear either on the notice or the envelope in which the notice is delivered.

BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional have adopted the following investment restrictions as additional non-fundamental policies:

(1) Each Fund may not purchase interests, leases, or limited partnership interests in oil, gas, or other mineral exploration or development programs.

(2) Each Fund may not write, purchase or sell puts, calls, straddles, spreads, warrants, options or any combination thereof, except that the Fund may purchase securities with put rights in order to maintain liquidity.

(3) Each Fund may not purchase securities on margin (except for short-term credits necessary for the clearance of transactions) or make short sales of securities.

Notwithstanding any other investment policy or restriction (whether or not fundamental), each Fund may (and does) invest all of its assets in the securities of a single open-end management investment company with substantially the same fundamental investment objective, policies and limitations as the Fund.

The fundamental and non-fundamental investment restrictions for each Master Portfolio are identical to the corresponding investment restrictions described above for the Fund that invests in such Master Portfolio, except that, in the case of the Government and Treasury Money Market Master Portfolios, industry concentration restriction (1), proviso (iii) does not limit investments in repurchase agreements collateralized by securities issued or guaranteed by the U.S., its agencies or instrumentalities.

INVESTMENTS AND RISKS. To the extent set forth in this SAI, each Fund, through its investment in the corresponding Master Portfolio, may invest in the securities described below. To avoid the need to refer to both the Funds and the Master Portfolios in every instance, the following sections generally refer to the Funds only.

The assets of each Fund consist only of obligations maturing within 397 calendar days from the date of acquisition (as determined in accordance with the regulations of the SEC), and the dollar-weighted average maturity of a Fund may not exceed 90 days. Under normal circumstances, BlackRock Cash Funds:
Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury expect to maintain a dollar-weighted average portfolio maturity of 60 days or less. The securities in which each Fund invests may not yield as high a level of current income as may be achieved from securities with less liquidity and less safety. There can be no assurance that a Fund's investment objective will be realized as described in its Prospectuses.

Under normal circumstances, BlackRock Cash Funds: Treasury invests at least 80% of its assets in U.S. Treasury obligations, repurchase agreements with regard to U.S. Treasury obligations and/or other money market funds that have substantially the same investment objective and strategies as the Fund. Under normal circumstances, BlackRock Cash Funds: Government invests at least 80% of its assets in certain obligations of the U.S. government, its agencies and instrumentalities, repurchase agreements with regard to such obligations and/or other money market funds that have substantially the same investment objective and strategies as the Fund. BlackRock Cash Funds: Treasury and BlackRock Cash Funds: Government may each invest up to 20% of their respective assets in any securities and other instruments in which money market funds are permitted to invest in accordance with Rule 2a-7 of the 1940 Act. Practices described below relating to illiquid securities, investment company securities, loans of portfolio securities and repurchase agreements also apply to BlackRock Cash Funds: Treasury and BlackRock Cash Funds: Government.

BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional may invest in any of the instruments or engage in any practice described below.

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ASSET-BACKED AND COMMERCIAL MORTGAGE-BACKED SECURITIES. BlackRock Cash Funds:
Institutional and BlackRock Cash Funds: Prime may invest in asset-backed and commercial mortgage-backed securities. Asset-backed securities are securities backed by installment contracts, credit-card receivables or other assets. Commercial mortgage-backed securities are securities backed by commercial real estate properties. Both asset-backed and commercial mortgage-backed securities represent interests in "pools" of assets in which payments of both interest and principal on the securities are made on a regular basis. The payments are, in effect, "passed through" to the holder of the securities (net of any fees paid to the issuer or guarantor of the securities). The average life of asset-backed and commercial mortgage-backed securities varies with the maturities of the underlying instruments and, as a result of prepayments, can often be shorter or longer (as the case may be) than the original maturity of the assets underlying the securities. For this and other reasons, an asset-backed and commercial mortgage-backed security's stated maturity may be shortened or extended, and the security's total return may be difficult to predict precisely. The Funds may invest in such securities up to the limits prescribed by Rule 2a-7 and other provisions of or under the 1940 Act. Changes in liquidity of these securities may result in significant, rapid and unpredictable changes in prices for credit-linked securities. Also see "Mortgage Pass-Through Securities" and "Mortgage Securities."

BANK OBLIGATIONS. BlackRock Cash Funds: Institutional and BlackRock Cash Funds:
Prime may invest in bank obligations, including certificates of deposit ("CDs"), time deposits, bankers' acceptances and other short-term obligations of domestic banks, foreign subsidiaries of domestic banks, foreign branches of domestic banks, and domestic branches of foreign banks, domestic savings and loan associations and other banking institutions. Certain bank obligations may benefit from existing or future governmental debt guarantee programs.

CDs are negotiable certificates evidencing the obligation of a bank to repay funds deposited with it for a specified period of time.

Time deposits ("TDs") are non-negotiable deposits maintained in a banking institution for a specified period of time at a stated interest rate. TDs that may be held by the Funds will not benefit from insurance from the Bank Insurance Fund or the Savings Association Insurance Fund administered by the Federal Deposit Insurance Corporation ("FDIC").

Bankers' acceptances are credit instruments evidencing the obligation of a bank to pay a draft drawn on it by a customer. These instruments reflect the obligation both of the bank and of the drawer to pay the face amount of the instrument upon maturity. The other short-term obligations may include uninsured, direct obligations bearing fixed-, floating- or variable- interest rates.

Domestic commercial banks organized under federal law are supervised and examined by the Comptroller of the Currency and are required to be members of the Federal Reserve System and to have their deposits insured by the FDIC. Domestic banks organized under state law are supervised and examined by state banking authorities and are members of the Federal Reserve System only if they elect to join. In addition, state banks whose CDs may be purchased by the Funds are insured by the FDIC (although such insurance may not be of material benefit to a Fund, depending on the principal amount of the CDs of each bank held by the Fund) and are subject to federal examination and to a substantial body of federal law and regulation. As a result of federal or state laws and regulations, domestic branches of domestic banks whose CDs may be purchased by the Funds generally are required, among other things, to maintain specified levels of reserves, are limited in the amounts that they can loan to a single borrower and are subject to other regulations designed to promote financial soundness. However, not all of such laws and regulations apply to the foreign branches of domestic banks.

Obligations of foreign branches of domestic banks, foreign subsidiaries of domestic banks and domestic and foreign branches of foreign banks, such as CDs and TDs, may be general obligations of the parent banks in addition to the issuing branch, or may be limited by the terms of a specific obligation and/or governmental regulation. Such obligations are subject to different risks than are those of domestic banks. These risks include foreign economic and political developments, foreign governmental restrictions that may adversely affect payment of principal and interest on the obligations, foreign exchange controls and foreign withholding and other taxes on amounts realized on the obligations. These foreign branches and subsidiaries are not necessarily subject to the same or similar regulatory requirements that apply to domestic banks, such as mandatory reserve requirements, loan limitations, and accounting, auditing and financial record keeping requirements. In addition, less information may be publicly available about a foreign branch of a domestic bank or about a foreign bank than about a domestic bank.

Obligations of U.S. branches of foreign banks may be general obligations of the parent bank in addition to the issuing branch, or may be limited by the terms of a specific obligation or by federal or state regulation, as well as governmental action in the country in which the foreign bank has its head office. A domestic branch of a foreign bank with assets in excess of $1 billion

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may be subject to reserve requirements imposed by the Federal Reserve System or by the state in which the branch is located if the branch is licensed in that state.

In addition, federal branches licensed by the Comptroller of the Currency and branches licensed by certain states may be required to: (1) pledge to the appropriate regulatory authority, by depositing assets with a designated bank within the relevant state, a certain percentage of their assets as fixed from time to time by such regulatory authority; and (2) maintain assets within the relevant state in an amount equal to a specified percentage of the aggregate amount of liabilities of the foreign bank payable at or through all of its agencies or branches within the state.

COMMERCIAL PAPER AND SHORT-TERM CORPORATE DEBT INSTRUMENTS. The Funds may invest in commercial paper (including variable amount master demand notes), which consists of short-term, unsecured promissory notes issued by corporations to finance short-term credit needs. Commercial paper is usually sold on a discount basis and usually has a maturity at the time of issuance not exceeding nine months. Variable amount master demand notes are demand obligations that permit a Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between a Fund, as lender, and the borrower. The interest on these notes varies pursuant to the arrangements between the Fund and the borrower. Both the borrower and the Fund have the right to vary the amount of the outstanding indebtedness on the notes. BFA monitors on an ongoing basis the ability of an issuer of a demand instrument to pay principal and interest on demand.

The Funds also may invest in non-convertible corporate debt securities (E.G., bonds and debentures) with not more than thirteen months remaining to maturity at the date of settlement. A Fund will invest only in such corporate bonds and debentures that are deemed appropriate by BFA in accordance with Rule 2a-7 under the 1940 Act. Subsequent to its purchase by a Fund, an issue of securities may cease to be rated or its rating may be reduced below the minimum rating required for purchase by the Fund. BFA will consider such an event in determining whether the Fund should continue to hold the obligation. To the extent the Fund continues to hold the obligation, it may be subject to additional risk of default.

ASSET-BACKED COMMERCIAL PAPER. A Fund may also invest in asset-backed commercial paper. Asset-backed commercial paper is a type of securitized commercial paper product used to fund purchases of financial assets by special purpose finance companies called conduits. The financial assets may include assets such as pools of trade receivables, car loans and leases, and credit card receivables, among others. Asset-backed commercial paper is typically tracked and rated by one or more credit rating agencies. Some asset-backed commercial paper programs maintain a back-up liquidity facility provided by a major bank, which is intended to be used if the issuer is unable to issue new asset-backed commercial paper.

FLOATING-RATE AND VARIABLE-RATE OBLIGATIONS. The Funds may purchase debt instruments with interest rates that are periodically adjusted at specified intervals or whenever a benchmark rate or index changes. The floating-rate and variable-rate instruments that the Funds may purchase include certificates of participation in such instruments. The interest rate adjustments generally limit the increase or decrease in the amount of interest received on the debt instruments. Floating-rate and variable-rate instruments are subject to interest rate risk and credit risk.

The Funds may purchase floating-rate and variable-rate demand notes and bonds, which are obligations ordinarily having stated maturities in excess of thirteen months, but which permit the holder to demand payment of principal at any time, or at specified intervals not exceeding 397 days, as defined in accordance with Rule 2a-7 and the 1940 Act. Variable-rate demand notes including master demand notes are demand obligations that permit a Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between a Fund, as lender, and the borrower. The interest rates on these notes fluctuate from time to time. The issuer of such obligations ordinarily has a corresponding right, after a given period, to prepay in its discretion the outstanding principal amount of the obligations plus accrued interest upon a specified number of days' notice to the holders of such obligations. The interest rate on a floating-rate demand obligation is based on a known lending rate, such as a bank's prime rate, and is adjusted automatically each time such rate is adjusted. The interest rate on a variable-rate demand obligation is adjusted automatically at specified intervals. Frequently, such obligations are secured by letters of credit or other credit support arrangements provided by banks.

These obligations are direct lending arrangements between the lender and borrower. There may not be an established secondary market for these obligations, although they are redeemable at face value. Accordingly, where these obligations are not secured by letters of credit or other credit support arrangements, a Fund's right to redeem is dependent on the ability of the borrower to pay principal and interest on demand. Such obligations frequently are not rated by credit rating agencies and a Fund may invest in obligations that are not so rated only if BFA determines that at the time of investment the obligations are of comparable quality to the other obligations in which a Fund may invest. BFA considers on an ongoing basis the creditworthiness of the issuers of the floating-rate and variable-rate demand obligations in a Fund's portfolio.

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FORWARD COMMITMENTS, WHEN-ISSUED PURCHASES AND DELAYED-DELIVERY TRANSACTIONS. The Funds may purchase or sell securities on a when-issued or delayed-delivery basis and make contracts to purchase or sell securities for a fixed price at a future date beyond customary settlement time. Securities purchased or sold on a when-issued, delayed-delivery or forward commitment basis involve a risk of loss if the value of the security to be purchased declines or the value of the security to be sold increases before the settlement date. Although the Funds will generally purchase securities with the intention of acquiring them, the Funds may dispose of securities purchased on a when-issued, delayed-delivery or a forward commitment basis before settlement when deemed appropriate by BFA.

FUNDING AGREEMENTS. The Funds may invest in short-term funding agreements. A funding agreement is a contract between an issuer and a purchaser that obligates the issuer to pay a guaranteed rate of interest on a principal sum deposited by the purchaser. Funding agreements will also guarantee the return of principal and may guarantee a stream of payments over time. A funding agreement has a fixed maturity and may have either a fixed-, variable- or floating-interest rate that is based on an index and guaranteed for a fixed time period. The Funds will purchase short-term funding agreements only from banks and insurance companies. The Funds may also purchase Guaranteed Investment Contracts.

The secondary market, if any, for these funding agreements is limited; thus, such investments purchased by the Funds may be treated as illiquid. If a funding agreement is determined to be illiquid it will be valued at its fair market value as determined by procedures approved by the Board of Trustees. Valuation of illiquid indebtedness involves a greater degree of judgment in determining the value of each Fund's assets than if the value were based on available market quotations.

ILLIQUID SECURITIES. Each Fund may invest in securities as to which a liquid trading market does not exist, provided such investments are consistent with its investment objective. Such securities may include securities that are not readily marketable, such as privately issued securities and other securities that are subject to legal or contractual restrictions on resale, floating-rate and variable-rate demand obligations as to which the Fund cannot exercise a demand feature on not more than seven days' notice and as to which there is no secondary market, and repurchase agreements providing for settlement more than seven days after notice.

INVESTMENT COMPANY SECURITIES. Each Fund may invest in shares of open-end investment companies, including investment companies that are affiliated with the Funds and BFA, that invest exclusively in high-quality short-term securities to the extent permitted under the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder; provided, however, that a Fund, if it has knowledge that its beneficial interests are purchased by another investment company investor pursuant to Section 12(d)(1)(G) of the 1940 Act, will not acquire any securities of registered open-end management investment companies or registered unit investment trusts in reliance on
Section 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act. Other investment companies in which a Fund invests can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Fund. A Fund may also purchase shares of exchange listed closed-end funds to the extent permitted under the 1940 Act. Under the 1940 Act, a Fund's investment in investment companies is limited to, subject to certain exceptions, (i) 3% of the total outstanding voting stock of any one investment company, (ii) 5% of the Fund's total assets with respect to any one investment company, and (iii) 10% of the Fund's total assets with respect to investment companies in the aggregate. To the extent allowed by law or regulation, each Fund may invest its assets in securities of investment companies that are money market funds, including those advised by BFA or otherwise affiliated with BFA, in excess of the limits discussed above.

LETTERS OF CREDIT. Certain of the debt obligations (including municipal securities, certificates of participation, commercial paper and other short-term obligations) that the Funds may purchase may be backed by an unconditional and irrevocable letter of credit issued by a bank, savings and loan association or insurance company that assumes the obligation for payment of principal and interest in the event of default by the issuer. Only banks, savings and loan associations and insurance companies that, in the opinion of BFA, are of comparable quality to issuers of other permitted investments of the Funds may be used for letter of credit-backed investments.

LOANS OF PORTFOLIO SECURITIES. Each Fund may lend portfolio securities to certain creditworthy borrowers, including borrowers affiliated with BFA. The borrowers provide collateral that is maintained in an amount at least equal to the current market value of the securities loaned plus any accrued interest. A Fund may terminate a loan at any time and obtain the return of the securities loaned. Each Fund is entitled to receive the value of any interest or cash or non-cash distributions paid on the loaned securities.

With respect to loans that are collateralized by cash, the borrower will be entitled to receive a fee based on the amount of cash collateral. The Fund is compensated by the difference between the amount earned on the reinvestment of cash

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collateral and the fee paid to the borrower. In the case of collateral other than cash, the Fund is compensated by a fee paid by the borrower equal to a percentage of the market value of the loaned securities. Any cash collateral may be reinvested in certain short-term instruments either directly on behalf of each lending Fund or through one or more joint accounts or money market funds, including those managed by BFA; such reinvestments are subject to investment risk.

Securities lending involves exposure to certain risks, including operational risk (I.E., the risk of losses resulting from problems in the settlement and accounting process), "gap" risk (I.E., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Fund has agreed to pay a borrower), and credit, legal, counterparty and market risk. In the event a borrower does not return a Fund's securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated plus the transaction costs incurred in purchasing replacement securities.

A Fund may pay a portion of the interest or fees earned from securities lending to a borrower as described above, and to a securities lending agent who administers the lending program in accordance with guidelines approved by the Trust's Board of Trustees. BTC acts as securities lending agent for the Funds subject to the overall supervision of BFA. BTC receives a portion of the revenues generated by securities lending activities as compensation for its services in this regard.

LOAN PARTICIPATION AGREEMENTS. Each Fund may purchase interests in loan participations that typically represent direct participation in a loan to a corporate borrower, and generally are offered by an intermediary bank or other financial institution or lending syndicate. Under these loan participation arrangements, a Fund will have the right to receive payments of principal, interest and any fees to which it is entitled from the bank selling the loan participation upon receipt by the bank of the payments from the borrower. The borrower in the underlying loan will be deemed to be the issuer of the participation interest except to the extent the Fund derives its rights from the intermediary bank that sold the loan participation. Such loans must be made to issuers in whose obligations the Funds may invest.

Because the bank issuing the loan participation does not guarantee the participation in any way, the participation is subject to the credit risks associated with the underlying corporate borrower. In addition, it may be necessary under the terms of the loan participation for the Funds to assert their rights against the underlying corporate borrower in the event that the underlying corporate borrower should fail to pay principal and interest when due. Thus, the Funds could be subject to delays, expenses, and risks that are greater than those that would have been involved if the Funds had purchased a direct obligation of the borrower. Moreover, under the terms of the loan participation, the Funds may be regarded as creditors of the issuing bank (rather than of the underlying corporate borrower), so that the Funds also may be subject to the risk that the issuing bank may become insolvent. Further, in the event of the bankruptcy or insolvency of the corporate borrower, the loan participation might be subject to certain defenses that can be asserted by the borrower as a result of improper conduct by the issuing bank.

The secondary market, if any, for these loan participation interests is limited; thus, such participations purchased by the Funds may be treated as illiquid. If a loan participation is determined to be illiquid, it will be valued at its fair market value as determined by procedures approved by the Board of Trustees. Valuation of illiquid indebtedness involves a greater degree of judgment in determining the value of each Fund's assets than if the value were based on available market quotations.

MEDIUM-TERM NOTES. A Fund may invest in medium-term notes that have remaining maturities that are consistent with the conditions of Rule 2a-7. Medium-term notes are a form of corporate debt financing. They are often issued on a regular or continuous basis without the requirement to produce a new set of legal documentation at the time of each issuance. Medium-term notes have maturities that range widely based on the needs of the issuer; although they most often mature between nine months and ten years, they may have longer maturities.

MORTGAGE PASS-THROUGH SECURITIES. Each Fund may invest in mortgage pass-through securities, which are a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. government entities or U.S. government-sponsored enterprises including: the Government National Mortgage Association ("Ginnie Mae"), the Federal National Mortgage Association ("Fannie Mae") and the Federal Home Loan Mortgage Corporation. In the basic mortgage pass-through structure, mortgages with similar issuer, term and coupon characteristics are collected and aggregated into a "pool" consisting of multiple mortgage loans. The pool is assigned a CUSIP number and undivided interests in the pool are traded and sold as pass-through securities. The holder of the security is entitled to a PRO RATA share of principal and interest payments (including unscheduled prepayments) from the pool of mortgage loans.

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The Funds may, to the extent permitted by Rule 2a-7 under the 1940 Act, invest in mortgage securities issued by private non-government entities. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities or government-sponsored enterprises. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information enabling investors to evaluate the practices of these mortgage originators.

In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities issued by government entities, government-sponsored enterprises or non-government entities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Should the government adopt new laws providing mortgage borrowers with additional rights to renegotiate interest rates, alter terms, obtain orders to modify their mortgage terms through the bankruptcy courts, or otherwise allow borrowers to modify or restructure existing mortgages, this may negatively impact mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate. Non-government mortgage securities may be subject to greater price changes than government issues.

An investment in a specific pool of pass-through securities requires an analysis of the specific prepayment risk of mortgages within the covered pool (since mortgagors typically have the option to prepay their loans). The level of prepayments on a pool of mortgage securities is difficult to predict and can impact the subsequent cash flows and value of the mortgage pool. In addition, when trading specific mortgage pools, precise execution, delivery and settlement arrangements must be negotiated for each transaction. These factors combine to make trading in mortgage pools somewhat cumbersome. For these and other reasons, the Funds may obtain exposure to U.S. agency mortgage pass-through securities primarily through the use of "to-be-announced" or "TBA" transactions. "TBA" refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Most transactions in mortgage pass-through securities occur through the use of TBA transactions. TBA transactions generally are conducted in accordance with widely-accepted guidelines that establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined two days prior to the settlement date. The Funds may use TBA transactions in several ways. For example, the Funds may regularly enter into TBA agreements and "roll over" such agreements prior to the settlement date stipulated in such agreements. This type of TBA transaction is sometimes known as a "TBA roll." In a TBA roll, a Fund generally will sell the obligation to purchase the pools stipulated in the TBA agreement prior to the stipulated settlement date and will enter into a new TBA agreement for future delivery of pools of mortgage pass-through securities. In addition, a Fund may enter into TBA agreements and settle such transactions on the stipulated settlement date by accepting actual receipt or delivery of the pools of mortgage pass-through securities stipulated in the TBA agreement. Default by or bankruptcy of a counterparty to a TBA transaction would expose a Fund to possible loss because of adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction. To minimize this risk, the Funds will enter into TBA transactions only with established counterparties (such as major broker-dealers) and BFA will monitor the creditworthiness of such counterparties. The use of TBA rolls may cause the Funds to experience higher portfolio turnover and to pay higher capital gain distributions, which may result in larger amounts of short-term capital gains allocable to shareholders.

MORTGAGE SECURITIES. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may invest in mortgage securities. Mortgage securities are issued by government and non-government entities such as banks, mortgage lenders, or other institutions. A mortgage security is an obligation of the issuer that is backed by a mortgage or pool of mortgages or a direct interest in an underlying pool of mortgages. Some mortgage securities, such as collateralized mortgage obligations, make payments of both principal and interest at a range of specified intervals; others make semi-annual interest payments at a pre-determined rate and repay principal at maturity (like a typical bond). Mortgage securities are based on different types of mortgages, including those on commercial real estate or residential properties. Stripped mortgage securities are created when the interest and principal components of a mortgage security are separated and sold as individual securities. In the

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case of a stripped mortgage security, the holder of the "principal-only" security (PO) receives the principal payments made by the underlying mortgage, while the holder of the "interest-only" security (IO) receives interest payments from the same underlying mortgage.

The value of mortgage securities may change due to shifts in the market's perception of the creditworthiness of issuers and changes in interest rates or liquidity. The value of some mortgage-backed securities may be particularly sensitive to changes in prevailing interest rates. In addition, regulatory or tax changes may adversely affect the mortgage securities market as a whole. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information required to evaluate the practices of these mortgage originators. In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate.

Non-government mortgage securities may be subject to greater price changes than government issues. Mortgage securities are subject to prepayment risk. Prepayment risk is the risk that early principal payments made on the underlying mortgages, usually in response to a reduction in interest rates, will result in the return of principal to the investor, causing the investor to be invested subsequently at a lower current interest rate. Alternatively, in a rising interest rate environment, mortgage security values may be adversely affected when prepayments on underlying mortgages do not occur as anticipated, resulting in the extension of the security's effective maturity and the related increase in interest rate sensitivity of a longer-term instrument. The prices of stripped mortgage securities tend to be more volatile in response to changes in interest rates than those of non-stripped mortgage securities. In addition, although mortgages and mortgage-related securities are generally supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Also see "Asset-Backed and Commercial Mortgage-Backed Securities" and "Mortgage Pass-Through Securities."

MUNICIPAL SECURITIES. Each Fund may invest in municipal securities. Municipal securities are generally issued by states and local governments and their agencies, authorities and other instrumentalities. Municipal bonds are subject to interest rate, credit and market risk. The ability of a municipal security issuer to make payments on that security could be affected by litigation, legislation or other political events or the bankruptcy of the issuer. Lower-rated municipal bonds are subject to greater credit and market risk than higher quality municipal bonds. Municipal securities in which the Funds may invest include, but are not limited to, municipal lease obligations and securities issued by entities whose underlying assets are municipal bonds. There is no guarantee that income from municipal securities will be exempt from federal and state taxes. Changes in federal or state tax treatment of municipal securities may make municipal securities less attractive as investments or cause them to lose value.

Each Fund will invest in high-quality, long-term municipal bonds, municipal notes and short-term commercial paper with remaining maturities not exceeding 397 calendar days.

NON-U.S. OBLIGATIONS. The Funds may invest in certain securities of non-U.S. issuers. Investing in the securities of non-U.S. issuers involves special risks and considerations not typically associated with investing in U.S. issuers. These include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or potentially confiscatory taxation, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, potential restrictions of the flow of international capital and transaction costs of foreign currency conversions. Non-U.S. issuers may be subject to less governmental regulation than U.S. issuers. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy with respect to growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions. The Funds may invest in U.S. dollar-denominated short-term obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions, agencies or instrumentalities that are determined by BFA to be of comparable quality to the other obligations in which the Funds may invest. The Funds may also invest in debt obligations of supranational entities. Supranational entities include international organizations designated or supported by governmental

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entities to promote economic reconstruction or development and international banking institutions and related government agencies. Examples include the International Bank for Reconstruction and Development (the World Bank), the Asian Development Bank and the InterAmerican Development Bank. The percentage of each Fund's assets invested in obligations of foreign governments and supranational entities will vary depending on the relative yields of such securities, the economic and financial markets of the countries in which the investments are made and the interest rate climate of such countries.

PARTICIPATION INTERESTS. Each Fund may invest in participation interests in any type of security in which the Fund may invest. A participation interest gives the Fund an undivided interest in the underlying securities in the proportion that the Fund's participation interest bears to the total principal amount of the underlying securities.

REPURCHASE AGREEMENTS. The Funds may enter into repurchase agreements. A repurchase agreement is an instrument under which the purchaser (I.E., the Fund) acquires the security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price, thereby determining the yield during the purchaser's holding period. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by each Fund but only to constitute collateral for the seller's obligation to pay the repurchase price, and, in the event of a default by the seller, each Fund may suffer time delays and incur costs or losses in connection with the disposition of the collateral.

In any repurchase transaction, the collateral for a repurchase agreement may include (i) cash items; (ii) obligations issued by the U.S. Government or its agencies or instrumentalities; or (iii) obligations that, at the time the repurchase agreement is entered into, are rated in the highest category generally by at least two nationally recognized statistical rating organizations ("NRSRO"), or, if unrated, determined to be of comparable quality by BFA. Collateral, however, is not limited to the foregoing and may include for example obligations rated below the highest category by NRSROs. Collateral for a repurchase agreement may also include securities that a Fund could not hold directly without the repurchase obligation. Irrespective of the type of collateral underlying the repurchase agreement, in the case of a repurchase agreement entered into by a money market fund, the repurchase obligation of a seller must involve minimal credit risk to a Fund, and otherwise satisfy credit quality standards set forth in the Fund's Rule 2a-7 procedures.

Repurchase agreements pose certain risks for a Fund that utilizes them. Such risks are not unique to the Fund but are inherent in repurchase agreements. The Funds seek to minimize such risks but because of the inherent legal uncertainties involved in repurchase agreements, such risks cannot be eliminated. Lower quality collateral and collateral with longer maturities may be subject to greater price fluctuations than higher quality collateral and collateral with shorter maturities. If the repurchase agreement counterparty were to default, lower quality collateral may be more difficult to liquidate than higher quality collateral. Should the counterparty default and the amount of collateral not be sufficient to cover the counterparty's repurchase obligation, the Fund would retain the status of an unsecured creditor of the counterparty (I.E., the position the Fund would normally be in if it were to hold, pursuant to its investment policies, other unsecured debt securities of the defaulting counterparty) with respect to the amount of the shortfall. As an unsecured creditor, a Fund would be at risk of losing some or all of the principal and income involved in the transaction.

RESTRICTED SECURITIES. Restricted securities are subject to legal restrictions on their sale. Difficulty in selling restricted securities may result in a loss or be costly to the Funds. Restricted securities generally can be sold in privately negotiated transactions, pursuant to an exemption from registration under the Securities Act of 1933, as amended, or in a registered public offering. Where registration is required, the restricted security's holder may be obligated to pay all or part of the registration expense and a considerable period may elapse between the time the holder decides to seek registration and the time the holder may be permitted to sell the security under an effective registration statement. If, during that period, adverse market conditions were to develop, the holder might obtain a less favorable price than prevailed when it decided to seek registration of the security.

UNRATED INVESTMENTS. Each Fund may purchase instruments that are not rated if, in the opinion of BFA, such obligations are of an investment quality that is comparable to other rated investments that are permitted for purchase by a Fund, and they are purchased in accordance with the Trust's procedures adopted by the Trust's Board of Trustees in accordance with Rule 2a-7 under the 1940 Act. Such procedures require approval or ratification by the Board of Trustees of the purchase of unrated securities. After purchase by a Fund, a security may cease to be rated or its rating may be reduced below the minimum required for purchase by the Fund. Neither event will require an immediate sale of such security by a Fund provided that,

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when a security ceases to be rated, BFA determines that such security presents minimal credit risks and, provided further that, when a security rating is downgraded below the eligible quality for investment or no longer presents minimal credit risks, BFA finds that the sale of such security would not be in a Fund's shareholders' best interests.

To the extent the ratings given by a NRSRO may change as a result of changes in such organization or its rating systems, the Funds will attempt to use comparable ratings as standards for investments in accordance with the investment policies contained in their Prospectuses and this SAI.

U.S. GOVERNMENT OBLIGATIONS. Each Fund may invest in U.S. government obligations, including securities issued or guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities. Payment of principal and interest on U.S. government obligations (i) may be backed by the full faith and credit of the United States (as with U.S. Treasury obligations and Ginnie Mae certificates), or (ii) may be backed solely by the issuing or guaranteeing agency or instrumentality itself (as with Fannie Mae notes). In the latter case, the investor must look principally to the agency or instrumentality issuing or guaranteeing the obligation for ultimate repayment, which agency or instrumentality may be privately owned. There can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. As a general matter, the value of debt instruments, including U.S. government obligations, declines when market interest rates increase and rises when market interest rates decrease. Certain types of U.S. government obligations are subject to fluctuations in yield or value due to their structure or contract terms.

U.S. TREASURY OBLIGATIONS. U.S. Treasury obligations are direct obligations of the U.S. government that are backed by the full faith and credit of the United States. U.S. Treasury obligations include, among other things, U.S. Treasury bills, notes, bonds, and the separately traded principal and interest components of securities guaranteed or issued by the U.S. Treasury if such components are traded independently under the Separate Trading of Registered Interest and Principal of Securities Program.

SELECTIVE DISCLOSURE OF PORTFOLIO HOLDINGS

Pursuant to policies and procedures adopted by the Trust, MIP and BFA, the Trust, MIP and BFA may, under certain circumstances as set forth below, make selective disclosure with respect to a Fund's or Master Portfolio's portfolio holdings. The Boards of Trustees of the Trust and MIP have approved the adoption by the Trust and MIP of the policies and procedures set forth below, and have delegated to BFA the responsibility for ongoing monitoring and supervision to ensure compliance with these policies and procedures. The Boards of Trustees provide ongoing oversight of the Trust's, MIP's and BFA's compliance with the policies and procedures. As part of this oversight function, the Trustees receive from the Trust's and MIP's Chief Compliance Officer at least quarterly and more often, as necessary, reports on compliance with these policies and procedures, including reports on any violations of these policies and procedures that may occur. In addition, the Trustees receive an annual assessment of the adequacy and effectiveness of the policies and procedures with respect to the Trust and MIP, and any changes thereto, and an annual review of the operation of the policies and procedures.

Examples of the information that may be disclosed pursuant to the Trust's and MIP's policies and procedures would include (but is not limited to) specific portfolio holdings -- including the number of shares held, weightings of particular holdings, specific sector and industry weightings, trading details, and the portfolio manager's discussion of Fund or Master Portfolio performance and reasoning for significant changes in portfolio composition. This information may be both material non-public information ("Confidential Information") and proprietary information of the firm. The Trust or MIP may disclose such information to individual investors, institutional investors, financial advisers and other financial intermediaries that sell the Trust's shares, affiliates of the Trust or MIP, third party service providers to the Trust or MIP, lenders to the Trust or MIP, and independent rating agencies and ranking organizations. The Trust, MIP, BFA and its affiliates receive no compensation or other consideration with respect to such disclosures.

Subject to the exceptions set forth below, Confidential Information relating to a Fund or Master Portfolio may not be disclosed to persons not employed by BFA or its affiliates unless such information has been publicly disclosed via a filing with the Commission (e.g., Trust annual report), a press release or placement on a publicly-available internet website. If the Confidential Information has not been publicly disclosed, an employee of BFA who wishes to distribute Confidential Information relating to the Trust or MIP must first do the following: (i) require the person or company receiving the Confidential Information to sign, before BFA will provide disclosure of any such information, a confidentiality agreement approved by an attorney in BFA's Legal Department in which the person or company (a) agrees to use the Confidential Information solely in connection with a legitimate business use (i.e., due diligence, etc.) and (b) agrees not to trade on the basis of the information so provided; (ii) obtain the authorization of an attorney in BFA's Legal Department prior to disclosure; and (iii) only distribute Confidential Information that is at least thirty (30) calendar days old unless a shorter period has specifically been approved by an attorney in BFA's Legal Department.

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Prior to providing any authorization for such disclosure of Confidential Information, an attorney in BFA's Legal Department must review the proposed arrangement and make a determination that it is in the best interests of the Trust's shareholders. In connection with day-to-day portfolio management, the Trust or MIP may disclose Confidential Information to executing broker-dealers that is less than 30 days old in order to facilitate the purchase and sale of portfolio holdings. The Trust and MIP have adopted policies and procedures, including a Code of Ethics, Code of Conduct, and various policies regarding securities trading and trade allocations, to address potential conflicts of interest that may arise in connection with disclosure of Confidential Information. These procedures are designed, among other things, to prohibit personal trading based on Confidential Information, to ensure that portfolio transactions are conducted in the best interests of the Trust and its shareholders and to prevent portfolio management from using Confidential Information for the benefit of one Fund, Master Portfolio or account at the expense of another. In addition, as noted, an attorney in BFA's Legal Department must determine that disclosure of Confidential Information is for a legitimate business purpose and is in the best interests of the Trust's shareholders, and that any conflicts of interest created by release of the Confidential Information have been addressed by BFA's existing policies and procedures. For more information with respect to potential conflicts of interest, see the section entitled "Management-- Potential Conflicts of Interest" in this Statement of Additional Information.

Confidential Information -- whether or not publicly disclosed -- may be disclosed to Trust Trustees, the independent Trustees' counsel, the Trust's outside counsel, accounting services provider and independent registered public accounting firm without meeting the conditions outlined above. Confidential Information may, with the prior approval of the Trust's Chief Compliance Officer or BFA's General Counsel, also be disclosed to any auditor of the parties to a service agreement involving the Trust or MIP, or as required by judicial or administrative process or otherwise by applicable law or regulation. If Confidential Information is disclosed to such persons, each such person will be subject to restrictions on trading in the subject securities under either the Trust's, MIP's and BFA's Code of Ethics or an applicable confidentiality agreement, or under applicable laws or regulations or court order.

BFA has entered into ongoing arrangements to provide monthly and quarterly selective disclosure of Trust and MIP portfolio holdings to the following persons or entities:

Trust's and MIP's Boards of Trustees and, if necessary independent Trustees' counsel and Trust counsel

Trust's Transfer Agent

Trust's and MIP's independent registered public accounting firm

Trust's and MIP's accounting services provider

MIP Custodian

MIP's pricing services - Interactive Data Corp. and Reuters, Inc.

Independent rating agencies -- Morningstar, Inc., Lipper Inc., Moody's Investors Service, Inc. and Standard & Poor's

Information aggregators -- Wall Street on Demand, Thomson Financial, eVestment Alliance, informa PSN investment solutions, Micropal, iMoneyNet and Bloomberg

Sponsors of 401(k) plans that include BlackRock-advised Funds -- E.I. Dupont de Nemours and Company, Inc.

Consultants for pension plans that invest in BlackRock-advised Funds -- Rocaton Investment Advisors, LLC; Mercer Investment Consulting; Watson Wyatt Investment Consulting; Towers Perrin HR Services; Pinnacle West; Callan Associates; Brockhouse & Cooper; Cambridge Associates; Mercer; Morningstar/Investorforce; Russell Investments (Mellon Analytical Solutions); and Wilshire Associates

Portfolio Compliance Consultants -- i-Flex Solutions, Inc.

Third-party feeder funds---Hewitt Money Market Fund, Hewitt Series Trust, Hewitt Financial Services LLC, PayPal Money Market Fund, PayPal Funds, PayPal Asset Management, Inc. Homestead, Inc., Transamerica and State Farm Mutual Fund Trust, and their respective boards, sponsors, administrators and other service providers

Affiliated feeder funds---BlackRock Cayman Prime Money Market Fund, Ltd. And BlackRock Cayman Treasury Money Market Fund Ltd., and their respective boards, sponsors, administrators and other service providers

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Other --- Chicago Mercantile Exchange, Inc., Be Creative, Inc. and Investment Company Institute

Other than with respect to the Board of Trustees, each of the persons or entities set forth above is subject to an agreement to keep the information disclosed confidential and to use it only for legitimate business purposes. Each Trustee has a fiduciary duty as a trustee to act in the best interests of the Trust and its shareholders. Selective disclosure is made to the Board of Trustees and independent registered public accounting firm at least quarterly and otherwise as frequently as necessary to enable such persons or entities to provide services to the Trust. Selective disclosure is made to the Trust's Transfer Agent, accounting services provider, and Custodian as frequently as necessary to enable such persons or entities to provide services to the Trust, typically on a daily basis. Disclosure is made to Lipper Inc. and Wall Street on Demand on a monthly basis and to Morningstar and Thomson Financial on a quarterly basis, and to each such firm upon specific request with the approval of BFA's Legal Department. Disclosure is made to 401(k) plan sponsors on a yearly basis and pension plan consultants on a quarterly basis.

The Trust and BFA monitor, to the extent possible, the use of Confidential Information by the individuals or firms to which it has been disclosed. To do so, in addition to the requirements of any applicable confidentiality agreement and/or the terms and conditions of the Trust's and BFA's Code of Ethics and Code of Conduct -- all of which require persons or entities in possession of Confidential Information to keep such information confidential and not to trade on such information for their own benefit -- BFA's compliance personnel under the supervision of the Trust's Chief Compliance Officer, monitor BFA's securities trading desks to determine whether individuals or firms who have received Confidential Information have made any trades on the basis of that information. In addition, BFA maintains an internal restricted list to prevent trading by the personnel of BFA or its affiliates in securities -- including securities held by the Trust or MIP -- about which BFA has Confidential Information. There can be no assurance, however, that the Trust's policies and procedures with respect to the selective disclosure of Trust portfolio holdings will prevent the misuse of such information by individuals or firms that receive such information

Management

The Board of Trustees of the Trust, consists of thirteen individuals (each, a "Trustee"), eleven of whom are Independent Trustees. The same individuals serve on the Board of Trustees of MIP. The registered investment companies advised by BFA or its affiliates (the "BlackRock-advised Funds") are organized into one complex of closed-end funds, two complexes of open-end funds (the Equity-Liquidity Complex and the Equity-Bond Complex) and one complex of exchange-traded funds (each, a "BlackRock Fund Complex"). The Trust and MIP are included in the BlackRock Fund Complex referred to as the Equity-Liquidity Complex. The Trustees also oversee as board members the operations of the other open-end registered investment companies included in the Equity-Liquidity Complex. The address for each Trustee and officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055.

The Board of Trustees has overall responsibility for the oversight of the Trust and the Funds. The Co-Chairs of the Board are Independent Trustees, and the Chair of each Board committee (each, a "Committee") is an Independent Trustee. The Board has five standing Committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight and Contract Committee and an Executive Committee. The Board also has one ad hoc committee, the Joint Product Pricing Committee. The role of the Co-Chairs of the Board is to preside at all meetings of the Board and to act as a liaison with service providers, officers, attorneys, and other Trustees generally between meetings. The Chair of each Committee performs a similar role with respect to the Committee. The Co-Chairs of the Board or the Chair of a Committee may also perform such other functions as may be delegated by the Board or the Committee from time to time. The Independent Trustees meet regularly outside the presence of Trust management, in executive session or with other service providers to the Trust and the Funds. The Board has regular meetings five times a year, and may hold special meetings if required before its next regular meeting. Each Committee meets regularly to conduct the oversight functions delegated to that Committee by the Board and reports its findings to the Board. The Board and each standing Committee conduct annual assessments of their oversight function and structure. The Board has determined that the Board's leadership structure is appropriate because it allows the Board to exercise independent judgment over management and to allocate areas of responsibility among Committees and the full Board to enhance effective oversight.

The Board has engaged BFA to manage the Funds on a day-to-day basis. The Board is responsible for overseeing BFA, other service providers, the operations of the Funds and associated risk in accordance with the provisions of the 1940 Act, state law, other applicable laws, the Trust's charter, and the Funds' investment objectives and strategies. The Board reviews, on an ongoing basis, the Funds' performance, operations, and investment strategies and techniques. The Board also conducts reviews of BFA and its role in running the operations of the Funds.

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Day-to-day risk management with respect to the Funds is the responsibility of BFA or of sub-advisers or other service providers (depending on the nature of the risk), subject to the supervision of BFA. The Funds are subject to a number of risks, including investment, compliance, operational and valuation risks, among others. While there are a number of risk management functions performed by BFA and the sub-advisers or other service providers, as applicable, it is not possible to eliminate all of the risks applicable to the Funds. Risk oversight forms part of the Board's general oversight of the Funds and is addressed as part of various Board and Committee activities. The Board, directly or through a Committee, also reviews reports from, among others, management, the independent registered public accounting firm for the Funds, sub-advisers, and internal auditors for the investment adviser or its affiliates, as appropriate, regarding risks faced by the Funds and management's or the service provider's risk functions. The Committee system facilitates the timely and efficient consideration of matters by the Trustees, and facilitates effective oversight of compliance with legal and regulatory requirements and of the Funds' activities and associated risks. The Board has appointed a Chief Compliance Officer, who oversees the implementation and testing of the Funds' compliance program and reports to the Board regarding compliance matters for the Funds and their service providers. The Independent Trustees have engaged independent legal counsel to assist them in performing their oversight responsibilities.

The members of the Audit Committee are Kenneth L. Urish (Chair), Herbert I. London and Frederick W. Winter, all of whom are Independent Trustees. The principal responsibilities of the Audit Committee are to approve the selection, retention, termination and compensation of the Trust's independent registered public accounting firm (the "independent auditors") and to oversee the independent auditors' work. The Audit Committee's responsibilities include, without limitation, to (1) evaluate the qualifications and independence of the independent auditors; (2) approve all audit engagement terms and fees for each Fund; (3) review the conduct and results of each independent audit of each Fund's financial statements; (4) review any issues raised by the independent auditors or Trust management regarding the accounting or financial reporting policies and practices of each Fund and the internal controls of each Fund and certain service providers; (5) oversee the performance of each Fund's internal audit function provided by its investment adviser, administrator, pricing agent or other service provider; (6) discuss with Trust management its policies regarding risk assessment and risk management and (7) resolve any disagreements between Trust management and the independent auditors regarding financial reporting. The Board has adopted a written charter for the Audit Committee. During the period December 1, 2009 through December 31, 2009, the Audit Committee met one time.

The members of the Governance and Nominating Committee (the "Governance Committee") are Dr. Matina Horner (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The principal responsibilities of the Governance Committee are to (1) identify individuals qualified to serve as Independent Trustees of the Trust and recommend Independent Trustee nominees for election by shareholders or appointment by the Board; (2) advise the Board with respect to Board composition, procedures and committees (other than the Audit Committee); (3) oversee periodic self-assessments of the Board and committees of the Board (other than the Audit Committee); (4) review and make recommendations regarding Independent Trustee compensation; and (5) monitor corporate governance matters and develop appropriate recommendations to the Board. The Governance Committee may consider nominations for the office of Trustee made by Fund shareholders as it deems appropriate. Fund shareholders who wish to recommend a nominee should send nominations to the Secretary of the Trust that include biographical information and set forth the qualifications of the proposed nominee. The Board has adopted a written charter for the Governance Committee. During the period December 1, 2009 through December 31, 2009, the Governance Committee met one time.

The members of the Compliance Committee are Joseph P. Platt, Jr. (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The Compliance Committee's purpose is to assist the Board in fulfilling its responsibility to oversee regulatory and fiduciary compliance matters involving the Trust, the Fund-related activities of BFA and the Trust's third party service providers. The Compliance Committee's responsibilities include, without limitation, to (1) oversee the compliance policies and procedures of the Trust and its service providers and recommend changes or additions to such policies and procedures; (2) review information on and, where appropriate recommend policies concerning, the Trust's compliance with applicable law; and (3) review reports from, oversee the annual performance review of, and make certain recommendations regarding the Trust's Chief Compliance Officer. The Board has adopted a written charter for the Compliance Committee. During the period December 1, 2009 through December 31, 2009, the Compliance Committee met two times.

The members of the Performance Oversight and Contract Committee (the "Performance Oversight Committee") are David O. Beim (Chair), Toby Rosenblatt (Vice Chair), Ronald W. Forbes and Rodney D. Johnson, all of whom are Independent Trustees. The Performance Oversight Committee's purpose is to assist the Board in fulfilling its responsibility to oversee each Fund's

15

investment performance relative to its agreed-upon performance objectives and to assist the Independent Trustees in their consideration of investment advisory agreements. The Performance Oversight Committee's responsibilities include, without limitation, to (1) review each Fund's investment objectives, policies and practices and each Fund's investment performance; (2) review personnel and resources devoted to management of each Fund and evaluate the nature and quality of information furnished to the Performance Oversight Committee; (3) recommend any required action regarding change in fundamental and non-fundamental investment policies and restrictions, fund mergers or liquidations; (4) request and review information on the nature, extent and quality of services provided to the shareholders; and (5) make recommendations to the Board concerning the approval or renewal of investment advisory agreements. The Board has adopted a written charter for the Performance Oversight Committee. During the period December 1, 2009 through December 31, 2009, the Performance Oversight Committee met one time.

The Boards of the Equity-Liquidity Complex, the Equity-Bond Complex and the closed-end BlackRock Fund Complex, established the ad hoc Joint Product Pricing Committee (the "Product Pricing Committee") comprised of eight members drawn from the independent board members serving on the boards of these BlackRock Fund Complexes. Ronald W. Forbes and Rodney D. Johnson are members of the Product Pricing Committee representing the Equity-Liquidity Complex. One independent board member representing the closed-end BlackRock Fund Complex and five independent board members representing the Equity-Bond Complex serve on the Product Pricing Committee. The Product Pricing Committee is chaired by an independent board member from the Equity-Bond Complex. The purpose of the Product Pricing Committee is to review the components and pricing structure of the non-money market funds in the BlackRock Fund Complexes. During the period from December 1, 2009 through December 31, 2009, the Product Pricing Committee did not meet.

The members of the Executive Committee are Ronald W. Forbes and Rodney D. Johnson, both of whom are Independent Trustees, and Richard S. Davis, who serves as an interested Trustee. The principal responsibilities of the Executive Committee are to (1) act on routine matters between meetings of the Board; (2) act on such matters as may require urgent action between meetings of the Board; and (3) exercise such other authority as may from time to time be delegated to the Executive Committee by the Board. The Board has adopted a written charter for the Executive Committee. During the period December 1, 2009 through December 31, 2009, the Executive Committee met one time.

The Governance Committee has adopted a statement of policy that describes the experience, qualifications, skills and attributes that are necessary and desirable for potential Independent Trustee candidates (the "Statement of Policy"). The Board believes that each Independent Trustee satisfied, at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. Furthermore, in determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, skills, attributes and qualifications, which allow the Board to operate effectively in governing the Trust and protecting the interests of shareholders. Among the attributes common to all Trustees are their ability to review critically, evaluate, question and discuss information provided to them, to interact effectively with the Trust's investment adviser, sub-advisers, other service providers, counsel and independent auditors, and to exercise effective business judgment in the performance of their duties as Trustees. Each Trustee's ability to perform his or her duties effectively is evidenced by his or her educational background or professional training; business, consulting, public service or academic positions; experience from service as a board member of the Trust and the other funds in the BlackRock Fund Complex (and any predecessor funds), other investment funds, public companies, or non-profit entities or other organizations; ongoing commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout the years; or other relevant life experiences. Information about the specific experience, skills, attributes and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a Trustee of the Trust, is provided below.

16

Certain biographical and other information relating to the Trustees of the Trust is set forth below, including their ages, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                             NUMBER OF
                                                                                            BLACKROCK-
                                                                                              ADVISED
                                                                                            REGISTERED
                                                                                            INVESTMENT
                                                                                             COMPANIES
                                                                                             ("RICS")
                                                                                           CONSISTING OF
                                                                                            INVESTMENT
                           POSITION(S)      LENGTH OF                                       PORTFOLIOS
           NAME             HELD WITH          TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
         AND AGE            THE TRUST       SERVED(2)         DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------ ---------------- --------------
INDEPENDENT TRUSTEES(1)
David O. Beim(3)          Trustee       2009 to present   Professor of Finance and       36 RICs          None
(69)                                                      Economics at the Columbia      consisting of
                                                          University Graduate School     104 Portfolios
                                                          of Business since 1991;
                                                          Trustee, Phillips Exeter
                                                          Academy since 2002;
                                                          Chairman, Wave Hill, Inc.
                                                          (public garden and cultural
                                                          center) from 1990 to 2006.

Ronald W. Forbes(4)       Trustee       2009 to present   Professor Emeritus of          36 RICs          None
(69)                                                      Finance, School of Business,   consisting of
                                                          State University of New York   104 Portfolios
                                                          at Albany since 2000.

Dr. Matina S. Horner(5)   Trustee       2009 to present   Executive Vice President of    36 RICs          NSTAR
(70)                                                      Teachers Insurance and         consisting of    (electric and
                                                          Annuity Association and        104 Portfolios   gas utility)
                                                          College Retirement Equities
                                                          Fund from 1989 to 2003.

Rodney D. Johnson(4)      Trustee       2009 to present   President, Fairmont Capital    36 RICs          None
(68)                                                      Advisors, Inc. since 1987;     consisting of
                                                          Director, Fox Chase Cancer     104 Portfolios
                                                          Center since 2004; Member
                                                          of Archdiocesan Investment
                                                          Committee of the
                                                          Archdiocese of Philadelphia
                                                          since 2004; Director, The
                                                          Committee of Seventy (civic)
                                                          since 2006.

17

                                                                                              NUMBER OF
                                                                                             BLACKROCK-
                                                                                               ADVISED
                                                                                             REGISTERED
                                                                                             INVESTMENT
                                                                                              COMPANIES
                                                                                              ("RICS")
                                                                                            CONSISTING OF
                                                                                             INVESTMENT
                           POSITION(S)      LENGTH OF                                        PORTFOLIOS
           NAME             HELD WITH          TIME           PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")         PUBLIC
         AND AGE            THE TRUST       SERVED(2)          DURING PAST FIVE YEARS         OVERSEEN        DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------- ---------------- -------------------
Herbert I. London         Trustee       2009 to present   Professor Emeritus, New         36 RICs          AIMS
(71)                                                      York University since 2005;     consisting of    Worldwide,
                                                          John M. Olin Professor of       104 Portfolios   Inc.
                                                          Humanities, New York                                 (marketing)
                                                          University from 1993 to 2005
                                                          and Professor thereof from
                                                          1980 to 2005; President,
                                                          Hudson Institute (policy
                                                          research organization) since
                                                          1997 and Trustee thereof
                                                          since 1980; Chairman of the
                                                          Board of Trustees for
                                                          Grantham University since
                                                          2006; Director, InnoCentive,
                                                          Inc. (strategic solutions
                                                          company) since 2005;
                                                          Director of Cerego, LLC
                                                          (software development and
                                                          design) since 2005.

Cynthia A.                Trustee       2009 to present   Professor, Harvard Business     36 RICs          Newell
Montgomery                                                School since 1989; Director,    consisting of    Rubbermaid,
(57)                                                      Harvard Business School         104 Portfolios   Inc.
                                                          Publishing since 2005;                           (manufacturing)
                                                          Director, McLean Hospital
                                                          since 2005.

Joseph P. Platt, Jr.(6)   Trustee       2009 to present   Director, The West Penn         36 RICs          Greenlight
(62)                                                      Allegheny Health System (a      consisting of    Capital Re,
                                                          not-for-profit health system)   104 Portfolios   Ltd
                                                          since 2008; Director, Jones                      (reinsurance
                                                          and Brown (Canadian                              company);
                                                          insurance broker) since                          WQED Multi-
                                                          1998; General Partner, Thorn                     Media (public
                                                          Partner, LP (private                             broadcasting
                                                          investment) since 1998;                          not-for-
                                                          Partner Amarna Corporation,                      profit)
                                                          LLC (private investment
                                                          company) from 2002 to
                                                          2008.

Robert C. Robb, Jr.       Trustee       2009 to present   Partner, Lewis, Eckert, Robb    36 RICs          None
(64)                                                      and Company (management         consisting of
                                                          and financial consulting        104 Portfolios
                                                          firm) since 1981.

18

                                                                                              NUMBER OF
                                                                                             BLACKROCK-
                                                                                               ADVISED
                                                                                             REGISTERED
                                                                                             INVESTMENT
                                                                                              COMPANIES
                                                                                              ("RICS")
                                                                                            CONSISTING OF
                                                                                             INVESTMENT
                           POSITION(S)      LENGTH OF                                        PORTFOLIOS
         NAME               HELD WITH          TIME           PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")        PUBLIC
       AND AGE              THE TRUST       SERVED(2)          DURING PAST FIVE YEARS         OVERSEEN       DIRECTORSHIPS
------------------------- ------------- ----------------- ------------------------------- ---------------- -----------------
Toby Rosenblatt(7)        Trustee       2009 to present   President, Founders             36 RICs          A.P. Pharma
(71)                                                      Investments Ltd. (private       consisting of    Inc. (specialty
                                                          investments) since 1999;        104 Portfolios   pharmaceuticals)
                                                          Director, College Access
                                                          Foundation of California
                                                          (philanthropic foundation)
                                                          since 2009; Director, Forward
                                                          Management, LLC since
                                                          2007; Director, the James
                                                          Irvine Foundation
                                                          (philanthropic foundation)
                                                          from 1998 to 2008.

Kenneth L. Urish(8)       Trustee       2009 to present   Managing Partner, Urish         36 RICs          None
(59)                                                      Popeck & Co., LLC (certified    consisting of
                                                          public accountants and          104 Portfolios
                                                          consultants) since 1976;
                                                          Member of External Advisory
                                                          Board, the Pennsylvania
                                                          State University Accounting
                                                          Department since 2001;
                                                          Trustee, The Holy Family
                                                          Foundation since 2001;
                                                          Committee Member,
                                                          Professional Ethics
                                                          Committee of the
                                                          Pennsylvania Institute of
                                                          Certified Public Accountants
                                                          from 2007 to 2010; President
                                                          and Trustee, Pittsburgh
                                                          Catholic Publishing
                                                          Associates from 2003 to
                                                          2008; Director, Inter-Tel from
                                                          2006 to 2007.

Frederick W. Winter       Trustee       2009 to present   Professor and Dean Emeritus     36 RICs          None
(65)                                                      of the Joseph M. Katz School    consisting of
                                                          of Business, University of      104 Portfolios
                                                          Pittsburgh since 2005 and
                                                          dean thereof from 1997 to
                                                          2005; Director, Alkon
                                                          Corporation (pneumatics)
                                                          since 1992; Director
                                                          Tippman Sports (recreation)
                                                          since 2005; Director,
                                                          Indotronix International (IT
                                                          services) from 2004 to 2008.

19

                                                                                               NUMBER OF
                                                                                              BLACKROCK-
                                                                                                ADVISED
                                                                                              REGISTERED
                                                                                              INVESTMENT
                                                                                               COMPANIES
                                                                                               ("RICS")
                                                                                             CONSISTING OF
                                                                                              INVESTMENT
                           POSITION(S)      LENGTH OF                                         PORTFOLIOS
       NAME                 HELD WITH          TIME            PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")      PUBLIC
      AND AGE               THE TRUST       SERVED(2)          DURING PAST FIVE YEARS          OVERSEEN      DIRECTORSHIPS
------------------------- ------------- ----------------- -------------------------------- ---------------- --------------
INTERESTED TRUSTEES(1),(9)
Richard S. Davis          Trustee       2009 to present   Managing Director,               169 RICs         None
(64)                                                      BlackRock, Inc. since 2005;      consisting of
                                                          Chief Executive Officer, State   298 Portfolios
                                                          Street Research &
                                                          Management Company from
                                                          2000 to 2005; Chairman of
                                                          the Board of Trustees, State
                                                          Street Research Mutual
                                                          Funds from 2000 to 2005;
                                                          Chairman, SSR Realty from
                                                          2000 to 2004.

Henry Gabbay              Trustee       2009 to present   Consultant, BlackRock, Inc.      169 RICs         None
(62)                                                      from 2007 to 2008;               consisting of
                                                          Managing Director,               298 Portfolios
                                                          BlackRock, Inc. from 1989 to
                                                          2007; Chief Administrative
                                                          Officer, BlackRock Advisors,
                                                          LLC from 1998 to 2007;
                                                          President of BlackRock
                                                          Funds and BlackRock Bond
                                                          Allocation Target Shares
                                                          from 2005 to 2007 and
                                                          Treasurer of certain closed-
                                                          end funds in the BlackRock
                                                          fund complex from 1989 to
                                                          2006.


(1) Trustees serve until their resignation, removal or death, or until December 31 of the year in which they turn 72. The Board of Trustees has approved one-year extensions in the terms of Trustees who turn 72 prior to December 31, 2013.
(2) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, the Trustees were elected to the Trust's Board. As a result, although the chart shows the Trustees as joining the Trust's Board in 2009, each Trustee first became a member of the boards of other funds advised by BlackRock Advisors, LLC or its affiliates as follows: David O. Beim, 1998; Ronald W. Forbes, 1977; Dr. Matina Horner, 2004; Rodney D. Johnson, 1995; Herbert I. London, 1987; Cynthia A. Montgomery, 1994; Joseph P. Platt, Jr., 1999; Robert C. Robb, Jr., 1999; Toby Rosenblatt, 2005; Kenneth L. Urish, 1999; and Frederick W. Winter, 1999.
(3) Chair of the Performance Oversight Committee.
(4) Co-Chair of the Board of Trustees.
(5) Chair of the Governance Committee.
(6) Chair of the Compliance Committee.
(7) Vice Chair of the Performance Oversight Committee.
(8) Chair of the Audit Committee.
(9) Mr. Davis is an "interested person," as defined in the 1940 Act, of the Trust based on his position with BlackRock, Inc. and its affiliates. Mr. Gabbay is an "interested person" of the Trust based on his former positions with BlackRock, Inc. and its affiliates as well as his ownership of BlackRock, Inc. and The PNC Financial Services Group, Inc. securities.

20

Certain biographical and other information relating to the officers of the Trust is set forth below, including their year of birth, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
          NAME             POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- --------------
Trust Officers(1)
----------------------

Anne F. Ackerley          President and      2009 to present   Managing Director of           169 RICs         None
1962                      Chief Executive                      BlackRock, Inc. since 2000;    consisting of
                          Officer                              Vice President of the          298 Portfolios
                                                               BlackRock-advised Funds
                                                               from 2007 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's Global Client
                                                               Group (GCG) since 2009;
                                                               Chief Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               from 2006 to 2009; Head of
                                                               BlackRock's Mutual Fund
                                                               Group from 2000 to 2006.

Richard Hoerner, CFA      Vice President     2009 to present   Managing Director of           24 RICs          None
1958                                                           BlackRock, Inc. since 2000;    consisting of
                                                               Co-head of BlackRock's Cash    73 Portfolios
                                                               Management Portfolio
                                                               Management Group since
                                                               2002; Member of the Cash
                                                               Management Group
                                                               Executive Committee since
                                                               2005.

Jeffrey Holland, CFA      Vice President     2009 to present   Managing Director of           70 RICs          None
1971                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    201 Portfolios
                                                               from 2006 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               since 2009; Co-head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group from 2007
                                                               to 2009; Product Manager of
                                                               Raymond James &
                                                               Associates from 2003 to
                                                               2006.

21

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
        NAME               POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")      PUBLIC
 AND YEAR OF BIRTH          WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- --------------
Brendan Kyne              Vice President     2009 to present   Managing Director of           169 RICs         None
1977                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    298 Portfolios
                                                               from 2008 to 2009; Head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group since 2009,
                                                               co-head thereof from 2007
                                                               to 2009; Vice President of
                                                               BlackRock, Inc. from 2005 to
                                                               2008.

Simon Mendelson           Vice President     2009 to present   Managing Director of           24 RICs          None
1964                                                           BlackRock, Inc. since 2005;    consisting of
                                                               Chief Operating Officer and    73 Portfolios
                                                               head of the Global Client
                                                               Group for BlackRock's Global
                                                               Cash Management Business
                                                               since 2007; Head of
                                                               BlackRock's Strategy and
                                                               Development Group from
                                                               2005 to 2007.

Brian Schmidt             Vice President     2009 to present   Managing Director of           70 RICs          None
1958                                                           BlackRock, Inc. since 2004;    consisting of
                                                               Various positions with U.S.    201 Portfolios
                                                               Trust Company from 1991 to
                                                               2003: Director from 2001 to
                                                               2003, Senior Vice President
                                                               from 1998 to 2003; Vice
                                                               President, Chief Financial
                                                               Officer and Treasurer of
                                                               Excelsior Funds, Inc.,
                                                               Excelsior Tax-Exempt Funds,
                                                               Inc. and Excelsior Funds
                                                               Trust from 2001 to 2003.

22

                                                                                                   NUMBER OF
                                                                                                  BLACKROCK-
                                                                                                    ADVISED
                                                                                                  REGISTERED
                                                                                                  INVESTMENT
                                                                                                   COMPANIES
                                                                                                    ("RICS"
                                                                                                 CONSISTING OF
                                                                                                  INVESTMENT
                                                                                                  PORTFOLIOS
          NAME             POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")      PUBLIC
    AND YEAR OF BIRTH       WITH THE TRUST      TIME SERVED         DURING PAST FIVE YEARS         OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------- ---------------- --------------
Christopher Stavrakos,    Vice President     2009 to present   Managing Director of            24 RICs          None
CFA                                                            BlackRock, Inc. since 2006;     consisting of
1959                                                           Co-head of BlackRock's Cash     73 Portfolios
                                                               Management Portfolio
                                                               Management Group since
                                                               2006; Senior Vice President,
                                                               CIO, and Director of Liability
                                                               Management for the
                                                               Securities Lending Group at
                                                               Mellon Bank from 1999 to
                                                               2006.

Neal J. Andrews           Chief Financial    2009 to present   Managing Director of            169 RICs         None
1966                      Officer and                          BlackRock, Inc. since 2006;     consisting of
                          Assistant                            Senior Vice President and       298 Portfolios
                          Treasurer                            Line of Business Head of
                                                               Fund Accounting and
                                                               Administration at PNC
                                                               Global Investment Servicing
                                                               (U.S.) Inc. from 1992 to
                                                               2006.

Jay M. Fife               Treasurer          2009 to present   Managing Director of            169 RICs         None
1970                                                           BlackRock, Inc. since 2007      consisting of
                                                               and Director in 2006;           298 Portfolios
                                                               Assistant Treasurer of the
                                                               Merrill Lynch Investment
                                                               Managers, L.P. ("MLIM") and
                                                               Fund Asset Management,
                                                               L.P. advised funds from 2005
                                                               to 2006; Director of MLIM
                                                               Fund Services Group from
                                                               2001 to 2006.

Brian P. Kindelan         Chief              2009 to present   Chief Compliance Officer of     169 RICs         None
1959                      Compliance                           the BlackRock-advised funds     consisting of
                          Officer and                          since 2007; Managing            298 Portfolios
                          Anti-Money                           Director and Senior Counsel
                          Laundering                           of BlackRock, Inc. since
                          Compliance                           2005.
                          Officer

23

                                                                                                NUMBER OF
                                                                                               BLACKROCK-
                                                                                                 ADVISED
                                                                                               REGISTERED
                                                                                               INVESTMENT
                                                                                                COMPANIES
                                                                                                 ("RICS"
                                                                                              CONSISTING OF
                                                                                               INVESTMENT
                                                                                               PORTFOLIOS
          NAME             POSITION(S) HELD      LENGTH OF        PRINCIPAL OCCUPATION(S)    ("PORTFOLIOS")      PUBLIC
   AND YEAR OF BIRTH        WITH THE TRUST      TIME SERVED       DURING PAST FIVE YEARS        OVERSEEN      DIRECTORSHIPS
------------------------- ------------------ ----------------- ---------------------------- ---------------- --------------
Howard B. Surloff         Secretary          2009 to present   Managing Director and        169 RICs         None

1965                                                           General Counsel of U.S.      consisting of
                                                               Funds at BlackRock, Inc.     298 Portfolios
                                                               since 2006; General Counsel
                                                               (U.S.) of Goldman Sachs
                                                               Asset Management, L.P.
                                                               from 1993 to 2006.


(1) Officers of the Trust serve at the pleasure of the Board of Trustees.

SHARE OWNERSHIP INFORMATION. Information relating to each Trustee's share ownership in the Funds and in all BlackRock-advised Funds that are overseen by the respective Trustee ("Supervised Funds") as of December 31, 2009 is set forth in the chart below:

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Interested Trustees    BlackRock     BlackRock        BlackRock    BlackRock    Aggregate
                       Cash          Cash             Cash         Cash         Dollar
                       Funds:        Funds:           Funds:       Funds:       Range of
                       Government    Institutional    Prime        Treasury     Securities
                                                                                in the
                                                                                Supervised
                                                                                Funds
Richard S. Davis       None          None             None         None         over
                                                                                $100,000
Henry Gabbay           None          None             None         None         over
                                                                                $100,000

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Independent Trustees   BlackRock     BlackRock        BlackRock    BlackRock    Aggregate
                       Cash          Cash             Cash         Cash         Dollar
                       Funds:        Funds:           Funds:       Funds:       Range of
                       Government    Institutional    Prime        Treasury     Securities
                                                                                in the
                                                                                Supervised
                                                                                Funds
David O. Beim          None          None             None         None         over
                                                                                $100,000
Ronald W. Forbes       None          None             None         None         over
                                                                                $100,000
Dr. Matina S. Horner   None          None             None         None         over
                                                                                $100,000

24

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Rodney D. Johnson      None          None             None         None         over
                                                                                $100,000
Herbert I. London      None          None             None         None         $ 50,001
                                                                                - $100,000
Cynthia A. Montgomery  None          None             None         None         over
                                                                                $100,000
Joseph P. Platt, Jr.   None          None             None         None         over
                                                                                $100,000
Robert C. Robb, Jr.    None          None             None         None         over
                                                                                $100,000
Toby Rosenblatt        None          None             None         None         over
                                                                                $100,000
Kenneth L. Urish       None          None             None         None         $ 50,001
                                                                                - $100,000
Frederick W. Winter    None          None             None         None         over
                                                                                $100,000

OWNERSHIP OF SECURITIES OF CERTAIN ENTITIES. As of March 31, 2010, the Trustees and officers of the Trust as a group owned an aggregate of less than 1% of the outstanding shares of any Fund. As of March 31, 2010, none of the Independent Trustees or their immediate family members owned beneficially or of record any securities of affiliates of the Investment Adviser.

COMPENSATION OF TRUSTEES. Each current Trustee who is an Independent Trustee is paid as compensation an annual retainer of $250,000 per year for his or her services as a Board member to the BlackRock-advised Funds in the Equity-Liquidity Complex, including the Trust and MIP, and a $5,000 Board meeting fee to be paid for each in-person Board meeting attended (a $2,500 Board meeting fee for telephonic attendance at regular Board meetings), for up to five Board meetings held in a calendar year (compensation for meetings in excess of this number to be determined on a case by case basis), together with out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. The Co-Chairs of the Boards of Trustees are each paid an additional annual retainer of $45,000. The Chairs of the Audit Committees, Compliance Committees, Governance Committees and Performance Oversight Committees and the Vice-Chair of the Performance Oversight Committees are each paid an additional annual retainer of $25,000. The Chair of the Product Pricing Committee, who oversees funds in the Equity-Bond Complex, is paid an annual retainer of $25,000 that is allocated among all of the non-money market funds in the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes.

Mr. Gabbay is an interested Trustee of the Trust and serves as an interested board member of the other funds which comprise the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes. Mr. Gabbay receives as compensation for his services as a board member of each of these three BlackRock Fund Complexes, (i) an annual retainer of $487,500, paid quarterly in arrears, allocated to the BlackRock-advised Funds in these three BlackRock Fund Complexes, including the Trust and MIP, and (ii) with respect to each of the two open-end BlackRock Fund Complexes, a board meeting fee of $3,750 (with respect to meetings of the Equity-Liquidity Complex) and $18,750 (with respect to meetings of the Equity-Bond Complex) to be paid for attendance at each board meeting up to five board meetings held in a calendar year by each such Complex (compensation for meetings in excess of this number to be determined on a case by case basis). Mr. Gabbay will also be reimbursed for out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. Mr. Gabbay's compensation for serving on the boards of funds in these three BlackRock Fund Complexes (including the Trust and MIP) is equal to 75% of each retainer and, as applicable, of each meeting fee (without regard to additional fees paid to Board and Committee chairs) received by the independent board members serving on such boards. The Board or any other BlackRock-advised Fund may modify the board members' compensation from time to time depending on market conditions and Mr. Gabbay's compensation would be impacted by those modifications.

Each of the Independent Trustees and Mr. Gabbay agreed to a 10% reduction in their compensation described above for the period December 1, 2009 through December 31, 2009.

25

From January 1, 2009 through November 30, 2009, the Trust paid each Independent Trustee then in office the Trust's allocable share of the following Independent Trustee fees and expenses: (i) an annual base fee of $60,000; (ii) a per meeting fee of $6,000 for meetings of the Board attended by the Trustee; (iii) a committee meeting fee of $2,500 for each Audit Committee meeting attended by the Trustee; and (iv) a committee meeting fee of $2,000 for each Nominating and Governance Committee meeting attended by the Trustee. The Chairperson of the Audit Committee was paid the Trust's allocable share of an annual fee of $10,000 and the Chairperson of the Nominating and Governance Committee was paid the Trust's allocable share of an annual fee of $5,000. The Lead Independent Trustee was paid the Trust's allocable share of an additional annual base fee of $17,500. These Independent Trustee fees and expenses were allocated between the Trust and MIP, based on their respective assets under management.

The Trust reimburses each Trustee for travel and other out-of-pocket expenses incurred by him/her in connection with attending Board and committee meetings. Currently, the Trustees do not receive any retirement benefits or deferred compensation from the fund complex, as defined in Form N-1A under the 1940 Act.

As of December 1, 2009, the members of the Board of Trustees of the Trust listed below resigned (each, a "Previous Trustee"). The table below indicates the amount of compensation each Previous Trustee was paid as of December 31, 2009. Compensation is not shown for the New Trustees because they did not serve as Trustees of the Trust until December 1, 2009, and the New Trustees did not receive compensation from the Trust in 2009.

COMPENSATION
FOR THE FISCAL YEAR ENDED DECEMBER 31, 2009

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INTERESTED TRUSTEE          FROM THE TRUST        FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Lee T. Kranefuss                           $0                       $0
H. Michael Williams                        $0                       $0

                                 AGGREGATE COMPENSATION    TOTAL COMPENSATION
 NAME OF INDEPENDENT TRUSTEES        FROM THE TRUST       FROM FUND COMPLEX/1/
------------------------------  ------------------------  ---------------------
Mary G. F. Bitterman/2/         $78,394                         $157,000
A. John Gambs/3/                $72,310                         $157,500
Hayne E. Leland                 $60,640                         $132,000
Jeffrey M. Lyons                $67,078                         $146,000
Wendy Paskin-Jordan             $64,552                         $140,500
Leo Soong/4/                    $72,584                         $158,000


/1/ Includes compensation for serving on the Board of Trustees of MIP. /2/ Previously the Nominating and Governance Committee Chair. /3/ Previously the Audit Committee Chair. /4/ Previously the Lead Independent Trustee.

MASTER/FEEDER STRUCTURE. Each Fund seeks to achieve its investment objective by investing all of its assets in the corresponding Master Portfolio of MIP. The Trust's Board of Trustees believes that under normal circumstances, none of the Funds or their shareholders will be adversely affected by investing Fund assets in a Master Portfolio. However, if a mutual fund or other investor redeems its interests from a Master Portfolio, the economic efficiencies (E.G., spreading fixed expenses over a larger asset base) that the Trust's Board of Trustees believes may be available through a Fund's investment in such Master Portfolio may not be fully achieved. In addition, although unlikely, the master/feeder structure may give rise to accounting or operational difficulties.

The fundamental policies of each Master Portfolio cannot be changed without approval by the holders of a majority (as defined in the 1940 Act) of a Master Portfolio's outstanding interests. Whenever a Fund, as an interestholder of a Master Portfolio, is requested to vote on any matter submitted to interestholders of the Master Portfolio, a Fund will either hold a meeting of its shareholders to consider such matters and cast its votes in proportion to the votes received from its shareholders (shares for which a Fund receives no voting instructions will be voted in the same proportion as the votes received from the other Fund shareholders) or cast its votes, as an interestholder of the Master Portfolio, in proportion to the votes received by the Master Portfolio from all other interestholders of the Master Portfolio.

Certain policies of the Master Portfolios that are non-fundamental may be changed by vote of a majority of MIP's Trustees without interestholder approval. If a Master Portfolio's investment objective or fundamental or non-fundamental policies are changed, a Fund may elect to change its objective or policies to correspond to those of the related Master Portfolio. Each Fund may redeem its interests from its Master Portfolio only if the Trust's Board of Trustees determines that such action is in the best interests of the Fund and its shareholders, for this or any other reason. Prior to such redemption, the Trust's Board of Trustees would consider alternatives, including whether to seek a new investment company with a matching investment objective in which to invest or retain its own investment adviser to manage the Fund's portfolio in accordance with its investment objective. In the latter case, a Fund's inability to find a substitute investment company in which to invest or equivalent management services could adversely affect shareholders' investments in the Fund.

CODES OF ETHICS. The Trust, BFA and SEI have adopted Codes of Ethics pursuant to Rule 17j-1 under the 1940 Act. The Codes of Ethics permit personnel subject to the Codes of Ethics to invest in securities, subject to certain limitations, including securities that may be purchased or held by the Funds. The Codes of Ethics are on public file with, and are available from, the SEC.

PROXY VOTING POLICIES OF THE MASTER PORTFOLIOS. The Board of Trustees of MIP has delegated the voting of proxies for each Master Portfolio's securities to BFA pursuant to MIP's proxy voting guidelines. Under these guidelines, BFA will vote proxies related to the securities held by each Master Portfolio in the best interests of the Master Portfolio and its stockholders. From time to time, a vote may present a conflict between the interests of the Master Portfolio's stockholders, on the one hand, and those of BFA, or any affiliated person of MIP or BFA, on the other. In such event, provided that Blackrock's Equity Investment Policy Oversight Committee, or a sub-committee thereof (the "Committee") is aware of the real or potential conflict or material non-routine matter and if the Committee does not reasonably believe it is able to follow its general voting guidelines (or if the particular proxy matter is not addressed in the guidelines) and vote impartially, the Committee may retain an independent fiduciary to advise the Committee on how to vote or to cast votes on behalf of BFA's clients. If BFA determines not to retain an independent fiduciary, or does not desire to follow the advice of such independent fiduciary, the Committee shall determine how to vote the proxy after consulting with BlackRock's Portfolio Management Group and/or BlackRock's Legal and Compliance Department and concluding that the vote cast is in its client's best interest notwithstanding the conflict. A copy of MIP's Proxy Voting Policies is attached as Appendix A.

Information on how a Master Portfolio voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available without charge, (i) at www.blackrock.com and (ii) on the SEC's website at http://www.sec.gov.

26

SHAREHOLDER COMMUNICATION TO THE BOARD OF TRUSTEES. The Board of Trustees has established a process for shareholders to communicate with the Board of Trustees. Shareholders may contact the Board of Trustees by mail. Correspondence should be addressed to BlackRock Funds III Board of Trustees, c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055. Shareholder communication to the Board of Trustees should include the following information: (a) the name and address of the shareholder; (b) the number of shares owned by the shareholder; (c) the Fund(s) of which the shareholder owns shares; and (d) if these shares are owned indirectly through a broker, financial intermediary or other record owner, the name of the broker, financial intermediary or other record owner. All correspondence received as set forth above shall be reviewed by the Secretary of the Trust and reported to the Board of Trustees.

27

Control Persons and Principal Holders of Securities

As of March 31, 2010, the shareholders below were known by the Trust to own 5% or more of the outstanding shares of the specified Fund's outstanding Capital, Institutional, Premium, Select, SL Agency, Trust and Aon Captives Shares, as the case may be, in the listed capacity.

                                                                                        PERCENTAGE
                                                                                         OF SHARE    NATURE OF
         NAME OF FUND                 NAME AND ADDRESS OF SHAREHOLDER                     CLASS      OWNERSHIP
--------------------------------  ---------------------------------------------------  -----------  ----------
BlackRock Cash Funds: Prime
Capital Shares                    Goldman, Sachs & Co.                                      17%       Record
                                  71 South Wacker Drive Suite 500
                                  Chicago, IL 60606
                                  Banc of America Securities LLC                            80%       Record
                                  200 N College Street
                                  Charlotte, NC 28255
Institutional Shares              Banc of America Securities LLC                             6%       Record
                                  200 N College Street
                                  Charlotte, NC 28255
                                  County of Santa Clara                                      7%       Record
                                  70 W. Hedding
                                  East Wing, 6TH Floor
                                  San Jose, CA 95110
                                  Nationwide Cash Management Company                         8%       Record
                                  One Nationwide Plaza Mailcode 1-05-502
                                  Columbus, OH 43215
                                  General Electric Capital Corporation                       8%       Record
                                  201 High Ridge Road
                                  Stamford, CT 06927
                                  Anadarko Petroleum Corporation                            10%       Record
                                  1201 Lake Robbins Drive
                                  Spring, TX 77380
                                  Hare & Co                                                 15%       Record
                                  c/o Bank of New York
                                  111 Sanders Creek Parkway
                                  East Syracuse, NY 13057

28

                                                                                        PERCENTAGE
                                                                                         OF SHARE    NATURE OF
      NAME OF FUND                          NAME AND ADDRESS OF SHAREHOLDER               CLASS      OWNERSHIP
--------------------------------  ---------------------------------------------------  -----------  ----------
                                  Government Development Bank for Puerto Rico               16%       Record
                                  De Diego Avenue, Stop 22
                                  San Juan, Puerto Rico 00907
Premium Shares                    Banc of America Securities LLC                             8%       Record
                                  200 N College Street
                                  Charlotte, NC 28255
                                  ADP Pacific, Inc.                                         12%       Record
                                  800 Delaware Avenue
                                  Wilmington, DE 19801
                                  Chicago Mercantile Exchange, Inc.                         13%       Record
                                  20 South Wacker Drive
                                  Chicago, IL 60606
                                  Hare & Co                                                 51%       Record
                                  c/o Bank of New York
                                  111 Sanders Creek Parkway
                                  East Syracuse, NY 13057
Select Shares                     Banc of America Securities LLC                            29%       Record
                                  200 N College Street
                                  Charlotte, NC 28255
                                  Barclays Capital Inc.                                     70%       Record
                                  200 Park Avenue
                                  New York, NY 10166
SL Agency Shares                  State Street Bank and Trust Company                       39%       Record
                                  f/b/o iShares Barclays Capital Aggregate Bond Fund
                                  200 Clarendon Street
                                  Boston, MA 02116
                                  BlackRock Institutional Trust Company, N.A.               52%       Record
                                  400 Howard Street
                                  San Francisco, CA 94105
Trust Shares                      Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
BlackRock Cash Funds:
Institutional
Capital Shares                    Goldman, Sachs & Co.                                      15%       Record
                                  71 South Wacker Drive Suite 500
                                  Chicago, IL 60606
                                  J.P. Morgan Clearing Corporation                          84%       Record
                                  One Metrotech Center North
                                  Brooklyn, NY 11201
Institutional Shares              UBATCO and Company                                         7%       Record
                                  6811 S. 27th Street
                                  Lincoln, NE 68512

29

                                                                                        PERCENTAGE
                                                                                         OF SHARE    NATURE OF
      NAME OF FUND                       NAME AND ADDRESS OF SHAREHOLDER                  CLASS      OWNERSHIP
--------------------------------  ---------------------------------------------------  -----------  ----------
                                  Barclays Bank Delaware                                     8%       Record
                                  100 S. West Street
                                  Wilmington, DE 19801
                                  BlackRock Institutional Trust Company, N.A.               21%       Record
                                  400 Howard Street
                                  San Francisco, CA 94105
                                  AT&T Inc.                                                 24%       Record
                                  208 S. Akard Street
                                  Room 2750.10
                                  Dallas, TX 75202
                                  Electronic Arts Inc.                                      38%       Record
                                  209 Redwood Shores Parkway
                                  Redwood City, CA 94065
Premium Shares                    Biogen Idec Inc.                                         100%       Record
                                  14 Cambridge Center
                                  Cambridge, MA 02142
Select Shares                     Bear Stearns Securities Corporation                       19%       Record
                                  One Metrotech Center North
                                  Brooklyn, NY 11201
                                  Barclays Capital Inc.                                     81%       Record
                                  200 Park Avenue
                                  New York, NY 10166
SL Agency Shares                  BlackRock Institutional Trust Company, N.A.               97%       Record
                                  400 Howard Street
                                  San Francisco, CA 94105
Trust Shares                      Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
Aon Captives Shares               Bom Ambiente Insurance Company                             7%       Record
                                  P.O. Box 69 GT
                                  Grand Cayman Island
                                  NRI Insurance Company                                     22%       Record
                                  76 St. Paul Street
                                  Burlington, VT 05401
                                  Barclays Nominees (Manx) LTD                              66%       Record
                                  Barclays House Victoria Street
                                  P.O. Box 9
                                  Douglas Isle of Man, UK IM99 1AJ
BlackRock Cash Funds:
Government
Institutional Shares              Southeastern Pennsylvania Transportation                  97%       Record
                                  1234 Market Street, 8th Floor
                                  Philadelphia, PA 19107

30

                                                                                        PERCENTAGE
                                                                                         OF SHARE    NATURE OF
          NAME OF FUND                  NAME AND ADDRESS OF SHAREHOLDER                   CLASS      OWNERSHIP
--------------------------------  ---------------------------------------------------  -----------  ----------
Select Shares                     Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
Trust Shares                      Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
BlackRock Cash Funds: Treasury
Capital Shares                    Banc of America Securities LLC                            21%       Record
                                  200 N College Street
                                  Charlotte, NC 28255
                                  Banc of America NAC                                       31%       Record
                                  135 S. Lasalle Street, Suite 1811
                                  Chicago, IL 60603
                                  Barclays Capital Inc.                                     48%       Record
                                  200 Park Avenue
                                  New York, NY 10166
Institutional Shares              Skadden, Arps, Slate, Meagher & Flom LLP                  17%       Record
                                  360 Hamilton Avenue
                                  White Plains, NY 10601
                                  Union Electric Company                                    20%       Record
                                  1901 Chouteau Avenue Street
                                  Louis, MO 63103
                                  The Hertz Corporation                                     63%       Record
                                  225 Brae Boulevard
                                  Park Ridge, NJ 07656
Premium Shares                    Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
Select Shares                     Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166
SL Agency Shares                  State Street Bank and Trust Company                       99%       Record
                                  200 Clarendon Street
                                  Boston, MA 02116
Trust Shares                      Barclays Capital Inc.                                    100%       Record
                                  200 Park Avenue
                                  New York, NY 10166

For purposes of the 1940 Act, any person who owns directly or through one or more controlled companies more than 25% of the voting securities of a company is presumed to "control" such company. Accordingly, to the extent that a shareholder identified in the foregoing table is identified as the beneficial holder of more than 25% of a Fund, or is identified as the holder of record of more than 25% of a Fund and has voting and/or investment powers, such shareholder may be presumed to control such Fund.

As of March 31, 2010, Trustees and officers of the Trust, as a group, beneficially owned less than 1% of the outstanding shares of the Trust.

31

POTENTIAL CONFLICTS OF INTEREST. The Bank of America Corporation ("BAC"), through its subsidiary Merrill Lynch & Co., Inc. ("Merrill Lynch"), Barclays PLC ("Barclays"), and The PNC Financial Services Group, Inc. ("PNC"), each have a significant economic interest in BlackRock, Inc., the parent of BFA, the Trust's investment adviser. PNC is considered to be an affiliate of BlackRock, Inc., under the 1940 Act. Certain activities of BFA, BlackRock Advisors, LLC, BlackRock, Inc. and their affiliates (collectively, "BlackRock") and PNC and its affiliates (collectively, "PNC" and together with BlackRock, "Affiliates"), and those of BAC, Merrill Lynch and their affiliates (collectively, the "BAC Entities") and Barclays and its affiliates (collectively, the "Barclays Entities") (BAC Entities and Barclays Entities, collectively, the "BAC/Barclays Entities"), with respect to the Funds and/or other accounts managed by BlackRock, PNC or BAC/Barclays Entities, may give rise to actual or perceived conflicts of interest such as those described below.

BlackRock is one of the world's largest asset management firms. BAC is a national banking corporation which through its affiliates and subsidiaries, including Merrill Lynch, provides a full range of financial services. Merrill Lynch is a full service investment banking, broker-dealer, asset management and financial services organization. PNC is a diversified financial services organization spanning the retail, business and corporate markets. Barclays is a major global financial services provider engaged in a range of activities including retail and commercial banking, credit cards, investment banking, and wealth management. BlackRock, BAC, Merrill Lynch, PNC, Barclays and their respective affiliates (including, for these purposes, their directors, partners, trustees, managing members, officers and employees), including the entities and personnel who may be involved in the investment activities and business operations of a Fund, are engaged worldwide in businesses, including equity, fixed income, cash management and alternative investments, and have interests other than those of managing the Funds. These are considerations of which investors in a Fund should be aware, and which may cause conflicts of interest that could disadvantage the Fund and its shareholders. These activities and interests include potential multiple advisory, transactional, financial and other interests in securities and other instruments, and companies that may be purchased or sold by a Fund.

BlackRock and its Affiliates, as well as the BAC/Barclays Entities, have proprietary interests in, and may manage or advise with respect to, accounts or funds (including separate accounts and other funds and collective investment vehicles) that have investment objectives similar to those of a Fund and/or that engage in transactions in the same types of securities, currencies and instruments as the Fund. One or more Affiliates and BAC/Barclays Entities are also major participants in the global currency, equities, swap and fixed income markets, in each case both on a proprietary basis and for the accounts of customers. As such, one or more Affiliates or BAC/Barclays Entities are or may be actively engaged in transactions in the same securities, currencies, and instruments in which a Fund invests. Such activities could affect the prices and availability of the securities, currencies, and instruments in which a Fund invests, which could have an adverse impact on the Fund's performance. Such transactions, particularly in respect of most proprietary accounts or customer accounts, will be executed independently of a Fund's transactions and thus at prices or rates that may be more or less favorable than those obtained by the Fund. When BlackRock and its Affiliates or the BAC/Barclays Entities seek to purchase or sell the same assets for their managed accounts, including a Fund, the assets actually purchased or sold may be allocated among the accounts on a basis determined in their good faith discretion to be equitable. In some cases, this system may adversely affect the size or price of the assets purchased or sold for a Fund. In addition, transactions in investments by one or more other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of a Fund, particularly, but not limited to, with respect to small capitalization, emerging market or less liquid strategies. This may occur when investment decisions regarding a Fund are based on research or other information that is also used to support decisions for other accounts. When BlackRock or its Affiliates or a BAC/Barclays Entity implements a portfolio decision or strategy on behalf of another account ahead of, or contemporaneously with, similar decisions or strategies for a Fund, market impact, liquidity constraints, or other factors could result in the Fund receiving less favorable trading results and the costs of implementing such decisions or strategies could be increased or the Fund could otherwise be disadvantaged. BlackRock or it Affiliates or a BAC/Barclays Entity may, in certain cases, elect to implement internal policies and procedures designed to limit such consequences, which may cause a Fund to be unable to engage in certain activities, including purchasing or disposing of securities, when it might otherwise be desirable for it to do so.

Conflicts may also arise because portfolio decisions regarding a Fund may benefit other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity. For example, the sale of a long position or establishment of a short position by a Fund may impair the price of the same security sold short by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts, and the purchase of a security or covering of a short position in a security by a Fund may increase the price of the same security held by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts.

32

BlackRock and its Affiliates or a BAC/Barclays Entity and their clients may pursue or enforce rights with respect to an issuer in which a Fund has invested, and those activities may have an adverse effect on the Fund. As a result, prices, availability, liquidity and terms of the Fund's investments may be negatively impacted by the activities of BlackRock or its Affiliates or a BAC/Barclays Entity or their clients, and transactions for the Fund may be impaired or effected at prices or terms that may be less favorable than would otherwise have been the case.

The results of a Fund's investment activities may differ significantly from the results achieved by BlackRock and its Affiliates or the BAC/Barclays Entities for their proprietary accounts or other accounts (including investment companies or collective investment vehicles) managed or advised by them. It is possible that one or more Affiliate- or BAC/Barclays Entity-managed accounts and such other accounts will achieve investment results that are substantially more or less favorable than the results achieved by a Fund. Moreover, it is possible that a Fund will sustain losses during periods in which one or more Affiliates or BAC/Barclays Entity-managed accounts achieve significant profits on their trading for proprietary or other accounts. The opposite result is also possible. The investment activities of one or more Affiliates or BAC/Barclays Entities for their proprietary accounts and accounts under their management may also limit the investment opportunities for a Fund in certain emerging and other markets in which limitations are imposed upon the amount of investment, in the aggregate or in individual issuers, by affiliated foreign investors.

From time to time, a Fund's activities may also be restricted because of regulatory restrictions applicable to one or more Affiliates or BAC/Barclays Entities, and/or their internal policies designed to comply with such restrictions. As a result, there may be periods, for example, when BlackRock, and/or one or more Affiliates or BAC/Barclays Entities, will not initiate or recommend certain types of transactions in certain securities or instruments with respect to which BlackRock and/or one or more Affiliates or BAC/Barclays Entities are performing services or when position limits have been reached.

In connection with its management of a Fund, BlackRock may have access to certain fundamental analysis and proprietary technical models developed by one or more Affiliates or BAC/Barclays Entities. BlackRock will not be under any obligation, however, to effect transactions on behalf of a Fund in accordance with such analysis and models. In addition, neither BlackRock nor any of its Affiliates, nor any BAC/Barclays Entity, will have any obligation to make available any information regarding their proprietary activities or strategies, or the activities or strategies used for other accounts managed by them, for the benefit of the management of a Fund and it is not anticipated that BlackRock will have access to such information for the purpose of managing the Fund. The proprietary activities or portfolio strategies of BlackRock and its Affiliates and the BAC/Barclays Entities, or the activities or strategies used for accounts managed by them or other customer accounts could conflict with the transactions and strategies employed by BlackRock in managing a Fund.

In addition, certain principals and certain employees of BlackRock are also principals or employees of BlackRock or another Affiliate. As a result, the performance by these principals and employees of their obligations to such other entities may be a consideration of which investors in a Fund should be aware.

BlackRock may enter into transactions and invest in securities, instruments and currencies on behalf of a Fund in which customers of BlackRock or its Affiliates or a BAC/Barclays Entity, or, to the extent permitted by the SEC, BlackRock or another Affiliate or a BAC/Barclays Entity, serves as the counterparty, principal or issuer. In such cases, such party's interests in the transaction will be adverse to the interests of the Fund, and such party may have no incentive to assure that the Fund obtains the best possible prices or terms in connection with the transactions. In addition, the purchase, holding and sale of such investments by a Fund may enhance the profitability of BlackRock or its Affiliates or a BAC/Barclays Entity. One or more Affiliates or BAC/Barclays Entities may also create, write or issue derivatives for their customers, the underlying securities, currencies or instruments of which may be those in which a Fund invests or which may be based on the performance of the Fund. A Fund may, subject to applicable law, purchase investments that are the subject of an underwriting or other distribution by one or more Affiliates or BAC/Barclays Entities and may also enter into transactions with other clients of an Affiliate or BAC/Barclays Entity where such other clients have interests adverse to those of the Fund.

At times, these activities may cause departments of BlackRock or its Affiliates or a BAC/Barclays Entity to give advice to clients that may cause these clients to take actions adverse to the interests of the Fund. To the extent affiliated transactions are permitted, a Fund will deal with BlackRock and its Affiliates or BAC/Barclays Entities on an arms-length basis. BlackRock or its Affiliates or a BAC/Barclays Entity may also have an ownership interest in certain trading or information systems used
by a Fund. A Fund's use of such trading or information systems may enhance the profitability of BlackRock and its Affiliates or BAC/Barclays Entities.

33

One or more Affiliates or one of the BAC/Barclays Entities may act as broker, dealer, agent, lender or adviser or in other commercial capacities for a Fund. It is anticipated that the commissions, mark-ups, mark-downs, financial advisory fees, underwriting and placement fees, sales fees, financing and commitment fees, brokerage fees, other fees, compensation or profits, rates, terms and conditions charged by an Affiliate or BAC/Barclays Entity will be in its view commercially reasonable, although each Affiliate or BAC/Barclays Entity, including its sales personnel, will have an interest in obtaining fees and other amounts that are favorable to the Affiliate or BAC/Barclays Entity and such sales personnel.

Subject to applicable law, the Affiliates and BAC/Barclays Entities (and their personnel and other distributors) will be entitled to retain fees and other amounts that they receive in connection with their service to the Funds as broker, dealer, agent, lender, adviser or in other commercial capacities and no accounting to the Funds or their shareholders will be required, and no fees or other compensation payable by the Funds or their shareholders will be reduced by reason of receipt by an Affiliate or BAC/Barclays Entity of any such fees or other amounts.

When an Affiliate or BAC/Barclays Entity acts as broker, dealer, agent, adviser or in other commercial capacities in relation to the Funds, the Affiliate or BAC/Barclays Entity may take commercial steps in its own interests, which may have an adverse
effect on the Funds. A Fund will be required to establish business relationships with its counterparties based on the Fund's own credit standing. Neither BlackRock nor any of the Affiliates, nor any BAC/Barclays Entity, will have any obligation to allow their credit to be used in connection with a Fund's establishment of its business relationships, nor is it expected that the Fund's counterparties will rely on the credit of BlackRock or any of the Affiliates or BAC/Barclays Entities in evaluating the Fund's creditworthiness.

Purchases and sales of securities for a Fund may be bunched or aggregated with orders for other BlackRock client accounts. BlackRock and its Affiliates and the BAC/Barclays Entities, however, are not required to bunch or aggregate orders if portfolio management decisions for different accounts are made separately, or if they determine that bunching or aggregating is not practicable, required or with cases involving client direction.

Prevailing trading activity frequently may make impossible the receipt of the same price or execution on the entire volume of securities purchased or sold. When this occurs, the various prices may be averaged, and the Funds will be charged or credited with the average price. Thus, the effect of the aggregation may operate on some occasions to the disadvantage of the Funds. In addition, under certain circumstances, the Funds will not be charged the same commission or commission equivalent rates in connection with a bunched or aggregated order.

BlackRock may select brokers (including, without limitation, Affiliates or BAC/Barclays Entities) that furnish BlackRock, the Funds, other BlackRock client accounts or other Affiliates or BAC/Barclays Entities or personnel, directly or through correspondent relationships, with research or other appropriate services which provide, in BlackRock's view, appropriate assistance to BlackRock in the investment decision-making process (including with respect to futures, fixed-price offerings and over-the-counter transactions). Such research or other services may include, to the extent permitted by law, research reports on companies, industries and securities; economic and financial data; financial publications; proxy analysis; trade industry seminars; computer data bases; research-oriented software and other services and products. Research or other services obtained in this manner may be used in servicing any or all of the Funds and other BlackRock client accounts, including in connection with BlackRock client accounts other than those that pay commissions to the broker relating to the research or other service arrangements. Such products and services may disproportionately benefit other BlackRock client accounts relative to the Funds based on the amount of brokerage commissions paid by the Funds and such other BlackRock client accounts. For example, research or other services that are paid for through one client's commissions may not be used in managing that client's account. In addition, other BlackRock client accounts may receive the benefit, including disproportionate benefits, of economies of scale or price discounts in connection with products and services that may be provided to the Funds and to such other BlackRock client accounts. To the extent that BlackRock uses soft dollars, it will not have to pay for those products and services itself.

BlackRock may receive research that is bundled with the trade execution, clearing, and/or settlement services provided by a particular broker-dealer. To the extent that BlackRock receives research on this basis, many of the same conflicts related to traditional soft dollars may exist. For example, the research effectively will be paid by client commissions that also will be used to pay for the execution, clearing, and settlement services provided by the broker-dealer and will not be paid by BlackRock.

BlackRock may endeavor to execute trades through brokers who, pursuant to such arrangements, provide research or other services in order to ensure the continued receipt of research or other services BlackRock believes are useful in its investment

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decision-making process. BlackRock may from time to time choose not to engage in the above described arrangements to varying degrees. BlackRock may also enter into commission sharing arrangements under which BlackRock may execute transactions through a broker-dealer, including, where permitted, an Affiliate or BAC/Barclays Entity, and request that the broker-dealer allocate a portion of the commissions or commission credits to another firm that provides research to BlackRock. To the extent that BlackRock engages in commission sharing arrangements, many of the same conflicts related to traditional soft dollars may exist.

BlackRock may utilize certain electronic crossing networks ("ECNs") in executing client securities transactions for certain types of securities. These ECNs may charge fees for their services, including access fees and transaction fees. The transaction fees, which are similar to commissions or markups/markdowns, will generally be charged to clients and, like commissions and markups/markdowns, would generally be included in the cost of the securities purchased. Access fees may be paid by BlackRock even though incurred in connection with executing transactions on behalf of clients, including the Funds. In certain circumstances, ECNs may offer volume discounts that will reduce the access fees typically paid by BlackRock. This would have the effect of reducing the access fees paid by BlackRock. BlackRock will only utilize ECNs consistent with its obligation to seek to obtain best execution in client transactions.

BlackRock has adopted policies and procedures designed to prevent conflicts of interest from influencing proxy voting decisions that it makes on behalf of advisory clients, including the Funds, and to help ensure that such decisions are made in accordance with BlackRock's fiduciary obligations to its clients. Nevertheless, notwithstanding such proxy voting policies and procedures, actual proxy voting decisions of BlackRock may have the effect of favoring the interests of other clients or businesses of other divisions or units of BlackRock and/or its Affiliates or a BAC/Barclays Entity, provided that BlackRock believes such voting decisions to be in accordance with its fiduciary obligations. For a more detailed discussion of these policies and procedures, see "Proxy Voting Policies of the Master Portfolios."

It is also possible that, from time to time, BlackRock or its Affiliates or a BAC/Barclays Entity may, although they are not required to, purchase and hold shares of a Fund. Increasing a Fund's assets may enhance investment flexibility and diversification and may contribute to economies of scale that tend to reduce the Fund's expense ratio. BlackRock and its Affiliates or BAC/Barclays Entities reserve the right to redeem at any time some or all of the shares of a Fund acquired for their own accounts. A large redemption of shares of a Fund by BlackRock or its Affiliates or by a BAC/Barclays Entity could significantly reduce the asset size of the Fund, which might have an adverse effect on the Fund's investment flexibility, portfolio diversification and expense ratio. BlackRock will consider the effect of redemptions on a Fund and other shareholders in deciding whether to redeem its shares.

It is possible that a Fund may invest in securities of companies with which an Affiliate or a BAC/Barclays Entity has or is trying to develop investment banking relationships as well as securities of entities in which BlackRock or its Affiliates or a BAC/Barclays Entity has significant debt or equity investments or in which an Affiliate or BAC/Barclays Entity makes a market. A Fund also may invest in securities of companies to which an Affiliate or a BAC/Barclays Entity provides or may some day provide research coverage. Such investments could cause conflicts between the interests of a Fund and the interests of other clients of BlackRock or its Affiliates or a BAC/Barclays Entity. In making investment decisions for a Fund, BlackRock is not permitted to obtain or use material non-public information acquired by any division, department or Affiliate of BlackRock or of a BAC/Barclays Entity in the course of these activities. In addition, from time to time, the activities of an Affiliate or a BAC/Barclays Entity may limit a Fund's flexibility in purchases and sales of securities. When an Affiliate is engaged in an underwriting or other distribution of securities of an entity, BlackRock may be prohibited from purchasing or recommending the purchase of certain securities of that entity for a Fund.

BlackRock and its Affiliates and the BAC/Barclays Entities, their personnel and other financial service providers have interests in promoting sales of the Funds. With respect to BlackRock and its Affiliates and BAC/Barclays Entities and their personnel, the remuneration and profitability relating to services to and sales of the Funds or other products may be greater than remuneration and profitability relating to services to and sales of certain funds or other products that might be provided or offered. BlackRock and its Affiliates or BAC/Barclays Entities and their sales personnel may directly or indirectly receive a portion of the fees and commissions charged to the Funds or their shareholders. BlackRock and its advisory or other personnel may also benefit from increased amounts of assets under management. Fees and commissions may also be higher than for other products or services, and the remuneration and profitability to BlackRock or its Affiliates or a BAC/Barclays Entity and such personnel resulting from transactions on behalf of or management of the Funds may be greater than the remuneration and profitability resulting from other funds or products.

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BlackRock and its Affiliates or a BAC/Barclays Entity and their personnel may receive greater compensation or greater profit in connection with an account for which BlackRock serves as an adviser than with an account advised by an unaffiliated investment adviser. Differentials in compensation may be related to the fact that BlackRock may pay a portion of its management fee to its Affiliate or to a BAC/Barclays Entity, or relate to compensation arrangements, including for portfolio management, brokerage transactions or account servicing. Any differential in compensation may create a financial incentive on the part of BlackRock or its Affiliates or BAC/Barclays Entities and their personnel to recommend BlackRock over unaffiliated investment advisers or to effect transactions differently in one account over another.

BlackRock and its Affiliates or a BAC/Barclays Entity may provide valuation assistance to certain clients with respect to certain securities or other investments and the valuation recommendations made for their clients' accounts may differ from the valuations for the same securities or investments assigned by a Fund's pricing vendors, especially if such valuations are based on broker-dealer quotes or other data sources unavailable to the Fund's pricing vendors. While BlackRock will generally communicate its valuation information or determinations to a Fund's pricing vendors and/or fund accountants, there may be instances where the Fund's pricing vendors or fund accountants assign a different valuation to a security or other investment than the valuation for such security or investment determined or recommended by BlackRock.

As disclosed in more detail in "Determination of Net Asset Value" in this SAI, when market quotations are not readily available or are believed by BlackRock to be unreliable, a Fund's investments may be valued at fair value by BlackRock, pursuant to procedures adopted by the Trust's Board of Trustees. When determining an asset's "fair value," BlackRock seeks to determine the price that a Fund might reasonably expect to receive from the current sale of that asset in an arm's-length transaction. The price generally may not be determined based on what a Fund might reasonably expect to receive for selling an asset at a later time or if it holds the asset to maturity. While fair value determinations will be based upon all available factors that BlackRock deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models, fair value represents only a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a Fund's net asset value. As a result, a Fund's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued by BlackRock (pursuant to Board-adopted procedures) at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

To the extent permitted by applicable law, a Fund may invest all or some of its short term cash investments in any money market fund or similarly-managed private fund advised or managed by BlackRock. In connection with any such investments, a Fund, to the extent permitted by the 1940 Act, may pay its share of expenses of a money market fund in which it invests, which may result in a Fund bearing some additional expenses.

BlackRock and its Affiliates or a BAC/Barclays Entity and their directors, officers and employees, may buy and sell securities or other investments for their own accounts, and may have conflicts of interest with respect to investments made on behalf of a Fund. As a result of differing trading and investment strategies or constraints, positions may be taken by directors, officers, employees and Affiliates of BlackRock or by BAC/Barclays Entities that are the same, different from or made at different times than positions taken for a Fund. To lessen the possibility that a Fund will be adversely affected by this personal trading, the Trust, SEI and BFA each have adopted a Code of Ethics in compliance with Section 17(j) of the 1940 Act that restricts securities trading in the personal accounts of investment professionals and others who normally come into possession of information regarding the Fund's portfolio transactions. Each Code of Ethics can be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling the SEC at (202) 551-8090. Each Code of Ethics is also available on the EDGAR Database on the SEC's Internet site at http://www.sec.gov, and copies may be obtained, after paying a duplicating fee, by e-mail at publicinfo@sec.gov or by writing the SEC's Public Reference Section, Washington, DC 20549-1520.

BlackRock and its Affiliates will not purchase securities or other property from, or sell securities or other property to, a Fund, except that the Fund may in accordance with rules adopted under the 1940 Act engage in transactions with accounts that are affiliated with the Fund as a result of common officers, directors, or investment advisers or pursuant to exemptive orders granted to the Funds and/or BlackRock by the SEC. These transactions would be affected in circumstances in which BlackRock determined that it would be appropriate for a Fund to purchase and another client of BlackRock to sell, or a Fund to sell and another client of BlackRock to purchase, the same security or instrument on the same day. From time to time, the activities of a Fund may be restricted because of regulatory requirements applicable to BlackRock or its Affiliates or a BAC/Barclays Entity and/or BlackRock's internal policies designed to comply with, limit the applicability of, or otherwise

36

relate to such requirements. A client not advised by BlackRock would not be subject to some of those considerations. There may be periods when BlackRock may not initiate or recommend certain types of transactions, or may otherwise restrict or limit their advice in certain securities or instruments issued by or related to companies for which an Affiliate or a BAC/Barclays Entity is performing investment banking, market making, advisory or other services or has proprietary positions. For example, when an Affiliate is engaged in an underwriting or other distribution of securities of, or advisory services for, a company, the Funds may be prohibited from or limited in purchasing or selling securities of that company. In addition, when BlackRock is engaged to provide advisory or risk management services for a company, BlackRock may be prohibited from or limited in purchasing or selling securities of that company on behalf of a Fund, particularly where such services result in BlackRock obtaining material non-public information about the company. Similar situations could arise if personnel of BlackRock or its Affiliates or a BAC/Barclays Entity serve as directors of companies the securities of which the Funds wish to purchase or sell. However, if permitted by applicable law, and where consistent with BlackRock's policies and procedures (including the necessary implementation of appropriate information barriers), the Funds may purchase securities or instruments that are issued by such companies, are the subject of an underwriting, distribution, or advisory assignment by an Affiliate or a BAC/Barclays Entity or are the subject of an advisory or risk management assignment by BlackRock, or where personnel of BlackRock or its Affiliates or of BAC/Barclays Entities are directors or officers of the issuer.

In certain circumstances where the Funds invest in securities issued by companies that operate in certain regulated industries, in certain emerging or international markets, or are subject to corporate or regulatory ownership definitions, there may be limits on the aggregate amount invested by Affiliates (including BlackRock) or BAC/Barclays Entities for their proprietary accounts and for client accounts (including the Funds) that may not be exceeded without the grant of a license or other regulatory or corporate consent, or, if exceeded, may cause BlackRock, the Funds or other client accounts to suffer disadvantages or business restrictions. As a result, BlackRock on behalf of its clients (including the Funds) may limit purchases, sell existing investments, or otherwise restrict or limit the exercise of rights (including voting rights) when BlackRock, in its sole discretion, deems it appropriate in light of potential regulatory or other restrictions on ownership or other consequences resulting from reaching investment thresholds.

In those circumstances where ownership thresholds or limitations must be observed, BlackRock seeks to equitably allocate limited investment opportunities among clients (including the Funds), taking into consideration benchmark weight and investment strategy. When ownership in certain securities nears an applicable threshold, BlackRock may limit purchases in such securities to the issuer's weighting in the applicable benchmark used by BlackRock to manage the Fund. If client (including Fund) holdings of an issuer exceed an applicable threshold and BlackRock is unable to obtain relief to enable the continued holding of such investments, it may be necessary to sell down these positions to meet the applicable limitations. In these cases, benchmark overweight positions will be sold prior to benchmark positions being reduced to meet applicable limitations.

In addition to the foregoing, other ownership thresholds may trigger reporting requirements to governmental and regulatory authorities, and such reports may entail the disclosure of the identity of a client or BlackRock's intended strategy with respect to such security or asset.

BlackRock and its Affiliates and BAC/Barclays Entities may maintain securities indexes as part of their product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including BlackRock and its Affiliates and BAC/Barclays Entities may be paid licensing fees for use of their index or index name. BlackRock and its Affiliates and BAC/Barclays Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with BlackRock and its Affiliates and BAC/Barclays Entities will be as favorable as those terms offered to other index licensees.

BlackRock and its Affiliates and BAC/Barclays Entities may serve as authorized participants in the creation and redemption of ETFs, including funds advised by affiliates of BlackRock. BlackRock and its Affiliates and BAC/Barclays Entities may therefore be deemed to be participants in a distribution of such ETFs, which could render them statutory underwriters.

The custody arrangement described in "Investment Adviser and Other Service Providers" may lead to potential conflicts of interest with BFA where BFA has agreed to waive fees and/or reimburse ordinary operating expenses in order to cap expenses of the Funds. This is because the custody arrangements with the Funds' custodian may have the effect of reducing custody fees when the Funds leave cash balances uninvested. When a Fund's actual operating expense ratio exceeds a stated cap, a reduction in custody fees reduces the amount of waivers and/or reimbursements BFA would be required to make to the Fund. This could be viewed as having the potential to provide BFA an incentive to keep high positive cash balances for Funds with expense caps in order to offset fund custody fees that BFA might otherwise reimburse. However, portfolio managers of BFA do not intentionally keep uninvested balances high, but rather make investment decisions that they anticipate will be beneficial to fund performance.

Present and future activities of BlackRock and its Affiliates and BAC/Barclays Entities, including BlackRock Advisers, LLC, in addition to those described in this Section, may give rise to additional conflicts of interest.

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Investment Adviser and Other Service Providers

INVESTMENT ADVISER. The Funds are feeder funds in a master/feeder structure. As a result each Fund invests all of its assets in a related Master Portfolio of MIP. The Master Portfolios have retained BFA as the investment adviser to manage their assets.

ADVISORY FEES. BFA is entitled to receive monthly fees at the annual rate of 0.10% of each Master Portfolio's average daily net assets. From time to time, BFA may waive such fees in whole or in part. Any such waiver will reduce the expenses of each Master Portfolio and, accordingly, have a favorable impact on its performance. BFA has contractually agreed to waive a portion of its management fees and accept payment at an annual rate of 0.07% from May 1, 2006 through close of business on November 30, 2011 with respect to each Master Portfolio. Pursuant to the advisory contracts between BFA and MIP on behalf of the Master Portfolios ("Advisory Contracts"), BFA furnishes MIP's Board of Trustees with periodic reports on the investment strategy and performance of the Master Portfolios.

BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc.

The applicable Advisory Contract is subject to annual approval by (i) MIP's Board of Trustees or (ii) the vote of a majority (as defined in the 1940 Act) of the outstanding voting interests of such Master Portfolio, provided that in either event the continuance also is approved by a majority of MIP's Board of Trustees who are not "interested persons" (as defined in the 1940 Act) of MIP, by a vote cast in person at a meeting called for the purpose of voting on such approval. The applicable Advisory Contract is terminable without penalty, on 60 days' written notice, by either party. The applicable Advisory Contract will terminate automatically, as to the relevant Master Portfolio, in the event of its assignment (as defined in the 1940 Act).

For the fiscal years shown below, the related Master Portfolio of each Fund paid, with respect to the Funds, the following management fees to BFA, net of waivers and/or offsetting credits:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                $6,437,462            $7,351,730          $ 9,745,383
BlackRock Cash Funds: Institutional        $4,501,600            $2,987,792          $16,321,027
BlackRock Cash Funds: Government           $   80,695            $  338,656          $   362,946
BlackRock Cash Funds: Treasury               ($12,949)           $  105,393          $ 1,218,613

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For the fiscal years shown below, BFA waived the following management fees with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $3,165,643           $5,840,665          $4,271,088
BlackRock Cash Funds: Institutional         $1,952,742           $1,738,528          $7,143,778
BlackRock Cash Funds: Government            $   45,410           $  385,042          $  423,221
BlackRock Cash Funds: Treasury              $  153,279           $  455,287          $1,502,333

The fees and expenses of the Independent Trustees of MIP, counsel to the Independent Trustees of MIP, and the independent registered public accounting firm that provides audit services in connection with the Master Portfolios (collectively referred to as the "MIP Independent Expenses") are paid directly by the Master Portfolios. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to each Master Portfolio for such MIP Independent Expenses.

For the fiscal years shown below, BFA provided an offsetting credit for MIP Independent Expenses, in the amounts shown, against management fees paid by the Master Portfolios in which the Funds invest:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $110,458             $142,232            $210,009
BlackRock Cash Funds: Institutional          $ 54,913             $ 68,692            $305,702
BlackRock Cash Funds: Government             $ 25,260             $ 14,818            $ 24,361
BlackRock Cash Funds: Treasury               $ 25,470             $ 14,890            $ 39,602

ADMINISTRATOR. The Trust has engaged BTC to provide certain administration services to the Funds. Pursuant to an Administration Agreement with the Trust, BTC and its affiliates provide as administration services, among other things:
supervision of the administrative operation of the Trust and the Funds, provision of management reporting and treasury administration services, financial reporting, legal and tax services, and preparation of proxy statements and shareholder reports for the Funds. BTC and its affiliates also furnish office space and certain facilities required for conducting the business of the Trust together with all other administrative services that are not being furnished by BFA. BTC and its affiliates also pay the compensation of the Trust's Trustees who are not Independent Trustees and of officers and employees who are affiliated with the Trust. For providing such services, BTC is entitled to a monthly fee at an annual rate of 0.05% of each Fund's average daily net assets for Aon Captives Shares and Institutional Shares, 0.07% of each Fund's average daily net assets for Capital Shares, 0.10% of each Fund's average daily net assets for Premium Shares, 0.15% of each Fund's average daily net assets for Select Shares (0.13% pursuant to BTC's contractual agreement to waive a portion of its administration fees for Select Shares from September 1, 2006 through close of business on November 30, 2011), 0.38% of each Fund's average daily net assets for Trust Shares and 0.02% of each Fund's average daily net assets for SL Agency Shares. BTC has contracted with State Street to provide certain sub-administration services to the Funds. BTC, not the Funds, is responsible for providing compensation to State Street for such services.

BTC also may engage and supervise Shareholder Servicing Agents and Servicing Agents, as defined in "Shareholder Servicing Agents" below, on behalf of the Funds.

In addition, BTC has agreed to bear all costs of the Funds' and the Trust's operations, including, in the case of each Fund's Institutional Shares and BlackRock Cash Funds: Institutional - Aon Captives Shares, shareholder servicing fees of up to 0.05%, in the case of each Fund's Capital Shares, shareholder servicing fees of up to 0.07%, in the case of each Fund's Premium Shares, shareholder servicing fees of up to 0.10%, in the case of each Fund's Select Shares, shareholder servicing fees of up to 0.15%, and, in the case of each Fund's Trust Shares, shareholder servicing fees of up to 0.25% and processing fees of up to 0.13%, but not including brokerage expenses, advisory fees, distribution plan expenses, certain fees and expenses related to the Trust's Independent Trustees and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses.

BTC is not entitled to compensation for providing administration services to a Master Portfolio for so long as BTC is entitled to compensation for providing administration services to the Fund that invests substantially all of its assets in the Master Portfolio, or BTC or an affiliate receives management fees from the Master Portfolio. Each Fund having multiple classes

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allocates all expenses of the Master Portfolio, including the Master Portfolio's management fee, to each share class in proportion to the aggregate net asset value of such class as compared to all classes of the Fund in accordance with the Fund's multi-class plan under Rule 18f-3 under the 1940 Act.

For the fiscal years shown below, the Funds paid the following administration fees to BTC, net of waivers and/or offsetting credits:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $5,744,756           $8,347,734          $7,214,293
BlackRock Cash Funds: Institutional         $3,486,851           $3,284,691          $6,511,988
BlackRock Cash Funds: Government            $  128,229           $  339,160          $  182,842
BlackRock Cash Funds: Treasury              $   60,324           $  137,759          $  532,403

For the fiscal years shown below, BTC waived the following administration fees with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $ 99,502             $262,311            $149,955
BlackRock Cash Funds: Institutional          $975,803             $  9,735            $ 47,541
BlackRock Cash Funds: Government             $  5,123             $ 71,481            $147,384
BlackRock Cash Funds: Treasury               $ 37,194             $201,343            $363,471

The fees and expenses of the Independent Trustees of the Trust, counsel to the Independent Trustees of the Trust, and the independent registered public accounting firm that provides audit services in connection with the Funds (collectively referred to as the "Independent Expenses") are paid directly by the Funds. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to the Funds for such Independent Expenses.

For the fiscal years shown below, BTC provided an offsetting credit, in the amounts shown, against administration fees paid with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $103,690             $151,738            $209,334
BlackRock Cash Funds: Institutional          $ 82,919             $ 60,278            $322,337
BlackRock Cash Funds: Government             $ 18,099             $ 13,706            $ 22,996
BlackRock Cash Funds: Treasury               $ 18,303             $ 13,953            $ 39,037

DISTRIBUTOR. SEI is the distributor for the Funds' shares. SEI is a registered broker-dealer located at One Freedom Valley Drive, Oaks, PA 19456. SEI is a provider of outsourced investment business solutions for fund administration and distribution, asset management and investment systems and processing.

SEI, as the principal underwriter of the Funds within the meaning of the 1940 Act, has entered into a distribution agreement (the "Distribution Agreement") with the Trust pursuant to which SEI has the responsibility for distributing Fund shares. The Distribution Agreement provides that SEI shall act as agent for the Funds for the sale of Fund shares, and may enter into sales support agreements with selling agents that wish to make available Fund shares to their respective customers ("Selling Agents"). BTC presently acts as a Selling Agent, but does not receive any fee from the Funds for such activities. In addition, SEI provides certain compliance related, sales related and other services for the Funds pursuant to a Service Standards Agreement with BTC, and BTC compensates SEI for these services.

BLACKROCK CASH FUNDS: INSTITUTIONAL - AON CAPTIVES SHARES DISTRIBUTION PLAN. With respect solely to BlackRock Cash Funds: Institutional, the Trust has adopted a distribution plan (a "Plan") for its Aon Captives Shares that authorizes, under Section 12(b) of the 1940 Act and Rule 12b-1 thereunder, payment for distribution-related expenses and compensation for distribution-related services, including on-going compensation to selling agents, in connection with Aon Captives Shares.

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The Plan was adopted by the Trust's Board of Trustees, including a majority of the Independent Trustees who had no direct or indirect financial interest in the Plan. The Plan was adopted because of its anticipated benefits to the Fund. The anticipated benefits include: easier and more effective management as a result of steady inflows of cash from the sale of new shares, a reduction in the expense ratio as a result of achieving economies of scale, lower transaction costs or better prices as a result of the ability to purchase larger blocks of securities, and avoidance of the forced sale of securities to meet redemptions that might adversely affect the performance of the Fund. Under the Plan and pursuant to the related Distribution Agreement with SEI, BlackRock Cash Funds: Institutional may pay the Distributor, as compensation for distribution-related services or as reimbursement for distribution-related expenses, monthly fees at the annual rate of up to 0.10% of the average daily NAV of BlackRock Cash Funds: Institutional's Aon Captives Shares. Aon Securities Corporation ("Aon") has executed a Selling Group Agreement with SEI that enables Aon to serve as the exclusive distributor for Aon Captives Shares. Aon Captives Shares are sold primarily to captive insurance companies administered by Aon Insurance Managers, the captive management and risk finance consulting arm of Aon.

The actual fee payable to the Distributor is determined, within such limits, from time to time by mutual agreement between the Trust and the Distributor and will not exceed the maximum sales charges payable by mutual funds sold by members of the Financial Industry Regulatory Authority, Inc. ("FINRA" and f/k/a the National Association of Securities Dealers, Inc. ("NASD")) under the NASD Conduct Rules. The Distributor may enter into selling agreements with one or more selling agents (which may include BTC and its affiliates) under which such agents may receive compensation for distribution-related services from the Distributor, including, but not limited to, commissions or other payments to such agents based on the average daily net assets of BlackRock Cash Funds:
Institutional shares attributable to their customers. The Distributor may retain any portion of the total distribution fee payable thereunder to compensate it for distribution-related services provided by it or to reimburse it for other distribution-related expenses.

The Plan will continue in effect from year to year if such continuance is approved by a majority vote of the Board of Trustees, including a majority of the Independent Trustees. The Distribution Agreement related to the Plan also must be approved by such vote of the Board of Trustees, including a majority of the Independent Trustees. The Distribution Agreement will terminate automatically if assigned and may be terminated at any time, without payment of any penalty, by a vote of a majority of the outstanding voting securities of Aon Captives Shares of the Fund or by the vote of a majority of the Independent Trustees on not more than 60 days' written notice. The Plan may not be amended to increase materially the amounts payable thereunder without the approval of a majority of the outstanding voting securities of the Fund, and no material amendment to the Plan may be made except by a majority of both the Board of Trustees and the Independent Trustees. The Plan requires that the Treasurer of the Trust shall provide to the Trustees, and the Trustees shall review, at least quarterly, a written report of the amounts expended (and purposes therefor) under the Plan. Rule 12b-1 also requires that the selection and nomination of Independent Trustees be made by such Independent Trustees.

BlackRock Cash Funds: Institutional currently does not have a distribution plan in place for its Premium, Capital, Institutional, Select or Trust Shares. Shareholders of Premium, Capital, Institutional, Select or Trust Shares of each Fund do not pay any fees for distribution services.

For the fiscal year ended December 31, 2009, Aon Captives Shares of BlackRock Cash Funds: Institutional paid distribution fees in the amount of $87,421 under the Plan. Payments are made by the Fund pursuant to the Plan regardless of expenses incurred by the Distributor. In addition to payments received from the Fund, selling or servicing agents may receive significant additional payments directly from BTC, BFA, SEI or their affiliates in connection with the sale of Fund shares.

SHAREHOLDER SERVICING AGENTS. Premium, Capital, Institutional, Select and Trust Shares of the Funds have adopted a Shareholder Servicing Plan pursuant to which they have entered into Shareholder Servicing Agreements with BTC and other entities, and BTC may also enter into Shareholder Servicing Agreements with such other entities (including BlackRock, SEI, BAC, Merrill Lynch, PNC, Barclays and their affiliates) (collectively, "Shareholder Servicing Agents") for the provision of certain services to Fund shareholders.

Trust Shares of the Funds have also adopted a Shareholder Servicing and Processing Plan pursuant to which they or BTC have entered into Shareholder Servicing and Processing Agreements with certain financial institutions, securities dealers and other industry professionals (collectively, "Servicing Agents") for providing services to the Trust Class shareholders.

The Shareholder Servicing Plan services provided by BTC or Shareholder Servicing Agents may include serving as an agent of the Funds for purposes of accepting orders for purchases and redemptions of Fund shares, providing administrative support and account service such as processing purchases and redemptions of shares on behalf of individual and omnibus Fund

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accounts, answering shareholder inquiries, keeping records, transmitting reports and communications from the Funds, and providing reports on the status of individual and omnibus accounts. Shareholder Servicing Agents may provide these services, in whole or in part, by operating electronic transaction systems or websites through which shareholders may obtain information or engage in purchase or redemption transactions of Fund shares. By operating these systems or providing other services described above, the Shareholder Servicing Agents make the Funds available to their clients.

A Shareholder Servicing Agent may make decisions about which investment options it will service and make available to its clients based on the payments the Shareholder Servicing Agent may be eligible to receive for its services. Therefore, payments to a Shareholder Servicing Agent may create potential conflicts of interest between the Shareholder Servicing Agent and its clients where the Shareholder Servicing Agent determines which investment options it will make available to those clients.

Pursuant to its Administration Agreement with the Trust, as described in the section entitled "Administrator," BTC pays shareholder servicing fees to certain Shareholder Servicing Agents in amounts not exceeding maximum fee rates approved by the Trust's Board of Trustees, for those shareholder servicing, sub-administration, recordkeeping, sub-transfer agency and processing services that the Shareholder Servicing Agents perform for their clients that would otherwise be performed by BTC or the Funds' other service providers. For providing some or all of these services, each Shareholder Servicing Agent is entitled to receive a monthly fee at the annual rate of up to 0.05% of the average daily net assets of each Fund represented by Institutional Shares owned, up to 0.07% of the average daily net assets of each Fund represented by Capital Shares owned, up to 0.10% of the average daily net assets of each Fund represented by Premium Shares owned, up to 0.15% of the average daily net assets of each Fund represented by Select Shares owned, and up to 0.25% of the average daily net assets of each Fund represented by Trust Shares owned during the period for which payment is being made by investors with whom the Shareholder Servicing Agent maintains a servicing relationship, or an amount that equals the maximum amount payable to the Shareholder Servicing Agent under applicable laws, regulations or rules, including the NASD Conduct Rules, whichever is less.

Pursuant to the Shareholder Servicing and Processing Plan for Trust Shares, Servicing Agents provide personal services relating to the aggregation and processing of purchase and redemption orders, processing of dividend payments, certain sub-accounting services, transmission and receipt of funds in connection with purchase and redemption orders, verification of certain personal information in connection with the purchase or redemption of Fund shares, and generating and distributing periodic statements and other information as required. For these services, each Servicing Agent is entitled to receive a monthly fee at the annual rate of up to 0.13% of the average daily net assets of each Fund represented by Trust Shares owned during the period for which payment is being made by investors with whom the Servicing Agent maintains a servicing arrangement.

For the fiscal years shown below, BTC paid shareholder servicing fees on behalf of the Funds in the following amounts:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $1,673,484           $2,934,362          $2,982,157
BlackRock Cash Funds: Institutional         $1,614,028           $1,004,246          $1,029,863
BlackRock Cash Funds: Government            $   88,618           $   71,378          $   51,666
BlackRock Cash Funds: Treasury              $   37,357           $   35,232          $  110,867

A Shareholder Servicing Agent (or Servicing Agent for the Trust Class) also may impose certain conditions on its customers, subject to the terms of the Funds' Prospectuses and this SAI, that are in addition to or different from those imposed by the Trust, such as requiring a minimum initial investment or payment of a separate fee for additional services.

Shareholder Servicing Agents may charge their clients additional fees for account-related services. Shareholder Servicing Agents may charge their customers a service fee in connection with the purchase or redemption of Fund shares. The amount and applicability of such a fee is determined and disclosed to its customers by each individual Shareholder Servicing Agent. Service fees typically are fixed, nominal dollar amounts and are in addition to the sales and other charges described in the Prospectuses and this SAI. Your Shareholder Servicing Agent will provide you with specific information about any service fees you will be charged.

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NON-PLAN PAYMENTS. BlackRock may make payments relating to distribution and sales support activities out of their past profits or other sources available to them (and not as an additional charge to a Fund). From time to time, BlackRock or its affiliates may compensate affiliated and unaffiliated entities (including BlackRock, SEI, BAC, Merrill Lynch, PNC, Barclays and their affiliates, and entities that may also be serving as distribution agents or Shareholder Servicing Agents of the Fund) (collectively, "Service Organizations") for the sale and distribution of shares of a Fund or for services to a Fund and its shareholders. These payments that are not associated with a Shareholder Servicing Plan or distribution plan and are therefore referred to as "non-Plan payments". The non-Plan payments would be in addition to a Fund's payments described in this SAI for distribution (if the Fund has adopted a distribution plan pursuant to Rule 12b-1) and shareholder servicing. These non-Plan payments may take the form of, among other things, "due diligence" payments for a dealer's examination of the Funds and payments for providing extra employee training and information relating to Funds; "listing" fees for the placement of the Funds on a dealer's list of mutual funds available for purchase by its customers; "finders" fees for directing investors to the Fund; "distribution and marketing support" fees or "revenue sharing" for providing assistance in promoting the sale of the Funds' shares; payments for the sale of shares and/or the maintenance of share balances; CUSIP fees; maintenance fees; and set-up fees regarding the establishment of new accounts. The payments made by BlackRock and its affiliates may be a fixed dollar amount or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization involved, and may be different for different Service Organizations. The payments described above are made from BlackRock's or its affiliates' own assets pursuant to agreements with Service Organizations and do not change the price paid by investors for the purchase of the Fund's shares or the amount the Fund will receive as proceeds from such sales.

The payments described above may be made, at the discretion of BlackRock or its affiliates, to Service Organizations in connection with the sale and distribution of Fund shares. Pursuant to applicable FINRA regulations, the details of certain of these payments, including the Service Organizations receiving such payments in connection with the sale and distribution of Fund shares, are required to be disclosed. The level of payments made to these Service Organizations in any year will vary and normally will not exceed the sum of (a) 0.25% of such year's Fund sales by that Service Organization, and
(b) 0.21% of the assets attributable to that Service Organization invested in a Fund. As of the date of this SAI, as amended or supplemented from time to time, the following Service Organizations are receiving such payments in association with sale and distribution of products other than the Funds, that are advised or offered by BlackRock or its affiliates: Ameriprise Financial Services, Inc., AXA Advisors, LLC, Banc of America Investment Services, Inc., Citigroup, Financial Network Investment Corporation, LPL Financial Corporation, Merrill Lynch, MetLife Securities, Inc., Morgan Stanley, Multi-Financial Services Corporation, New England Securities Corporation, Oppenheimer & Co. Inc., PrimeVest Financial Services, Raymond James & Associates, Inc., Raymond James Financial Services, Inc., RBC Capital Markets, Tower Square Securities Inc., UBS, Wachovia Securities, Walnut Street Securities Inc., Commonwealth Equity Services, LLP (Commonwealth Financial Network), Wells Fargo and/or broker-dealers and other financial services firms under common control with the above organizations (or their assignees).

OTHER DISTRIBUTION ARRANGEMENTS. If investment advisers, distributors or affiliates of mutual funds pay bonuses and incentives in differing amounts, financial firms and their financial consultants may have financial incentives for recommending a particular mutual fund over other mutual funds. In addition, depending on the arrangements in place at any particular time, a financial firm and its financial consultants may also have a financial incentive for recommending a particular share class over other share classes. You should consult your financial adviser and review carefully any disclosure by the financial firm as to compensation received by your financial adviser for more information about the payments described above.

Furthermore, BlackRock and its affiliates may contribute to various non-cash and cash incentive arrangements to promote the sale of shares, and may sponsor various contests and promotions subject to applicable FINRA regulations in which participants may receive prizes such as travel awards, merchandise and cash. Subject to applicable FINRA regulations, BlackRock and its affiliates may also: (i) pay for the travel expenses, meals, lodging and entertainment of broker/dealers, financial institutions and their salespersons in connection with educational and sales promotional programs, (ii) sponsor speakers, educational seminars and charitable events and (iii) provide other sales and marketing conferences and other resources to broker-dealers, financial institutions and their salespersons.

CUSTODIAN. State Street has been retained to act as custodian for the Funds and the Master Portfolios and is located at 200 Clarendon Street, Boston, MA 02116. The custodian, among other things, maintains a custody account or accounts in the name of the Funds and the Master Portfolios; receives and delivers all assets for each Fund and each Master Portfolio upon purchase and upon sale or maturity, and collects and receives all income and other payments and distributions on account of

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the assets of the Funds and the Master Portfolios. State Street is not entitled to compensation for providing custody services to each Fund and each Master Portfolio pursuant to the Custody Agreement so long as it receives compensation from BTC for providing sub-administration services to the Trust, on behalf of the Funds.

TRANSFER AND DIVIDEND DISBURSING AGENT. State Street has also been retained to act as the transfer and dividend disbursing agent for the Funds and the Master Portfolios. For its services as transfer and dividend disbursing agent to the Funds and the Master Portfolios, State Street is paid fees based on the Funds' and the Master Portfolios' net assets. State Street is entitled to be reimbursed for out-of-pocket expenses or advances incurred by it in performing its obligations under the Transfer Agency Agreement. BTC has agreed to pay these fees and expenses pursuant to its Administration Agreement with the Trust. In addition, the Transfer Agency Agreement contemplates that State Street will be reimbursed for other expenses incurred by it at the request or with the written consent of the Funds, including, without limitation, any equipment or supplies that the Trust specifically orders or requires State Street to order.

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM. PricewaterhouseCoopers LLP, located at Three Embarcadero Center, San Francisco, CA 94111, serves as the independent registered public accounting firm for the Trust.

LEGAL COUNSEL. Sidley Austin LLP, located at 787 Seventh Avenue, New York, NY 10019, serves as legal counsel to the Trust, MIP and BFA.

Determination of Net Asset Value

The Master Portfolios use the amortized cost method to determine the value of their respective securities pursuant to Rule 2a-7 under the 1940 Act. The amortized cost method involves valuing a security at its cost and amortizing any discount or premium over the period until maturity, regardless of the impact of fluctuating interest rates on the market value of the security. While this method provides certainty in valuation, it may result in periods during which the value, as determined by amortized cost, is higher or lower than the price that the Funds would receive if the security were sold. During these periods the yield to a shareholder may differ somewhat from that which could be obtained from a similar fund that uses a method of valuation based upon market prices. Thus, during periods of declining interest rates, if the use of the amortized cost method results in a lower value of each Fund's portfolio on a particular day, a prospective investor in the Funds would be able to obtain a somewhat higher yield than would result from making an investment in the Funds using solely market values, and existing Fund shareholders would receive correspondingly less income. The converse would apply during periods of rising interest rates.

Rule 2a-7 provides that in order to value their portfolios using the amortized cost method, the Funds must maintain a dollar-weighted average portfolio maturity of 90 days or less, purchase securities having remaining maturities (as defined in Rule 2a-7) of 397 calendar days (about 13 months) or less, and invest only in those high-quality securities that are determined by the Board of Trustees to present minimal credit risks. The maturity of an instrument is generally deemed to be the period remaining until the date when the principal amount thereof is due or the date on which the instrument is to be redeemed. However, Rule 2a-7 provides that the maturity of an instrument may be deemed shorter in the case of certain instruments, including certain variable-rate and floating-rate instruments subject to demand features. Pursuant to Rule 2a-7, the Board is required to establish procedures designed to stabilize, to the extent reasonably possible, each Fund's price per share as computed for the purpose of sales and redemptions at $1.00. Such procedures include review of each Fund's portfolio holdings by the Board of Trustees, at such intervals as it may deem appropriate, to determine whether a Fund's net asset value per share as determined by using available market quotations (or an appropriate substitute which reflects current market conditions) deviates from $1.00 per share based on amortized cost. The extent of any deviation will be examined by the Board of Trustees. If such deviation exceeds 1/2 of 1%, the Board will promptly consider what action, if any, will be initiated. In the event the Board determines that a deviation exists that may result in material dilution or other unfair results to shareholders, the Board will take such corrective action as it regards as necessary and appropriate, such action may include redeeming shares in-kind, selling portfolio securities prior to maturity, reducing or withholding dividends, shortening the average portfolio maturity, reducing the number of outstanding shares without monetary consideration, and utilizing a net asset value per share as determined by using available market quotations.

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Purchase, Redemption and Pricing of Shares

TERMS OF PURCHASE AND REDEMPTION. The Funds are generally open Monday through Friday and are closed on weekends and are generally closed on all other days that the Fedwire Funds Service (the "Fedwire") is closed or the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on any day the Funds are open (a "Business Day") prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day. BlackRock Cash Funds:
Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00 p.m. Eastern time) on such Business Day. The holidays on which both the Fedwire and the primary markets for the Master Portfolios' portfolio securities are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. Each Fund reserves the right to change the amount of the minimum investment and subsequent purchases in the Fund. An investor's investment in the Funds and/or other investment vehicles managed or maintained by BFA or its affiliates may be aggregated when determining whether an investor meets a minimum investment amount. The minimum initial investment amounts for the classes of the Funds may be reduced or waived by BFA. On any day a Fund closes early, purchase and redemption orders received after the Funds' closing time will be executed on the next business day. In addition, the Funds reserve the right to advance the time by which purchase and redemption orders must be received to be executed on the same business day as permitted by the SEC and applicable law.

IN-KIND PURCHASES. Payment for shares of the Funds may, at the discretion of BFA, be made in the form of securities that are permissible investments for the Funds and must meet the investment objectives, policies and limitations of the Funds as described in their Prospectuses. In connection with an in-kind securities payment, the Funds may require, among other things, that the securities (i) be valued on the day of purchase in accordance with the pricing methods used by the Funds or the Master Portfolios; (ii) are accompanied by satisfactory assurance that the Funds will have good and marketable title to such securities received by them; (iii) are not subject to any restrictions upon resale by the Funds; (iv) be in proper form for transfer to the Funds; and
(v) are accompanied by adequate information concerning the basis and other tax matters relating to the securities. All dividends, interest, subscription or other rights pertaining to such securities shall become the property of the Funds engaged in the in-kind purchase transaction and must be delivered to such Fund or Funds by the investor upon receipt from the issuer. Securities acquired through an in-kind purchase will be acquired for investment and not for immediate resale. A Fund immediately will transfer to its Master Portfolio any and all securities received by it in connection with an in-kind purchase transaction, in exchange for interests in such Master Portfolio. Shares purchased in exchange for securities generally cannot be redeemed until the transfer has settled.

SUSPENSION OF REDEMPTION RIGHTS OR PAYMENT OF REDEMPTION PROCEEDS. The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, each Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances. Generally, those extraordinary circumstances are when (i) the New York Stock Exchange ("NYSE") is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the SEC by order may permit.

DECLARATION OF TRUST PROVISIONS REGARDING REDEMPTIONS AT OPTION OF TRUST. As provided in the Trust's Declaration of Trust, the Trustees may require shareholders to redeem shares for any reason under terms set by the Trustees, including, but not limited to, the failure of a shareholder to supply a taxpayer identification number if required to do so, or to have the minimum investment required, or to pay when due for the purchase of shares issued to such shareholder.

Portfolio Transactions

Since the Funds invest all of their assets in portfolios of MIP, set forth below is a description of the Master Portfolios' policies governing portfolio securities transactions.

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GENERAL. Subject to policies established by the Board of Trustees, BFA is primarily responsible for the execution of a Master Portfolio's portfolio transactions and the allocation of brokerage. BFA does not execute transactions through any particular broker or dealer, but seeks to obtain the best net results for the Master Portfolio, taking into account such factors as price (including the applicable brokerage commission or dealer spread), size of order, difficulty of execution, operational facilities of the firm and the firm's risk and skill in positioning blocks of securities. While BFA generally seeks reasonable trade execution costs, a Master Portfolio does not necessarily pay the lowest spread or commission available, and payment of the lowest commission or spread is not necessarily consistent with obtaining the best price and execution in particular transactions. The following disclosure provides some more detail regarding the Master Portfolio's practices regarding Portfolio Transactions. Depending on its investment objective, a Master Portfolio may not engage in some of the transactions described below.

BFA does not consider the provision or value of research, products or services a broker or dealer may provide, if any, as a factor in the selection of a broker or dealer or the determination of the reasonableness of commissions paid in connection with portfolio transactions. BFA does not consider sales of shares of the mutual funds it advises as a factor in the selection of brokers or dealers to execute portfolio transactions for a Master Portfolio; however, whether or not a particular broker or dealer sells shares of the mutual funds advised by BFA neither qualifies nor disqualifies such broker or dealer to execute transactions for those mutual funds.

A Master Portfolio's purchase and sale orders for securities may be combined with those of other accounts that BFA manages or advises, and for which it has brokerage placement authority. If purchases or sales of portfolio securities of a Master Portfolio and one or more other accounts managed or advised by BFA are considered at or about the same time, transactions in such securities are allocated among the Master Portfolio and the other accounts in a manner deemed equitable to all by BFA. In some cases, this procedure could have a detrimental effect on the price or volume of the security as far as a Master Portfolio is concerned. However, in other cases, it is possible that the ability to participate in volume transactions and to negotiate lower brokerage commissions will be beneficial to a Master Portfolio.

Payments of commissions to brokers who are affiliated persons of the Master Portfolio with respect to the Fund (or affiliated persons of such persons), will be made in accordance with Rule 17e-1 under the 1940 Act.

Each Master Portfolio anticipates that its brokerage transactions involving foreign securities generally will be conducted primarily on the principal stock exchanges of the applicable country. Foreign equity securities may be held by a Master Portfolio in the form of depositary receipts, or other securities convertible into foreign equity securities. Depositary receipts may be listed on stock exchanges, or traded in over-the-counter markets in the United States or Europe, as the case may be. American Depositary Receipts, like other securities traded in the United States, will be subject to negotiated commission rates. Because the shares of each Fund and interests of the Master Portfolios are redeemable on a daily basis in U.S. dollars, each Master Portfolio intends to manage its portfolio so as to give reasonable assurance that it will be able to obtain U.S. dollars to the extent necessary to meet anticipated redemptions. Under present conditions, it is not believed that these considerations will have a significant effect on a Master Portfolio's portfolio strategies.

Each Master Portfolio may invest in certain securities traded in the over-the-counter ("OTC") market and intends to deal directly with the dealers who make a market in the particular securities, except in those circumstances in which better prices and execution are available elsewhere. Under the 1940 Act, persons affiliated with a Master Portfolio and persons who are affiliated with such affiliated persons are prohibited from dealing with the Master Portfolio as principal in the purchase and sale of securities unless a permissive order allowing such transactions is obtained from the SEC. Since transactions in the OTC market usually involve transactions with the dealers acting as principal for their own accounts, the Master Portfolios will not deal with affiliated persons, including PNC and its affiliates, in connection with such transactions. However, an affiliated person of a Master Portfolio may serve as its broker in OTC transactions conducted on an agency basis provided that, among other things, the fee or commission received by such affiliated broker is reasonable and fair compared to the fee or commission received by non-affiliated brokers in connection with comparable transactions. In addition, a Master Portfolio may not purchase securities during the existence of any underwriting syndicate for such securities of which PNC is a member or in a private placement in which PNC serves as placement agent except pursuant to procedures approved by the Board that either comply with rules adopted by the SEC or with interpretations of the SEC staff.

OTC issues, including most fixed income securities such as corporate debt and U.S. Government securities, are normally traded on a "net" basis without a stated commission, through dealers acting for their own account and not as brokers. The Master Portfolios will primarily engage in transactions with these dealers or deal directly with the issuer unless a better price or execution could be obtained by using a broker. Prices paid to a dealer with respect to both foreign and domestic securities

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will generally include a "spread," which is the difference between the prices at which the dealer is willing to purchase and sell the specific security at the time, and includes the dealer's normal profit.

Purchases of money market instruments by a Master Portfolio are made from dealers, underwriters and issuers. The Master Portfolios do not currently expect to incur any brokerage commission expense on such transactions because money market instruments are generally traded on a "net" basis with dealers acting as principal for their own accounts without a stated commission. The price of the security, however, usually includes a profit to the dealer. Each Master Portfolio intends to purchase only securities with remaining maturities of 13 months or less as determined in accordance with the rules of the SEC and the policies or investment objectives of the Fund and Master Portfolio. As a result, the portfolio turnover rates of a Master Portfolio will be relatively high. However, because brokerage commissions will not normally be paid with respect to investments made by a money market fund, the turnover rates should not adversely affect the Master Portfolio's net asset values or net income.

A Master Portfolio will not purchase securities during the existence of any underwriting or selling group relating to such securities of which BFA, PNC or any affiliated person (as defined in the 1940 Act) thereof is a member except pursuant to procedures adopted by the Board in accordance with Rule 10f-3 under the 1940 Act. In no instance will portfolio securities be purchased from or sold to BFA, PNC or any affiliated person of the foregoing entities except as permitted by SEC exemptive order or by applicable law.

PORTFOLIO TURNOVER. Portfolio turnover may vary from year to year, as well as within a year. Because the portfolios of the Funds consist of securities with relatively short-term maturities, the Funds expect to experience high portfolio turnover. A high portfolio turnover rate should not adversely affect the Funds since portfolio transactions ordinarily will be made directly with principals on a net basis and, consequently, the Funds usually will not incur brokerage expenses or excessive transaction costs.

SECURITIES OF REGULAR BROKER-DEALERS. As of December 31, 2009, none of the Master Portfolios owned securities of their "regular brokers or dealers" (as defined in the 1940 Act) or their parents, except as disclosed below:

MASTER PORTFOLIO                        REGULAR BROKER-DEALER OR PARENT       AMOUNT
-------------------------------------  ---------------------------------  --------------
Money Market Master Portfolio          UBS AG                              $60,000,000
Prime Money Market Master Portfolio    UBS AG                              $30,000,000

Distributions and Taxes

The following information supplements, and should be read in conjunction with, the section in each Prospectus entitled "Account Information - Taxes." The Prospectuses generally describe the U.S. federal income tax treatment of distributions by the Funds. This section of the SAI provides additional information concerning U.S. federal income taxes. It is based on the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), applicable Treasury Regulations, judicial

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authority, and administrative rulings and practice, all as of the date of this SAI and all of which are subject to change, including changes with retroactive effect. The following discussion does not address any state, local or foreign tax matters.

A shareholder's tax treatment may vary depending upon his or her particular situation. This discussion only applies to shareholders who are U.S. persons, I.E., U.S. citizens or residents or U.S. corporations, partnerships, trusts or estates, and who are subject to U.S. federal income tax and hold Fund shares as capital assets within the meaning of the Internal Revenue Code. Except as otherwise noted, it may not apply to certain types of shareholders who may be subject to special rules, such as insurance companies, tax-exempt organizations, shareholders holding Fund shares through tax-advantaged accounts (such as 401(k) plan accounts or individual retirement accounts ("IRAs")), financial institutions, broker-dealers, entities that are not organized under the laws of the United States or a political subdivision thereof, persons who are neither citizens nor residents of the United States, shareholders holding Fund shares as part of a hedge, straddle or conversion transaction, and shareholders who are subject to the U.S. federal alternative minimum tax.

The Trust has not requested and will not request an advance ruling from the Internal Revenue Service (the "IRS") as to the U.S. federal income tax matters described below. The IRS could adopt positions contrary to those discussed below and such positions could be sustained. In addition, the foregoing discussion and the discussions in the Prospectuses applicable to each shareholder address only some of the U.S. federal income tax considerations generally affecting investments in the Funds. Prospective shareholders are urged to consult with their own tax advisers and financial planners as to the particular U.S. federal tax consequences to them of an investment in the Funds, as well as the applicability and effect of any state, local or foreign laws, and the effect of possible changes in applicable tax laws.

QUALIFICATION AS A REGULATED INVESTMENT COMPANY. Each Fund has elected to be treated, has qualified and intends to continue to qualify each year, as a "regulated investment company" under Subchapter M of the Internal Revenue Code as long as such qualification is in the best interests of the Fund's shareholders. Each Fund will be treated as a separate entity for U.S. federal income tax purposes. Thus, the provisions of the Internal Revenue Code applicable to regulated investment companies generally will apply separately to each Fund, even though each Fund is a series of a trust. Furthermore, each Fund separately determines its income, gains, losses and expenses for U.S. federal income tax purposes.

In order to qualify as a regulated investment company under the Internal Revenue Code, each Fund must, among other things, derive at least 90% of its annual gross income from dividends, interest, certain payments with respect to securities loans, gains from the sale or other disposition of stock, securities or foreign currencies, or other income attributable to its business of investing in such stock, securities or foreign currencies (including, but not limited to, gains from options, futures or forward contracts) and net income derived from an interest in a qualified publicly-traded partnership as defined in Section 851(h) of the Internal Revenue Code. Pursuant to regulations that may be promulgated in the future, the IRS may limit qualifying income from foreign currency gains to the amount of such currency gains that are directly related to a regulated investment company's principal business of investing in stock or securities. Each Fund must also diversify its holdings so that, at the end of each quarter of each taxable year: (i) at least 50% of the value of its assets consists of (A) cash and cash items (including receivables), U.S. government securities and securities of other regulated investment companies, and (B) other securities, with such other securities limited, in respect to any one issuer, to an amount not greater than 5% of the value of the Fund's total assets and to not more than 10% of the outstanding voting securities of such issuer and (ii) not more than 25% of the value of the Fund's total assets is invested in (A) the securities (other than U.S. government securities and securities of other regulated investment companies) of any one issuer, (B) the securities (other than the securities of other regulated investment companies) of two or more issuers that the Fund controls and that are engaged in the same, similar, or related trades or businesses, or (C) the securities of one or more qualified publicly-traded partnerships. The qualifying income and diversification requirements applicable to a Fund may limit the extent to which it can engage in transactions in options, futures contracts, forward contracts and swap agreements.

In addition, each Fund generally must distribute to its shareholders an amount equal to or exceeding the sum of (i) 90% of its "investment company taxable income," as that term is defined in the Internal Revenue Code (which generally includes, among other things, dividends, taxable interest, and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses) without regard to the deduction for dividends paid and (ii) 90% of its net tax-exempt income earned in each taxable year. A Fund generally will not be subject to U.S. federal income tax on the investment company taxable income and "net capital gain" (I.E., the excess of net long-term capital gain over net short-term capital loss) it distributes to its shareholders. However, if a Fund meets such distribution requirements, but chooses to retain some portion of its investment company taxable income or net capital gain, it generally will be subject to U.S. federal income tax at regular corporate rates on the amount retained. Although dividends generally will be treated as distributed when paid,

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if a Fund declares a distribution to shareholders of record in October, November or December of one year and pays the distribution by January 31 of the following year, the Fund and its shareholders will be treated as if the Fund paid the distribution by December 31 of the calendar year in which it was declared. Each Fund intends to distribute its net income and gain in a timely manner to maintain its status as a regulated investment company and eliminate fund-level U.S. federal income taxation of such income and gain. However, no assurance can be given that a Fund will not be subject to U.S. federal income taxation.

If, in any taxable year, a Fund fails to qualify as a regulated investment company under the Internal Revenue Code or fails to meet the distribution requirements described above, the Fund would be taxed in the same manner as an ordinary U.S. corporation without any deduction for distributions to shareholders, and all distributions from the Fund's earnings and profits (including any distributions of net tax-exempt income and net capital gain) to its shareholders would also be taxable as ordinary income at the shareholder level. To qualify again to be taxed as a regulated investment company in a subsequent year, the Fund may be required to pay an interest charge and penalty to the IRS as well as distribute to its shareholders its earnings and profits attributable to non-regulated investment company years. In addition, if the Fund fails to qualify as a regulated investment company for a period greater than two taxable years, the Fund may be required to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the Fund had been liquidated) or, alternatively, to be subject to taxation on such built-in gain recognized for a period of ten years, in order to qualify as a regulated investment company in a subsequent year.

EXCISE TAX. A 4% non-deductible excise tax will be imposed on each Fund to the extent it fails to distribute during each calendar year (i) at least 98% of its ordinary income (excluding capital gains and losses) for the calendar year,
(ii) at least 98% of its net capital gain income (generally the excess of capital gains over capital losses as adjusted for ordinary losses) for the 12 month period ending on October 31, and (iii) all of its ordinary income and net capital gain income from previous years that was not distributed or subject to tax during such years. Each Fund intends to distribute substantially all of its net income and gains, if any, by the end of each calendar year and, thus, expects not to be subject to the excise tax. However, no assurance can be given that a Fund will not be subject to the excise tax.

CAPITAL LOSS CARRY-FORWARDS. A Fund is permitted to carry forward a net capital loss from any year to offset its capital gains, if any, realized during the eight years following the year of the loss. A Fund's capital loss carry-forward is treated as a short-term capital loss in the year to which it is carried. If future capital gains are offset by carried-forward capital losses, such future capital gains are not subject to Fund-level U.S. federal income taxation, regardless of whether they are distributed to shareholders. Accordingly, the Funds do not expect to distribute any such capital gains. The Funds cannot carry back or carry forward any net operating losses. As a money market fund, each Fund does not expect to have material capital loss carry-forwards, but no assurance can be given to this effect. As of December 31, 2009, the Funds had capital loss carry-forwards approximating the amount indicated for U.S. federal income tax purposes, expiring in the year indicated:

                                            EXPIRING
FUND                                       12/31/2016
---------------------------------------  -------------
  BlackRock Cash Funds: Prime            $4,310,000
  BlackRock Cash Funds: Institutional         -
  BlackRock Cash Funds: Government            -
  BlackRock Cash Funds: Treasury              -

INVESTMENT THROUGH THE MASTER PORTFOLIOS. The Funds seek to continue to qualify as regulated investment companies by investing their assets through the Master Portfolios. Each Master Portfolio is treated as a non-publicly traded partnership (or, in the event that a Fund is the sole investor in a Master Portfolio, as disregarded from the Fund) for U.S. federal income tax purposes rather than as a regulated investment company or a corporation under the Internal Revenue Code. Under the rules applicable to a non-publicly traded partnership (or disregarded entity), a proportionate share of any interest, dividends, gains and losses of a Master Portfolio will be deemed to have been realized by (I.E., "passed-through" to) its investors, including the corresponding Fund, regardless of whether any amounts are actually distributed by the Master Portfolio. Each investor in a Master Portfolio will be taxable on such share, as determined in accordance with the governing instruments of the particular Master Portfolio, the Internal Revenue Code and Treasury Regulations. Therefore, to the extent that a Master Portfolio were to accrue but not distribute any income or gains, the corresponding Fund would be deemed to have realized its proportionate share of such income or gains without receipt of any corresponding distribution. However, each of the Master Portfolios will

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seek to minimize recognition by its investors (such as the Funds) of income and gains without a corresponding distribution. Furthermore, each Master Portfolio's assets, income and distributions will be managed in such a way that an investor in a Master Portfolio will be able to continue to qualify as a regulated investment company by investing its assets through the Master Portfolio.

TAXATION OF FUND INVESTMENTS. In general, if a Fund realizes gains or losses on the sale of portfolio securities, such gains or losses are capital gains or losses. If the Fund has held the disposed securities for more than one year at the time of disposition, such gains and losses generally are treated as long-term capital gains or losses.

If a Fund purchases a debt obligation with original issue discount ("OID"), generally at a price less than its principal amount, such as a zero-coupon bond, the Fund may be required to annually include in its taxable income a portion of the OID as ordinary income, even though the Fund will not receive cash payments for such discount until maturity or disposition of the obligation. A portion of the OID includible in income with respect to certain high-yield corporate debt securities may be treated as a dividend for U.S. federal income tax purposes. Gains recognized on the disposition of a debt obligation (including a municipal obligation) purchased by a Fund at a market discount, usually at a price less than its principal amount, generally will be treated as ordinary income to the extent of the portion of market discount which accrued, but was not previously recognized pursuant to an available election, during the term that the Fund held the debt obligation. A Fund generally will be required to make distributions to shareholders representing the OID on debt securities that is currently includible in income, even though the cash representing such income may not have been received by the Fund. Cash to pay such distributions may be obtained from borrowing or from sales of securities held by a Fund which the Fund otherwise might have continued to hold.

If an option granted by a Fund lapses or is terminated through a closing transaction, such as a repurchase by the Fund of the option from its holder, the Fund generally will realize a short-term capital gain or loss, depending on whether the premium income is greater or less than the amount paid by the Fund in the closing transaction. If securities are sold by a Fund pursuant to the exercise of a call option granted by it, the Fund will add the premium received to the sale price of the securities delivered in determining the amount of gain or loss on the sale. If securities are purchased by a Fund pursuant to the exercise of a put option written by it, the Fund will subtract the premium received from its cost basis in the securities purchased.

Foreign exchange gains and losses realized by a Fund in connection with certain transactions involving foreign currency-denominated debt securities, certain options and futures contracts relating to foreign currency, foreign currency forward contracts, foreign currencies, or payables or receivables denominated in a foreign currency are subject to Section 988 of the Internal Revenue Code, which generally causes such gains and losses to be treated as ordinary income and losses and may affect the amount and timing of recognition of the Fund's income. Under Treasury Regulations that may be promulgated in the future, any such transactions that are not directly related to a Fund's principal business of investing in stock or securities (or its options contracts or futures contracts with respect to stock or securities) may have to be limited in order to enable the Fund to satisfy the 90% income test described above. If the net foreign exchange loss for a year exceeds a Fund's investment company taxable income (computed without regard to such loss), the resulting ordinary loss for such year will not be deductible by the Fund or its shareholders in future years.

If a Fund enters into a "constructive sale" of any appreciated financial position in stock, a partnership interest, or certain debt instruments, the Fund will be treated as if it had sold and immediately repurchased the property and must recognize gain (but not loss) with respect to that position. A constructive sale occurs when a Fund enters into one of the following transactions with respect to the same or substantially identical property: (i) a short sale; (ii) an offsetting notional principal contract; (iii) a futures or forward contract; or (iv) other transactions identified in Treasury Regulations that may be promulgated in the future. The character of the gain from constructive sales will depend upon a Fund's holding period in the property. Losses from a constructive sale of property will be recognized when the property is subsequently disposed of. The character of such losses will depend upon a Fund's holding period in the property and the application of various loss deferral provisions in the Internal Revenue Code. Constructive sale treatment does not apply to a transaction if such transaction is closed before the end of the 30th day after the close of the Fund's taxable year, the Fund holds the appreciated financial position throughout the 60-day period beginning with the day such transaction was closed, and the Fund's risk of loss with respect to such position is not reduced at any time during such 60-day period.

In addition to the investments described above, prospective shareholders should be aware that other investments made by the Funds may involve sophisticated tax rules that may result in income or gain recognition by the Funds without

50

corresponding current cash receipts. Although the Funds seek to avoid significant non-cash income, such non-cash income could be recognized by the Funds, in which case the Funds may distribute cash derived from other sources in order to meet the minimum distribution requirements described above. In this regard, the Funds could be required at times to liquidate investments prematurely in order to satisfy their minimum distribution requirements.

TAXATION OF DISTRIBUTIONS. For U.S. federal income tax purposes, a Fund's earnings and profits, described above, are determined at the end of the Fund's taxable year and are allocated PRO RATA to distributions made throughout the entire year. All distributions paid out of a Fund's earnings and profits (as determined at the end of the year), whether paid in cash or reinvested in the Fund, generally are deemed to be taxable distributions and must generally be reported on each Fund shareholder's U.S. federal income tax return. Distributions in excess of a Fund's earnings and profits will first be treated as a return of capital up to the amount of a shareholder's tax basis in the shareholder's Fund shares and any such amount in excess of that basis as capital gain from the sale of shares, as discussed below. A Fund may make distributions in excess of earnings and profits to a limited extent, from time to time.

In general, assuming that each Fund has sufficient earnings and profits, distributions from investment company taxable income are taxable as ordinary income. Since each Fund's income is derived from sources that do not pay "qualified dividend income," as defined in Section 1(h)(11)(B) of the Internal Revenue Code, distributions from investment company taxable income of the Funds generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

Distributions designated by a Fund as a "capital gain dividend", if any, will be taxed to shareholders as long-term capital gain (to the extent such distributions do not exceed the Fund's actual net capital gain for the taxable year), regardless of how long a shareholder has held Fund shares. Each Fund will designate capital gains dividends, if any, in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of a Fund's taxable year. Normally the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Distributions from each Fund paid to corporate shareholders are not expected to qualify for the dividends-received deductions generally available to corporate taxpayers. The U.S. federal income tax status of all distributions will be reported to shareholders annually.

Some states will not tax distributions made to individual shareholders that are attributable to interest a Fund earned on direct obligations of the U.S. government if the Fund meets the state's minimum investment or reporting requirements, if any. Investments in Ginnie Mae or Fannie Mae securities, bankers' acceptances, commercial paper and repurchase agreements collateralized by U.S. government securities generally do not qualify for tax-free treatment. This exemption may not apply to corporate shareholders.

SALES OF FUND SHARES. Redemptions generally are taxable events for shareholders that are subject to tax. Shareholders should consult their own tax adviser with reference to their individual circumstances to determine whether any particular transaction in Fund shares is properly treated as a sale for tax purposes, as the following discussion assumes, and the tax treatment of any gains or losses recognized in such transaction. In general, if Fund shares are sold, a shareholder will recognize gain or loss equal to the difference between the amount realized on the sale and the shareholder's adjusted tax basis in the shares. As long as the Funds maintain a constant net asset value of $1.00 per share, generally no gain or loss should be recognized upon the sale of Fund shares. If a shareholder recognizes gain or loss on the sale of Fund shares, this gain or loss will be long-term capital gain or loss if the shareholder has held such Fund shares for more than one year at the time of the sale. If a shareholder receives a capital gain dividend with respect to any Fund share and such Fund share is held for six months or less, then (unless otherwise disallowed) any loss on the sale or exchange of that Fund share will be treated as a long-term capital loss to the extent of the capital gain dividend. Losses on redemptions or other dispositions of shares may be disallowed under "wash sale" rules in the event of other investments in the same Fund (including those made pursuant to reinvestment of dividends and/or capital gain distributions) within a period of 61 days beginning 30 days before and ending 30 days after a redemption or other disposition of shares. In such a case, the disallowed portion of any loss generally would be included in the U.S. federal tax basis of the shares acquired in the other investments.

FOREIGN TAXES. Amounts realized by a Fund on foreign securities may be subject to withholding and other taxes imposed by foreign countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a Fund's total assets at the close of its taxable year were to consist of securities of non-U.S.

51

corporations, the Fund would be eligible to file an annual election with the IRS pursuant to which the Fund could pass-through to its shareholders on a PRO RATA basis foreign income and similar taxes paid by the Fund, which could be claimed, subject to certain limitations, either as a tax credit or deduction by shareholders. However, none of the Funds expects to qualify for this election.

FEDERAL INCOME TAX RATES. As of the date of this SAI, the maximum stated individual U.S. federal income tax rate applicable to (i) ordinary income generally is 35%; (ii) capital gain dividends is 15%; and (iii) long-term capital gains generally is 15%. An individual shareholder also should be aware that the benefits of the favorable tax rates applicable to capital gain dividends and long-term capital gains may be impacted by the application of the alternative minimum tax. Under current law, the maximum 35% U.S. federal income tax rate on ordinary income and the maximum 15% U.S. federal income tax rate on capital gain dividends and long-term capital gains will cease to apply to taxable years beginning after December 31, 2010.

The current maximum stated corporate U.S. federal income tax rate applicable to ordinary income, capital gain dividends, and long-term capital gains generally is 35%. Actual marginal tax rates may be higher for some shareholders, for example, through reductions in deductions. Naturally, the amount of tax payable by any taxpayer will be affected by a combination of tax laws covering, for example, deductions, credits, deferrals, exemptions, sources of income and other matters.

BACK-UP WITHHOLDING. The Trust may be required to withhold, subject to certain exemptions, at a rate of 28% ("back-up withholding") on all distributions and redemption proceeds (including proceeds from exchanges and redemptions in-kind) paid or credited to a Fund shareholder, unless the shareholder generally certifies under penalties of perjury that the shareholder's social security or other "taxpayer identification number" ("TIN") provided is correct and that the shareholder is not subject to back-up withholding, or the IRS notifies the Fund that the shareholder's TIN is incorrect or that the shareholder is subject to back-up withholding. This tax is not an additional U.S. federal income tax imposed on the shareholder, and the shareholder may claim the tax withheld as a tax payment on his or her federal income tax return, provided that the required information is furnished to the IRS. An investor must provide a valid TIN upon opening or reopening an account. If a shareholder fails to furnish a valid TIN upon request, the shareholder can also be subject to IRS penalties. The rate of back-up withholding is set to increase for taxable years beginning after December 31, 2010.

TAX-DEFERRED PLANS. Shares of the Funds may be available for a variety of tax-deferred retirement and other tax-advantaged plans and accounts, including IRAs, Simplified Employee Pension Plans, Savings Incentive Match Plans for Employees, Roth IRAs, and Coverdell Education Savings Accounts. Prospective investors should contact their tax advisers and financial planners regarding the tax consequences to them of holding Fund shares through a tax-advantaged plan or account.

FOREIGN SHAREHOLDERS. With respect to taxable years of a Fund beginning before January 1, 2010, certain distributions, if designated by a Fund as "interest-related dividends," that are generally attributable to the Fund's net interest income earned on certain debt obligations paid to a non-resident alien individual, foreign trust (I.E., a trust other than a trust which a U.S. court is able to exercise primary supervision over administration of that trust and one or more U.S. persons have authority to control substantial decisions of that trust), foreign estate (I.E., the income of which is not subject to U.S. tax regardless of source) or a foreign corporation (each, a "foreign shareholder") generally will be exempt from U.S. federal income tax withholding tax, provided the Fund obtains a properly completed and signed certificate of foreign status from such foreign shareholder ("exempt foreign shareholder"). If applicable, each Fund may choose to designate any interest-related dividends in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year. All other distributions made to exempt foreign shareholders attributable to net investment income, such as dividends received by a Fund, generally will be subject to non-refundable U.S. federal income tax withholding at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Notwithstanding the foregoing, if a distribution described above is "effectively connected" with a U.S. trade or business (or, if an income tax treaty applies, is attributable to a permanent establishment) of the recipient foreign shareholder, U.S. federal income tax withholding and exemptions attributable to foreign persons will not apply and the distribution will be subject to the tax, reporting and withholding requirements generally applicable to U.S. persons.

In general, a foreign shareholder's capital gains realized on the disposition of Fund shares, capital gain distributions and, with respect to taxable years of a Fund beginning before January 1, 2010, "short-term capital gain distributions" (defined below) are not subject to U.S. federal income tax withholding, provided that the Fund obtains a properly completed and signed certificate of foreign status, unless: (i) such gains or distributions are "effectively connected" with a U.S. trade or business (or, if an income tax treaty applies, are attributable to a permanent establishment) of the foreign shareholder; (ii) in the case of an individual foreign shareholder, the shareholder is present in the U.S. for a period or periods aggregating 183 days or more

52

during the year of the sale and certain other conditions are met; or (iii) with respect to taxable years of a Fund beginning before January 1, 2010, such gains or distributions are attributable to gain from the sale or exchange of a U.S. real property interest. If such gains or distributions are "effectively connected" with a U.S. trade or business or are attributable to a U.S. permanent establishment of the foreign shareholder pursuant to an income tax treaty, the tax, reporting and withholding requirements applicable to U.S. persons generally apply. If such gains or distributions are not "effectively connected" for this purpose, but the foreign shareholder meets the requirements of clause (ii) described above, such gains and distributions will be subject to U.S. federal income withholding tax at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Gains or distributions attributable to gain from sales or exchanges of U.S. real property interests are taxed to a foreign shareholder as if that gain were "effectively connected" with the shareholder's conduct of a U.S. trade or business, and therefore such gains or distributions may be required to be reported by a foreign shareholder on a U.S. federal income tax return. Such gains or distributions also will be subject to U.S. federal income tax at the rates applicable to U.S. holders and/or may be subject to U.S. federal income tax withholding. While the Funds do not expect Fund shares to constitute U.S. real property interests, a portion of a Fund's distributions may be attributable to gain from the sale or exchange of U.S. real property interests. Foreign shareholders should contact their tax advisers and financial planners regarding the tax consequences to them of such distributions. "Short-term capital gain distributions" are certain distributions that a Fund may choose to designate as such in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year generally attributable to the Fund's net short-term capital gain.

If a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, Fund shares will be deemed to be property situated in the United States and will be subject to U.S. federal estate taxes (at current graduated rates of 18% to 45% of the total value, less allowable deductions and credits). With respect to estates of decedents dying before January 1, 2010, if a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, Fund shares are not deemed to be property situated in the United States in the proportion that, at the end of the quarter of the Fund's taxable year immediately preceding the shareholder's date of death, the assets of the Fund that are "qualifying assets" (I.E., bank deposits, debt obligations or property not within the United States) with respect to the decedent bear to the total assets of the Fund. In general, no U.S. federal gift tax will be imposed on gifts of Fund shares made by foreign shareholders.

The availability of reduced U.S. taxes pursuant to the 1972 Convention or the applicable estate tax convention depends upon compliance with established procedures for claiming the benefits thereof, and may, under certain circumstances, depend upon the foreign shareholder making a satisfactory demonstration to U.S. tax authorities that the shareholder qualifies as a foreign person under U.S. federal income tax laws and the 1972 Convention.

Special rules apply to foreign partnerships and those holding Fund shares through foreign partnerships.

RECENTLY ENACTED LEGISLATION. Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012, to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code) unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

Capital Stock

As of the date of this SAI, the beneficial interests in the Trust are divided into transferable shares of 11 separate and distinct series authorized and established by the Board of Trustees. The number of shares of each series, and class thereof, is unlimited and each share has no par value. The Board of Trustees may, in the future, authorize the issuance of other series representing shares of additional investment portfolios or funds. Except to the extent the 1940 Act expressly grants to shareholders the power to vote on such termination(s), the Trust, or any series (or class) thereof, may be terminated at any time by the Trustees with written notice to the shareholders.

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Although the Trust is not required to hold regular annual shareholder meetings, occasional annual or special meetings may be required for purposes such as electing and removing Trustees, approving advisory contracts, and changing a Fund's fundamental investment policies.

VOTING. All shares of the Trust have equal voting rights and will be voted separately by individual series, except: (i) when required by the 1940 Act, shares will be voted in the aggregate and not by individual series; and (ii) when the Trustees have determined that the matter affects the interests of more than one series, then the shareholders of all such affected series will be entitled to vote thereon in the aggregate and not by individual series. The Trustees also may determine that a matter affects only the interests of one or more classes of a series, in which case any such matter will be voted on separately by such class or classes. For example, a change in a Fund's fundamental investment policy would be voted upon only by shareholders of that Fund. Additionally, approval of a Master Portfolio's Advisory Contract is a matter to be determined separately by each Master Portfolio. Approval by the shareholders of a Fund is effective as to that Fund whether or not sufficient votes are received from the shareholders of the other investment portfolios to approve the proposal as to those investment portfolios. As used in the Prospectuses of each Fund and in this SAI, the term "1940 Act majority," when referring to approvals to be obtained from shareholders of a Fund, means the vote of the lesser of (i) 67% of the shares of the Fund represented at a meeting if the holders of more than 50% of the outstanding shares of the Fund are present in person or by proxy, or (ii) more than 50% of the outstanding shares of the Fund. The term "majority," when referring to the approvals to be obtained from shareholders of the Trust as a whole, means the vote of the lesser of (i) 67% of the Trust's shares represented at a meeting if the holders of more than 50% of the Trust's outstanding shares are present in person or by proxy, or (ii) more than 50% of the Trust's outstanding shares.

Each share will entitle the holder thereof to one vote for each dollar (and each fractional dollar thereof) of NAV (number of shares owned times NAV per share) of shares outstanding in such holder's name on the books of the Trust. There shall be no cumulative voting in the election of Trustees. For additional voting information and a discussion of the possible effects of changes to a Master Portfolio's investment objective or policies on a Fund, as an interestholder in the Master Portfolio, or the Fund's shareholders, see "Description of the Funds and their Investments and Risks - Master/Feeder Structure."

The Trust may dispense with an annual meeting of shareholders in any year in which it is not required to elect Trustees under the 1940 Act. However, the Trust will hold a special meeting of its shareholders for the purpose of voting on the question of removal of a Trustee or Trustees if requested in writing by the holders of at least 10% of the Trust's outstanding voting securities, and to assist in communicating with other shareholders as required by Section 16(c) of the 1940 Act.

DIVIDENDS AND DISTRIBUTIONS. Each share of a Fund represents an equal proportional interest in the Fund with each other share and is entitled to such dividends and distributions out of the income earned on the assets belonging to the Fund as are declared in the discretion of the Trustees. In the event of the liquidation or dissolution of the Trust, shareholders of a Fund are entitled to receive the assets attributable to the Fund that are available for distribution, and a distribution of any general assets not attributable to a particular investment portfolio that are available for distribution in such manner and on such basis as the Trustees in their sole discretion may determine. Shareholders are not entitled to any preemptive rights. All shares, when issued, will be fully paid and non-assessable by the Trust.

MASTER PORTFOLIOS. MIP is an open-end, series management investment company organized as a Delaware statutory trust on October 20, 1993. MIP's Declaration of Trust provides that obligations of MIP are not binding upon its Trustees individually but only upon the property of MIP and that the Trustees will not be liable for any action or failure to act, but nothing in the Declaration of Trust protects a Trustee against any liability to which the Trustee would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of the Trustee's office.

Interests in each Master Portfolio of MIP have voting and other rights generally corresponding to those rights enumerated above for shares of the Funds. MIP also intends to dispense with annual meetings, but is required by
Section 16(c) of the 1940 Act to hold a special meeting and assist investor communications under the circumstances described above with respect to the Trust. Whenever a Fund is requested to vote on a matter with respect to its Master Portfolio, the Fund will follow its voting procedures, as described in "Voting."

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Additional Information on the Funds

The Trust provides annual and semi-annual reports to all shareholders. The annual reports contain audited financial statements and other information about the Funds, including additional information on performance. Shareholders may obtain a copy of the Trust's most recent annual or semi-annual reports without charge by calling 1-800-768-2836 (toll-free).

The registration statement, including the Prospectuses, this SAI and the exhibits filed therewith, may be examined at the office of the SEC in Washington, D.C. Statements contained in the Prospectuses or this SAI as to the contents of any contract or other document referred to herein or in the Prospectuses are not necessarily complete and, in each instance, reference is made to the copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference.

No person has been authorized to give any information or to make any representations other than those contained in the Prospectuses, this SAI and in the Trust's official sales literature in connection with the offer of the Trust's shares and, if given or made, such other information or representations must not be relied upon as having been authorized by the Trust. This SAI does not constitute an offer in any state in which, or to any person to whom, such offering may not lawfully be made.

Financial Statements

The audited financial statements, including the schedule of investments, financial highlights and independent registered public accounting firm's reports for the fiscal year ended December 31, 2009 for each Fund and related Master Portfolio are hereby incorporated by reference to the Trust's annual report, as filed with the SEC on March 10, 2010. The annual report, which contains the referenced audited financial statements, is available upon request and without charge.

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APPENDIX A

Proxy Voting Policies

For The BlackRock-Advised Funds

December, 2009

Copyright(C) 2009 BlackRock, Inc.
All rights reserved.


Table of Contents

Page

I. INTRODUCTION............................................................1
II. PROXY VOTING POLICIES...................................................2
A. Boards of Directors................................................2
B. Auditors...........................................................2
C. Compensation and Benefits..........................................2
D. Capital Structure..................................................2
E. Corporate Charter and By-Laws......................................3
F. Environmental and Social Issues....................................3
IV. REPORTS TO THE BOARD....................................................3


I. INTRODUCTION

The Trustees/Directors ("Directors") of the BlackRock-Advised Funds (the "Funds") have the responsibility for voting proxies relating to portfolio securities of the Funds, and have determined that it is in the best interests of the Funds and their shareholders to delegate that responsibility to BlackRock Advisors, LLC and its affiliated U.S. registered investment advisers ("BlackRock"), the investment adviser to the Funds, as part of BlackRock's authority to manage, acquire and dispose of account assets. The Directors hereby direct BlackRock to vote such proxies in accordance with this Policy, and any proxy voting guidelines that the Adviser determines are appropriate and in the best interests of the Funds' shareholders and which are consistent with the principles outlined in this Policy. The Directors have authorized BlackRock to utilize an unaffiliated third-party as its agent to vote portfolio proxies in accordance with this Policy and to maintain records of such portfolio proxy voting.

Rule 206(4)-6 under the Investment Advisers Act of 1940 requires, among other things, that an investment adviser that exercises voting authority over clients' proxy voting adopt policies and procedures reasonably designed to ensure that the adviser votes proxies in the best interests of clients, discloses to its clients information about those policies and procedures and also discloses to clients how they may obtain information on how the adviser has voted their proxies.

BlackRock has adopted separate but substantially similar guidelines and procedures that are consistent with the principles of this Policy. BlackRock's Corporate Governance Committee (the "Committee"), addresses proxy voting issues on behalf of BlackRock and its clients, including the Funds. The Committee is comprised of senior members of BlackRock's Portfolio Management and Administration Groups and is advised by BlackRock's Legal and Compliance Department.

BlackRock votes (or refrains from voting) proxies for each Fund in a manner that BlackRock, in the exercise of its independent business judgment, concludes are in the best economic interests of such Fund. In some cases, BlackRock may determine that it is in the best economic interests of a Fund to refrain from exercising the Fund's proxy voting rights (such as, for example, proxies on certain non-U.S. securities that might impose costly or time-consuming in-person voting requirements). With regard to the relationship between securities lending and proxy voting, BlackRock's approach is also driven by our clients' economic interests. The evaluation of the economic desirability of recalling loans involves balancing the revenue producing value of loans against the likely economic value of casting votes. Based on our evaluation of this relationship, BlackRock believes that the likely economic value of casting a vote generally is less than the securities lending income, either because the votes will not have significant economic consequences or because the outcome of the vote would not be affected by BlackRock recalling loaned securities in order to ensure they are voted. Periodically, BlackRock analyzes the process and benefits of voting proxies for securities on loan, and will consider whether any modification of its proxy voting policies or procedures are necessary in light of any regulatory changes.

BlackRock will normally vote on specific proxy issues in accordance with BlackRock's proxy voting guidelines. BlackRock's proxy voting guidelines provide detailed guidance as to how to vote proxies on certain important or commonly raised issues. BlackRock may, in the exercise of its business judgment, conclude that the proxy voting guidelines do not cover the specific matter upon which a proxy vote is requested, or that an exception to the proxy voting guidelines would be in the best economic interests of a Fund. BlackRock

1

votes (or refrains from voting) proxies without regard to the relationship of the issuer of the proxy (or any shareholder of such issuer) to the Fund, the Fund's affiliates (if any), BlackRock or BlackRock's affiliates. When voting proxies, BlackRock attempts to encourage companies to follow practices that enhance shareholder value and increase transparency and allow the market to place a proper value on their assets.

II. PROXY VOTING POLICIES

A. BOARDS OF DIRECTORS

The Funds generally support the board's nominees in the election of directors and generally supports proposals that strengthen the independence of boards of directors. As a general matter, the Funds believe that a company's board of directors (rather than shareholders) is most likely to have access to important, nonpublic information regarding a company's business and prospects, and is therefore best-positioned to set corporate policy and oversee management. The Funds therefore believe that the foundation of good corporate governance is the election of responsible, qualified, independent corporate directors who are likely to diligently represent the interests of shareholders and oversee management of the corporation in a manner that will seek to maximize shareholder value over time. In individual cases, consideration may be given to a director nominee's history of representing shareholder interests as a director of the company issuing the proxy or other companies, or other factors to the extent deemed relevant by the Committee.

B. AUDITORS

These proposals concern those issues submitted to shareholders related to the selection of auditors. As a general matter, the Funds believe that corporate auditors have a responsibility to represent the interests of shareholders and provide an independent view on the propriety of financial reporting decisions of corporate management. While the Funds anticipate that BlackRock will generally defer to a corporation's choice of auditor, in individual cases, consideration may be given to an auditors' history of representing shareholder interests as auditor of the company issuing the proxy or other companies, to the extent deemed relevant.

C. COMPENSATION AND BENEFITS

These proposals concern those issues submitted to shareholders related to management compensation and employee benefits. As a general matter, the Funds favor disclosure of a company's compensation and benefit policies and oppose excessive compensation, but believe that compensation matters are normally best determined by a corporation's board of directors, rather than shareholders. Proposals to "micro-manage" a company's compensation practices or to set arbitrary restrictions on compensation or benefits should therefore generally not be supported.

D. CAPITAL STRUCTURE

These proposals relate to various requests, principally from management, for approval of amendments that would alter the capital structure of a company, such as an increase in authorized shares. As a general matter, the Funds expect that BlackRock will support requests that it believes enhance the rights of common shareholders and oppose requests that appear to be unreasonably dilutive.

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E. CORPORATE CHARTER AND BY-LAWS

These proposals relate to various requests for approval of amendments to a corporation's charter or by-laws. As a general matter, the Funds generally vote against anti-takeover proposals and proposals that would create additional barriers or costs to corporate transactions that are likely to deliver a premium to shareholders.

F. ENVIRONMENTAL AND SOCIAL ISSUES

These are shareholder proposals addressing either corporate social and environmental policies or requesting specific reporting on these issues. The Funds generally do not support proposals on social issues that lack a demonstrable economic benefit to the issuer and the Fund investing in such issuer. BlackRock seeks to make proxy voting decisions in the manner most likely to protect and promote the long-term economic value of the securities held in client accounts. We intend to support economically advantageous corporate practices while leaving direct oversight of company management and strategy to boards of directors. We seek to avoid micromanagement of companies, as we believe that a company's board of directors is best positioned to represent shareholders and oversee management on shareholders behalf. Issues of corporate social and environmental responsibility are evaluated on a case-by-case basis within this framework.

III. CONFLICTS MANAGEMENT

BlackRock maintains policies and procedures that are designed to prevent any relationship between the issuer of the proxy (or any shareholder of the issuer) and a Fund, a Fund's affiliates (if any), BlackRock or BlackRock's affiliates, from having undue influence on BlackRock's proxy voting activity. In certain instances, BlackRock may determine to engage an independent fiduciary to vote proxies as a further safeguard against potential conflicts of interest or as otherwise required by applicable law. The independent fiduciary may either vote such proxies or provide BlackRock with instructions as to how to vote such proxies. In the latter case, BlackRock votes the proxy in accordance with the independent fiduciary's determination.

IV. REPORTS TO THE BOARD

BlackRock will report to the Directors on proxy votes it has made on behalf of the Funds at least annually.

SAI-BR3-CFA-0510

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BLACKROCK FUNDS III

Statement of Additional Information

Dated May 1, 2010

FUND/SHARE CLASS
-------------------------------------------------------
BlackRock Cash Funds: Institutional - SL Agency Shares
BlackRock Cash Funds: Prime - SL Agency Shares
BlackRock Cash Funds: Government - SL Agency Shares
BlackRock Cash Funds: Treasury - SL Agency Shares

BlackRock Funds III (the "Trust") is an open-end, series management investment company. This combined Statement of Additional Information ("SAI") contains additional information about SL Agency Shares of the following series of the Trust - BlackRock Cash Funds: Prime, BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury (each, a "Fund" and collectively, the "Funds"). The Funds have additional share classes which are described in separate prospectuses and a separate SAI.

Each Fund seeks to achieve its investment objective by investing all of its assets in a master portfolio of Master Investment Portfolio ("MIP"). BlackRock Cash Funds: Institutional invests in Money Market Master Portfolio; BlackRock Cash Funds: Prime invests in Prime Money Market Master Portfolio; BlackRock Cash Funds: Government invests in Government Money Market Master Portfolio; and BlackRock Cash Funds: Treasury invests in Treasury Money Market Master Portfolio (each, a "Master Portfolio" and collectively, the "Master Portfolios"). MIP is an open-end, series management investment company. BlackRock Fund Advisors ("BFA" or the "Investment Adviser") (formerly, Barclays Global Fund Advisors) serves as investment adviser to each Master Portfolio. References to the investments, investment policies and risks of a Fund, unless otherwise indicated, should be understood to include references to the investments, investment policies and risks of such Fund's Master Portfolio.

This SAI is not a prospectus and should be read in conjunction with the current prospectus for SL Agency Shares of the Funds, dated May 1, 2010, as amended from time to time (the "Prospectus"). All terms used in this SAI that are defined in the Prospectus have the meanings assigned in the Prospectus. The audited financial statements for the Funds, which include the schedules of investments and report of the independent registered public accounting firm for the fiscal year ended December 31, 2009 are hereby incorporated by reference to the Funds' annual reports, semi-annual reports and prospectus for SL Agency Shares of the Funds. Copies of such prospectus, annual reports and semi-annual reports may be obtained without charge by writing to BlackRock Funds III, c/o SEI Investments Distribution Co., One Freedom Valley Drive, Oaks, PA 19456, or by calling 1-800-768-2836 (toll-free).


TABLE OF CONTENTS

                                                                                    PAGE
                                                                                   -----
History of the Trust                                                                  1
Description of the Funds and their Investments and Risks                              1
   Investment Objectives and Policies                                                 1
Investment Restrictions                                                               1
   Fundamental Investment Restrictions of the Funds                                   1
   Non-Fundamental Investment Restrictions of the Funds                               3
   Investments and Risks                                                              4
   Asset-Backed and Commercial Mortgage-Backed Securities                             4
   Bank Obligations                                                                   4
   Commercial Paper and Short-Term Corporate Debt Instruments                         5
   Floating-Rate and Variable-Rate Obligations                                        5
   Forward Commitments, When-Issued Purchases and Delayed-Delivery Transactions       6
   Funding Agreements                                                                 6
   Illiquid Securities                                                                6
   Investment Company Securities                                                      6
   Letters of Credit                                                                  7
   Loans of Portfolio Securities                                                      8
   Loan Participation Agreements                                                      8
   Mortgage Pass-Through Securities                                                   8
   Mortgage Securities                                                                9
   Municipal Securities                                                              10
   Non-U.S. Obligations                                                              10
   Participation Interests                                                           11
   Repurchase Agreements                                                             11
   Restricted Securities                                                             11
   Unrated Investments                                                               11
   U.S. Government Obligations                                                       12
   U.S. Treasury Obligations                                                         12
Portfolio Holdings Information                                                       12
   Service Providers                                                                 12
   Third-Party Feeder Funds                                                          13
   Securities and Exchange Commission Filings                                        14
   Other Public Disclosure                                                           14
   Approved Recipients                                                               14
Management                                                                           14
   Share Ownership Information                                                       24

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                                                                                    PAGE
                                                                                   -----
   Ownership of Securities of Certain Entities                                       25
   Compensation of Trustees                                                          25
   Master/Feeder Structure                                                           26
   Codes of Ethics                                                                   26
   Proxy Voting Policies of the Master Portfolios                                    26
   Shareholder Communication to the Board of Trustees                                27
Control Persons and Principal Holders of Securities                                  28
Investment Adviser and Other Service Providers                                       38
   Investment Adviser                                                                38
   Advisory Fees                                                                     38
   Administrator                                                                     39
   Distributor                                                                       40
   Custodian                                                                         41
   Transfer and Dividend Disbursing Agent                                            41
   Independent Registered Public Accounting Firm                                     41
   Legal Counsel                                                                     41
Determination of Net Asset Value                                                     41
Purchase, Redemption and Pricing of Shares                                           42
   Terms of Purchase and Redemption                                                  42
   In-Kind Purchases                                                                 42
   Suspension of Redemption Rights or Payment of Redemption Proceeds                 42
   Declaration of Trust Provisions Regarding Redemptions at Option of Trust          43
Portfolio Transactions                                                               43
   General                                                                           43
   Portfolio Turnover                                                                44
   Securities of Regular Broker-Dealers                                              44
   Frequent Trading of Fund Shares                                                   44
Distributions and Taxes                                                              45
   Qualification as a Regulated Investment Company                                   45
   Excise Tax                                                                        46
   Capital Loss Carry-Forwards                                                       46
   Investment Through the Master Portfolios                                          46
   Taxation of Fund Investments                                                      47
   Taxation of Distributions                                                         48
   Sales of Fund Shares                                                              48
   Foreign Taxes                                                                     49
   Federal Income Tax Rates                                                          49

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                                                                                    PAGE
                                                                                   -----
   Back-Up Withholding                                                               49
   Tax-Deferred Plans                                                                49
   Foreign Shareholders                                                              49
   Recently Enacted Legislation                                                      50
Capital Stock                                                                        50
   Voting                                                                            51
   Dividends and Distributions                                                       51
   Master Portfolios                                                                 51
Additional Information on the Funds                                                  52
Financial Statements                                                                 52
Appendix A                                                                          A-1

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History of the Trust

The Trust was organized on December 4, 2001 as a statutory trust under the laws of the State of Delaware. On August 21, 2001, the Board of Directors of Barclays Global Investors Funds, Inc. (the "Company") approved a proposal to redomicile the Company from a Maryland corporation to a Delaware statutory trust (the "Redomiciling"). Shareholders of the Company approved the Redomiciling on November 16, 2001. The Trust was established with multiple series, including the Funds, corresponding to, and having identical designations as, the Company's series. The Redomiciling was effected on January 11, 2002, at which time the Trust assumed the operations of the Company and adopted the Company's registration statement. Shortly thereafter, the Company was dissolved.

The Trust's principal office is located at 400 Howard Street, San Francisco, CA 94105. Each Fund invests all of its assets in a Master Portfolio of MIP (as shown below), which has substantially the same investment objective, policies and restrictions as the related Fund.

FUND                                          MASTER PORTFOLIO IN WHICH THE FUND INVESTS
--------------------------------------------  -------------------------------------------
       BlackRock Cash Funds: Prime            Prime Money Market Master Portfolio
       BlackRock Cash Funds: Institutional    Money Market Master Portfolio
       BlackRock Cash Funds: Government       Government Money Market Master Portfolio
       BlackRock Cash Funds: Treasury         Treasury Money Market Master Portfolio

The Trust consists of multiple series, including the Funds. Each Fund issues shares in multiple classes, currently including SL Agency, Premium, Capital, Institutional, Select and Trust Shares, and with respect only to BlackRock Cash Funds: Institutional, Aon Captives Shares. On August 14, 2002, the Trust's board of trustees (the "Board of Trustees" or the "Board") approved changing the name of BlackRock Cash Funds: Institutional Distributor Shares to the "Aon Captives Shares."

On December 1, 2009, the Trust was renamed BlackRock Funds III and certain of its series were also renamed. Prime Money Market Fund was renamed BlackRock Cash Funds: Prime. Institutional Money Market Fund was renamed BlackRock Cash Funds: Institutional. Government Money Market Fund was renamed BlackRock Cash Funds: Government. Treasury Money Market Fund was renamed BlackRock Cash Funds:
Treasury.

Description of the Funds and their Investments and Risks

INVESTMENT OBJECTIVES AND POLICIES. The Trust is an open-end, series management investment company. Each Fund and Master Portfolio has adopted an investment objective and investment policies that may be fundamental or non-fundamental. Fundamental policies cannot be changed without approval by the holders of a majority (as defined in the Investment Company Act of 1940, as amended (the "1940 Act")) of the outstanding voting securities of such Fund or Master Portfolio, as the case may be. Non-fundamental policies may be changed without shareholder approval by the vote of a majority of the trustees of the Trust or of MIP (the "Trustees"), as the case may be, at any time.

The Funds and the Master Portfolios in which they invest are diversified funds as defined in the 1940 Act. Each Fund's investment objective is set forth in the Prospectus. Each Fund's investment objective is non-fundamental and can be changed by the Trust's Board of Trustees without shareholder approval. The investment objective and investment policies of a Fund determine the types of portfolio securities in which the Fund invests, the degree of risk to which the Fund is subject and, ultimately, the Fund's performance. There can be no assurance that the investment objective of any Fund will be achieved.

Investment Restrictions

FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds are subject to the following investment restrictions, all of which are fundamental policies. Each Fund may not:

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(1) Purchase the securities of issuers conducting their principal business activity in the same industry if, immediately after the purchase and as a result thereof, the value of the Fund's investments in that industry would equal or exceed 25% of the current value of the Fund's total assets, provided that this restriction does not limit the Fund's: (i) investments in securities of other investment companies, (ii) investments in securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or (iii) investments in repurchase agreements collateralized by U.S. government securities; and further provided that, with respect to BlackRock Cash Funds: Prime and BlackRock Cash Funds:
Institutional, the Fund reserves the right to concentrate in the obligations of domestic banks (as such term is interpreted by the Securities and Exchange Commission ("SEC") or its staff);

(2) Purchase the securities of any single issuer if, as a result, with respect to 75% of the Fund's total assets, more than 5% of the value of its total assets would be invested in the securities of such issuer or the Fund's ownership would be more than 10% of the outstanding voting securities of such issuer, provided that this restriction does not limit the Fund's cash or cash items, investments in U.S. government securities, or investments in securities of other investment companies;

(3) Borrow money or issue senior securities, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder;

(4) Make loans to other parties, except to the extent permitted under the 1940 Act, including the rules, regulations and any orders obtained thereunder. For the purposes of this limitation, entering into repurchase agreements, lending securities and acquiring any debt securities are not deemed to be the making of loans;

(5) Underwrite securities of other issuers, except to the extent that the purchase of permitted investments directly from the issuer thereof or from an underwriter for an issuer and the later disposition of such securities in accordance with the Fund's investment program may be deemed to be an underwriting; and provided further, that the purchase by the Fund of securities issued by an open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Fund shall not constitute an underwriting for purposes of this paragraph;

(6) Purchase or sell real estate unless acquired as a result of ownership of securities or other instruments (but this shall not prevent the Fund from investing in securities or other instruments backed by real estate or securities of companies engaged in the real estate business); and

(7) Purchase or sell commodities, provided that: (i) currency will not be deemed to be a commodity for purposes of this restriction, (ii) this restriction does not limit the purchase or sale of futures contracts, forward contracts or options, and (iii) this restriction does not limit the purchase or sale of securities or other instruments backed by commodities or the purchase or sale of commodities acquired as a result of ownership of securities or other instruments.

With respect to the fundamental policy relating to concentration set forth in paragraph (1) above, the 1940 Act does not define what constitutes "concentration" in an industry and it is possible that interpretations of concentration could change in the future. Accordingly, the policy in paragraph
(1) above will be interpreted to refer to concentration as that term may be interpreted from time to time. In this respect, and in accordance with SEC staff interpretations, the ability of BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional to concentrate in the obligations of domestic banks means that these Funds are permitted to invest, without limit, in bankers' acceptances, certificates of deposit and other short-term obligations issued by
(a) U.S. banks, (b) U.S. branches of foreign banks (in circumstances in which the U.S. branches of foreign banks are subject to the same regulation as U.S. banks), and (c) foreign branches of U.S. banks (in circumstances in which the Funds will have recourse to the U.S. bank for the obligations of the foreign branch).

The Trust has delegated to BFA the ability to determine the methodology used by the Master Portfolios to classify issuers by industry. BFA defines industries and classifies each issuer according to the industry in which the issuer conducts its principal business activity pursuant to its proprietary industry classification system. In classifying companies by industry, BFA may draw on its credit, research and investment resources and those of BlackRock Institutional Trust Company, N.A. ("BTC") (formerly, Barclays Global Investors, N.A.) or its other affiliates, and BFA may (but need not) consider classifications by third-party industry classification systems. BFA believes that its system is reasonably designed so that issuers with primary economic characteristics that are materially the same are classified in the same industry. For example, asset-backed commercial paper may be classified in an industry based on the nature of the assets backing the commercial paper, and foreign banks may be classified in an industry based on the region in which they do business if BFA has determined that the foreign banks within that industry have primary economic characteristics that are materially the same.

A fund that invests a significant percentage of its total assets in a single industry may be particularly susceptible to adverse events affecting that industry and may be more risky than a fund that does not concentrate in an industry. To the extent BFA's

2

classification system results in broad categories, concentration risk may be decreased. On the other hand, to the extent it results in narrow categories, concentration risk may be increased.

With respect to paragraph (3) above, the 1940 Act currently allows each Fund to borrow up to one-third of the value of its total assets (including the amount borrowed) valued at the lesser of cost or market, less liabilities (not including the amount borrowed) at the time the borrowing is made. With respect to paragraph (4) above, the 1940 Act and regulatory interpretations currently limit the percentage of each Fund's securities that may be loaned to one-third of the value of its total assets.

NON-FUNDAMENTAL INVESTMENT RESTRICTIONS OF THE FUNDS. The Funds have adopted the following investment restrictions as non-fundamental policies. These restrictions may be changed without shareholder approval by a majority of the Trustees of the Trust at any time.

(1) Each Fund may invest in shares of other open-end management investment companies, subject to the limitations of Section 12(d)(1) of the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder;

(2) Each Fund may not invest more than 10% of its net assets in illiquid securities. For this purpose, illiquid securities include, among others,
(i) securities that are illiquid by virtue of the absence of a readily available market or legal or contractual restrictions on resale, (ii) fixed time deposits that are subject to withdrawal penalties and that have maturities of more than seven days, and (iii) repurchase agreements not terminable within seven days;

(3) Each Fund may lend securities from its portfolio to brokers, dealers and financial institutions, in amounts not to exceed (in the aggregate) one-third of a Fund's total assets. Any such loans of portfolio securities will be fully collateralized based on values that are marked-to-market daily; and

(4) Each Fund may not make investments for the purpose of exercising control or management; provided that a Fund may invest all of its assets in a diversified, open-end management investment company, or a series thereof, with substantially the same investment objective, policies and restrictions as the Fund, without regard to the limitations set forth in this paragraph.

BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury have adopted the following investment restriction as an additional non-fundamental policy:

Each Fund will provide shareholders with at least 60 days' notice of any change to the Fund's non-fundamental policy to invest at least 80% of the Fund's assets in the types of securities described in the Fund's principal investment strategies. The notice will be provided in plain English in a separate written document, and will contain the following prominent statement or similar statement in bold-face type: "Important Notice Regarding Change in Investment Policy." This statement will appear on both the notice and the envelope in which it is delivered, unless it is delivered separately from other communications to investors, in which case the statement will appear either on the notice or the envelope in which the notice is delivered.

BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional have adopted the following investment restrictions as additional non-fundamental policies:

(1) Each Fund may not purchase interests, leases, or limited partnership interests in oil, gas, or other mineral exploration or development programs.

(2) Each Fund may not write, purchase or sell puts, calls, straddles, spreads, warrants, options or any combination thereof, except that the Fund may purchase securities with put rights in order to maintain liquidity.

(3) Each Fund may not purchase securities on margin (except for short-term credits necessary for the clearance of transactions) or make short sales of securities.

Notwithstanding any other investment policy or restriction (whether or not fundamental), each Fund may (and does) invest all of its assets in the securities of a single open-end management investment company with substantially the same fundamental investment objective, policies and limitations as the Fund.

The fundamental and non-fundamental investment restrictions for each Master Portfolio are identical to the corresponding investment restrictions described above for the Fund that invests in such Master Portfolio, except that, in the case of the Government and Treasury Money Market Master Portfolios, industry concentration restriction (1), proviso (iii) does not limit investments in repurchase agreements collateralized by securities issued or guaranteed by the U.S., its agencies or instrumentalities.

3

INVESTMENTS AND RISKS. To the extent set forth in this SAI, each Fund, through its investment in the corresponding Master Portfolio, may invest in the securities described below. To avoid the need to refer to both the Funds and the Master Portfolios in every instance, the following sections generally refer to the Funds only.

The assets of each Fund consist only of obligations maturing within 397 calendar days from the date of acquisition (as determined in accordance with the regulations of the SEC), and the dollar-weighted average maturity of a Fund may not exceed 90 days. Under normal circumstances, BlackRock Cash Funds:
Prime, BlackRock Cash Funds: Government and BlackRock Cash Funds: Treasury expect to maintain a dollar-weighted average portfolio maturity of 60 days or less. The securities in which each Fund invests may not yield as high a level of current income as may be achieved from securities with less liquidity and less safety. There can be no assurance that a Fund's investment objective will be realized as described in the Prospectus.

Under normal circumstances, BlackRock Cash Funds: Treasury invests at least 80% of its assets in U.S. Treasury obligations, repurchase agreements with regard to U.S. Treasury obligations and/or other money market funds that have substantially the same investment objective and strategies as the Fund. Under normal circumstances, BlackRock Cash Funds: Government invests at least 80% of its assets in certain obligations of the U.S. government, its agencies and instrumentalities, repurchase agreements with regard to such obligations and/or other money market funds that have substantially the same investment objective and strategies as the Fund. BlackRock Cash Funds: Treasury and BlackRock Cash Funds: Government may each invest up to 20% of their respective assets in any securities and other instruments in which money market funds are permitted to invest in accordance with Rule 2a-7 of the 1940 Act. Practices described below relating to illiquid securities, investment company securities, loans of portfolio securities and repurchase agreements also apply to BlackRock Cash Funds: Treasury and BlackRock Cash Funds: Government.

BlackRock Cash Funds: Prime and BlackRock Cash Funds: Institutional may invest in any of the instruments or engage in any practice described below.

ASSET-BACKED AND COMMERCIAL MORTGAGE-BACKED SECURITIES. BlackRock Cash Funds:
Institutional and BlackRock Cash Funds: Prime may invest in asset-backed and commercial mortgage-backed securities. Asset-backed securities are securities backed by installment contracts, credit-card receivables or other assets. Commercial mortgage-backed securities are securities backed by commercial real estate properties. Both asset-backed and commercial mortgage-backed securities represent interests in "pools" of assets in which payments of both interest and principal on the securities are made on a regular basis. The payments are, in effect, "passed through" to the holder of the securities (net of any fees paid to the issuer or guarantor of the securities). The average life of asset-backed and commercial mortgage-backed securities varies with the maturities of the underlying instruments and, as a result of prepayments, can often be shorter or longer (as the case may be) than the original maturity of the assets underlying the securities. For this and other reasons, an asset-backed and commercial mortgage-backed security's stated maturity may be shortened or extended, and the security's total return may be difficult to predict precisely. The Funds may invest in such securities up to the limits prescribed by Rule 2a-7 and other provisions of or under the 1940 Act. Changes in liquidity of these securities may result in significant, rapid and unpredictable changes in prices for credit-linked securities. Also see "Mortgage Pass-Through Securities" and "Mortgage Securities."

BANK OBLIGATIONS. BlackRock Cash Funds: Institutional and BlackRock Cash Funds:
Prime may invest in bank obligations, including certificates of deposit ("CDs"), time deposits, bankers' acceptances and other short-term obligations of domestic banks, foreign subsidiaries of domestic banks, foreign branches of domestic banks, and domestic branches of foreign banks, domestic savings and loan associations and other banking institutions. Certain bank obligations may benefit from existing or future governmental debt guarantee programs.

CDs are negotiable certificates evidencing the obligation of a bank to repay funds deposited with it for a specified period of time.

Time deposits ("TDs") are non-negotiable deposits maintained in a banking institution for a specified period of time at a stated interest rate. TDs that may be held by the Funds will not benefit from insurance from the Bank Insurance Fund or the Savings Association Insurance Fund administered by the Federal Deposit Insurance Corporation ("FDIC").

Bankers' acceptances are credit instruments evidencing the obligation of a bank to pay a draft drawn on it by a customer. These instruments reflect the obligation both of the bank and of the drawer to pay the face amount of the instrument upon maturity. The other short-term obligations may include uninsured, direct obligations bearing fixed-, floating- or variable- interest rates.

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Domestic commercial banks organized under federal law are supervised and examined by the Comptroller of the Currency and are required to be members of the Federal Reserve System and to have their deposits insured by the FDIC. Domestic banks organized under state law are supervised and examined by state banking authorities and are members of the Federal Reserve System only if they elect to join. In addition, state banks whose CDs may be purchased by the Funds are insured by the FDIC (although such insurance may not be of material benefit to a Fund, depending on the principal amount of the CDs of each bank held by the Fund) and are subject to federal examination and to a substantial body of federal law and regulation. As a result of federal or state laws and regulations, domestic branches of domestic banks whose CDs may be purchased by the Funds generally are required, among other things, to maintain specified levels of reserves, are limited in the amounts that they can loan to a single borrower and are subject to other regulations designed to promote financial soundness. However, not all of such laws and regulations apply to the foreign branches of domestic banks.

Obligations of foreign branches of domestic banks, foreign subsidiaries of domestic banks and domestic and foreign branches of foreign banks, such as CDs and TDs, may be general obligations of the parent banks in addition to the issuing branch, or may be limited by the terms of a specific obligation and/or governmental regulation. Such obligations are subject to different risks than are those of domestic banks. These risks include foreign economic and political developments, foreign governmental restrictions that may adversely affect payment of principal and interest on the obligations, foreign exchange controls and foreign withholding and other taxes on amounts realized on the obligations. These foreign branches and subsidiaries are not necessarily subject to the same or similar regulatory requirements that apply to domestic banks, such as mandatory reserve requirements, loan limitations, and accounting, auditing and financial record keeping requirements. In addition, less information may be publicly available about a foreign branch of a domestic bank or about a foreign bank than about a domestic bank.

Obligations of U.S. branches of foreign banks may be general obligations of the parent bank in addition to the issuing branch, or may be limited by the terms of a specific obligation or by federal or state regulation, as well as governmental action in the country in which the foreign bank has its head office. A domestic branch of a foreign bank with assets in excess of $1 billion may be subject to reserve requirements imposed by the Federal Reserve System or by the state in which the branch is located if the branch is licensed in that state.

In addition, federal branches licensed by the Comptroller of the Currency and branches licensed by certain states may be required to: (1) pledge to the appropriate regulatory authority, by depositing assets with a designated bank within the relevant state, a certain percentage of their assets as fixed from time to time by such regulatory authority; and (2) maintain assets within the relevant state in an amount equal to a specified percentage of the aggregate amount of liabilities of the foreign bank payable at or through all of its agencies or branches within the state.

COMMERCIAL PAPER AND SHORT-TERM CORPORATE DEBT INSTRUMENTS. The Funds may invest in commercial paper (including variable amount master demand notes), which consists of short-term, unsecured promissory notes issued by corporations to finance short-term credit needs. Commercial paper is usually sold on a discount basis and usually has a maturity at the time of issuance not exceeding nine months. Variable amount master demand notes are demand obligations that permit a Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between a Fund, as lender, and the borrower. The interest on these notes varies pursuant to the arrangements between the Fund and the borrower. Both the borrower and the Fund have the right to vary the amount of the outstanding indebtedness on the notes. BFA monitors on an ongoing basis the ability of an issuer of a demand instrument to pay principal and interest on demand.

The Funds also may invest in non-convertible corporate debt securities (E.G., bonds and debentures) with not more than thirteen months remaining to maturity at the date of settlement. A Fund will invest only in such corporate bonds and debentures that are deemed appropriate by BFA in accordance with Rule 2a-7 under the 1940 Act. Subsequent to its purchase by a Fund, an issue of securities may cease to be rated or its rating may be reduced below the minimum rating required for purchase by the Fund. BFA will consider such an event in determining whether the Fund should continue to hold the obligation. To the extent the Fund continues to hold the obligation, it may be subject to additional risk of default.

FLOATING-RATE AND VARIABLE-RATE OBLIGATIONS. The Funds may purchase debt instruments with interest rates that are periodically adjusted at specified intervals or whenever a benchmark rate or index changes. The floating-rate and variable-rate instruments that the Funds may purchase include certificates of participation in such instruments. The interest rate adjustments generally limit the increase or decrease in the amount of interest received on the debt instruments. Floating-rate and variable-rate instruments are subject to interest rate risk and credit risk.

5

The Funds may purchase floating-rate and variable-rate demand notes and bonds, which are obligations ordinarily having stated maturities in excess of thirteen months, but which permit the holder to demand payment of principal at any time, or at specified intervals not exceeding 397 days, as defined in accordance with Rule 2a-7 and the 1940 Act. Variable-rate demand notes including master demand notes are demand obligations that permit a Fund to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between a Fund, as lender, and the borrower. The interest rates on these notes fluctuate from time to time. The issuer of such obligations ordinarily has a corresponding right, after a given period, to prepay in its discretion the outstanding principal amount of the obligations plus accrued interest upon a specified number of days' notice to the holders of such obligations. The interest rate on a floating-rate demand obligation is based on a known lending rate, such as a bank's prime rate, and is adjusted automatically each time such rate is adjusted. The interest rate on a variable-rate demand obligation is adjusted automatically at specified intervals. Frequently, such obligations are secured by letters of credit or other credit support arrangements provided by banks.

These obligations are direct lending arrangements between the lender and borrower. There may not be an established secondary market for these obligations, although they are redeemable at face value. Accordingly, where these obligations are not secured by letters of credit or other credit support arrangements, a Fund's right to redeem is dependent on the ability of the borrower to pay principal and interest on demand. Such obligations frequently are not rated by credit rating agencies and a Fund may invest in obligations that are not so rated only if BFA determines that at the time of investment the obligations are of comparable quality to the other obligations in which a Fund may invest. BFA considers on an ongoing basis the creditworthiness of the issuers of the floating-rate and variable-rate demand obligations in a Fund's portfolio.

FORWARD COMMITMENTS, WHEN-ISSUED PURCHASES AND DELAYED-DELIVERY TRANSACTIONS. The Funds may purchase or sell securities on a when-issued or delayed-delivery basis and make contracts to purchase or sell securities for a fixed price at a future date beyond customary settlement time. Securities purchased or sold on a when-issued, delayed-delivery or forward commitment basis involve a risk of loss if the value of the security to be purchased declines or the value of the security to be sold increases before the settlement date. Although the Funds will generally purchase securities with the intention of acquiring them, the Funds may dispose of securities purchased on a when-issued, delayed-delivery or a forward commitment basis before settlement when deemed appropriate by BFA.

FUNDING AGREEMENTS. The Funds may invest in short-term funding agreements. A funding agreement is a contract between an issuer and a purchaser that obligates the issuer to pay a guaranteed rate of interest on a principal sum deposited by the purchaser. Funding agreements will also guarantee the return of principal and may guarantee a stream of payments over time. A funding agreement has a fixed maturity and may have either a fixed-, variable- or floating-interest rate that is based on an index and guaranteed for a fixed time period. The Funds will purchase short-term funding agreements only from banks and insurance companies. The Funds may also purchase Guaranteed Investment Contracts.

The secondary market, if any, for these funding agreements is limited; thus, such investments purchased by the Funds may be treated as illiquid. If a funding agreement is determined to be illiquid it will be valued at its fair market value as determined by procedures approved by the Board of Trustees. Valuation of illiquid indebtedness involves a greater degree of judgment in determining the value of each Fund's assets than if the value were based on available market quotations.

ILLIQUID SECURITIES. Each Fund may invest in securities as to which a liquid trading market does not exist, provided such investments are consistent with its investment objective. Such securities may include securities that are not readily marketable, such as privately issued securities and other securities that are subject to legal or contractual restrictions on resale, floating-rate and variable-rate demand obligations as to which the Fund cannot exercise a demand feature on not more than seven days' notice and as to which there is no secondary market, and repurchase agreements providing for settlement more than seven days after notice.

INVESTMENT COMPANY SECURITIES. Each Fund may invest in shares of open-end investment companies, including investment companies that are affiliated with the Funds and BFA, that invest exclusively in high-quality short-term securities to the extent permitted under the 1940 Act, including the rules, regulations and exemptive orders obtained thereunder; provided, however, that a Fund, if it has knowledge that its beneficial interests are purchased by another investment company investor pursuant to Section 12(d)(1)(G) of the 1940 Act, will not acquire any securities of registered open-end management investment companies or registered unit investment trusts in reliance on
Section 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act. Other investment companies in which a Fund invests can be expected to charge fees for operating expenses, such as investment advisory and administration fees, that would be in addition to those charged by the Fund. A Fund may also purchase shares of exchange listed closed-end funds to the extent permitted under the 1940 Act. Under the 1940 Act, a

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Fund's investment in investment companies is limited to, subject to certain exceptions, (i) 3% of the total outstanding voting stock of any one investment company, (ii) 5% of the Fund's total assets with respect to any one investment company, and (iii) 10% of the Fund's total assets with respect to investment companies in the aggregate. To the extent allowed by law or regulation, each Fund may invest its assets in securities of investment companies that are money market funds, including those advised by BFA or otherwise affiliated with BFA, in excess of the limits discussed above.

LETTERS OF CREDIT. Certain of the debt obligations (including municipal securities, certificates of participation, commercial paper and other short-term obligations) that the Funds may purchase may be backed by an unconditional and irrevocable letter of credit issued by a bank, savings and loan association or insurance company that assumes the obligation for payment of principal and interest in the event of default by the issuer. Only banks, savings and loan associations and insurance companies that, in the opinion of BFA, are of comparable quality to issuers of other permitted investments of the Funds may be used for letter of credit-backed investments.

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LOANS OF PORTFOLIO SECURITIES./1/ Each Fund may lend portfolio securities to certain creditworthy borrowers, including borrowers affiliated with BFA. The borrowers provide collateral that is maintained in an amount at least equal to the current market value of the securities loaned plus any accrued interest. A Fund may terminate a loan at any time and obtain the return of the securities loaned. Each Fund is entitled to receive the value of any interest or cash or non-cash distributions paid on the loaned securities.

With respect to loans that are collateralized by cash, the borrower will be entitled to receive a fee based on the amount of cash collateral. The Fund is compensated by the difference between the amount earned on the reinvestment of cash collateral and the fee paid to the borrower. In the case of collateral other than cash, the Fund is compensated by a fee paid by the borrower equal to a percentage of the market value of the loaned securities. Any cash collateral may be reinvested in certain short-term instruments either directly on behalf of each lending Fund or through one or more joint accounts or money market funds, including those managed by BFA; such reinvestments are subject to investment risk.


(1) Note that "Loans of Portfolio Securities" describes lending of securities by the Funds/Master Portfolios. SL Agency Shares of the Funds are designed, among other things, for the investment of cash collateral provided by borrowers to lenders of securities for which BTC acts as securities lending agent.

Securities lending involves exposure to certain risks, including operational risk (I.E., the risk of losses resulting from problems in the settlement and accounting process), "gap" risk (I.E., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Fund has agreed to pay a borrower), and credit, legal, counterparty and market risk. In the event a borrower does not return a Fund's securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated plus the transaction costs incurred in purchasing replacement securities.

A Fund may pay a portion of the interest or fees earned from securities lending to a borrower as described above, and to a securities lending agent who administers the lending program in accordance with guidelines approved by the Trust's Board of Trustees. BTC acts as securities lending agent for the Funds subject to the overall supervision of BFA. BTC receives a portion of the revenues generated by securities lending activities as compensation for its services in this regard.

LOAN PARTICIPATION AGREEMENTS. Each Fund may purchase interests in loan participations that typically represent direct participation in a loan to a corporate borrower, and generally are offered by an intermediary bank or other financial institution or lending syndicate. Under these loan participation arrangements, a Fund will have the right to receive payments of principal, interest and any fees to which it is entitled from the bank selling the loan participation upon receipt by the bank of the payments from the borrower. The borrower in the underlying loan will be deemed to be the issuer of the participation interest except to the extent the Fund derives its rights from the intermediary bank that sold the loan participation. Such loans must be made to issuers in whose obligations the Funds may invest.

Because the bank issuing the loan participation does not guarantee the participation in any way, the participation is subject to the credit risks associated with the underlying corporate borrower. In addition, it may be necessary under the terms of the loan participation for the Funds to assert their rights against the underlying corporate borrower in the event that the underlying corporate borrower should fail to pay principal and interest when due. Thus, the Funds could be subject to delays, expenses, and risks that are greater than those that would have been involved if the Funds had purchased a direct obligation of the borrower. Moreover, under the terms of the loan participation, the Funds may be regarded as creditors of the issuing bank (rather than of the underlying corporate borrower), so that the Funds also may be subject to the risk that the issuing bank may become insolvent. Further, in the event of the bankruptcy or insolvency of the corporate borrower, the loan participation might be subject to certain defenses that can be asserted by the borrower as a result of improper conduct by the issuing bank.

The secondary market, if any, for these loan participation interests is limited; thus, such participations purchased by the Funds may be treated as illiquid. If a loan participation is determined to be illiquid, it will be valued at its fair market value as determined by procedures approved by the Board of Trustees. Valuation of illiquid indebtedness involves a greater degree of judgment in determining the value of each Fund's assets than if the value were based on available market quotations.

MORTGAGE PASS-THROUGH SECURITIES. Each Fund may invest in mortgage pass-through securities, which are a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. government entities or U.S. government-sponsored enterprises including: the Government National Mortgage Association ("Ginnie Mae"), the Federal

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National Mortgage Association ("Fannie Mae") and the Federal Home Loan Mortgage Corporation. In the basic mortgage pass-through structure, mortgages with similar issuer, term and coupon characteristics are collected and aggregated into a "pool" consisting of multiple mortgage loans. The pool is assigned a CUSIP number and undivided interests in the pool are traded and sold as pass-through securities. The holder of the security is entitled to a PRO RATA share of principal and interest payments (including unscheduled prepayments) from the pool of mortgage loans.

The Funds may, to the extent permitted by Rule 2a-7 under the 1940 Act, invest in mortgage securities issued by private non-government entities. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities or government-sponsored enterprises. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information enabling investors to evaluate the practices of these mortgage originators.

In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities issued by government entities, government-sponsored enterprises or non-government entities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Should the government adopt new laws providing mortgage borrowers with additional rights to renegotiate interest rates, alter terms, obtain orders to modify their mortgage terms through the bankruptcy courts, or otherwise allow borrowers to modify or restructure existing mortgages, this may negatively impact mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate. Non-government mortgage securities may be subject to greater price changes than government issues.

An investment in a specific pool of pass-through securities requires an analysis of the specific prepayment risk of mortgages within the covered pool (since mortgagors typically have the option to prepay their loans). The level of prepayments on a pool of mortgage securities is difficult to predict and can impact the subsequent cash flows and value of the mortgage pool. In addition, when trading specific mortgage pools, precise execution, delivery and settlement arrangements must be negotiated for each transaction. These factors combine to make trading in mortgage pools somewhat cumbersome. For these and other reasons, the Funds may obtain exposure to U.S. agency mortgage pass-through securities primarily through the use of "to-be-announced" or "TBA" transactions. "TBA" refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Most transactions in mortgage pass-through securities occur through the use of TBA transactions. TBA transactions generally are conducted in accordance with widely-accepted guidelines that establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined two days prior to the settlement date. The Funds may use TBA transactions in several ways. For example, the Funds may regularly enter into TBA agreements and "roll over" such agreements prior to the settlement date stipulated in such agreements. This type of TBA transaction is sometimes known as a "TBA roll." In a TBA roll, a Fund generally will sell the obligation to purchase the pools stipulated in the TBA agreement prior to the stipulated settlement date and will enter into a new TBA agreement for future delivery of pools of mortgage pass-through securities. In addition, a Fund may enter into TBA agreements and settle such transactions on the stipulated settlement date by accepting actual receipt or delivery of the pools of mortgage pass-through securities stipulated in the TBA agreement. Default by or bankruptcy of a counterparty to a TBA transaction would expose a Fund to possible loss because of adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction. To minimize this risk, the Funds will enter into TBA transactions only with established counterparties (such as major broker-dealers) and BFA will monitor the creditworthiness of such counterparties. The use of TBA rolls may cause the Funds to experience higher portfolio turnover and to pay higher capital gain distributions, which may result in larger amounts of short-term capital gains allocable to shareholders.

MORTGAGE SECURITIES. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime may invest in mortgage securities. Mortgage securities are issued by government and non-government entities such as banks, mortgage lenders, or other institutions. A mortgage security is an obligation of the issuer that is backed by a mortgage or pool of mortgages or a direct interest in an underlying pool of mortgages. Some mortgage securities, such as collateralized mortgage obligations,

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make payments of both principal and interest at a range of specified intervals; others make semi-annual interest payments at a pre-determined rate and repay principal at maturity (like a typical bond). Mortgage securities are based on different types of mortgages, including those on commercial real estate or residential properties. Stripped mortgage securities are created when the interest and principal components of a mortgage security are separated and sold as individual securities. In the case of a stripped mortgage security, the holder of the "principal-only" security (PO) receives the principal payments made by the underlying mortgage, while the holder of the "interest-only" security (IO) receives interest payments from the same underlying mortgage.

The value of mortgage securities may change due to shifts in the market's perception of the creditworthiness of issuers and changes in interest rates or liquidity. The value of some mortgage-backed securities may be particularly sensitive to changes in prevailing interest rates. In addition, regulatory or tax changes may adversely affect the mortgage securities market as a whole. Mortgage securities issued by non-government entities may be subject to greater credit risk than those issued by government entities. The performance of privately-issued mortgage securities may depend on the integrity and competence of the institutions that originate the underlying mortgages, yet investors in these mortgage securities may have only limited access to information required to evaluate the practices of these mortgage originators. In order to prevent defaults by troubled mortgage borrowers, the sponsors of mortgage securities may have to renegotiate and investors in mortgage securities may have to accept less favorable interest rates or other terms on the mortgages underlying these securities. Unanticipated mortgage defaults or renegotiations of mortgage terms are likely to depress the prices of related mortgage securities. Although mortgage securities may be supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Guarantees, insurance and other forms of credit enhancement supporting mortgage securities may also be insufficient to cover all losses on underlying mortgages if mortgage borrowers default at a greater than expected rate.

Non-government mortgage securities may be subject to greater price changes than government issues. Mortgage securities are subject to prepayment risk. Prepayment risk is the risk that early principal payments made on the underlying mortgages, usually in response to a reduction in interest rates, will result in the return of principal to the investor, causing the investor to be invested subsequently at a lower current interest rate. Alternatively, in a rising interest rate environment, mortgage security values may be adversely affected when prepayments on underlying mortgages do not occur as anticipated, resulting in the extension of the security's effective maturity and the related increase in interest rate sensitivity of a longer-term instrument. The prices of stripped mortgage securities tend to be more volatile in response to changes in interest rates than those of non-stripped mortgage securities. In addition, although mortgages and mortgage-related securities are generally supported by some form of government or private guarantee and/or insurance, there is no assurance that private guarantors or insurers will meet their obligations. Also see "Asset-Backed and Commercial Mortgage-Backed Securities" and "Mortgage Pass-Through Securities."

MUNICIPAL SECURITIES. Each Fund may invest in municipal securities. Municipal securities are generally issued by states and local governments and their agencies, authorities and other instrumentalities. Municipal bonds are subject to interest rate, credit and market risk. The ability of a municipal security issuer to make payments on that security could be affected by litigation, legislation or other political events or the bankruptcy of the issuer. Lower-rated municipal bonds are subject to greater credit and market risk than higher quality municipal bonds. Municipal securities in which the Funds may invest include, but are not limited to, municipal lease obligations and securities issued by entities whose underlying assets are municipal bonds. There is no guarantee that income from municipal securities will be exempt from federal and state taxes. Changes in federal or state tax treatment of municipal securities may make municipal securities less attractive as investments or cause them to lose value.

Each Fund will invest in high-quality, long-term municipal bonds, municipal notes and short-term commercial paper with remaining maturities not exceeding 397 calendar days.

NON-U.S. OBLIGATIONS. The Funds may invest in certain securities of non-U.S. issuers. Investing in the securities of non-U.S. issuers involves special risks and considerations not typically associated with investing in U.S. issuers. These include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or potentially confiscatory taxation, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, potential restrictions of the flow of international capital and transaction costs of foreign currency conversions. Non-U.S. issuers may be subject to less governmental regulation than U.S. issuers. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy with respect to growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions.

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The Funds may invest in U.S. dollar-denominated short-term obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions, agencies or instrumentalities that are determined by BFA to be of comparable quality to the other obligations in which the Funds may invest. The Funds may also invest in debt obligations of supranational entities. Supranational entities include international organizations designated or supported by governmental entities to promote economic reconstruction or development and international banking institutions and related government agencies. Examples include the International Bank for Reconstruction and Development (the World Bank), the Asian Development Bank and the InterAmerican Development Bank. The percentage of each Fund's assets invested in obligations of foreign governments and supranational entities will vary depending on the relative yields of such securities, the economic and financial markets of the countries in which the investments are made and the interest rate climate of such countries.

PARTICIPATION INTERESTS. Each Fund may invest in participation interests in any type of security in which the Fund may invest. A participation interest gives the Fund an undivided interest in the underlying securities in the proportion that the Fund's participation interest bears to the total principal amount of the underlying securities.

REPURCHASE AGREEMENTS. The Funds may enter into repurchase agreements. A repurchase agreement is an instrument under which the purchaser (I.E., the Fund) acquires the security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price, thereby determining the yield during the purchaser's holding period. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by each Fund but only to constitute collateral for the seller's obligation to pay the repurchase price, and, in the event of a default by the seller, each Fund may suffer time delays and incur costs or losses in connection with the disposition of the collateral.

In any repurchase transaction, the collateral for a repurchase agreement may include (i) cash items; (ii) obligations issued by the U.S. Government or its agencies or instrumentalities; or (iii) obligations that, at the time the repurchase agreement is entered into, are rated in the highest category generally by at least two nationally recognized statistical rating organizations ("NRSRO"), or, if unrated, determined to be of comparable quality by BFA. Collateral, however, is not limited to the foregoing and may include for example obligations rated below the highest category by NRSROs. Collateral for a repurchase agreement may also include securities that a Fund could not hold directly without the repurchase obligation. Irrespective of the type of collateral underlying the repurchase agreement, in the case of a repurchase agreement entered into by a money market fund, the repurchase obligation of a seller must involve minimal credit risk to a Fund, and otherwise satisfy credit quality standards set forth in the Fund's Rule 2a-7 procedures.

Repurchase agreements pose certain risks for a Fund that utilizes them. Such risks are not unique to the Fund but are inherent in repurchase agreements. The Funds seek to minimize such risks but because of the inherent legal uncertainties involved in repurchase agreements, such risks cannot be eliminated. Lower quality collateral and collateral with longer maturities may be subject to greater price fluctuations than higher quality collateral and collateral with shorter maturities. If the repurchase agreement counterparty were to default, lower quality collateral may be more difficult to liquidate than higher quality collateral. Should the counterparty default and the amount of collateral not be sufficient to cover the counterparty's repurchase obligation, the Fund would retain the status of an unsecured creditor of the counterparty (I.E., the position the Fund would normally be in if it were to hold, pursuant to its investment policies, other unsecured debt securities of the defaulting counterparty) with respect to the amount of the shortfall. As an unsecured creditor, a Fund would be at risk of losing some or all of the principal and income involved in the transaction.

RESTRICTED SECURITIES. Restricted securities are subject to legal restrictions on their sale. Difficulty in selling restricted securities may result in a loss or be costly to the Funds. Restricted securities generally can be sold in privately negotiated transactions, pursuant to an exemption from registration under the Securities Act of 1933, as amended, or in a registered public offering. Where registration is required, the restricted security's holder may be obligated to pay all or part of the registration expense and a considerable period may elapse between the time the holder decides to seek registration and the time the holder may be permitted to sell the security under an effective registration statement. If, during that period, adverse market conditions were to develop, the holder might obtain a less favorable price than prevailed when it decided to seek registration of the security.

UNRATED INVESTMENTS. Each Fund may purchase instruments that are not rated if, in the opinion of BFA, such obligations are of an investment quality that is comparable to other rated investments that are permitted for purchase by a Fund, and they are purchased in accordance with the Trust's procedures adopted by the Trust's Board of Trustees in accordance with Rule

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2a-7 under the 1940 Act. Such procedures require approval or ratification by the Board of Trustees of the purchase of unrated securities. After purchase by a Fund, a security may cease to be rated or its rating may be reduced below the minimum required for purchase by the Fund. Neither event will require an immediate sale of such security by a Fund provided that, when a security ceases to be rated, BFA determines that such security presents minimal credit risks and, provided further that, when a security rating is downgraded below the eligible quality for investment or no longer presents minimal credit risks, BFA finds that the sale of such security would not be in a Fund's shareholders' best interests.

To the extent the ratings given by a NRSRO may change as a result of changes in such organization or its rating systems, the Funds will attempt to use comparable ratings as standards for investments in accordance with the investment policies contained in the Prospectus and this SAI.

U.S. GOVERNMENT OBLIGATIONS. Each Fund may invest in U.S. government obligations, including securities issued or guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities. Payment of principal and interest on U.S. government obligations (i) may be backed by the full faith and credit of the United States (as with U.S. Treasury obligations and Ginnie Mae certificates), or (ii) may be backed solely by the issuing or guaranteeing agency or instrumentality itself (as with Fannie Mae notes). In the latter case, the investor must look principally to the agency or instrumentality issuing or guaranteeing the obligation for ultimate repayment, which agency or instrumentality may be privately owned. There can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. As a general matter, the value of debt instruments, including U.S. government obligations, declines when market interest rates increase and rises when market interest rates decrease. Certain types of U.S. government obligations are subject to fluctuations in yield or value due to their structure or contract terms.

U.S. TREASURY OBLIGATIONS. U.S. Treasury obligations are direct obligations of the U.S. government that are backed by the full faith and credit of the United States. U.S. Treasury obligations include, among other things, U.S. Treasury bills, notes, bonds, and the separately traded principal and interest components of securities guaranteed or issued by the U.S. Treasury if such components are traded independently under the Separate Trading of Registered Interest and Principal of Securities Program.

SELECTIVE DISCLOSURE OF PORTFOLIO HOLDINGS

Pursuant to policies and procedures adopted by the Trust, MIP and BFA, the Trust, MIP and BFA may, under certain circumstances as set forth below, make selective disclosure with respect to a Fund's or Master Portfolio's portfolio holdings. The Boards of Trustees of the Trust and MIP have approved the adoption by the Trust and MIP of the policies and procedures set forth below, and have delegated to BFA the responsibility for ongoing monitoring and supervision to ensure compliance with these policies and procedures. The Boards of Trustees provide ongoing oversight of the Trust's, MIP's and BFA's compliance with the policies and procedures. As part of this oversight function, the Trustees receive from the Trust's and MIP's Chief Compliance Officer at least quarterly and more often, as necessary, reports on compliance with these policies and procedures, including reports on any violations of these policies and procedures that may occur. In addition, the Trustees receive an annual assessment of the adequacy and effectiveness of the policies and procedures with respect to the Trust and MIP, and any changes thereto, and an annual review of the operation of the policies and procedures.

Examples of the information that may be disclosed pursuant to the Trust's and MIP's policies and procedures would include (but is not limited to) specific portfolio holdings -- including the number of shares held, weightings of particular holdings, specific sector and industry weightings, trading details, and the portfolio manager's discussion of Fund or Master Portfolio performance and reasoning for significant changes in portfolio composition. This information may be both material non-public information ("Confidential Information") and proprietary information of the firm. The Trust or MIP may disclose such information to individual investors, institutional investors, financial advisers and other financial intermediaries that sell the Trust's shares, affiliates of the Trust or MIP, third party service providers to the Trust or MIP, lenders to the Trust or MIP, and independent rating agencies and ranking organizations. The Trust, MIP, BFA and its affiliates receive no compensation or other consideration with respect to such disclosures.

Subject to the exceptions set forth below, Confidential Information relating to a Fund or Master Portfolio may not be disclosed to persons not employed by BFA or its affiliates unless such information has been publicly disclosed via a filing with the Commission (e.g., Trust annual report), a press release or placement on a publicly-available internet website. If the Confidential Information has not been publicly disclosed, an employee of BFA who wishes to distribute Confidential Information relating to the Trust or MIP must first do the following: (i) require the person or company receiving the Confidential Information to sign, before BFA will provide disclosure of any such information, a confidentiality agreement approved by an attorney in BFA's Legal Department in which the person or company (a) agrees to use the Confidential Information solely in connection with a legitimate business use (i.e., due diligence, etc.) and (b) agrees not to trade on the basis of the information so provided; (ii) obtain the authorization of an attorney in BFA's Legal Department prior to disclosure; and (iii) only distribute Confidential Information that is at least thirty (30) calendar days old unless a shorter period has specifically been approved by an attorney in BFA's Legal Department.

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Prior to providing any authorization for such disclosure of Confidential Information, an attorney in BFA's Legal Department must review the proposed arrangement and make a determination that it is in the best interests of the Trust's shareholders. In connection with day-to-day portfolio management, the Trust or MIP may disclose Confidential Information to executing broker-dealers that is less than 30 days old in order to facilitate the purchase and sale of portfolio holdings. The Trust and MIP have adopted policies and procedures, including a Code of Ethics, Code of Conduct, and various policies regarding securities trading and trade allocations, to address potential conflicts of interest that may arise in connection with disclosure of Confidential Information. These procedures are designed, among other things, to prohibit personal trading based on Confidential Information, to ensure that portfolio transactions are conducted in the best interests of the Trust and its shareholders and to prevent portfolio management from using Confidential Information for the benefit of one Fund, Master Portfolio or account at the expense of another. In addition, as noted, an attorney in BFA's Legal Department must determine that disclosure of Confidential Information is for a legitimate business purpose and is in the best interests of the Trust's shareholders, and that any conflicts of interest created by release of the Confidential Information have been addressed by BFA's existing policies and procedures. For more information with respect to potential conflicts of interest, see the section entitled "Management-- Potential Conflicts of Interest" in this Statement of Additional Information.

Confidential Information -- whether or not publicly disclosed -- may be disclosed to Trust Trustees, the independent Trustees' counsel, the Trust's outside counsel, accounting services provider and independent registered public accounting firm without meeting the conditions outlined above. Confidential Information may, with the prior approval of the Trust's Chief Compliance Officer or BFA's General Counsel, also be disclosed to any auditor of the parties to a service agreement involving the Trust or MIP, or as required by judicial or administrative process or otherwise by applicable law or regulation. If Confidential Information is disclosed to such persons, each such person will be subject to restrictions on trading in the subject securities under either the Trust's, MIP's and BFA's Code of Ethics or an applicable confidentiality agreement, or under applicable laws or regulations or court order.

BFA has entered into ongoing arrangements to provide monthly and quarterly selective disclosure of Trust and MIP portfolio holdings to the following persons or entities:

Trust's and MIP's Boards of Trustees and, if necessary independent Trustees' counsel and Trust counsel

Trust's Transfer Agent

Trust's and MIP's independent registered public accounting firm

Trust's and MIP's accounting services provider

MIP Custodian

MIP's pricing services - Interactive Data Corp. and Reuters, Inc.

Independent rating agencies -- Morningstar, Inc., Lipper Inc., Moody's Investors Service, Inc. and Standard & Poor's Information aggregators -- Wall Street on Demand, Thomson Financial, eVestment Alliance, informa PSN investment solutions, Micropal, iMoneyNet and Bloomberg

Sponsors of 401(k) plans that include BlackRock-advised Funds -- E.I. Dupont de Nemours and Company, Inc.

Consultants for pension plans that invest in BlackRock-advised Funds -- Rocaton Investment Advisors, LLC; Mercer Investment Consulting; Watson Wyatt Investment Consulting; Towers Perrin HR Services; Pinnacle West; Callan Associates; Brockhouse & Cooper; Cambridge Associates; Mercer; Morningstar/Investorforce; Russell Investments (Mellon Analytical Solutions); and Wilshire Associates

Portfolio Compliance Consultants -- i-Flex Solutions, Inc.

Third-party feeder funds--Hewitt Money Market Fund, Hewitt Series Trust, Hewitt Financial Services LLC, PayPal Money Market Fund, PayPal Funds, PayPal Asset Management, Inc. Homestead, Inc., Transamerica and State Farm Mutual Fund Trust, and their respective boards, sponsors, administrators and other service providers

Affiliated feeder funds--BlackRock Cayman Prime Money Market Fund, Ltd. And BlackRock Cayman Treasury Money Market Fund Ltd., and their respective boards, sponsors, administrators and other service providers

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Other -- Chicago Mercantile Exchange, Inc., Be Creative, Inc. and Investment Company Institute

Other than with respect to the Board of Trustees, each of the persons or entities set forth above is subject to an agreement to keep the information disclosed confidential and to use it only for legitimate business purposes. Each Trustee has a fiduciary duty as a trustee to act in the best interests of the Trust and its shareholders. Selective disclosure is made to the Board of Trustees and independent registered public accounting firm at least quarterly and otherwise as frequently as necessary to enable such persons or entities to provide services to the Trust. Selective disclosure is made to the Trust's Transfer Agent, accounting services provider, and Custodian as frequently as necessary to enable such persons or entities to provide services to the Trust, typically on a daily basis. Disclosure is made to Lipper Inc. and Wall Street on Demand on a monthly basis and to Morningstar and Thomson Financial on a quarterly basis, and to each such firm upon specific request with the approval of BFA's Legal Department. Disclosure is made to 401(k) plan sponsors on a yearly basis and pension plan consultants on a quarterly basis.

The Trust and BFA monitor, to the extent possible, the use of Confidential Information by the individuals or firms to which it has been disclosed. To do so, in addition to the requirements of any applicable confidentiality agreement and/or the terms and conditions of the Trust's and BFA's Code of Ethics and Code of Conduct -- all of which require persons or entities in possession of Confidential Information to keep such information confidential and not to trade on such information for their own benefit -- BFA's compliance personnel under the supervision of the Trust's Chief Compliance Officer, monitor BFA's securities trading desks to determine whether individuals or firms who have received Confidential Information have made any trades on the basis of that information. In addition, BFA maintains an internal restricted list to prevent trading by the personnel of BFA or its affiliates in securities -- including securities held by the Trust or MIP -- about which BFA has Confidential Information. There can be no assurance, however, that the Trust's policies and procedures with respect to the selective disclosure of Trust portfolio holdings will prevent the misuse of such information by individuals or firms that receive such information

Management

The Board of Trustees of the Trust, consists of thirteen individuals (each, a "Trustee"), eleven of whom are Independent Trustees. The same individuals serve on the Board of Trustees of MIP. The registered investment companies advised by BFA or its affiliates (the "BlackRock-advised Funds") are organized into one complex of closed-end funds, two complexes of open-end funds (the Equity-Liquidity Complex and the Equity-Bond Complex) and one complex of exchange-traded funds (each, a "BlackRock Fund Complex"). The Trust and MIP are included in the BlackRock Fund Complex referred to as the Equity-Liquidity Complex. The Trustees also oversee as board members the operations of the other open-end registered investment companies included in the Equity-Liquidity Complex. The address for each Trustee and officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055.

The Board of Trustees has overall responsibility for the oversight of the Trust and the Funds. The Co-Chairs of the Board are Independent Trustees, and the Chair of each Board committee (each, a "Committee") is an Independent Trustee. The Board has five standing Committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight and Contract Committee and an Executive Committee. The Board also has one ad hoc committee, the Joint Product Pricing Committee. The role of the Co-Chairs of the Board is to preside at all meetings of the Board and to act as a liaison with service providers, officers, attorneys, and other Trustees generally between meetings. The Chair of each Committee performs a similar role with respect to the Committee. The Co-Chairs of the Board or the Chair of a Committee may also perform such other functions as may be delegated by the Board or the Committee from time to time. The Independent Trustees meet regularly outside the presence of Trust management, in executive session or with other service providers to the Trust and the Funds. The Board has regular meetings five times a year, and may hold special meetings if required before its next regular meeting. Each Committee meets regularly to conduct the oversight functions delegated to that Committee by the Board and reports its findings to the Board. The Board and each standing Committee conduct annual assessments of their oversight function and structure. The Board has determined that the Board's leadership structure is appropriate because it allows the Board to exercise independent judgment over management and to allocate areas of responsibility among Committees and the full Board to enhance effective oversight.

The Board has engaged BFA to manage the Funds on a day-to-day basis. The Board is responsible for overseeing BFA, other service providers, the operations of the Funds and associated risk in accordance with the provisions of the 1940 Act, state

14

law, other applicable laws, the Trust's charter, and the Funds' investment objectives and strategies. The Board reviews, on an ongoing basis, the Funds' performance, operations, and investment strategies and techniques. The Board also conducts reviews of BFA and its role in running the operations of the Funds.

Day-to-day risk management with respect to the Funds is the responsibility of BFA or of sub-advisers or other service providers (depending on the nature of the risk), subject to the supervision of BFA. The Funds are subject to a number of risks, including investment, compliance, operational and valuation risks, among others. While there are a number of risk management functions performed by BFA and the sub-advisers or other service providers, as applicable, it is not possible to eliminate all of the risks applicable to the Funds. Risk oversight forms part of the Board's general oversight of the Funds and is addressed as part of various Board and Committee activities. The Board, directly or through a Committee, also reviews reports from, among others, management, the independent registered public accounting firm for the Funds, sub-advisers, and internal auditors for the investment adviser or its affiliates, as appropriate, regarding risks faced by the Funds and management's or the service provider's risk functions. The Committee system facilitates the timely and efficient consideration of matters by the Trustees, and facilitates effective oversight of compliance with legal and regulatory requirements and of the Funds' activities and associated risks. The Board has appointed a Chief Compliance Officer, who oversees the implementation and testing of the Funds' compliance program and reports to the Board regarding compliance matters for the Funds and their service providers. The Independent Trustees have engaged independent legal counsel to assist them in performing their oversight responsibilities.

The members of the Audit Committee are Kenneth L. Urish (Chair), Herbert I. London and Frederick W. Winter, all of whom are Independent Trustees. The principal responsibilities of the Audit Committee are to approve the selection, retention, termination and compensation of the Trust's independent registered public accounting firm (the "independent auditors") and to oversee the independent auditors' work. The Audit Committee's responsibilities include, without limitation, to (1) evaluate the qualifications and independence of the independent auditors; (2) approve all audit engagement terms and fees for each Fund; (3) review the conduct and results of each independent audit of each Fund's financial statements; (4) review any issues raised by the independent auditors or Trust management regarding the accounting or financial reporting policies and practices of each Fund and the internal controls of each Fund and certain service providers; (5) oversee the performance of each Fund's internal audit function provided by its investment adviser, administrator, pricing agent or other service provider; (6) discuss with Trust management its policies regarding risk assessment and risk management and (7) resolve any disagreements between Trust management and the independent auditors regarding financial reporting. The Board has adopted a written charter for the Audit Committee. During the period December 1, 2009 through December 31, 2009, the Audit Committee met one time.

The members of the Governance and Nominating Committee (the "Governance Committee") are Dr. Matina Horner (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The principal responsibilities of the Governance Committee are to (1) identify individuals qualified to serve as Independent Trustees of the Trust and recommend Independent Trustee nominees for election by shareholders or appointment by the Board; (2) advise the Board with respect to Board composition, procedures and committees (other than the Audit Committee); (3) oversee periodic self-assessments of the Board and committees of the Board (other than the Audit Committee); (4) review and make recommendations regarding Independent Trustee compensation; and (5) monitor corporate governance matters and develop appropriate recommendations to the Board. The Governance Committee may consider nominations for the office of Trustee made by Fund shareholders as it deems appropriate. Fund shareholders who wish to recommend a nominee should send nominations to the Secretary of the Trust that include biographical information and set forth the qualifications of the proposed nominee. The Board has adopted a written charter for the Governance Committee. During the period December 1, 2009 through December 31, 2009, the Governance Committee met one time.

The members of the Compliance Committee are Joseph P. Platt, Jr. (Chair), Cynthia A. Montgomery and Robert C. Robb, Jr., all of whom are Independent Trustees. The Compliance Committee's purpose is to assist the Board in fulfilling its responsibility to oversee regulatory and fiduciary compliance matters involving the Trust, the Fund-related activities of BFA and the Trust's third party service providers. The Compliance Committee's responsibilities include, without limitation, to (1) oversee the compliance policies and procedures of the Trust and its service providers and recommend changes or additions to such policies and procedures; (2) review information on and, where appropriate recommend policies concerning, the Trust's compliance with applicable law; and (3) review reports from, oversee the annual performance review of, and make certain recommendations regarding the Trust's Chief Compliance Officer. The Board has adopted a written charter for the Compliance Committee. During the period December 1, 2009 through December 31, 2009, the Compliance Committee met two times.

15

The members of the Performance Oversight and Contract Committee (the "Performance Oversight Committee") are David O. Beim (Chair), Toby Rosenblatt (Vice Chair), Ronald W. Forbes and Rodney D. Johnson, all of whom are Independent Trustees. The Performance Oversight Committee's purpose is to assist the Board in fulfilling its responsibility to oversee each Fund's investment performance relative to its agreed-upon performance objectives and to assist the Independent Trustees in their consideration of investment advisory agreements. The Performance Oversight Committee's responsibilities include, without limitation, to (1) review each Fund's investment objectives, policies and practices and each Fund's investment performance; (2) review personnel and resources devoted to management of each Fund and evaluate the nature and quality of information furnished to the Performance Oversight Committee; (3) recommend any required action regarding change in fundamental and non-fundamental investment policies and restrictions, fund mergers or liquidations; (4) request and review information on the nature, extent and quality of services provided to the shareholders; and (5) make recommendations to the Board concerning the approval or renewal of investment advisory agreements. The Board has adopted a written charter for the Performance Oversight Committee. During the period December 1, 2009 through December 31, 2009, the Performance Oversight Committee met one time.

The Boards of the Equity-Liquidity Complex, the Equity-Bond Complex and the closed-end BlackRock Fund Complex, established the ad hoc Joint Product Pricing Committee (the "Product Pricing Committee") comprised of eight members drawn from the independent board members serving on the boards of these BlackRock Fund Complexes. Ronald W. Forbes and Rodney D. Johnson are members of the Product Pricing Committee representing the Equity-Liquidity Complex. One independent board member representing the closed-end BlackRock Fund Complex and five independent board members representing the Equity-Bond Complex serve on the Product Pricing Committee. The Product Pricing Committee is chaired by an independent board member from the Equity-Bond Complex. The purpose of the Product Pricing Committee is to review the components and pricing structure of the non-money market funds in the BlackRock Fund Complexes. During the period from December 1, 2009 through December 31, 2009, the Product Pricing Committee did not meet.

The members of the Executive Committee are Ronald W. Forbes and Rodney D. Johnson, both of whom are Independent Trustees, and Richard S. Davis, who serves as an interested Trustee. The principal responsibilities of the Executive Committee are to (1) act on routine matters between meetings of the Board; (2) act on such matters as may require urgent action between meetings of the Board; and (3) exercise such other authority as may from time to time be delegated to the Executive Committee by the Board. The Board has adopted a written charter for the Executive Committee. During the period December 1, 2009 through December 31, 2009, the Executive Committee met one time.

The Governance Committee has adopted a statement of policy that describes the experience, qualifications, skills and attributes that are necessary and desirable for potential Independent Trustee candidates (the "Statement of Policy"). The Board believes that each Independent Trustee satisfied, at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. Furthermore, in determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, skills, attributes and qualifications, which allow the Board to operate effectively in governing the Trust and protecting the interests of shareholders. Among the attributes common to all Trustees are their ability to review critically, evaluate, question and discuss information provided to them, to interact effectively with the Trust's investment adviser, sub-advisers, other service providers, counsel and independent auditors, and to exercise effective business judgment in the performance of their duties as Trustees. Each Trustee's ability to perform his or her duties effectively is evidenced by his or her educational background or professional training; business, consulting, public service or academic positions; experience from service as a board member of the Trust and the other funds in the BlackRock Fund Complex (and any predecessor funds), other investment funds, public companies, or non-profit entities or other organizations; ongoing commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout the years; or other relevant life experiences. Information about the specific experience, skills, attributes and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a Trustee of the Trust, is provided below.

16

Certain biographical and other information relating to the Trustees of the Trust is set forth below, including their ages, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                              POSITION(S)        LENGTH OF                                       PORTFOLIOS
           NAME                HELD WITH            TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")       PUBLIC
         AND AGE               THE TRUST         SERVED/2/         DURING PAST FIVE YEARS         OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
INDEPENDENT TRUSTEES/1/
David O. Beim/3/          Trustee            2009 to present   Professor of Finance and       36 RICs          None
(69)                                                           Economics at the Columbia      consisting of
                                                               University Graduate School     104 Portfolios
                                                               of Business since 1991;
                                                               Trustee, Phillips Exeter
                                                               Academy since 2002;
                                                               Chairman, Wave Hill, Inc.
                                                               (public garden and cultural
                                                               center) from 1990 to 2006.

Ronald W. Forbes/4/       Trustee            2009 to present   Professor Emeritus of          36 RICs          None
(69)                                                           Finance, School of Business,   consisting of
                                                               State University of New York   104 Portfolios
                                                               at Albany since 2000.

Dr. Matina S. Horner/5/   Trustee            2009 to present   Executive Vice President of    36 RICs          NSTAR
(70)                                                           Teachers Insurance and         consisting of    (electric and
                                                               Annuity Association and        104 Portfolios   gas utility)
                                                               College Retirement Equities
                                                               Fund from 1989 to 2003.

Rodney D. Johnson/4/      Trustee            2009 to present   President, Fairmont Capital    36 RICs          None
(68)                                                           Advisors, Inc. since 1987;     consisting of
                                                               Director, Fox Chase Cancer     104 Portfolios
                                                               Center since 2004; Member
                                                               of Archdiocesan Investment
                                                               Committee of the
                                                               Archdiocese of Philadelphia
                                                               since 2004; Director, The
                                                               Committee of Seventy (civic)
                                                               since 2006.

17

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                              POSITION(S)        LENGTH OF                                       PORTFOLIOS
           NAME                HELD WITH            TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")        PUBLIC
         AND AGE               THE TRUST         SERVED/2/          DURING PAST FIVE YEARS        OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
Herbert I. London         Trustee            2009 to present   Professor Emeritus, New        36 RICs          AIMS
(71)                                                           York University since 2005;    consisting of    Worldwide,
                                                               John M. Olin Professor of      104 Portfolios   Inc.
                                                               Humanities, New York                                (marketing)
                                                               University from 1993 to 2005
                                                               and Professor thereof from
                                                               1980 to 2005; President,
                                                               Hudson Institute (policy
                                                               research organization) since
                                                               1997 and Trustee thereof
                                                               since 1980; Chairman of the
                                                               Board of Trustees for
                                                               Grantham University since
                                                               2006; Director, InnoCentive,
                                                               Inc. (strategic solutions
                                                               company) since 2005;
                                                               Director of Cerego, LLC
                                                               (software development and
                                                               design) since 2005.

Cynthia A.                Trustee            2009 to present   Professor, Harvard Business    36 RICs          Newell
Montgomery                                                     School since 1989; Director,   consisting of    Rubbermaid,
(57)                                                           Harvard Business School        104 Portfolios   Inc.
                                                               Publishing since 2005;                          (manufacturing)
                                                               Director, McLean Hospital
                                                               since 2005.

Joseph P. Platt, Jr./6/   Trustee            2009 to present   Director, The West Penn        36 RICs          Greenlight
(62)                                                           Allegheny Health System (a     consisting of    Capital Re,
                                                               not-for-profit health system)  104 Portfolios   Ltd
                                                               since 2008; Director, Jones                     (reinsurance
                                                               and Brown (Canadian                             company);
                                                               insurance broker) since                         WQED Multi-
                                                               1998; General Partner, Thorn                    Media (public
                                                               Partner, LP (private                            broadcasting
                                                               investment) since 1998;                         not-for-
                                                               Partner Amarna Corporation,                     profit)
                                                               LLC (private investment
                                                               company) from 2002 to
                                                               2008.

Robert C. Robb, Jr.       Trustee            2009 to present   Partner, Lewis, Eckert, Robb   36 RICs          None
(64)                                                           and Company (management        consisting of
                                                               and financial consulting       104 Portfolios
                                                               firm) since 1981.

18

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                              POSITION(S)        LENGTH OF                                       PORTFOLIOS
         NAME                  HELD WITH            TIME           PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")        PUBLIC
       AND AGE                 THE TRUST         SERVED/2/          DURING PAST FIVE YEARS        OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
Toby Rosenblatt/7/        Trustee            2009 to present   President, Founders            36 RICs          A.P. Pharma
(71)                                                           Investments Ltd. (private      consisting of    Inc. (specialty
                                                               investments) since 1999;       104 Portfolios   pharmaceuticals)
                                                               Director, College Access
                                                               Foundation of California
                                                               (philanthropic foundation)
                                                               since 2009; Director, Forward
                                                               Management, LLC since
                                                               2007; Director, the James
                                                               Irvine Foundation
                                                               (philanthropic foundation)
                                                               from 1998 to 2008.

Kenneth L. Urish/8/       Trustee            2009 to present   Managing Partner, Urish        36 RICs          None
(59)                                                           Popeck & Co., LLC (certified   consisting of
                                                               public accountants and         104 Portfolios
                                                               consultants) since 1976;
                                                               Member of External Advisory
                                                               Board, the Pennsylvania
                                                               State University Accounting
                                                               Department since 2001;
                                                               Trustee, The Holy Family
                                                               Foundation since 2001;
                                                               Committee Member,
                                                               Professional Ethics
                                                               Committee of the
                                                               Pennsylvania Institute of
                                                               Certified Public Accountants
                                                               from 2007 to 2010; President
                                                               and Trustee, Pittsburgh
                                                               Catholic Publishing
                                                               Associates from 2003 to
                                                               2008; Director, Inter-Tel from
                                                               2006 to 2007.

Frederick W. Winter       Trustee            2009 to present   Professor and Dean Emeritus    36 RICs          None
(65)                                                           of the Joseph M. Katz School   consisting of
                                                               of Business, University of     104 Portfolios
                                                               Pittsburgh since 2005 and
                                                               dean thereof from 1997 to
                                                               2005; Director, Alkon
                                                               Corporation (pneumatics)
                                                               since 1992; Director
                                                               Tippman Sports (recreation)
                                                               since 2005; Director,
                                                               Indotronix International (IT
                                                               services) from 2004 to 2008.

19

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                  ("RICS")
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                              POSITION(S)        LENGTH OF                                       PORTFOLIOS
       NAME                    HELD WITH            TIME            PRINCIPAL OCCUPATION(S)    ("PORTFOLIOS")       PUBLIC
      AND AGE                  THE TRUST         SERVED/2/          DURING PAST FIVE YEARS        OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
INTERESTED TRUSTEES/1/,/9/
Richard S. Davis          Trustee            2009 to present   Managing Director,             169 RICs         None
(64)                                                           BlackRock, Inc. since 2005;    consisting of
                                                               Chief Executive Officer, State 298 Portfolios
                                                               Street Research &
                                                               Management Company from
                                                               2000 to 2005; Chairman of
                                                               the Board of Trustees, State
                                                               Street Research Mutual
                                                               Funds from 2000 to 2005;
                                                               Chairman, SSR Realty from
                                                               2000 to 2004.

Henry Gabbay              Trustee            2009 to present   Consultant, BlackRock, Inc.    169 RICs         None
(62)                                                           from 2007 to 2008;             consisting of
                                                               Managing Director,             298 Portfolios
                                                               BlackRock, Inc. from 1989 to
                                                               2007; Chief Administrative
                                                               Officer, BlackRock Advisors,
                                                               LLC from 1998 to 2007;
                                                               President of BlackRock
                                                               Funds and BlackRock Bond
                                                               Allocation Target Shares
                                                               from 2005 to 2007 and
                                                               Treasurer of certain closed-
                                                               end funds in the BlackRock
                                                               fund complex from 1989 to
                                                               2006.


/1/ Trustees serve until their resignation, removal or death, or until December 31 of the year in which they turn 72. The Board of Trustees has approved one-year extensions in the terms of Trustees who turn 72 prior to December 31, 2013.
/2/ In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, the Trustees were elected to the Trust's Board. As a result, although the chart shows the Trustees as joining the Trust's Board in 2009, each Trustee first became a member of the boards of other funds advised by BlackRock Advisors, LLC or its affiliates as follows: David O. Beim, 1998; Ronald W. Forbes, 1977; Dr. Matina Horner, 2004; Rodney D. Johnson, 1995; Herbert I. London, 1987; Cynthia A. Montgomery, 1994; Joseph P. Platt, Jr., 1999; Robert C. Robb, Jr., 1999; Toby Rosenblatt, 2005; Kenneth L. Urish, 1999; and Frederick W. Winter, 1999.
/3/ Chair of the Performance Oversight Committee. /4/ Co-Chair of the Board of Trustees. /5/ Chair of the Governance Committee. /6/ Chair of the Compliance Committee.
/7/ Vice Chair of the Performance Oversight Committee. /8/ Chair of the Audit Committee.
/9/ Mr. Davis is an "interested person," as defined in the 1940 Act, of the Trust based on his position with BlackRock, Inc. and its affiliates. Mr. Gabbay is an "interested person" of the Trust based on his former positions with BlackRock, Inc. and its affiliates as well as his ownership of BlackRock, Inc. and The PNC Financial Services Group, Inc. securities.

20

Certain biographical and other information relating to the officers of the Trust is set forth below, including their year of birth, their principal occupations for at least the last five years, the length of time served, the total number of registered investment companies and portfolios overseen in the BlackRock-advised Funds and any public directorships.

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
         NAME              POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")       PUBLIC
   AND YEAR OF BIRTH        WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
Trust Officers/1/
----------------------

Anne F. Ackerley          President and      2009 to present   Managing Director of           169 RICs         None
1962                      Chief Executive                      BlackRock, Inc. since 2000;    consisting of
                          Officer                              Vice President of the          298 Portfolios
                                                               BlackRock-advised Funds
                                                               from 2007 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's Global Client
                                                               Group (GCG) since 2009;
                                                               Chief Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               from 2006 to 2009; Head of
                                                               BlackRock's Mutual Fund
                                                               Group from 2000 to 2006.

Richard Hoerner, CFA      Vice President     2009 to present   Managing Director of           24 RICs          None
1958                                                           BlackRock, Inc. since 2000;    consisting of
                                                               Co-head of BlackRock's Cash    73 Portfolios
                                                               Management Portfolio
                                                               Management Group since
                                                               2002; Member of the Cash
                                                               Management Group
                                                               Executive Committee since
                                                               2005.

Jeffrey Holland, CFA      Vice President     2009 to present   Managing Director of           70 RICs          None
1971                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    201 Portfolios
                                                               from 2006 to 2009; Chief
                                                               Operating Officer of
                                                               BlackRock's U.S. Retail Group
                                                               since 2009; Co-head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group from 2007
                                                               to 2009; Product Manager of
                                                               Raymond James &
                                                               Associates from 2003 to
                                                               2006.

21

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
        NAME               POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)     ("PORTFOLIOS")       PUBLIC
 AND YEAR OF BIRTH          WITH THE TRUST      TIME SERVED        DURING PAST FIVE YEARS         OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
Brendan Kyne              Vice President     2009 to present   Managing Director of           169 RICs         None
1977                                                           BlackRock, Inc. since 2010;    consisting of
                                                               Director of BlackRock, Inc.    298 Portfolios
                                                               from 2008 to 2009; Head of
                                                               Product Development and
                                                               Management for BlackRock's
                                                               U.S. Retail Group since 2009,
                                                               co-head thereof from 2007
                                                               to 2009; Vice President of
                                                               BlackRock, Inc. from 2005 to
                                                               2008.

Simon Mendelson           Vice President     2009 to present   Managing Director of           24 RICs          None
1964                                                           BlackRock, Inc. since 2005;    consisting of
                                                               Chief Operating Officer and    73 Portfolios
                                                               head of the Global Client
                                                               Group for BlackRock's Global
                                                               Cash Management Business
                                                               since 2007; Head of
                                                               BlackRock's Strategy and
                                                               Development Group from
                                                               2005 to 2007.

Brian Schmidt             Vice President     2009 to present   Managing Director of           70 RICs          None
1958                                                           BlackRock, Inc. since 2004;    consisting of
                                                               Various positions with U.S.    201 Portfolios
                                                               Trust Company from 1991 to
                                                               2003: Director from 2001 to
                                                               2003, Senior Vice President
                                                               from 1998 to 2003; Vice
                                                               President, Chief Financial
                                                               Officer and Treasurer of
                                                               Excelsior Funds, Inc.,
                                                               Excelsior Tax-Exempt Funds,
                                                               Inc. and Excelsior Funds
                                                               Trust from 2001 to 2003.

22

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
          NAME            POSITION(S) HELD      LENGTH OF         PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")       PUBLIC
    AND YEAR OF BIRTH      WITH THE TRUST      TIME SERVED         DURING PAST FIVE YEARS         OVERSEEN       DIRECTORSHIPS
------------------------ ------------------ ----------------- ------------------------------- ---------------- -----------------
Christopher Stavrakos,   Vice President     2009 to present   Managing Director of            24 RICs          None
CFA                                                           BlackRock, Inc. since 2006;     consisting of
1959                                                          Co-head of BlackRock's Cash     73 Portfolios
                                                              Management Portfolio
                                                              Management Group since
                                                              2006; Senior Vice President,
                                                              CIO, and Director of Liability
                                                              Management for the
                                                              Securities Lending Group at
                                                              Mellon Bank from 1999 to
                                                              2006.

Neal J. Andrews          Chief Financial    2009 to present   Managing Director of            169 RICs         None
1966                     Officer and                          BlackRock, Inc. since 2006;     consisting of
                         Assistant                            Senior Vice President and       298 Portfolios
                         Treasurer                            Line of Business Head of
                                                              Fund Accounting and
                                                              Administration at PNC
                                                              Global Investment Servicing
                                                              (U.S.) Inc. from 1992 to
                                                              2006.

Jay M. Fife              Treasurer          2009 to present   Managing Director of            169 RICs         None
1970                                                          BlackRock, Inc. since 2007      consisting of
                                                              and Director in 2006;           298 Portfolios
                                                              Assistant Treasurer of the
                                                              Merrill Lynch Investment
                                                              Managers, L.P. ("MLIM") and
                                                              Fund Asset Management,
                                                              L.P. advised funds from 2005
                                                              to 2006; Director of MLIM
                                                              Fund Services Group from
                                                              2001 to 2006.

Brian P. Kindelan        Chief              2009 to present   Chief Compliance Officer of     169 RICs         None
1959                     Compliance                           the BlackRock-advised funds     consisting of
                         Officer and                          since 2007; Managing            298 Portfolios
                         Anti-Money                           Director and Senior Counsel
                         Laundering                           of BlackRock, Inc. since
                         Compliance                           2005.
                         Officer

23

                                                                                                  NUMBER OF
                                                                                                 BLACKROCK-
                                                                                                   ADVISED
                                                                                                 REGISTERED
                                                                                                 INVESTMENT
                                                                                                  COMPANIES
                                                                                                   ("RICS"
                                                                                                CONSISTING OF
                                                                                                 INVESTMENT
                                                                                                 PORTFOLIOS
        NAME               POSITION(S) HELD      LENGTH OF        PRINCIPAL OCCUPATION(S)      ("PORTFOLIOS")       PUBLIC
 AND YEAR OF BIRTH          WITH THE TRUST      TIME SERVED       DURING PAST FIVE YEARS          OVERSEEN       DIRECTORSHIPS
------------------------- ------------------ ----------------- ------------------------------ ---------------- -----------------
Howard B. Surloff         Secretary          2009 to present   Managing Director and          169 RICs         None

1965                                                           General Counsel of U.S.        consisting of
                                                               Funds at BlackRock, Inc.       298 Portfolios
                                                               since 2006; General Counsel
                                                               (U.S.) of Goldman Sachs
                                                               Asset Management, L.P.
                                                               from 1993 to 2006.


/1/ Officers of the Trust serve at the pleasure of the Board of Trustees.

SHARE OWNERSHIP INFORMATION. Information relating to each Trustee's share ownership in the Funds and in all BlackRock-advised Funds that are overseen by the respective Trustee ("Supervised Funds") as of December 31, 2009 is set forth in the chart below:

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Interested Trustees    BlackRock     BlackRock        BlackRock    BlackRock    Aggregate
                       Cash          Cash             Cash         Cash         Dollar
                       Funds:        Funds:           Funds:       Funds:       Range of
                       Government    Institutional    Prime        Treasury     Securities
                                                                                in the
                                                                                Supervised
                                                                                Funds
Richard S. Davis       None          None             None         None         over
                                                                                $100,000
Henry Gabbay           None          None             None         None         over
                                                                                $100,000

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Independent Trustees   BlackRock     BlackRock        BlackRock    BlackRock    Aggregate
                       Cash          Cash             Cash         Cash         Dollar
                       Funds:        Funds:           Funds:       Funds:       Range of
                       Government    Institutional    Prime        Treasury     Securities
                                                                                in the
                                                                                Supervised
                                                                                Funds
David O. Beim          None          None             None         None         over
                                                                                $100,000
Ronald W. Forbes       None          None             None         None         over
                                                                                $100,000
Dr. Matina S. Horner   None          None             None         None         over
                                                                                $100,000

24

                                  DOLLAR RANGE OF EQUITY SECURITIES
                       -------------------------------------------------------
Rodney D. Johnson      None          None             None         None         over
                                                                                $100,000
Herbert I. London      None          None             None         None         $ 50,001
                                                                                - $100,000
Cynthia A. Montgomery  None          None             None         None         over
                                                                                $100,000
Joseph P. Platt, Jr.   None          None             None         None         over
                                                                                $100,000
Robert C. Robb, Jr.    None          None             None         None         over
                                                                                $100,000
Toby Rosenblatt        None          None             None         None         over
                                                                                $100,000
Kenneth L. Urish       None          None             None         None         $ 50,001
                                                                                - $100,000
Frederick W. Winter    None          None             None         None         over
                                                                                $100,000

OWNERSHIP OF SECURITIES OF CERTAIN ENTITIES. As of March 31, 2010, the Trustees and officers of the Trust as a group owned an aggregate of less than 1% of the outstanding shares of any Fund. As of March 31, 2010, none of the Independent Trustees or their immediate family members owned beneficially or of record any securities of affiliates of the Investment Adviser.

COMPENSATION OF TRUSTEES. Each current Trustee who is an Independent Trustee is paid as compensation an annual retainer of $250,000 per year for his or her services as a Board member to the BlackRock-advised Funds in the Equity-Liquidity Complex, including the Trust and MIP, and a $5,000 Board meeting fee to be paid for each in-person Board meeting attended (a $2,500 Board meeting fee for telephonic attendance at regular Board meetings), for up to five Board meetings held in a calendar year (compensation for meetings in excess of this number to be determined on a case by case basis), together with out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. The Co-Chairs of the Boards of Trustees are each paid an additional annual retainer of $45,000. The Chairs of the Audit Committees, Compliance Committees, Governance Committees and Performance Oversight Committees and the Vice-Chair of the Performance Oversight Committees are each paid an additional annual retainer of $25,000. The Chair of the Product Pricing Committee, who oversees funds in the Equity-Bond Complex, is paid an annual retainer of $25,000 that is allocated among all of the non-money market funds in the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes.

Mr. Gabbay is an interested Trustee of the Trust and serves as an interested board member of the other funds which comprise the Equity-Liquidity, the Equity-Bond and the closed-end BlackRock Fund Complexes. Mr. Gabbay receives as compensation for his services as a board member of each of these three BlackRock Fund Complexes, (i) an annual retainer of $487,500, paid quarterly in arrears, allocated to the BlackRock-advised Funds in these three BlackRock Fund Complexes, including the Trust and MIP, and (ii) with respect to each of the two open-end BlackRock Fund Complexes, a board meeting fee of $3,750 (with respect to meetings of the Equity-Liquidity Complex) and $18,750 (with respect to meetings of the Equity-Bond Complex) to be paid for attendance at each board meeting up to five board meetings held in a calendar year by each such Complex (compensation for meetings in excess of this number to be determined on a case by case basis). Mr. Gabbay will also be reimbursed for out of pocket expenses in accordance with a Board policy on travel and other business expenses relating to attendance at meetings. Mr. Gabbay's compensation for serving on the boards of funds in these three BlackRock Fund Complexes (including the Trust and MIP) is equal to 75% of each retainer and, as applicable, of each meeting fee (without regard to additional fees paid to Board and Committee chairs) received by the independent board members serving on such boards. The Board or any other BlackRock-advised Fund may modify the board members' compensation from time to time depending on market conditions and Mr. Gabbay's compensation would be impacted by those modifications.

Each of the Independent Trustees and Mr. Gabbay agreed to a 10% reduction in their compensation described above for the period December 1, 2009 through December 31, 2009.

25

From January 1, 2009 through November 30, 2009, the Trust paid each Independent Trustee then in office the Trust's allocable share of the following Independent Trustee fees and expenses: (i) an annual base fee of $60,000; (ii) a per meeting fee of $6,000 for meetings of the Board attended by the Trustee; (iii) a committee meeting fee of $2,500 for each Audit Committee meeting attended by the Trustee; and (iv) a committee meeting fee of $2,000 for each Nominating and Governance Committee meeting attended by the Trustee. The Chairperson of the Audit Committee was paid the Trust's allocable share of an annual fee of $10,000 and the Chairperson of the Nominating and Governance Committee was paid the Trust's allocable share of an annual fee of $5,000. The Lead Independent Trustee was paid the Trust's allocable share of an additional annual base fee of $17,500. These Independent Trustee fees and expenses were allocated between the Trust and MIP, based on their respective assets under management.

The Trust reimburses each Trustee for travel and other out-of-pocket expenses incurred by him/her in connection with attending Board and committee meetings. Currently, the Trustees do not receive any retirement benefits or deferred compensation from the fund complex, as defined in Form N-1A under the 1940 Act.

As of December 1, 2009, the members of the Board of Trustees of the Trust listed below resigned (each, a "Previous Trustee"). The table below indicates the amount of compensation each Previous Trustee was paid as of December 31, 2009. Compensation is not shown for the New Trustees because they did not serve as Trustees of the Trust until December 1, 2009, and the New Trustees did not receive compensation from the Trust in 2009.

COMPENSATION
FOR THE FISCAL YEAR ENDED DECEMBER 31, 2009

                                 AGGREGATE COMPENSATION     TOTAL COMPENSATION
 NAME OF INTERESTED TRUSTEE          FROM THE TRUST        FROM FUND COMPLEX(1)
----------------------------    ------------------------  ---------------------
Lee T. Kranefuss                           $0                       $0
H. Michael Williams                        $0                       $0

                                 AGGREGATE COMPENSATION    TOTAL COMPENSATION
 NAME OF INDEPENDENT TRUSTEES        FROM THE TRUST       FROM FUND COMPLEX(1)
------------------------------  ------------------------  ---------------------
Mary G. F. Bitterman(2)         $78,394                         $157,000
A. John Gambs(3)                $72,310                         $157,500
Hayne E. Leland                 $60,640                         $132,000
Jeffrey M. Lyons                $67,078                         $146,000
Wendy Paskin-Jordan             $64,552                         $140,500
Leo Soong(4)                    $72,584                         $158,000


(1) Includes compensation for serving on the Board of Trustees of MIP.
(2) Previously the Nominating and Governance Committee Chair.
(3) Previously the Audit Committee Chair.
(4) Previously the Lead Independent Trustee.

MASTER/FEEDER STRUCTURE. Each Fund seeks to achieve its investment objective by investing all of its assets in the corresponding Master Portfolio of MIP. The Trust's Board of Trustees believes that under normal circumstances, none of the Funds or their shareholders will be adversely affected by investing Fund assets in a Master Portfolio. However, if a mutual fund or other investor redeems its interests from a Master Portfolio, the economic efficiencies (E.G., spreading fixed expenses over a larger asset base) that the Trust's Board of Trustees believes may be available through a Fund's investment in such Master Portfolio may not be fully achieved. In addition, although unlikely, the master/feeder structure may give rise to accounting or operational difficulties.

The fundamental policies of each Master Portfolio cannot be changed without approval by the holders of a majority (as defined in the 1940 Act) of a Master Portfolio's outstanding interests. Whenever a Fund, as an interestholder of a Master Portfolio, is requested to vote on any matter submitted to interestholders of the Master Portfolio, a Fund will either hold a meeting of its shareholders to consider such matters and cast its votes in proportion to the votes received from its shareholders (shares for which a Fund receives no voting instructions will be voted in the same proportion as the votes received from the other Fund shareholders) or cast its votes, as an interestholder of the Master Portfolio, in proportion to the votes received by the Master Portfolio from all other interestholders of the Master Portfolio.

Certain policies of the Master Portfolios that are non-fundamental may be changed by vote of a majority of MIP's Trustees without interestholder approval. If a Master Portfolio's investment objective or fundamental or non-fundamental policies are changed, a Fund may elect to change its objective or policies to correspond to those of the related Master Portfolio. Each Fund may redeem its interests from its Master Portfolio only if the Trust's Board of Trustees determines that such action is in the best interests of the Fund and its shareholders, for this or any other reason. Prior to such redemption, the Trust's Board of Trustees would consider alternatives, including whether to seek a new investment company with a matching investment objective in which to invest or retain its own investment adviser to manage the Fund's portfolio in accordance with its investment objective. In the latter case, a Fund's inability to find a substitute investment company in which to invest or equivalent management services could adversely affect shareholders' investments in the Fund.

CODES OF ETHICS. The Trust, BFA and SEI have adopted Codes of Ethics pursuant to Rule 17j-1 under the 1940 Act. The Codes of Ethics permit personnel subject to the Codes of Ethics to invest in securities, subject to certain limitations, including securities that may be purchased or held by the Funds. The Codes of Ethics are on public file with, and are available from, the SEC.

PROXY VOTING POLICIES OF THE MASTER PORTFOLIOS. The Board of Trustees of MIP has delegated the voting of proxies for each Master Portfolio's securities to BFA pursuant to MIP's proxy voting guidelines. Under these guidelines, BFA will vote proxies related to the securities held by each Master Portfolio in the best interests of the Master Portfolio and its stockholders. From time to time, a vote may present a conflict between the interests of the Master Portfolio's stockholders, on the one hand, and those of BFA, or any affiliated person of MIP or BFA, on the other. In such event, provided that Blackrock's Equity Investment Policy Oversight Committee, or a sub-committee thereof (the "Committee") is aware of the real or potential conflict or material non-routine matter and if the Committee does not reasonably believe it is able to follow its general voting guidelines (or if the particular proxy matter is not addressed in the guidelines) and vote impartially, the Committee may retain an independent fiduciary to advise the Committee on how to vote or to cast votes on behalf of BFA's clients. If BFA determines not to retain an independent fiduciary, or does not desire to follow the advice of such independent fiduciary, the Committee shall determine how to vote the proxy after consulting with BlackRock's Portfolio Management Group and/or BlackRock's Legal and Compliance Department and concluding that the vote cast is in its client's best interest notwithstanding the conflict. A copy of MIP's Proxy Voting Policies is attached as Appendix A.

Information on how a Master Portfolio voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available without charge, (i) at www.blackrock.com and (ii) on the SEC's website at http://www.sec.gov.

26

SHAREHOLDER COMMUNICATION TO THE BOARD OF TRUSTEES. The Board of Trustees has established a process for shareholders to communicate with the Board of Trustees. Shareholders may contact the Board of Trustees by mail. Correspondence should be addressed to BlackRock Funds III Board of Trustees, c/o BlackRock, Inc., 55 East 52nd Street, New York, NY 10055. Shareholder communication to the Board of Trustees should include the following information: (a) the name and address of the shareholder; (b) the number of shares owned by the shareholder; (c) the Fund(s) of which the shareholder owns shares; and (d) if these shares are owned indirectly through a broker, financial intermediary or other record owner, the name of the broker, financial intermediary or other record owner. All correspondence received as set forth above shall be reviewed by the Secretary of the Trust and reported to the Board of Trustees.

27

Control Persons and Principal Holders of Securities

As of March 31, 2010, the shareholders below were known by the Trust to own 5% or more of the outstanding shares of the specified Fund's outstanding Capital, Institutional, Premium, Select, SL Agency, Trust and Aon Captives Shares, as the case may be, in the listed capacity.

                                                                         PERCENTAGE
                                                                          OF SHARE    NATURE OF
         NAME OF FUND              NAME AND ADDRESS OF SHAREHOLDER         CLASS      OWNERSHIP
-----------------------------  ---------------------------------------  -----------  ----------
BlackRock Cash Funds: Prime
Capital Shares                 Goldman, Sachs & Co.                          17%       Record
                               71 South Wacker Drive Suite 500
                               Chicago, IL 60606
                               Banc of America Securities LLC                80%       Record
                               200 N College Street
                               Charlotte, NC 28255
Institutional Shares           Banc of America Securities LLC                 6%       Record
                               200 N College Street
                               Charlotte, NC 28255
                               County of Santa Clara                          7%       Record
                               70 W. Hedding
                               East Wing, 6TH Floor
                               San Jose, CA 95110
                               Nationwide Cash Management Company             8%       Record
                               One Nationwide Plaza Mailcode 1-05-502
                               Columbus, OH 43215
                               General Electric Capital Corporation           8%       Record
                               201 High Ridge Road
                               Stamford, CT 06927
                               Anadarko Petroleum Corporation                10%       Record
                               1201 Lake Robbins Drive
                               Spring, TX 77380
                               Hare & Co                                     15%       Record
                               c/o Bank of New York
                               111 Sanders Creek Parkway
                               East Syracuse, NY 13057

28

                                                                                   PERCENTAGE
                                                                                    OF SHARE    NATURE OF
      NAME OF FUND                     NAME AND ADDRESS OF SHAREHOLDER               CLASS      OWNERSHIP
-----------------------      ---------------------------------------------------  -----------  ----------
                             Government Development Bank for Puerto Rico               16%       Record
                             De Diego Avenue, Stop 22
                             San Juan, Puerto Rico 00907
Premium Shares               Banc of America Securities LLC                             8%       Record
                             200 N College Street
                             Charlotte, NC 28255
                             ADP Pacific, Inc.                                         12%       Record
                             800 Delaware Avenue
                             Wilmington, DE 19801
                             Chicago Mercantile Exchange, Inc.                         13%       Record
                             20 South Wacker Drive
                             Chicago, IL 60606
                             Hare & Co                                                 51%       Record
                             c/o Bank of New York
                             111 Sanders Creek Parkway
                             East Syracuse, NY 13057
Select Shares                Banc of America Securities LLC                            29%       Record
                             200 N College Street
                             Charlotte, NC 28255
                             Barclays Capital Inc.                                     70%       Record
                             200 Park Avenue
                             New York, NY 10166
SL Agency Shares             State Street Bank and Trust Company                       39%       Record
                             f/b/o iShares Barclays Capital Aggregate Bond Fund
                             200 Clarendon Street
                             Boston, MA 02116
                             BlackRock Institutional Trust Company, N.A.               52%       Record
                             400 Howard Street
                             San Francisco, CA 94105
Trust Shares                 Barclays Capital Inc.                                    100%       Record
                             200 Park Avenue
                             New York, NY 10166
BlackRock Cash Funds:
Institutional
Capital Shares               Goldman, Sachs & Co.                                      15%       Record
                             71 South Wacker Drive Suite 500
                             Chicago, IL 60606
                             J.P. Morgan Clearing Corporation                          84%       Record
                             One Metrotech Center North
                             Brooklyn, NY 11201
Institutional Shares         UBATCO and Company                                         7%       Record
                             6811 S. 27th Street
                             Lincoln, NE 68512

29

                                                                                   PERCENTAGE
                                                                                   OF SHARE     NATURE OF
      NAME OF FUND                       NAME AND ADDRESS OF SHAREHOLDER            CLASS       OWNERSHIP
--------------------------------  ---------------------------------------------- -----------   ----------
                                  Barclays Bank Delaware                               8%        Record
                                  100 S. West Street
                                  Wilmington, DE 19801
                                  BlackRock Institutional Trust Company, N.A.         21%        Record
                                  400 Howard Street
                                  San Francisco, CA 94105
                                  AT&T Inc.                                           24%        Record
                                  208 S. Akard Street
                                  Room 2750.10
                                  Dallas, TX 75202
                                  Electronic Arts Inc.                                38%        Record
                                  209 Redwood Shores Parkway
                                  Redwood City, CA 94065
Premium Shares                    Biogen Idec Inc.                                   100%        Record
                                  14 Cambridge Center
                                  Cambridge, MA 02142
Select Shares                     Bear Stearns Securities Corporation                 19%        Record
                                  One Metrotech Center North
                                  Brooklyn, NY 11201
                                  Barclays Capital Inc.                               81%        Record
                                  200 Park Avenue
                                  New York, NY 10166
SL Agency Shares                  BlackRock Institutional Trust Company, N.A.         97%        Record
                                  400 Howard Street
                                  San Francisco, CA 94105
Trust Shares                      Barclays Capital Inc.                              100%        Record
                                  200 Park Avenue
                                  New York, NY 10166
Aon Captives Shares               Bom Ambiente Insurance Company                       7%        Record
                                  P.O. Box 69 GT
                                  Grand Cayman Island
                                  NRI Insurance Company                               22%        Record
                                  76 St. Paul Street
                                  Burlington, VT 05401
                                  Barclays Nominees (Manx) LTD                        66%        Record
                                  Barclays House Victoria Street
                                  P.O. Box 9
                                  Douglas Isle of Man, UK IM99 1AJ
BlackRock Cash Funds:
Government
Institutional Shares              Southeastern Pennsylvania Transportation            97%        Record
                                  1234 Market Street, 8th Floor
                                  Philadelphia, PA 19107

30

                                                                                 PERCENTAGE
                                                                                  OF SHARE      NATURE OF
          NAME OF FUND                  NAME AND ADDRESS OF SHAREHOLDER            CLASS        OWNERSHIP
--------------------------------  ------------------------------------------    -----------    ----------
Select Shares                     Barclays Capital Inc.                             100%         Record
                                  200 Park Avenue
                                  New York, NY 10166
Trust Shares                      Barclays Capital Inc.                             100%         Record
                                  200 Park Avenue
                                  New York, NY 10166
BlackRock Cash Funds: Treasury
Capital Shares                    Banc of America Securities LLC                     21%         Record
                                  200 N College Street
                                  Charlotte, NC 28255
                                  Banc of America NAC                                31%         Record
                                  135 S. Lasalle Street, Suite 1811
                                  Chicago, IL 60603
                                  Barclays Capital Inc.                              48%         Record
                                  200 Park Avenue
                                  New York, NY 10166
Institutional Shares              Skadden, Arps, Slate, Meagher & Flom LLP           17%         Record
                                  360 Hamilton Avenue
                                  White Plains, NY 10601
                                  Union Electric Company                             20%         Record
                                  1901 Chouteau Avenue Street
                                  Louis, MO 63103
                                  The Hertz Corporation                              63%         Record
                                  225 Brae Boulevard
                                  Park Ridge, NJ 07656
Premium Shares                    Barclays Capital Inc.                             100%         Record
                                  200 Park Avenue
                                  New York, NY 10166
Select Shares                     Barclays Capital Inc.                             100%         Record
                                  200 Park Avenue
                                  New York, NY 10166
SL Agency Shares                  State Street Bank and Trust Company                99%         Record
                                  200 Clarendon Street
                                  Boston, MA 02116
Trust Shares                      Barclays Capital Inc.                             100%         Record
                                  200 Park Avenue
                                  New York, NY 10166

For purposes of the 1940 Act, any person who owns directly or through one or more controlled companies more than 25% of the voting securities of a company is presumed to "control" such company. Accordingly, to the extent that a shareholder identified in the foregoing table is identified as the beneficial holder of more than 25% of a Fund, or is identified as the holder of record of more than 25% of a Fund and has voting and/or investment powers, such shareholder may be presumed to control such Fund.

As of March 31, 2010, Trustees and officers of the Trust, as a group, beneficially owned less than 1% of the outstanding shares of the Trust.

31

POTENTIAL CONFLICTS OF INTEREST. The Bank of America Corporation ("BAC"), through its subsidiary Merrill Lynch & Co., Inc. ("Merrill Lynch"), Barclays PLC ("Barclays"), and The PNC Financial Services Group, Inc. ("PNC"), each have a significant economic interest in BlackRock, Inc., the parent of BFA, the Trust's investment adviser. PNC is considered to be an affiliate of BlackRock, Inc., under the 1940 Act. Certain activities of BFA, BlackRock Advisors, LLC, BlackRock, Inc. and their affiliates (collectively, "BlackRock") and PNC and its affiliates (collectively, "PNC" and together with BlackRock, "Affiliates"), and those of BAC, Merrill Lynch and their affiliates (collectively, the "BAC Entities") and Barclays and its affiliates (collectively, the "Barclays Entities") (BAC Entities and Barclays Entities, collectively, the "BAC/Barclays Entities"), with respect to the Funds and/or other accounts managed by BlackRock, PNC or BAC/Barclays Entities, may give rise to actual or perceived conflicts of interest such as those described below.

BlackRock is one of the world's largest asset management firms. BAC is a national banking corporation which through its affiliates and subsidiaries, including Merrill Lynch, provides a full range of financial services. Merrill Lynch is a full service investment banking, broker-dealer, asset management and financial services organization. PNC is a diversified financial services organization spanning the retail, business and corporate markets. Barclays is a major global financial services provider engaged in a range of activities including retail and commercial banking, credit cards, investment banking, and wealth management. BlackRock, BAC, Merrill Lynch, PNC, Barclays and their respective affiliates (including, for these purposes, their directors, partners, trustees, managing members, officers and employees), including the entities and personnel who may be involved in the investment activities and business operations of a Fund, are engaged worldwide in businesses, including equity, fixed income, cash management and alternative investments, and have interests other than those of managing the Funds. These are considerations of which investors in a Fund should be aware, and which may cause conflicts of interest that could disadvantage the Fund and its shareholders. These activities and interests include potential multiple advisory, transactional, financial and other interests in securities and other instruments, and companies that may be purchased or sold by a Fund.

BlackRock and its Affiliates, as well as the BAC/Barclays Entities, have proprietary interests in, and may manage or advise with respect to, accounts or funds (including separate accounts and other funds and collective investment vehicles) that have investment objectives similar to those of a Fund and/or that engage in transactions in the same types of securities, currencies and instruments as the Fund. One or more Affiliates and BAC/Barclays Entities are also major participants in the global currency, equities, swap and fixed income markets, in each case both on a proprietary basis and for the accounts of customers. As such, one or more Affiliates or BAC/Barclays Entities are or may be actively engaged in transactions in the same securities, currencies, and instruments in which a Fund invests. Such activities could affect the prices and availability of the securities, currencies, and instruments in which a Fund invests, which could have an adverse impact on the Fund's performance. Such transactions, particularly in respect of most proprietary accounts or customer accounts, will be executed independently of a Fund's transactions and thus at prices or rates that may be more or less favorable than those obtained by the Fund. When BlackRock and its Affiliates or the BAC/Barclays Entities seek to purchase or sell the same assets for their managed accounts, including a Fund, the assets actually purchased or sold may be allocated among the accounts on a basis determined in their good faith discretion to be equitable. In some cases, this system may adversely affect the size or price of the assets purchased or sold for a Fund. In addition, transactions in investments by one or more other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of a Fund, particularly, but not limited to, with respect to small capitalization, emerging market or less liquid strategies. This may occur when investment decisions regarding a Fund are based on research or other information that is also used to support decisions for other accounts. When BlackRock or its Affiliates or a BAC/Barclays Entity implements a portfolio decision or strategy on behalf of another account ahead of, or contemporaneously with, similar decisions or strategies for a Fund, market impact, liquidity constraints, or other factors could result in the Fund receiving less favorable trading results and the costs of implementing such decisions or strategies could be increased or the Fund could otherwise be disadvantaged. BlackRock or it Affiliates or a BAC/Barclays Entity may, in certain cases, elect to implement internal policies and procedures designed to limit such consequences, which may cause a Fund to be unable to engage in certain activities, including purchasing or disposing of securities, when it might otherwise be desirable for it to do so.

Conflicts may also arise because portfolio decisions regarding a Fund may benefit other accounts managed by BlackRock or its Affiliates or a BAC/Barclays Entity. For example, the sale of a long position or establishment of a short position by a Fund may impair the price of the same security sold short by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts, and the purchase of a security or covering of a short position in a security by a Fund may increase the price of the same security held by (and therefore benefit) one or more Affiliates or BAC/Barclays Entities or their other accounts.

32

BlackRock and its Affiliates or a BAC/Barclays Entity and their clients may pursue or enforce rights with respect to an issuer in which a Fund has invested, and those activities may have an adverse effect on the Fund. As a result, prices, availability, liquidity and terms of the Fund's investments may be negatively impacted by the activities of BlackRock or its Affiliates or a BAC/Barclays Entity or their clients, and transactions for the Fund may be impaired or effected at prices or terms that may be less favorable than would otherwise have been the case.

The results of a Fund's investment activities may differ significantly from the results achieved by BlackRock and its Affiliates or the BAC/Barclays Entities for their proprietary accounts or other accounts (including investment companies or collective investment vehicles) managed or advised by them. It is possible that one or more Affiliate- or BAC/Barclays Entity-managed accounts and such other accounts will achieve investment results that are substantially more or less favorable than the results achieved by a Fund. Moreover, it is possible that a Fund will sustain losses during periods in which one or more Affiliates or BAC/Barclays Entity-managed accounts achieve significant profits on their trading for proprietary or other accounts. The opposite result is also possible. The investment activities of one or more Affiliates or BAC/Barclays Entities for their proprietary accounts and accounts under their management may also limit the investment opportunities for a Fund in certain emerging and other markets in which limitations are imposed upon the amount of investment, in the aggregate or in individual issuers, by affiliated foreign investors.

From time to time, a Fund's activities may also be restricted because of regulatory restrictions applicable to one or more Affiliates or BAC/Barclays Entities, and/or their internal policies designed to comply with such restrictions. As a result, there may be periods, for example, when BlackRock, and/or one or more Affiliates or BAC/Barclays Entities, will not initiate or recommend certain types of transactions in certain securities or instruments with respect to which BlackRock and/or one or more Affiliates or BAC/Barclays Entities are performing services or when position limits have been reached.

In connection with its management of a Fund, BlackRock may have access to certain fundamental analysis and proprietary technical models developed by one or more Affiliates or BAC/Barclays Entities. BlackRock will not be under any obligation, however, to effect transactions on behalf of a Fund in accordance with such analysis and models. In addition, neither BlackRock nor any of its Affiliates, nor any BAC/Barclays Entity, will have any obligation to make available any information regarding their proprietary activities or strategies, or the activities or strategies used for other accounts managed by them, for the benefit of the management of a Fund and it is not anticipated that BlackRock will have access to such information for the purpose of managing the Fund. The proprietary activities or portfolio strategies of BlackRock and its Affiliates and the BAC/Barclays Entities, or the activities or strategies used for accounts managed by them or other customer accounts could conflict with the transactions and strategies employed by BlackRock in managing a Fund.

In addition, certain principals and certain employees of BlackRock are also principals or employees of BlackRock or another Affiliate. As a result, the performance by these principals and employees of their obligations to such other entities may be a consideration of which investors in a Fund should be aware.

BlackRock may enter into transactions and invest in securities, instruments and currencies on behalf of a Fund in which customers of BlackRock or its Affiliates or a BAC/Barclays Entity, or, to the extent permitted by the SEC, BlackRock or another Affiliate or a BAC/Barclays Entity, serves as the counterparty, principal or issuer. In such cases, such party's interests in the transaction will be adverse to the interests of the Fund, and such party may have no incentive to assure that the Fund obtains the best possible prices or terms in connection with the transactions. In addition, the purchase, holding and sale of such investments by a Fund may enhance the profitability of BlackRock or its Affiliates or a BAC/Barclays Entity. One or more Affiliates or BAC/Barclays Entities may also create, write or issue derivatives for their customers, the underlying securities, currencies or instruments of which may be those in which a Fund invests or which may be based on the performance of the Fund. A Fund may, subject to applicable law, purchase investments that are the subject of an underwriting or other distribution by one or more Affiliates or BAC/Barclays Entities and may also enter into transactions with other clients of an Affiliate or BAC/Barclays Entity where such other clients have interests adverse to those of the Fund.

At times, these activities may cause departments of BlackRock or its Affiliates or a BAC/Barclays Entity to give advice to clients that may cause these clients to take actions adverse to the interests of the Fund. To the extent affiliated transactions are permitted, a Fund will deal with BlackRock and its Affiliates or BAC/Barclays Entities on an arms-length basis. BlackRock or its Affiliates or a BAC/Barclays Entity may also have an ownership interest in certain trading or information systems used
by a Fund. A Fund's use of such trading or information systems may enhance the profitability of BlackRock and its Affiliates or BAC/Barclays Entities.

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One or more Affiliates or one of the BAC/Barclays Entities may act as broker, dealer, agent, lender or adviser or in other commercial capacities for a Fund. It is anticipated that the commissions, mark-ups, mark-downs, financial advisory fees, underwriting and placement fees, sales fees, financing and commitment fees, brokerage fees, other fees, compensation or profits, rates, terms and conditions charged by an Affiliate or BAC/Barclays Entity will be in its view commercially reasonable, although each Affiliate or BAC/Barclays Entity, including its sales personnel, will have an interest in obtaining fees and other amounts that are favorable to the Affiliate or BAC/Barclays Entity and such sales personnel.

Subject to applicable law, the Affiliates and BAC/Barclays Entities (and their personnel and other distributors) will be entitled to retain fees and other amounts that they receive in connection with their service to the Funds as broker, dealer, agent, lender, adviser or in other commercial capacities and no accounting to the Funds or their shareholders will be required, and no fees or other compensation payable by the Funds or their shareholders will be reduced by reason of receipt by an Affiliate or BAC/Barclays Entity of any such fees or other amounts.

When an Affiliate or BAC/Barclays Entity acts as broker, dealer, agent, adviser or in other commercial capacities in relation to the Funds, the Affiliate or BAC/Barclays Entity may take commercial steps in its own interests, which may have an adverse
effect on the Funds. A Fund will be required to establish business relationships with its counterparties based on the Fund's own credit standing. Neither BlackRock nor any of the Affiliates, nor any BAC/Barclays Entity, will have any obligation to allow their credit to be used in connection with a Fund's establishment of its business relationships, nor is it expected that the Fund's counterparties will rely on the credit of BlackRock or any of the Affiliates or BAC/Barclays Entities in evaluating the Fund's creditworthiness.

Purchases and sales of securities for a Fund may be bunched or aggregated with orders for other BlackRock client accounts. BlackRock and its Affiliates and the BAC/Barclays Entities, however, are not required to bunch or aggregate orders if portfolio management decisions for different accounts are made separately, or if they determine that bunching or aggregating is not practicable, required or with cases involving client direction.

Prevailing trading activity frequently may make impossible the receipt of the same price or execution on the entire volume of securities purchased or sold. When this occurs, the various prices may be averaged, and the Funds will be charged or credited with the average price. Thus, the effect of the aggregation may operate on some occasions to the disadvantage of the Funds. In addition, under certain circumstances, the Funds will not be charged the same commission or commission equivalent rates in connection with a bunched or aggregated order.

BlackRock may select brokers (including, without limitation, Affiliates or BAC/Barclays Entities) that furnish BlackRock, the Funds, other BlackRock client accounts or other Affiliates or BAC/Barclays Entities or personnel, directly or through correspondent relationships, with research or other appropriate services which provide, in BlackRock's view, appropriate assistance to BlackRock in the investment decision-making process (including with respect to futures, fixed-price offerings and over-the-counter transactions). Such research or other services may include, to the extent permitted by law, research reports on companies, industries and securities; economic and financial data; financial publications; proxy analysis; trade industry seminars; computer data bases; research-oriented software and other services and products. Research or other services obtained in this manner may be used in servicing any or all of the Funds and other BlackRock client accounts, including in connection with BlackRock client accounts other than those that pay commissions to the broker relating to the research or other service arrangements. Such products and services may disproportionately benefit other BlackRock client accounts relative to the Funds based on the amount of brokerage commissions paid by the Funds and such other BlackRock client accounts. For example, research or other services that are paid for through one client's commissions may not be used in managing that client's account. In addition, other BlackRock client accounts may receive the benefit, including disproportionate benefits, of economies of scale or price discounts in connection with products and services that may be provided to the Funds and to such other BlackRock client accounts. To the extent that BlackRock uses soft dollars, it will not have to pay for those products and services itself.

BlackRock may receive research that is bundled with the trade execution, clearing, and/or settlement services provided by a particular broker-dealer. To the extent that BlackRock receives research on this basis, many of the same conflicts related to traditional soft dollars may exist. For example, the research effectively will be paid by client commissions that also will be used to pay for the execution, clearing, and settlement services provided by the broker-dealer and will not be paid by BlackRock.

BlackRock may endeavor to execute trades through brokers who, pursuant to such arrangements, provide research or other services in order to ensure the continued receipt of research or other services BlackRock believes are useful in its investment

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decision-making process. BlackRock may from time to time choose not to engage in the above described arrangements to varying degrees. BlackRock may also enter into commission sharing arrangements under which BlackRock may execute transactions through a broker-dealer, including, where permitted, an Affiliate or BAC/Barclays Entity, and request that the broker-dealer allocate a portion of the commissions or commission credits to another firm that provides research to BlackRock. To the extent that BlackRock engages in commission sharing arrangements, many of the same conflicts related to traditional soft dollars may exist.

BlackRock may utilize certain electronic crossing networks ("ECNs") in executing client securities transactions for certain types of securities. These ECNs may charge fees for their services, including access fees and transaction fees. The transaction fees, which are similar to commissions or markups/markdowns, will generally be charged to clients and, like commissions and markups/markdowns, would generally be included in the cost of the securities purchased. Access fees may be paid by BlackRock even though incurred in connection with executing transactions on behalf of clients, including the Funds. In certain circumstances, ECNs may offer volume discounts that will reduce the access fees typically paid by BlackRock. This would have the effect of reducing the access fees paid by BlackRock. BlackRock will only utilize ECNs consistent with its obligation to seek to obtain best execution in client transactions.

BlackRock has adopted policies and procedures designed to prevent conflicts of interest from influencing proxy voting decisions that it makes on behalf of advisory clients, including the Funds, and to help ensure that such decisions are made in accordance with BlackRock's fiduciary obligations to its clients. Nevertheless, notwithstanding such proxy voting policies and procedures, actual proxy voting decisions of BlackRock may have the effect of favoring the interests of other clients or businesses of other divisions or units of BlackRock and/or its Affiliates or a BAC/Barclays Entity, provided that BlackRock believes such voting decisions to be in accordance with its fiduciary obligations. For a more detailed discussion of these policies and procedures, see "Proxy Voting Policies of the Master Portfolios."

It is also possible that, from time to time, BlackRock or its Affiliates or a BAC/Barclays Entity may, although they are not required to, purchase and hold shares of a Fund. Increasing a Fund's assets may enhance investment flexibility and diversification and may contribute to economies of scale that tend to reduce the Fund's expense ratio. BlackRock and its Affiliates or BAC/Barclays Entities reserve the right to redeem at any time some or all of the shares of a Fund acquired for their own accounts. A large redemption of shares of a Fund by BlackRock or its Affiliates or by a BAC/Barclays Entity could significantly reduce the asset size of the Fund, which might have an adverse effect on the Fund's investment flexibility, portfolio diversification and expense ratio. BlackRock will consider the effect of redemptions on a Fund and other shareholders in deciding whether to redeem its shares.

It is possible that a Fund may invest in securities of companies with which an Affiliate or a BAC/Barclays Entity has or is trying to develop investment banking relationships as well as securities of entities in which BlackRock or its Affiliates or a BAC/Barclays Entity has significant debt or equity investments or in which an Affiliate or BAC/Barclays Entity makes a market. A Fund also may invest in securities of companies to which an Affiliate or a BAC/Barclays Entity provides or may some day provide research coverage. Such investments could cause conflicts between the interests of a Fund and the interests of other clients of BlackRock or its Affiliates or a BAC/Barclays Entity. In making investment decisions for a Fund, BlackRock is not permitted to obtain or use material non-public information acquired by any division, department or Affiliate of BlackRock or of a BAC/Barclays Entity in the course of these activities. In addition, from time to time, the activities of an Affiliate or a BAC/Barclays Entity may limit a Fund's flexibility in purchases and sales of securities. When an Affiliate is engaged in an underwriting or other distribution of securities of an entity, BlackRock may be prohibited from purchasing or recommending the purchase of certain securities of that entity for a Fund.

BlackRock and its Affiliates and the BAC/Barclays Entities, their personnel and other financial service providers have interests in promoting sales of the Funds. With respect to BlackRock and its Affiliates and BAC/Barclays Entities and their personnel, the remuneration and profitability relating to services to and sales of the Funds or other products may be greater than remuneration and profitability relating to services to and sales of certain funds or other products that might be provided or offered. BlackRock and its Affiliates or BAC/Barclays Entities and their sales personnel may directly or indirectly receive a portion of the fees and commissions charged to the Funds or their shareholders. BlackRock and its advisory or other personnel may also benefit from increased amounts of assets under management. Fees and commissions may also be higher than for other products or services, and the remuneration and profitability to BlackRock or its Affiliates or a BAC/Barclays Entity and such personnel resulting from transactions on behalf of or management of the Funds may be greater than the remuneration and profitability resulting from other funds or products.

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BlackRock and its Affiliates or a BAC/Barclays Entity and their personnel may receive greater compensation or greater profit in connection with an account for which BlackRock serves as an adviser than with an account advised by an unaffiliated investment adviser. Differentials in compensation may be related to the fact that BlackRock may pay a portion of its management fee to its Affiliate or to a BAC/Barclays Entity, or relate to compensation arrangements, including for portfolio management, brokerage transactions or account servicing. Any differential in compensation may create a financial incentive on the part of BlackRock or its Affiliates or BAC/Barclays Entities and their personnel to recommend BlackRock over unaffiliated investment advisers or to effect transactions differently in one account over another.

BlackRock and its Affiliates or a BAC/Barclays Entity may provide valuation assistance to certain clients with respect to certain securities or other investments and the valuation recommendations made for their clients' accounts may differ from the valuations for the same securities or investments assigned by a Fund's pricing vendors, especially if such valuations are based on broker-dealer quotes or other data sources unavailable to the Fund's pricing vendors. While BlackRock will generally communicate its valuation information or determinations to a Fund's pricing vendors and/or fund accountants, there may be instances where the Fund's pricing vendors or fund accountants assign a different valuation to a security or other investment than the valuation for such security or investment determined or recommended by BlackRock.

As disclosed in more detail in "Determination of Net Asset Value" in this SAI, when market quotations are not readily available or are believed by BlackRock to be unreliable, a Fund's investments may be valued at fair value by BlackRock, pursuant to procedures adopted by the Trust's Board of Trustees. When determining an asset's "fair value," BlackRock seeks to determine the price that a Fund might reasonably expect to receive from the current sale of that asset in an arm's-length transaction. The price generally may not be determined based on what a Fund might reasonably expect to receive for selling an asset at a later time or if it holds the asset to maturity. While fair value determinations will be based upon all available factors that BlackRock deems relevant at the time of the determination, and may be based on analytical values determined by BlackRock using proprietary or third party valuation models, fair value represents only a good faith approximation of the value of a security. The fair value of one or more securities may not, in retrospect, be the price at which those assets could have been sold during the period in which the particular fair values were used in determining a Fund's net asset value. As a result, a Fund's sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued by BlackRock (pursuant to Board-adopted procedures) at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

To the extent permitted by applicable law, a Fund may invest all or some of its short term cash investments in any money market fund or similarly-managed private fund advised or managed by BlackRock. In connection with any such investments, a Fund, to the extent permitted by the 1940 Act, may pay its share of expenses of a money market fund in which it invests, which may result in a Fund bearing some additional expenses.

BlackRock and its Affiliates or a BAC/Barclays Entity and their directors, officers and employees, may buy and sell securities or other investments for their own accounts, and may have conflicts of interest with respect to investments made on behalf of a Fund. As a result of differing trading and investment strategies or constraints, positions may be taken by directors, officers, employees and Affiliates of BlackRock or by BAC/Barclays Entities that are the same, different from or made at different times than positions taken for a Fund. To lessen the possibility that a Fund will be adversely affected by this personal trading, the Trust, SEI and BFA each have adopted a Code of Ethics in compliance with Section 17(j) of the 1940 Act that restricts securities trading in the personal accounts of investment professionals and others who normally come into possession of information regarding the Fund's portfolio transactions. Each Code of Ethics can be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling the SEC at (202) 551-8090. Each Code of Ethics is also available on the EDGAR Database on the SEC's Internet site at http://www.sec.gov, and copies may be obtained, after paying a duplicating fee, by e-mail at publicinfo@sec.gov or by writing the SEC's Public Reference Section, Washington, DC 20549-1520.

BlackRock and its Affiliates will not purchase securities or other property from, or sell securities or other property to, a Fund, except that the Fund may in accordance with rules adopted under the 1940 Act engage in transactions with accounts that are affiliated with the Fund as a result of common officers, directors, or investment advisers or pursuant to exemptive orders granted to the Funds and/or BlackRock by the SEC. These transactions would be affected in circumstances in which BlackRock determined that it would be appropriate for a Fund to purchase and another client of BlackRock to sell, or a Fund to sell and another client of BlackRock to purchase, the same security or instrument on the same day. From time to time, the activities of a Fund may be restricted because of regulatory requirements applicable to BlackRock or its Affiliates or a BAC/Barclays Entity and/or BlackRock's internal policies designed to comply with, limit the applicability of, or otherwise

36

relate to such requirements. A client not advised by BlackRock would not be subject to some of those considerations. There may be periods when BlackRock may not initiate or recommend certain types of transactions, or may otherwise restrict or limit their advice in certain securities or instruments issued by or related to companies for which an Affiliate or a BAC/Barclays Entity is performing investment banking, market making, advisory or other services or has proprietary positions. For example, when an Affiliate is engaged in an underwriting or other distribution of securities of, or advisory services for, a company, the Funds may be prohibited from or limited in purchasing or selling securities of that company. In addition, when BlackRock is engaged to provide advisory or risk management services for a company, BlackRock may be prohibited from or limited in purchasing or selling securities of that company on behalf of a Fund, particularly where such services result in BlackRock obtaining material non-public information about the company. Similar situations could arise if personnel of BlackRock or its Affiliates or a BAC/Barclays Entity serve as directors of companies the securities of which the Funds wish to purchase or sell. However, if permitted by applicable law, and where consistent with BlackRock's policies and procedures (including the necessary implementation of appropriate information barriers), the Funds may purchase securities or instruments that are issued by such companies, are the subject of an underwriting, distribution, or advisory assignment by an Affiliate or a BAC/Barclays Entity or are the subject of an advisory or risk management assignment by BlackRock, or where personnel of BlackRock or its Affiliates or of BAC/Barclays Entities are directors or officers of the issuer.

In certain circumstances where the Funds invest in securities issued by companies that operate in certain regulated industries, in certain emerging or international markets, or are subject to corporate or regulatory ownership definitions, there may be limits on the aggregate amount invested by Affiliates (including BlackRock) or BAC/Barclays Entities for their proprietary accounts and for client accounts (including the Funds) that may not be exceeded without the grant of a license or other regulatory or corporate consent, or, if exceeded, may cause BlackRock, the Funds or other client accounts to suffer disadvantages or business restrictions. As a result, BlackRock on behalf of its clients (including the Funds) may limit purchases, sell existing investments, or otherwise restrict or limit the exercise of rights (including voting rights) when BlackRock, in its sole discretion, deems it appropriate in light of potential regulatory or other restrictions on ownership or other consequences resulting from reaching investment thresholds.

In those circumstances where ownership thresholds or limitations must be observed, BlackRock seeks to equitably allocate limited investment opportunities among clients (including the Funds), taking into consideration benchmark weight and investment strategy. When ownership in certain securities nears an applicable threshold, BlackRock may limit purchases in such securities to the issuer's weighting in the applicable benchmark used by BlackRock to manage the Fund. If client (including Fund) holdings of an issuer exceed an applicable threshold and BlackRock is unable to obtain relief to enable the continued holding of such investments, it may be necessary to sell down these positions to meet the applicable limitations. In these cases, benchmark overweight positions will be sold prior to benchmark positions being reduced to meet applicable limitations.

In addition to the foregoing, other ownership thresholds may trigger reporting requirements to governmental and regulatory authorities, and such reports may entail the disclosure of the identity of a client or BlackRock's intended strategy with respect to such security or asset.

BlackRock and its Affiliates and BAC/Barclays Entities may maintain securities indexes as part of their product offerings. Index based funds seek to track the performance of securities indexes and may use the name of the index in the fund name. Index providers, including BlackRock and its Affiliates and BAC/Barclays Entities may be paid licensing fees for use of their index or index name. BlackRock and its Affiliates and BAC/Barclays Entities will not be obligated to license their indexes to BlackRock, and BlackRock cannot be assured that the terms of any index licensing agreement with BlackRock and its Affiliates and BAC/Barclays Entities will be as favorable as those terms offered to other index licensees.

BlackRock and its Affiliates and BAC/Barclays Entities may serve as authorized participants in the creation and redemption of ETFs, including funds advised by affiliates of BlackRock. BlackRock and its Affiliates and BAC/Barclays Entities may therefore be deemed to be participants in a distribution of such ETFs, which could render them statutory underwriters.

The custody arrangement described in "Investment Adviser and Other Service Providers" may lead to potential conflicts of interest with BFA where BFA has agreed to waive fees and/or reimburse ordinary operating expenses in order to cap expenses of the Funds. This is because the custody arrangements with the Funds' custodian may have the effect of reducing custody fees when the Funds leave cash balances uninvested. When a Fund's actual operating expense ratio exceeds a stated cap, a reduction in custody fees reduces the amount of waivers and/or reimbursements BFA would be required to make to the Fund. This could be viewed as having the potential to provide BFA an incentive to keep high positive cash balances for Funds with expense caps in order to offset fund custody fees that BFA might otherwise reimburse. However, portfolio managers of BFA do not intentionally keep uninvested balances high, but rather make investment decisions that they anticipate will be beneficial to fund performance.

Present and future activities of BlackRock and its Affiliates and BAC/Barclays Entities, including BlackRock Advisors, LLC, in addition to those described in this section, may give rise to additional conflicts of interest.

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Investment Adviser and Other Service Providers

INVESTMENT ADVISER. The Funds are feeder funds in a master/feeder structure. As a result each Fund invests all of its assets in a related Master Portfolio of MIP. The Master Portfolios have retained BFA as the investment adviser to manage their assets.

ADVISORY FEES. BFA is entitled to receive monthly fees at the annual rate of 0.10% of each Master Portfolio's average daily net assets. From time to time, BFA may waive such fees in whole or in part. Any such waiver will reduce the expenses of each Master Portfolio and, accordingly, have a favorable impact on its performance. BFA has contractually agreed to waive a portion of its management fees and accept payment at an annual rate of 0.07% from May 1, 2006 through close of business on November 30, 2011 with respect to each Master Portfolio. Pursuant to the advisory contract between BFA and MIP on behalf of the Master Portfolios ("Advisory Contract"), BFA furnishes MIP's Board of Trustees with periodic reports on the investment strategy and performance of the Master Portfolios.

BFA is a wholly-owned subsidiary of BTC, which in turn is indirectly wholly-owned by BlackRock, Inc.

The applicable Advisory Contract is subject to annual approval by (i) MIP's Board of Trustees or (ii) the vote of a majority (as defined in the 1940 Act) of the outstanding voting interests of such Master Portfolio, provided that in either event the continuance also is approved by a majority of MIP's Board of Trustees who are not "interested persons" (as defined in the 1940 Act) of MIP, by a vote cast in person at a meeting called for the purpose of voting on such approval. The applicable Advisory Contract is terminable without penalty, on 60 days' written notice, by either party. The applicable Advisory Contract will terminate automatically, as to the relevant Master Portfolio, in the event of its assignment (as defined in the 1940 Act).

For the fiscal years shown below, the related Master Portfolio of each Fund paid, with respect to the Funds, the following management fees to BFA, net of waivers and/or offsetting credits:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                $6,437,462            $7,351,730          $ 9,745,383
BlackRock Cash Funds: Institutional        $4,501,600            $2,987,792          $16,321,027
BlackRock Cash Funds: Government           $   80,695            $  338,656          $   362,946
BlackRock Cash Funds: Treasury               ($12,949)           $  105,393          $ 1,218,613

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For the fiscal years shown below, BFA waived the following management fees with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $3,165,643           $5,840,665          $4,271,088
BlackRock Cash Funds: Institutional         $1,952,742           $1,738,528          $7,143,778
BlackRock Cash Funds: Government            $   45,410           $  385,042          $  423,221
BlackRock Cash Funds: Treasury              $  153,279           $  455,287          $1,502,333

The fees and expenses of the Independent Trustees of MIP, counsel to the Independent Trustees of MIP, and the independent registered public accounting firm that provides audit services in connection with the Master Portfolios (collectively referred to as the "MIP Independent Expenses") are paid directly by the Master Portfolios. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to each Master Portfolio for such MIP Independent Expenses.

For the fiscal years shown below, BFA provided an offsetting credit for MIP Independent Expenses against management fees paid by the Master Portfolios in which the Funds invest:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $110,458             $142,232            $210,009
BlackRock Cash Funds: Institutional          $ 54,913             $ 68,692            $305,702
BlackRock Cash Funds: Government             $ 25,260             $ 14,818            $ 24,361
BlackRock Cash Funds: Treasury               $ 25,470             $ 14,890            $ 39,602

ADMINISTRATOR. The Trust has engaged BTC to provide certain administration services to the Funds. Pursuant to an Administration Agreement with the Trust, BTC and its affiliates provide as administration services, among other things:
supervision of the administrative operation of the Trust and the Funds, provision of management reporting and treasury administration services, financial reporting, legal and tax services, and preparation of proxy statements and shareholder reports for the Funds. BTC and its affiliates also furnish office space and certain facilities required for conducting the business of the Trust together with all other administrative services that are not being furnished by BFA. BTC and its affiliates also pay the compensation of the Trust's Trustees who are not Independent Trustees and of officers and employees who are affiliated with the Trust. For providing such services, BTC is entitled to a monthly fee at an annual rate of 0.02% of each Fund's average daily net assets for SL Agency Shares, 0.05% of each Fund's average daily net assets for Aon Captives Shares and Institutional Shares, 0.07% of each Fund's average daily net assets for Capital Shares, 0.10% of each Fund's average daily net assets for Premium Shares, 0.15% of each Fund's average daily net assets for Select Shares (0.13% pursuant to BTC's contractual agreement to waive a portion of its administration fees for Select Shares from September 1, 2006 through close of business on November 30, 2011) and 0.38% of each Fund's average daily net assets for Trust Shares. BTC has contracted with State Street to provide certain sub-administration services to the Funds. BTC, not the Funds, is responsible for providing compensation to State Street for such services.

In addition, BTC has agreed to bear all costs of the Funds' and the Trust's operations, including, in the case of each Fund's Institutional Shares and BlackRock Cash Funds: Institutional - Aon Captives Shares, shareholder servicing fees of up to 0.05%, in the case of each Fund's Capital Shares, shareholder servicing fees of up to 0.07%, in the case of each Fund's Premium Shares, shareholder servicing fees of up to 0.10%, in the case of each Fund's Select Shares, shareholder servicing fees of up to 0.15%, and, in the case of each Fund's Trust Shares, shareholder servicing fees of up to 0.25% and processing fees of up to 0.13%, but not including brokerage expenses, advisory fees, distribution plan expenses, certain fees and expenses related to the Trust's Independent Trustees and their counsel, auditing fees, litigation expenses, taxes or other extraordinary expenses. SL Agency Shares are not subject to shareholder servicing fees.

BTC is not entitled to compensation for providing administration services to a Master Portfolio for so long as BTC is entitled to compensation for providing administration services to the Fund that invests substantially all of its assets in the Master Portfolio, or BTC or an affiliate receives management fees from the Master Portfolio. Each Fund having multiple classes allocates all expenses of the Master Portfolio, including the Master Portfolio's management fee, to each share class in

39

proportion to the aggregate net asset value of such class as compared to all classes of the Fund in accordance with the Fund's multi-class plan under Rule 18f-3 under the 1940 Act.

For the fiscal years shown below, the Funds paid the following administration fees to BTC, net of waivers and/or offsetting credits:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $5,744,756           $8,347,734          $7,214,293
BlackRock Cash Funds: Institutional         $3,486,851           $3,284,691          $6,511,988
BlackRock Cash Funds: Government            $  128,229           $  339,160          $  182,842
BlackRock Cash Funds: Treasury              $   60,324           $  137,759          $  532,403

For the fiscal years shown below, BTC waived the following administration fees with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $ 99,502             $262,311            $149,955
BlackRock Cash Funds: Institutional          $975,803             $  9,735            $ 47,541
BlackRock Cash Funds: Government             $  5,123             $ 71,481            $147,384
BlackRock Cash Funds: Treasury               $ 37,194             $201,343            $363,471

The fees and expenses of the Independent Trustees of the Trust, counsel to the Independent Trustees of the Trust, and the independent registered public accounting firm that provides audit services in connection with the Funds (collectively referred to as the "Independent Expenses") are paid directly by the Funds. For the period from January 1, 2007 through close of business on November 30, 2011, each of BTC and BFA, as applicable, has contractually undertaken to reimburse or provide an offsetting credit to the Funds for such Independent Expenses.

For the fiscal years shown below, BTC provided an offsetting credit, in the amounts shown, against administration fees paid with respect to the Funds:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                  $103,690             $151,738            $209,334
BlackRock Cash Funds: Institutional          $ 82,919             $ 60,278            $322,337
BlackRock Cash Funds: Government             $ 18,099             $ 13,706            $ 22,996
BlackRock Cash Funds: Treasury               $ 18,303             $ 13,953            $ 39,037

DISTRIBUTOR. SEI is the distributor for the Funds' shares. SEI is a registered broker-dealer located at One Freedom Valley Drive, Oaks, PA 19456. SEI is a provider of outsourced investment business solutions for fund administration and distribution, asset management and investment systems and processing.

SEI, as the principal underwriter of the Funds within the meaning of the 1940 Act, has entered into a distribution agreement (the "Distribution Agreement") with the Trust pursuant to which SEI has the responsibility for distributing Fund shares. The Distribution Agreement provides that SEI shall act as agent for the Funds for the sale of Fund shares, and may enter into sales support agreements with selling agents that wish to make available Fund shares to their respective customers ("Selling Agents"). BTC presently acts as a Selling Agent, but does not receive any fee from the Funds for such activities. In addition, SEI provides certain compliance related, sales related and other services for the Funds pursuant to a Service Standards Agreement with BTC, and BTC compensates SEI for these services.

Pursuant to its Administration Agreement with the Trust, as described in the section entitled "Administrator," BTC pays shareholder servicing fees to certain Shareholder Servicing Agents in amounts not exceeding maximum fee rates approved by the Trust's Board of Trustees, for those shareholder servicing, sub-administration, recordkeeping, sub-transfer agency and processing services that the Shareholder Servicing Agents perform for their clients that would otherwise be performed by BTC or the Funds' other service providers. SL Agency Shares are not subject to shareholder servicing fees.

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For the fiscal years shown below, BTC paid shareholder servicing fees on behalf of the Funds in the following amounts:

                                        FISCAL YEAR ENDED    FISCAL YEAR ENDED    FISCAL YEAR ENDED
FUND                                        12/31/2007           12/31/2008          12/31/2009
-------------------------------------  -------------------  -------------------  ------------------
BlackRock Cash Funds: Prime                 $1,673,484           $2,934,362          $2,982,157
BlackRock Cash Funds: Institutional         $1,614,028           $1,004,246          $1,029,863
BlackRock Cash Funds: Government            $   88,618           $   71,378          $   51,666
BlackRock Cash Funds: Treasury              $   37,357           $   35,232          $  110,867

Payments to Shareholder Servicing Agents may create potential conflicts of interest between potential investors and a Shareholder Servicing Agent that determines which investment options it will service and/or make available to those investors.

CUSTODIAN. State Street has been retained to act as custodian for the Funds and the Master Portfolios and is located at 200 Clarendon Street, Boston, MA 02116. The custodian, among other things, maintains a custody account or accounts in the name of the Funds and the Master Portfolios; receives and delivers all assets for each Fund and each Master Portfolio upon purchase and upon sale or maturity, and collects and receives all income and other payments and distributions on account of the assets of the Funds and the Master Portfolios. State Street is not entitled to compensation for providing custody services to each Fund and each Master Portfolio pursuant to the Custody Agreement so long as it receives compensation from BTC for providing sub-administration services to the Trust, on behalf of the Funds.

TRANSFER AND DIVIDEND DISBURSING AGENT. State Street has also been retained to act as the transfer and dividend disbursing agent for the Funds and the Master Portfolios. For its services as transfer and dividend disbursing agent to the Funds and the Master Portfolios, State Street is paid fees based on the Funds' and the Master Portfolios' net assets. State Street is entitled to be reimbursed for out-of-pocket expenses or advances incurred by it in performing its obligations under the Transfer Agency Agreement. BTC has agreed to pay these fees and expenses pursuant to its Administration Agreement with the Trust. In addition, the Transfer Agency Agreement contemplates that State Street will be reimbursed for other expenses incurred by it at the request or with the written consent of the Funds, including, without limitation, any equipment or supplies that the Trust specifically orders or requires State Street to order.

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM. PricewaterhouseCoopers LLP, located at Three Embarcadero Center, San Francisco, CA 94111, serves as the independent registered public accounting firm for the Trust.

LEGAL COUNSEL. Sidley Austin LLP, located at 787 Seventh Avenue, New York, NY 10019, serves as legal counsel to the Trust, MIP and BFA.

Determination of Net Asset Value

The Master Portfolios use the amortized cost method to determine the value of their respective securities pursuant to Rule 2a-7 under the 1940 Act. The amortized cost method involves valuing a security at its cost and amortizing any discount or premium over the period until maturity, regardless of the impact of fluctuating interest rates on the market value of the security. While this method provides certainty in valuation, it may result in periods during which the value, as determined by amortized cost, is higher or lower than the price that the Funds would receive if the security were sold. During these periods the yield to a shareholder may differ somewhat from that which could be obtained from a similar fund that uses a method of valuation based upon market prices. Thus, during periods of declining interest rates, if the use of the amortized cost method results in a lower value of each Fund's portfolio on a particular day, a prospective investor in the Funds would be able to obtain a somewhat higher yield than would result from making an investment in the Funds using solely market values, and existing Fund shareholders would receive correspondingly less income. The converse would apply during periods of rising interest rates.

Rule 2a-7 provides that in order to value their portfolios using the amortized cost method, the Funds must maintain a dollar-weighted average portfolio maturity of 90 days or less, purchase securities having remaining maturities (as defined in Rule 2a-7) of 397 calendar days (about 13 months) or less, and invest only in those high-quality securities that are determined by the Board of Trustees to present minimal credit risks. The maturity of an instrument is generally deemed to be the period remaining until the date when the principal amount thereof is due or the date on which the instrument is to be redeemed.

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However, Rule 2a-7 provides that the maturity of an instrument may be deemed shorter in the case of certain instruments, including certain variable-rate and floating-rate instruments subject to demand features. Pursuant to Rule 2a-7, the Board is required to establish procedures designed to stabilize, to the extent reasonably possible, each Fund's price per share as computed for the purpose of sales and redemptions at $1.00. Such procedures include review of each Fund's portfolio holdings by the Board of Trustees, at such intervals as it may deem appropriate, to determine whether a Fund's net asset value per share as determined by using available market quotations (or an appropriate substitute which reflects current market conditions) deviates from $1.00 per share based on amortized cost. The extent of any deviation will be examined by the Board of Trustees. If such deviation exceeds 1/2 of 1%, the Board will promptly consider what action, if any, will be initiated. In the event the Board determines that a deviation exists that may result in material dilution or other unfair results to shareholders, the Board will take such corrective action as it regards as necessary and appropriate, such action may include redeeming shares in-kind, selling portfolio securities prior to maturity, reducing or withholding dividends, shortening the average portfolio maturity, reducing the number of outstanding shares without monetary consideration, and utilizing a net asset value per share as determined by using available market quotations.

Purchase, Redemption and Pricing of Shares

TERMS OF PURCHASE AND REDEMPTION. The Funds are generally open Monday through Friday and are closed on weekends and are generally closed on all other days that the Fedwire Funds Service (the "Fedwire") is closed or the primary markets for the Master Portfolios' portfolio securities (I.E., the bond markets) are closed. BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Prime do not intend to (but reserve the right to) close early on any day the Funds are open (a "Business Day") prior to a U.S. national holiday for the bond markets if the bond markets close early on such Business Day. BlackRock Cash Funds:
Government and BlackRock Cash Funds: Treasury generally will close early on a Business Day prior to a U.S. national holiday for the bond markets if the bond markets close early (typically 2:00 p.m. Eastern time) on such Business Day. The holidays on which both the Fedwire and the primary markets for the Master Portfolios' portfolio securities are closed currently are: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day. The Funds are also closed on Good Friday. Each Fund reserves the right to change the amount of the minimum investment and subsequent purchases in the Fund. An investor's investment in the Funds and/or other investment vehicles managed or maintained by BFA or its affiliates may be aggregated when determining whether an investor meets a minimum investment amount. The minimum initial investment amounts for the classes of the Funds may be reduced or waived by BFA. On any day a Fund closes early, purchase and redemption orders received after the Funds' closing time will be executed on the next business day. In addition, the Funds reserve the right to advance the time by which purchase and redemption orders must be received to be executed on the same business day as permitted by the SEC and applicable law.

IN-KIND PURCHASES. Payment for shares of the Funds may, at the discretion of BFA, be made in the form of securities that are permissible investments for the Funds and must meet the investment objectives, policies and limitations of the Funds as described in their Prospectus. In connection with an in-kind securities payment, the Funds may require, among other things, that the securities (i) be valued on the day of purchase in accordance with the pricing methods used by the Funds or the Master Portfolios; (ii) are accompanied by satisfactory assurance that the Funds will have good and marketable title to such securities received by them; (iii) are not subject to any restrictions upon resale by the Funds; (iv) be in proper form for transfer to the Funds; and
(v) are accompanied by adequate information concerning the basis and other tax matters relating to the securities. All dividends, interest, subscription or other rights pertaining to such securities shall become the property of the Funds engaged in the in-kind purchase transaction and must be delivered to such Fund or Funds by the investor upon receipt from the issuer. Securities acquired through an in-kind purchase will be acquired for investment and not for immediate resale. A Fund immediately will transfer to its Master Portfolio any and all securities received by it in connection with an in-kind purchase transaction, in exchange for interests in such Master Portfolio. Shares purchased in exchange for securities generally cannot be redeemed until the transfer has settled.

SUSPENSION OF REDEMPTION RIGHTS OR PAYMENT OF REDEMPTION PROCEEDS. The Funds generally remit the proceeds from a sale the same Business Day after receiving a properly executed order to sell. Each Fund can delay payment for one Business Day. In addition, each Fund reserves the right to delay delivery of your redemption proceeds and to suspend your right of redemption for more than one Business Day under extraordinary circumstances. Generally, those extraordinary circumstances are when (i) the New York Stock Exchange ("NYSE") is closed (other than customary weekend and holiday closings); (ii) trading on the NYSE is restricted; (iii) an emergency exists as a result of which disposal or valuation of a Fund's investment is not reasonably practicable; or (iv) for such other periods as the SEC by order may permit.

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DECLARATION OF TRUST PROVISIONS REGARDING REDEMPTIONS AT OPTION OF TRUST. As provided in the Trust's Declaration of Trust, the Trustees may require shareholders to redeem shares for any reason under terms set by the Trustees, including, but not limited to, the failure of a shareholder to supply a taxpayer identification number if required to do so, or to have the minimum investment required, or to pay when due for the purchase of shares issued to such shareholder.

Portfolio Transactions

Since the Funds invest all of their assets in portfolios of MIP, set forth below is a description of the Master Portfolios' policies governing portfolio securities transactions.

GENERAL. Subject to policies established by the Board of Trustees, BFA is primarily responsible for the execution of a Master Portfolio's portfolio transactions and the allocation of brokerage. BFA does not execute transactions through any particular broker or dealer, but seeks to obtain the best net results for the Master Portfolio, taking into account such factors as price (including the applicable brokerage commission or dealer spread), size of order, difficulty of execution, operational facilities of the firm and the firm's risk and skill in positioning blocks of securities. While BFA generally seeks reasonable trade execution costs, a Master Portfolio does not necessarily pay the lowest spread or commission available, and payment of the lowest commission or spread is not necessarily consistent with obtaining the best price and execution in particular transactions. The following disclosure provides some more detail regarding the Master Portfolio's practices regarding Portfolio Transactions. Depending on its investment objective, a Master Portfolio may not engage in some of the transactions described below.

BFA does not consider the provision or value of research, products or services a broker or dealer may provide, if any, as a factor in the selection of a broker or dealer or the determination of the reasonableness of commissions paid in connection with portfolio transactions. BFA does not consider sales of shares of the mutual funds it advises as a factor in the selection of brokers or dealers to execute portfolio transactions for a Master Portfolio; however, whether or not a particular broker or dealer sells shares of the mutual funds advised by BFA neither qualifies nor disqualifies such broker or dealer to execute transactions for those mutual funds.

A Master Portfolio's purchase and sale orders for securities may be combined with those of other accounts that BFA manages or advises, and for which it has brokerage placement authority. If purchases or sales of portfolio securities of a Master Portfolio and one or more other accounts managed or advised by BFA are considered at or about the same time, transactions in such securities are allocated among the Master Portfolio and the other accounts in a manner deemed equitable to all by BFA. In some cases, this procedure could have a detrimental effect on the price or volume of the security as far as a Master Portfolio is concerned. However, in other cases, it is possible that the ability to participate in volume transactions and to negotiate lower brokerage commissions will be beneficial to a Master Portfolio.

Payments of commissions to brokers who are affiliated persons of the Master Portfolio with respect to the Fund (or affiliated persons of such persons), will be made in accordance with Rule 17e-1 under the 1940 Act.

Each Master Portfolio anticipates that its brokerage transactions involving foreign securities generally will be conducted primarily on the principal stock exchanges of the applicable country. Foreign equity securities may be held by a Master Portfolio in the form of depositary receipts, or other securities convertible into foreign equity securities. Depositary receipts may be listed on stock exchanges, or traded in over-the-counter markets in the United States or Europe, as the case may be. American Depositary Receipts, like other securities traded in the United States, will be subject to negotiated commission rates. Because the shares of each Fund and interests of the Master Portfolios are redeemable on a daily basis in U.S. dollars, each Master Portfolio intends to manage its portfolio so as to give reasonable assurance that it will be able to obtain U.S. dollars to the extent necessary to meet anticipated redemptions. Under present conditions, it is not believed that these considerations will have a significant effect on a Master Portfolio's portfolio strategies.

Each Master Portfolio may invest in certain securities traded in the over-the-counter ("OTC") market and intends to deal directly with the dealers who make a market in the particular securities, except in those circumstances in which better prices and execution are available elsewhere. Under the 1940 Act, persons affiliated with a Master Portfolio and persons who are affiliated with such affiliated persons are prohibited from dealing with the Master Portfolio as principal in the purchase and sale of securities unless a permissive order allowing such transactions is obtained from the SEC. Since transactions in the OTC market usually involve transactions with the dealers acting as principal for their own accounts, the Master Portfolios will not deal with affiliated persons, including PNC and its affiliates, in connection with such transactions. However, an affiliated person of a Master Portfolio may serve as its broker in OTC transactions conducted on an agency basis provided that, among

43

other things, the fee or commission received by such affiliated broker is reasonable and fair compared to the fee or commission received by non-affiliated brokers in connection with comparable transactions. In addition, a Master Portfolio may not purchase securities during the existence of any underwriting syndicate for such securities of which PNC is a member or in a private placement in which PNC serves as placement agent except pursuant to procedures approved by the Board that either comply with rules adopted by the SEC or with interpretations of the SEC staff.

OTC issues, including most fixed income securities such as corporate debt and U.S. Government securities, are normally traded on a "net" basis without a stated commission, through dealers acting for their own account and not as brokers. The Master Portfolios will primarily engage in transactions with these dealers or deal directly with the issuer unless a better price or execution could be obtained by using a broker. Prices paid to a dealer with respect to both foreign and domestic securities will generally include a "spread," which is the difference between the prices at which the dealer is willing to purchase and sell the specific security at the time, and includes the dealer's normal profit.

Purchases of money market instruments by a Master Portfolio are made from dealers, underwriters and issuers. The Master Portfolios do not currently expect to incur any brokerage commission expense on such transactions because money market instruments are generally traded on a "net" basis with dealers acting as principal for their own accounts without a stated commission. The price of the security, however, usually includes a profit to the dealer. Each Master Portfolio intends to purchase only securities with remaining maturities of 13 months or less as determined in accordance with the rules of the SEC and the policies or investment objectives of the Fund and Master Portfolio. As a result, the portfolio turnover rates of a Master Portfolio will be relatively high. However, because brokerage commissions will not normally be paid with respect to investments made by a money market fund, the turnover rates should not adversely affect the Master Portfolio's net asset values or net income.

A Master Portfolio will not purchase securities during the existence of any underwriting or selling group relating to such securities of which BFA, PNC or any affiliated person (as defined in the 1940 Act) thereof is a member except pursuant to procedures adopted by the Board in accordance with Rule 10f-3 under the 1940 Act. In no instance will portfolio securities be purchased from or sold to BFA, PNC or any affiliated person of the foregoing entities except as permitted by SEC exemptive order or by applicable law.

PORTFOLIO TURNOVER. Portfolio turnover may vary from year to year, as well as within a year. Because the portfolios of the Funds consist of securities with relatively short-term maturities, the Funds expect to experience high portfolio turnover. A high portfolio turnover rate should not adversely affect the Funds since portfolio transactions ordinarily will be made directly with principals on a net basis and, consequently, the Funds usually will not incur brokerage expenses or excessive transaction costs.

SECURITIES OF REGULAR BROKER-DEALERS. As of December 31, 2009, none of the Master Portfolios owned securities of their "regular brokers or dealers" (as defined in the 1940 Act) or their parents, except as disclosed below:

MASTER PORTFOLIO                        REGULAR BROKER-DEALER OR PARENT       AMOUNT
-------------------------------------  ---------------------------------  --------------
Money Market Master Portfolio          UBS AG                              $60,000,000
Prime Money Market Master Portfolio    UBS AG                              $30,000,000

FREQUENT TRADING OF FUND SHARES. Frequent purchases and redemptions of mutual fund shares ("frequent trading") may have a detrimental effect on funds and their shareholders. Depending on various factors, such as the size of a fund's portfolio and the amount of assets maintained in cash, frequent trading may harm the performance of a fund by interfering with the implementation of its investment strategies and/or increasing transaction costs and taxes, and/or may dilute the value of fund shares held by long-term investors. Frequent trading may include activity that appears to attempt to take advantage of a potential arbitrage opportunity presented by a lag between a change in the value of a fund's portfolio securities after the close of the primary markets for those portfolio securities and the reflection of that change in the fund's net asset value ("market timing").

The Funds invest only in interests of the Master Portfolios, and the Boards of Trustees of the Trust and MIP have each considered the issues of frequent trading and market timing, including the fact that money market funds are a type of mutual fund that is designed to offer maximum liquidity. MIP's Board of Trustees has adopted a policy of not monitoring for possible market timing or any other frequent trading activity because of the investment objectives and strategies of the Master Portfolios. The Trust's Board of Trustees has not adopted a policy of monitoring for market timing or other frequent trading

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activity in the Funds in light of the nature of the Funds' investments in Master Portfolios, the policies of the Master Portfolios, and the historical nature of flows into and out of the Funds.

Distributions and Taxes

The following information supplements, and should be read in conjunction with, the section in each Prospectus entitled "Account Information - Taxes." The Prospectus generally describes the U.S. federal income tax treatment of distributions by the Funds. This section of the SAI provides additional information concerning U.S. federal income taxes. It is based on the U.S. Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"), applicable Treasury Regulations, judicial authority, and administrative rulings and practice, all as of the date of this SAI and all of which are subject to change, including changes with retroactive effect. The following discussion does not address any state, local or foreign tax matters.

A shareholder's tax treatment may vary depending upon his or her particular situation. This discussion only applies to shareholders who are U.S. persons, I.E., U.S. citizens or residents or U.S. corporations, partnerships, trusts or estates, and who are subject to U.S. federal income tax and hold Fund shares as capital assets within the meaning of the Internal Revenue Code. Except as otherwise noted, it may not apply to certain types of shareholders who may be subject to special rules, such as insurance companies, tax-exempt organizations, shareholders holding Fund shares through tax-advantaged accounts (such as 401(k) plan accounts or individual retirement accounts ("IRAs")), financial institutions, broker-dealers, entities that are not organized under the laws of the United States or a political subdivision thereof, persons who are neither citizens nor residents of the United States, shareholders holding Fund shares as part of a hedge, straddle or conversion transaction, and shareholders who are subject to the U.S. federal alternative minimum tax.

The Trust has not requested and will not request an advance ruling from the Internal Revenue Service (the "IRS") as to the U.S. federal income tax matters described below. The IRS could adopt positions contrary to those discussed below and such positions could be sustained. In addition, the foregoing discussion and the discussions in the Prospectus applicable to each shareholder address only some of the U.S. federal income tax considerations generally affecting investments in the Funds. Prospective shareholders are urged to consult with their own tax advisers and financial planners as to the particular U.S. federal tax consequences to them of an investment in the Funds, as well as the applicability and effect of any state, local or foreign laws, and the effect of possible changes in applicable tax laws.

QUALIFICATION AS A REGULATED INVESTMENT COMPANY. Each Fund has elected to be treated, has qualified and intends to continue to qualify each year, as a "regulated investment company" under Subchapter M of the Internal Revenue Code as long as such qualification is in the best interests of the Fund's shareholders. Each Fund will be treated as a separate entity for U.S. federal income tax purposes. Thus, the provisions of the Internal Revenue Code applicable to regulated investment companies generally will apply separately to each Fund, even though each Fund is a series of a trust. Furthermore, each Fund separately determines its income, gains, losses and expenses for U.S. federal income tax purposes.

In order to qualify as a regulated investment company under the Internal Revenue Code, each Fund must, among other things, derive at least 90% of its annual gross income from dividends, interest, certain payments with respect to securities loans, gains from the sale or other disposition of stock, securities or foreign currencies, or other income attributable to its business of investing in such stock, securities or foreign currencies (including, but not limited to, gains from options, futures or forward contracts) and net income derived from an interest in a qualified publicly-traded partnership as defined in Section 851(h) of the Internal Revenue Code. Pursuant to regulations that may be promulgated in the future, the IRS may limit qualifying income from foreign currency gains to the amount of such currency gains that are directly related to a regulated investment company's principal business of investing in stock or securities. Each Fund must also diversify its holdings so that, at the end of each quarter of each taxable year: (i) at least 50% of the value of its assets consists of (A) cash and cash items (including receivables), U.S. government securities and securities of other regulated investment companies, and (B) other securities, with such other securities limited, in respect to any one issuer, to an amount not greater than 5% of the value of the Fund's total assets and to not more than 10% of the outstanding voting securities of such issuer and (ii) not more than 25% of the value of the Fund's total assets is invested in (A) the securities (other than U.S. government securities and securities of other regulated investment companies) of any one issuer, (B) the securities (other than the securities of other regulated investment companies) of two or more issuers that the Fund controls and that are engaged in the same, similar, or related trades or businesses, or (C) the securities of one or more qualified publicly-traded partnerships. The qualifying income and diversification requirements applicable to a Fund may limit the extent to which it can engage in transactions in options, futures contracts, forward contracts and swap agreements.

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In addition, each Fund generally must distribute to its shareholders an amount equal to or exceeding the sum of (i) 90% of its "investment company taxable income," as that term is defined in the Internal Revenue Code (which generally includes, among other things, dividends, taxable interest, and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses) without regard to the deduction for dividends paid and (ii) 90% of its net tax-exempt income earned in each taxable year. A Fund generally will not be subject to U.S. federal income tax on the investment company taxable income and "net capital gain" (I.E., the excess of net long-term capital gain over net short-term capital loss) it distributes to its shareholders. However, if a Fund meets such distribution requirements, but chooses to retain some portion of its investment company taxable income or net capital gain, it generally will be subject to U.S. federal income tax at regular corporate rates on the amount retained. Although dividends generally will be treated as distributed when paid, if a Fund declares a distribution to shareholders of record in October, November or December of one year and pays the distribution by January 31 of the following year, the Fund and its shareholders will be treated as if the Fund paid the distribution by December 31 of the calendar year in which it was declared. Each Fund intends to distribute its net income and gain in a timely manner to maintain its status as a regulated investment company and eliminate fund-level U.S. federal income taxation of such income and gain. However, no assurance can be given that a Fund will not be subject to U.S. federal income taxation.

If, in any taxable year, a Fund fails to qualify as a regulated investment company under the Internal Revenue Code or fails to meet the distribution requirements described above, the Fund would be taxed in the same manner as an ordinary U.S. corporation without any deduction for distributions to shareholders, and all distributions from the Fund's earnings and profits (including any distributions of net tax-exempt income and net capital gain) to its shareholders would also be taxable as ordinary income at the shareholder level. To qualify again to be taxed as a regulated investment company in a subsequent year, the Fund may be required to pay an interest charge and penalty to the IRS as well as distribute to its shareholders its earnings and profits attributable to non-regulated investment company years. In addition, if the Fund fails to qualify as a regulated investment company for a period greater than two taxable years, the Fund may be required to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the Fund had been liquidated) or, alternatively, to be subject to taxation on such built-in gain recognized for a period of ten years, in order to qualify as a regulated investment company in a subsequent year.

EXCISE TAX. A 4% non-deductible excise tax will be imposed on each Fund to the extent it fails to distribute during each calendar year (i) at least 98% of its ordinary income (excluding capital gains and losses) for the calendar year,
(ii) at least 98% of its net capital gain income (generally the excess of capital gains over capital losses as adjusted for ordinary losses) for the 12 month period ending on October 31, and (iii) all of its ordinary income and net capital gain income from previous years that was not distributed or subject to tax during such years. Each Fund intends to distribute substantially all of its net income and gains, if any, by the end of each calendar year and, thus, expects not to be subject to the excise tax. However, no assurance can be given that a Fund will not be subject to the excise tax.

CAPITAL LOSS CARRY-FORWARDS. A Fund is permitted to carry forward a net capital loss from any year to offset its capital gains, if any, realized during the eight years following the year of the loss. A Fund's capital loss carry-forward is treated as a short-term capital loss in the year to which it is carried. If future capital gains are offset by carried-forward capital losses, such future capital gains are not subject to Fund-level U.S. federal income taxation, regardless of whether they are distributed to shareholders. Accordingly, the Funds do not expect to distribute any such capital gains. The Funds cannot carry back or carry forward any net operating losses. As a money market fund, each Fund does not expect to have material capital loss carry-forwards, but no assurance can be given to this effect. As of December 31, 2009, the Funds had capital loss carry-forwards approximating the amount indicated for U.S. federal income tax purposes, expiring in the year indicated:

                                            EXPIRING
FUND                                       12/31/2016
---------------------------------------  -------------
  BlackRock Cash Funds: Prime            $4,310,000
  BlackRock Cash Funds: Institutional         -
  BlackRock Cash Funds: Government            -
  BlackRock Cash Funds: Treasury              -

INVESTMENT THROUGH THE MASTER PORTFOLIOS. The Funds seek to continue to qualify as regulated investment companies by investing their assets through the Master Portfolios. Each Master Portfolio is treated as a non-publicly traded partnership (or, in the event that a Fund is the sole investor in a Master Portfolio, as disregarded from the Fund) for U.S. federal income tax purposes rather than as a regulated investment company or a corporation under the Internal Revenue Code. Under the rules

46

applicable to a non-publicly traded partnership (or disregarded entity), a proportionate share of any interest, dividends, gains and losses of a Master Portfolio will be deemed to have been realized by (I.E., "passed-through" to) its investors, including the corresponding Fund, regardless of whether any amounts are actually distributed by the Master Portfolio. Each investor in a Master Portfolio will be taxable on such share, as determined in accordance with the governing instruments of the particular Master Portfolio, the Internal Revenue Code and Treasury Regulations. Therefore, to the extent that a Master Portfolio were to accrue but not distribute any income or gains, the corresponding Fund would be deemed to have realized its proportionate share of such income or gains without receipt of any corresponding distribution. However, each of the Master Portfolios will seek to minimize recognition by its investors (such as the Funds) of income and gains without a corresponding distribution. Furthermore, each Master Portfolio's assets, income and distributions will be managed in such a way that an investor in a Master Portfolio will be able to continue to qualify as a regulated investment company by investing its assets through the Master Portfolio.

TAXATION OF FUND INVESTMENTS. In general, if a Fund realizes gains or losses on the sale of portfolio securities, such gains or losses are capital gains or losses. If the Fund has held the disposed securities for more than one year at the time of disposition, such gains and losses generally are treated as long-term capital gains or losses.

If a Fund purchases a debt obligation with original issue discount ("OID"), generally at a price less than its principal amount, such as a zero-coupon bond, the Fund may be required to annually include in its taxable income a portion of the OID as ordinary income, even though the Fund will not receive cash payments for such discount until maturity or disposition of the obligation. A portion of the OID includible in income with respect to certain high-yield corporate debt securities may be treated as a dividend for U.S. federal income tax purposes. Gains recognized on the disposition of a debt obligation (including a municipal obligation) purchased by a Fund at a market discount, usually at a price less than its principal amount, generally will be treated as ordinary income to the extent of the portion of market discount which accrued, but was not previously recognized pursuant to an available election, during the term that the Fund held the debt obligation. A Fund generally will be required to make distributions to shareholders representing the OID on debt securities that is currently includible in income, even though the cash representing such income may not have been received by the Fund. Cash to pay such distributions may be obtained from borrowing or from sales of securities held by a Fund which the Fund otherwise might have continued to hold.

If an option granted by a Fund lapses or is terminated through a closing transaction, such as a repurchase by the Fund of the option from its holder, the Fund generally will realize a short-term capital gain or loss, depending on whether the premium income is greater or less than the amount paid by the Fund in the closing transaction. If securities are sold by a Fund pursuant to the exercise of a call option granted by it, the Fund will add the premium received to the sale price of the securities delivered in determining the amount of gain or loss on the sale. If securities are purchased by a Fund pursuant to the exercise of a put option written by it, the Fund will subtract the premium received from its cost basis in the securities purchased.

Foreign exchange gains and losses realized by a Fund in connection with certain transactions involving foreign currency-denominated debt securities, certain

options and futures contracts relating to foreign currency, foreign currency forward contracts, foreign currencies, or payables or receivables denominated in a foreign currency are subject to Section 988 of the Internal Revenue Code, which generally causes such gains and losses to be treated as ordinary income and losses and may affect the amount and timing of recognition of the Fund's income. Under Treasury Regulations that may be promulgated in the future, any such transactions that are not directly related to a Fund's principal business of investing in stock or securities (or its options contracts or futures contracts with respect to stock or securities) may have to be limited in order to enable the Fund to satisfy the 90% income test described above. If the net foreign exchange loss for a year exceeds a Fund's investment company taxable income (computed without regard to such loss), the resulting ordinary loss for such year will not be deductible by the Fund or its shareholders in future years.

If a Fund enters into a "constructive sale" of any appreciated financial position in stock, a partnership interest, or certain debt instruments, the Fund will be treated as if it had sold and immediately repurchased the property and must recognize gain (but not loss) with respect to that position. A constructive sale occurs when a Fund enters into one of the following transactions with respect to the same or substantially identical property: (i) a short sale; (ii) an offsetting notional principal contract; (iii) a futures or forward contract; or (iv) other transactions identified in Treasury Regulations that may be promulgated in the future. The character of the gain from constructive sales will depend upon a Fund's holding period in the property. Losses from a constructive sale of property will be recognized when the property is subsequently disposed of. The character of such losses will depend upon a Fund's holding period in the property and the application of various loss deferral

47

provisions in the Internal Revenue Code. Constructive sale treatment does not apply to a transaction if such transaction is closed before the end of the 30th day after the close of the Fund's taxable year, the Fund holds the appreciated financial position throughout the 60-day period beginning with the day such transaction was closed, and the Fund's risk of loss with respect to such position is not reduced at any time during such 60-day period.

In addition to the investments described above, prospective shareholders should be aware that other investments made by the Funds may involve sophisticated tax rules that may result in income or gain recognition by the Funds without corresponding current cash receipts. Although the Funds seek to avoid significant non-cash income, such non-cash income could be recognized by the Funds, in which case the Funds may distribute cash derived from other sources in order to meet the minimum distribution requirements described above. In this regard, the Funds could be required at times to liquidate investments prematurely in order to satisfy their minimum distribution requirements.

TAXATION OF DISTRIBUTIONS. For U.S. federal income tax purposes, a Fund's earnings and profits, described above, are determined at the end of the Fund's taxable year and are allocated PRO RATA to distributions made throughout the entire year. All distributions paid out of a Fund's earnings and profits (as determined at the end of the year), whether paid in cash or reinvested in the Fund, generally are deemed to be taxable distributions and must generally be reported on each Fund shareholder's U.S. federal income tax return. Distributions in excess of a Fund's earnings and profits will first be treated as a return of capital up to the amount of a shareholder's tax basis in the shareholder's Fund shares and any such amount in excess of that basis as capital gain from the sale of shares, as discussed below. A Fund may make distributions in excess of earnings and profits to a limited extent, from time to time.

In general, assuming that each Fund has sufficient earnings and profits, distributions from investment company taxable income are taxable as ordinary income. Since each Fund's income is derived from sources that do not pay "qualified dividend income," as defined in Section 1(h)(11)(B) of the Internal Revenue Code, distributions from investment company taxable income of the Funds generally will not qualify for taxation at the maximum 15% U.S. federal income tax rate available to individuals on qualified dividend income.

Distributions designated by a Fund as a "capital gain dividend", if any, will be taxed to shareholders as long-term capital gain (to the extent such distributions do not exceed the Fund's actual net capital gain for the taxable year), regardless of how long a shareholder has held Fund shares. Each Fund will designate capital gains dividends, if any, in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of a Fund's taxable year. Normally the Funds do not expect to realize or distribute a significant amount of long-term capital gains (if any).

Distributions from each Fund paid to corporate shareholders are not expected to qualify for the dividends-received deductions generally available to corporate taxpayers. The U.S. federal income tax status of all distributions will be reported to shareholders annually.

Some states will not tax distributions made to individual shareholders that are attributable to interest a Fund earned on direct obligations of the U.S. government if the Fund meets the state's minimum investment or reporting requirements, if any. Investments in Ginnie Mae or Fannie Mae securities, bankers' acceptances, commercial paper and repurchase agreements collateralized by U.S. government securities generally do not qualify for tax-free treatment. This exemption may not apply to corporate shareholders.

SALES OF FUND SHARES. Redemptions generally are taxable events for shareholders that are subject to tax. Shareholders should consult their own tax adviser with reference to their individual circumstances to determine whether any particular transaction in Fund shares is properly treated as a sale for tax purposes, as the following discussion assumes, and the tax treatment of any gains or losses recognized in such transaction. In general, if Fund shares are sold, a shareholder will recognize gain or loss equal to the difference between the amount realized on the sale and the shareholder's adjusted tax basis in the shares. As long as the Funds maintain a constant net asset value of $1.00 per share, generally no gain or loss should be recognized upon the sale of Fund shares. If a shareholder recognizes gain or loss on the sale of Fund shares, this gain or loss will be long-term capital gain or loss if the shareholder has held such Fund shares for more than one year at the time of the sale. If a shareholder receives a capital gain dividend with respect to any Fund share and such Fund share is held for six months or less, then (unless otherwise disallowed) any loss on the sale or exchange of that Fund share will be treated as a long-term capital loss to the extent of the capital gain dividend. Losses on redemptions or other dispositions of shares may be disallowed under "wash sale" rules in the event of other investments in the same Fund (including those made

48

pursuant to reinvestment of dividends and/or capital gain distributions) within a period of 61 days beginning 30 days before and ending 30 days after a redemption or other disposition of shares. In such a case, the disallowed portion of any loss generally would be included in the U.S. federal tax basis of the shares acquired in the other investments.

FOREIGN TAXES. Amounts realized by a Fund on foreign securities may be subject to withholding and other taxes imposed by foreign countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a Fund's total assets at the close of its taxable year were to consist of securities of non-U.S. corporations, the Fund would be eligible to file an annual election with the IRS pursuant to which the Fund could pass-through to its shareholders on a PRO RATA basis foreign income and similar taxes paid by the Fund, which could be claimed, subject to certain limitations, either as a tax credit or deduction by shareholders. However, none of the Funds expects to qualify for this election.

FEDERAL INCOME TAX RATES. As of the date of this SAI, the maximum stated individual U.S. federal income tax rate applicable to (i) ordinary income generally is 35%; (ii) capital gain dividends is 15%; and (iii) long-term capital gains generally is 15%. An individual shareholder also should be aware that the benefits of the favorable tax rates applicable to capital gain dividends and long-term capital gains may be impacted by the application of the alternative minimum tax. Under current law, the maximum 35% U.S. federal income tax rate on ordinary income and the maximum 15% U.S. federal income tax rate on capital gain dividends and long-term capital gains will cease to apply to taxable years beginning after December 31, 2010.

The current maximum stated corporate U.S. federal income tax rate applicable to ordinary income, capital gain dividends, and long-term capital gains generally is 35%. Actual marginal tax rates may be higher for some shareholders, for example, through reductions in deductions. Naturally, the amount of tax payable by any taxpayer will be affected by a combination of tax laws covering, for example, deductions, credits, deferrals, exemptions, sources of income and other matters.

BACK-UP WITHHOLDING. The Trust may be required to withhold, subject to certain exemptions, at a rate of 28% ("back-up withholding") on all distributions and redemption proceeds (including proceeds from exchanges and redemptions in-kind) paid or credited to a Fund shareholder, unless the shareholder generally certifies under penalties of perjury that the shareholder's social security or other "taxpayer identification number" ("TIN") provided is correct and that the shareholder is not subject to back-up withholding, or the IRS notifies the Fund that the shareholder's TIN is incorrect or that the shareholder is subject to back-up withholding. This tax is not an additional U.S. federal income tax imposed on the shareholder, and the shareholder may claim the tax withheld as a tax payment on his or her federal income tax return, provided that the required information is furnished to the IRS. An investor must provide a valid TIN upon opening or reopening an account. If a shareholder fails to furnish a valid TIN upon request, the shareholder can also be subject to IRS penalties. The rate of back-up withholding is set to increase for taxable years beginning after December 31, 2010.

TAX-DEFERRED PLANS. Shares of the Funds may be available for a variety of tax-deferred retirement and other tax-advantaged plans and accounts, including IRAs, Simplified Employee Pension Plans, Savings Incentive Match Plans for Employees, Roth IRAs, and Coverdell Education Savings Accounts. Prospective investors should contact their tax advisers and financial planners regarding the tax consequences to them of holding Fund shares through a tax-advantaged plan or account.

FOREIGN SHAREHOLDERS. With respect to taxable years of a Fund beginning before January 1, 2010, certain distributions, if designated by a Fund as "interest-related dividends," that are generally attributable to the Fund's net interest income earned on certain debt obligations paid to a non-resident alien individual, foreign trust (I.E., a trust other than a trust which a U.S. court is able to exercise primary supervision over administration of that trust and one or more U.S. persons have authority to control substantial decisions of that trust), foreign estate (I.E., the income of which is not subject to U.S. tax regardless of source) or a foreign corporation (each, a "foreign shareholder") generally will be exempt from U.S. federal income tax withholding tax, provided the Fund obtains a properly completed and signed certificate of foreign status from such foreign shareholder ("exempt foreign shareholder"). If applicable, each Fund may choose to designate any interest-related dividends in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year. All other distributions made to exempt foreign shareholders attributable to net investment income, such as dividends received by a Fund, generally will be subject to non-refundable U.S. federal income tax withholding at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Notwithstanding the foregoing, if a distribution described above is "effectively connected" with a U.S. trade or business (or, if an income tax treaty applies, is attributable to a permanent establishment) of the recipient foreign shareholder, U.S. federal income tax withholding and exemptions attributable to foreign persons will not apply and the distribution will be subject to the tax, reporting and withholding requirements generally applicable to U.S. persons.

49

In general, a foreign shareholder's capital gains realized on the disposition of Fund shares, capital gain distributions and, with respect to taxable years of a Fund beginning before January 1, 2010, "short-term capital gain distributions" (defined below) are not subject to U.S. federal income tax withholding, provided that the Fund obtains a properly completed and signed certificate of foreign status, unless: (i) such gains or distributions are "effectively connected" with a U.S. trade or business (or, if an income tax treaty applies, are attributable to a permanent establishment) of the foreign shareholder; (ii) in the case of an individual foreign shareholder, the shareholder is present in the U.S. for a period or periods aggregating 183 days or more during the year of the sale and certain other conditions are met; or
(iii) with respect to taxable years of a Fund beginning before January 1, 2010, such gains or distributions are attributable to gain from the sale or exchange of a U.S. real property interest. If such gains or distributions are "effectively connected" with a U.S. trade or business or are attributable to a U.S. permanent establishment of the foreign shareholder pursuant to an income tax treaty, the tax, reporting and withholding requirements applicable to U.S. persons generally apply. If such gains or distributions are not "effectively connected" for this purpose, but the foreign shareholder meets the requirements of clause (ii) described above, such gains and distributions will be subject to U.S. federal income withholding tax at a 30% rate (or a lower rate if so provided under an applicable income tax treaty). Gains or distributions attributable to gain from sales or exchanges of U.S. real property interests are taxed to a foreign shareholder as if that gain were "effectively connected" with the shareholder's conduct of a U.S. trade or business, and therefore such gains or distributions may be required to be reported by a foreign shareholder on a U.S. federal income tax return. Such gains or distributions also will be subject to U.S. federal income tax at the rates applicable to U.S. holders and/or may be subject to U.S. federal income tax withholding. While the Funds do not expect Fund shares to constitute U.S. real property interests, a portion of a Fund's distributions may be attributable to gain from the sale or exchange of U.S. real property interests. Foreign shareholders should contact their tax advisers and financial planners regarding the tax consequences to them of such distributions. "Short-term capital gain distributions" are certain distributions that a Fund may choose to designate as such in a written notice mailed by the Fund to its shareholders not later than 60 days after the close of the Fund's taxable year generally attributable to the Fund's net short-term capital gain.

If a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, Fund shares will be deemed to be property situated in the United States and will be subject to U.S. federal estate taxes (at current graduated rates of 18% to 45% of the total value, less allowable deductions and credits). With respect to estates of decedents dying before January 1, 2010, if a foreign shareholder is a resident of a foreign country but is not a citizen or resident of the United States at the time of the shareholder's death, Fund shares are not deemed to be property situated in the United States in the proportion that, at the end of the quarter of the Fund's taxable year immediately preceding the shareholder's date of death, the assets of the Fund that are "qualifying assets" (I.E., bank deposits, debt obligations or property not within the United States) with respect to the decedent bear to the total assets of the Fund. In general, no U.S. federal gift tax will be imposed on gifts of Fund shares made by foreign shareholders.

The availability of reduced U.S. taxes pursuant to the 1972 Convention or the applicable estate tax convention depends upon compliance with established procedures for claiming the benefits thereof, and may, under certain circumstances, depend upon the foreign shareholder making a satisfactory demonstration to U.S. tax authorities that the shareholder qualifies as a foreign person under U.S. federal income tax laws and the 1972 Convention.

Special rules apply to foreign partnerships and those holding Fund shares through foreign partnerships.

RECENTLY ENACTED LEGISLATION. Recently enacted legislation will impose a 3.8% tax on the net investment income (which includes taxable dividends and redemption proceeds) of certain individuals, trusts and estates, for taxable years beginning after December 31, 2012.

Other recently enacted legislation will impose a 30% withholding tax on dividends and redemption proceeds paid after December 31, 2012, to (i) foreign financial institutions (as defined in Section 1471(d)(4) of the Internal Revenue Code) unless they agree to collect and disclose to the IRS information regarding their direct and indirect United States account holders and (ii) certain other foreign entities unless they certify certain information regarding their direct and indirect United States owners. Under some circumstances, a foreign shareholder may be eligible for refunds or credits of such taxes.

Capital Stock

As of the date of this SAI, the beneficial interests in the Trust are divided into transferable shares of 11 separate and distinct series authorized and established by the Board of Trustees. The number of shares of each series, and class thereof, is

50

unlimited and each share has no par value. The Board of Trustees may, in the future, authorize the issuance of other series representing shares of additional investment portfolios or funds. Except to the extent the 1940 Act expressly grants to shareholders the power to vote on such termination(s), the Trust, or any series (or class) thereof, may be terminated at any time by the Trustees with written notice to the shareholders.

Although the Trust is not required to hold regular annual shareholder meetings, occasional annual or special meetings may be required for purposes such as electing and removing Trustees, approving advisory contracts, and changing a Fund's fundamental investment policies.

VOTING. All shares of the Trust have equal voting rights and will be voted separately by individual series, except: (i) when required by the 1940 Act, shares will be voted in the aggregate and not by individual series; and (ii) when the Trustees have determined that the matter affects the interests of more than one series, then the shareholders of all such affected series will be entitled to vote thereon in the aggregate and not by individual series. The Trustees also may determine that a matter affects only the interests of one or more classes of a series, in which case any such matter will be voted on separately by such class or classes. For example, a change in a Fund's fundamental investment policy would be voted upon only by shareholders of that Fund. Additionally, approval of a Master Portfolio's Advisory Contract is a matter to be determined separately by each Master Portfolio. Approval by the shareholders of a Fund is effective as to that Fund whether or not sufficient votes are received from the shareholders of the other investment portfolios to approve the proposal as to those investment portfolios. As used in the Prospectus of each Fund and in this SAI, the term "1940 Act majority," when referring to approvals to be obtained from shareholders of a Fund, means the vote of the lesser of (i) 67% of the shares of the Fund represented at a meeting if the holders of more than 50% of the outstanding shares of the Fund are present in person or by proxy, or (ii) more than 50% of the outstanding shares of the Fund. The term "majority," when referring to the approvals to be obtained from shareholders of the Trust as a whole, means the vote of the lesser of (i) 67% of the Trust's shares represented at a meeting if the holders of more than 50% of the Trust's outstanding shares are present in person or by proxy, or (ii) more than 50% of the Trust's outstanding shares.

Each share will entitle the holder thereof to one vote for each dollar (and each fractional dollar thereof) of NAV (number of shares owned times NAV per share) of shares outstanding in such holder's name on the books of the Trust. There shall be no cumulative voting in the election of Trustees. For additional voting information and a discussion of the possible effects of changes to a Master Portfolio's investment objective or policies on a Fund, as an interestholder in the Master Portfolio, or the Fund's shareholders, see "Description of the Funds and their Investments and Risks - Master/Feeder Structure."

The Trust may dispense with an annual meeting of shareholders in any year in which it is not required to elect Trustees under the 1940 Act. However, the Trust will hold a special meeting of its shareholders for the purpose of voting on the question of removal of a Trustee or Trustees if requested in writing by the holders of at least 10% of the Trust's outstanding voting securities, and to assist in communicating with other shareholders as required by Section 16(c) of the 1940 Act.

DIVIDENDS AND DISTRIBUTIONS. Each share of a Fund represents an equal proportional interest in the Fund with each other share and is entitled to such dividends and distributions out of the income earned on the assets belonging to the Fund as are declared in the discretion of the Trustees. In the event of the liquidation or dissolution of the Trust, shareholders of a Fund are entitled to receive the assets attributable to the Fund that are available for distribution, and a distribution of any general assets not attributable to a particular investment portfolio that are available for distribution in such manner and on such basis as the Trustees in their sole discretion may determine. Shareholders are not entitled to any preemptive rights. All shares, when issued, will be fully paid and non-assessable by the Trust.

MASTER PORTFOLIOS. MIP is an open-end, series management investment company organized as a Delaware statutory trust on October 20, 1993. MIP's Declaration of Trust provides that obligations of MIP are not binding upon its Trustees individually but only upon the property of MIP and that the Trustees will not be liable for any action or failure to act, but nothing in the Declaration of Trust protects a Trustee against any liability to which the Trustee would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of the Trustee's office.

Interests in each Master Portfolio of MIP have voting and other rights generally corresponding to those rights enumerated above for shares of the Funds. MIP also intends to dispense with annual meetings, but is required by
Section 16(c) of the 1940 Act to hold a special meeting and assist investor communications under the circumstances described above with respect to the Trust. Whenever a Fund is requested to vote on a matter with respect to its Master Portfolio, the Fund will follow its voting procedures, as described in "Voting."

51

Additional Information on the Funds

The Trust provides annual and semi-annual reports to all shareholders. The annual reports contain audited financial statements and other information about the Funds, including additional information on performance. Shareholders may obtain a copy of the Trust's most recent annual or semi-annual reports without charge by calling 1-800-768-2836 (toll-free).

The registration statement, including the Prospectus, this SAI and the exhibits filed therewith, may be examined at the office of the SEC in Washington, D.C. Statements contained in the Prospectus or this SAI as to the contents of any contract or other document referred to herein or in the Prospectus are not necessarily complete and, in each instance, reference is made to the copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference.

No person has been authorized to give any information or to make any representations other than those contained in the Prospectus, this SAI and in the Trust's official sales literature in connection with the offer of the Trust's shares and, if given or made, such other information or representations must not be relied upon as having been authorized by the Trust. This SAI does not constitute an offer in any state in which, or to any person to whom, such offering may not lawfully be made.

Financial Statements

The audited financial statements, including the schedule of investments, financial highlights and independent registered public accounting firm's reports for the fiscal year ended December 31, 2009 for each Fund and related Master Portfolio are hereby incorporated by reference to the Trust's annual report, as filed with the SEC on March 10, 2010. The annual report, which contains the referenced audited financial statements, is available upon request and without charge.

52

APPENDIX A

PROXY VOTING POLICIES

For The BlackRock-Advised Funds

December, 2009


Table of Contents

                                                                            Page
I.   INTRODUCTION                                                              1
II.  PROXY VOTING POLICIES................................................     2
     A.  BOARDS OF DIRECTORS..............................................     2
     B.  AUDITORS.........................................................     2
     C.  COMPENSATION AND BENEFITS........................................     2
     D.  CAPITAL STRUCTURE................................................     2
     E.  CORPORATE CHARTER AND BY-LAWS....................................     3
     F.  ENVIRONMENTAL AND SOCIAL ISSUES..................................     3
IV.  REPORTS TO THE BOARD.................................................     3


I INTRODUCTION

The Trustees/Directors ("Directors") of the BlackRock-Advised Funds (the "Funds") have the responsibility for voting proxies relating to portfolio securities of the Funds, and have determined that it is in the best interests of the Funds and their shareholders to delegate that responsibility to BlackRock Advisors, LLC and its affiliated U.S. registered investment advisers ("BlackRock"), the investment adviser to the Funds, as part of BlackRock's authority to manage, acquire and dispose of account assets. The Directors hereby direct BlackRock to vote such proxies in accordance with this Policy, and any proxy voting guidelines that the Adviser determines are appropriate and in the best interests of the Funds' shareholders and which are consistent with the principles outlined in this Policy. The Directors have authorized BlackRock to utilize an unaffiliated third-party as its agent to vote portfolio proxies in accordance with this Policy and to maintain records of such portfolio proxy voting.

Rule 206(4)-6 under the Investment Advisers Act of 1940 requires, among other things, that an investment adviser that exercises voting authority over clients' proxy voting adopt policies and procedures reasonably designed to ensure that the adviser votes proxies in the best interests of clients, discloses to its clients information about those policies and procedures and also discloses to clients how they may obtain information on how the adviser has voted their proxies.

BlackRock has adopted separate but substantially similar guidelines and procedures that are consistent with the principles of this Policy. BlackRock's Corporate Governance Committee (the "Committee"), addresses proxy voting issues on behalf of BlackRock and its clients, including the Funds. The Committee is comprised of senior members of BlackRock's Portfolio Management and Administration Groups and is advised by BlackRock's Legal and Compliance Department.

BlackRock votes (or refrains from voting) proxies for each Fund in a manner that BlackRock, in the exercise of its independent business judgment, concludes are in the best economic interests of such Fund. In some cases, BlackRock may determine that it is in the best economic interests of a Fund to refrain from exercising the Fund's proxy voting rights (such as, for example, proxies on certain non-U.S. securities that might impose costly or time-consuming in-person voting requirements). With regard to the relationship between securities lending and proxy voting, BlackRock's approach is also driven by our clients' economic interests. The evaluation of the economic desirability of recalling loans involves balancing the revenue producing value of loans against the likely economic value of casting votes. Based on our evaluation of this relationship, BlackRock believes that the likely economic value of casting a vote generally is less than the securities lending income, either because the votes will not have significant economic consequences or because the outcome of the vote would not be affected by BlackRock recalling loaned securities in order to ensure they are voted. Periodically, BlackRock analyzes the process and benefits of voting proxies for securities on loan, and will consider whether any modification of its proxy voting policies or procedures are necessary in light of any regulatory changes.

BlackRock will normally vote on specific proxy issues in accordance with BlackRock's proxy voting guidelines. BlackRock's proxy voting guidelines provide detailed guidance as to how to vote proxies on certain important or commonly raised issues. BlackRock may, in the exercise of its business judgment, conclude that the proxy voting guidelines do not cover the specific matter upon which a proxy vote is requested, or that an exception to the proxy voting guidelines would be in the best economic interests of a Fund. BlackRock

1

votes (or refrains from voting) proxies without regard to the relationship of the issuer of the proxy (or any shareholder of such issuer) to the Fund, the Fund's affiliates (if any), BlackRock or BlackRock's affiliates. When voting proxies, BlackRock attempts to encourage companies to follow practices that enhance shareholder value and increase transparency and allow the market to place a proper value on their assets.

II. PROXY VOTING POLICIES

A. BOARDS OF DIRECTORS

The Funds generally support the board's nominees in the election of directors and generally supports proposals that strengthen the independence of boards of directors. As a general matter, the Funds believe that a company's board of directors (rather than shareholders) is most likely to have access to important, nonpublic information regarding a company's business and prospects, and is therefore best-positioned to set corporate policy and oversee management. The Funds therefore believe that the foundation of good corporate governance is the election of responsible, qualified, independent corporate directors who are likely to diligently represent the interests of shareholders and oversee management of the corporation in a manner that will seek to maximize shareholder value over time. In individual cases, consideration may be given to a director nominee's history of representing shareholder interests as a director of the company issuing the proxy or other companies, or other factors to the extent deemed relevant by the Committee.

B. AUDITORS

These proposals concern those issues submitted to shareholders related to the selection of auditors. As a general matter, the Funds believe that corporate auditors have a responsibility to represent the interests of shareholders and provide an independent view on the propriety of financial reporting decisions of corporate management. While the Funds anticipate that BlackRock will generally defer to a corporation's choice of auditor, in individual cases, consideration may be given to an auditors' history of representing shareholder interests as auditor of the company issuing the proxy or other companies, to the extent deemed relevant.

C. COMPENSATION AND BENEFITS

These proposals concern those issues submitted to shareholders related to management compensation and employee benefits. As a general matter, the Funds favor disclosure of a company's compensation and benefit policies and oppose excessive compensation, but believe that compensation matters are normally best determined by a corporation's board of directors, rather than shareholders. Proposals to "micro-manage" a company's compensation practices or to set arbitrary restrictions on compensation or benefits should therefore generally not be supported.

D. CAPITAL STRUCTURE

These proposals relate to various requests, principally from management, for approval of amendments that would alter the capital structure of a company, such as an increase in authorized shares. As a general matter, the Funds expect that BlackRock will support requests that it believes enhance the rights of common shareholders and oppose requests that appear to be unreasonably dilutive.

2

E. CORPORATE CHARTER AND BY-LAWS

These proposals relate to various requests for approval of amendments to a corporation's charter or by-laws. As a general matter, the Funds generally vote against anti-takeover proposals and proposals that would create additional barriers or costs to corporate transactions that are likely to deliver a premium to shareholders.

F. ENVIRONMENTAL AND SOCIAL ISSUES

These are shareholder proposals addressing either corporate social and environmental policies or requesting specific reporting on these issues. The Funds generally do not support proposals on social issues that lack a demonstrable economic benefit to the issuer and the Fund investing in such issuer. BlackRock seeks to make proxy voting decisions in the manner most likely to protect and promote the long-term economic value of the securities held in client accounts. We intend to support economically advantageous corporate practices while leaving direct oversight of company management and strategy to boards of directors. We seek to avoid micromanagement of companies, as we believe that a company's board of directors is best positioned to represent shareholders and oversee management on shareholders behalf. Issues of corporate social and environmental responsibility are evaluated on a case-by-case basis within this framework.

III. CONFLICTS MANAGEMENT

BlackRock maintains policies and procedures that are designed to prevent any relationship between the issuer of the proxy (or any shareholder of the issuer) and a Fund, a Fund's affiliates (if any), BlackRock or BlackRock's affiliates, from having undue influence on BlackRock's proxy voting activity. In certain instances, BlackRock may determine to engage an independent fiduciary to vote proxies as a further safeguard against potential conflicts of interest or as otherwise required by applicable law. The independent fiduciary may either vote such proxies or provide BlackRock with instructions as to how to vote such proxies. In the latter case, BlackRock votes the proxy in accordance with the independent fiduciary's determination.

IV. REPORTS TO THE BOARD

BlackRock will report to the Directors on proxy votes it has made on behalf of the Funds at least annually.

SAI-BR3-CFSLA-0510


BLACKROCK FUNDS III
FILE NOS. 33-54126; 811-07332

PART C

OTHER INFORMATION

POST-EFFECTIVE AMENDMENT NO. 88

ITEM 28. EXHIBITS

  EXHIBIT                               DESCRIPTION
------------  -----------------------------------------------------------------

    (a)       Amended and Restated Agreement and Declaration of Trust,
              dated November 17, 2006, is incorporated herein by reference
              to BlackRock Funds III's/1/ (the "Registrant," and the series
              thereof, the "Funds") Post-Effective Amendment No. 59, filed
              April 30, 2007 ("PEA No. 59").

   (a)(1)     Amendment No. 1, dated December 11, 2007, to the Amended
              and Restated Agreement and Declaration of Trust is
              incorporated herein by reference to the Registrant's Post-
              Effective Amendment No. 62, filed December 27, 2007.

   (a)(2)     Amendment No. 2, dated November 13, 2009, to the Amended
              and Restated Agreement and Declaration of Trust is
              incorporated herein by reference to the Registrant's Post-
              Effective Amendment No. 81, filed December 29, 2009 ("PEA
              No. 81").

   (a)(3)     Restated Certificate of Trust of the Registrant, dated April 22,
              2010, is filed herein.

    (b)       Amended and Restated By-Laws, dated November 17, 2006,
              are incorporated herein by reference to PEA No. 59.

   (c)(1)     Article VII of the Amended and Restated Agreement and
              Declaration of Trust is incorporated herein by reference to
              Exhibit (a)(1) to PEA No. 59.

   (c)(2)     Article IV of the Amended and Restated By-Laws is
              incorporated herein by reference to Exhibit (b)(1) to PEA No.
              59.

    (d)       Not applicable.

   (e)(1)     Distribution Agreement between Registrant and SEI
              Investments Distribution Co. ("SEI") on behalf of certain
              Funds, dated March 31, 2003, is incorporated herein by
              reference to the Registrant's Post-Effective Amendment No. 42,
              filed May 1, 2003.

   (e)(2)     Amended Schedule I, dated September 3, 2009, to the
              Distribution Agreement between Registrant and SEI is
              incorporated herein by reference to the Registrant's Post-
              Effective Amendment No. 78, filed October 30, 2009 ("PEA
              No. 78").

   (e)(3)     Form of Distribution Agreement between the Registrant and
              BlackRock Investments, LLC ("BRIL") is incorporated herein
              by reference to Exhibit 5(a) to Post-Effective Amendment No.
              24 to the Registration Statement on Form N-1A of BlackRock
              Global Emerging Markets Fund, Inc. (File No. 33-28248), filed
              on October 28, 2008.

    (f)       Not applicable.

   (g)(1)     Custody Agreement between Registrant and Investors Bank &
              Trust Company ("IBT")/2/ on behalf of the Funds, dated
              October 21, 1996, is incorporated herein by reference to the
              Registrant's Post-Effective Amendment No. 22, filed July 30,
              1999 ("PEA No. 22").

   (g)(2)     Amendment to Custody Agreement, effective September 1,
              2004, between Registrant and IBT/2/ is incorporated herein by
              reference to the Registrant's Post-Effective Amendment No. 57,
              filed March 2, 2006 ("PEA No. 57").

   (g)(3)     Amendment to Custody Agreement, effective January 1, 2006,
              between Registrant and IBT/2/ is incorporated herein by
              reference to PEA No. 59.

  EXHIBIT                               DESCRIPTION
-----------  ------------------------------------------------------------------

  (g)(4)     Amended Schedule A, dated March 26, 2008, to Custody
             Agreement between Registrant and IBT/2/ is incorporated herein
             by reference to the Registrant's Post-Effective Amendment No.
             66, filed April 29, 2008 ("PEA No. 66").

  (h)(1)     Transfer Agency and Service Agreement between Registrant
             and IBT/2/ on behalf of the Funds, dated February 27, 1998, is
             incorporated herein by reference to PEA No. 22.

  (h)(2)     Amendment to Transfer Agency and Service Agreement,
             effective June 1, 2001, between Registrant and IBT/2/ is
             incorporated herein by reference to PEA No. 57.

  (h)(3)     Amendment to Transfer Agency and Service Agreement,
             effective September 1, 2004, between Registrant and IBT/2/ is
             incorporated herein by reference to PEA No. 57.

  (h)(4)     Amendment to Transfer Agency and Service Agreement, dated
             July 8, 2005, between Registrant and IBT/2/ is incorporated
             herein by reference to PEA No. 57.

  (h)(5)     Amendment to Transfer Agency and Service Agreement,
             effective January 1, 2006, between Registrant and IBT/2/ is
             incorporated herein by reference to PEA No. 59.

  (h)(6)     Appendix A, dated March 26, 2008, to Transfer Agency and
             Service Agreement between Registrant and IBT/2/ is incorporated
             herein by reference to PEA No. 66.

 (h)(7)(A)   Amended and Restated Shareholder Servicing Plan, with
             respect to only the Funds and their relevant classes as listed in
             Schedule 1 thereto, dated March 26, 2008, is incorporated
             herein by reference to PEA No. 66.

 (h)(7)(B)   Shareholder Servicing Plan, with respect to only the Funds and
             their relevant classes as listed in Schedule 1 thereto, is
             incorporated herein by reference to the Registrant's Post-
             Effective Amendment No. 84 ("PEA No. 84).

  (h)(8)     Amended and Restated Shareholder Servicing and Processing
             Plan is incorporated herein by reference to PEA No. 84.

 (h)(9)(A)   Amended and Restated Administration Agreement between
             Registrant and Barclays Global Investors, N.A. ("BGI")/ 3/, dated
             May 1, 2006, is incorporated herein by reference to the
             Registrant's Post-Effective Amendment No. 58, filed April 28,
             2006 ("PEA No. 58").

 (h)(9)(B)   Amended Appendix A, dated September 3, 2009, to the
             Amended and Restated Administration Agreement between the
             Registrant and BGI/3/ is incorporated herein by reference to PEA
             No. 78.

 (h)(9)(C)   Amended Appendix B, dated November 18, 2008, to the
             Amended and Restated Administration Agreement between the
             Registrant and BGI/3/ is incorporated herein by reference to
             Exhibit (h)(9)(B) to the Registrant's Post-Effective Amendment
             No. 67, filed November 21, 2008.

  (h)(10)    Master Administration Fee Waiver Agreement between
             Registrant and BGI/3/, dated September 1, 2006, is incorporated
             herein by reference to PEA No. 59.

  (h)(11)    Schedule A, dated November 13, 2009, to the Master
             Administration Fee Waiver Agreement between Registrant and
             BGI/3/ is incorporated herein by reference to PEA No. 81.

  (h)(12)    Sub-Administration Agreement among Registrant, BGI/3/, and
             IBT/2/ on behalf of the Funds, dated October 21, 1996, is
             incorporated herein by reference to the Registrant's Post-
             Effective Amendment No. 14, filed June 30, 1997.

  (h)(13)    Amendment to Sub-Administration Agreement, effective
             December 31, 2002, among Registrant, BGI/3/ and IBT/2/ is
             incorporated herein by reference to PEA No. 57.

  (h)(14)    Amendment to Sub-Administration Agreement, effective
             September 1, 2004, among Registrant, BGI/3/ and IBT/2/ is
             incorporated herein by reference to PEA No. 58.

  (h)(15)    Amendment to Sub-Administration Agreement, effective
             January 1, 2006, among Registrant, BGI/3/ and IBT/2/ is
             incorporated herein by reference to PEA No. 59.


  EXHIBIT                               DESCRIPTION
------------  -----------------------------------------------------------------

  (h)(16)     Amendment to Sub-Administration Agreement, effective
              January 1, 2007, among Registrant, BGI/3/ and IBT/2/ is
              incorporated herein by reference to PEA No. 59.

  (h)(17)     Revised Master Fee Schedule, dated January 1, 2006, to each of
              the Sub-Administration, Custody and Transfer Agency and
              Service Agreements between Registrant and IBT/2/ is
              incorporated herein by reference to PEA No. 59.

  (h)(18)     Service Agreement between Registrant and Merrill Lynch,
              Pierce, Fenner & Smith Incorporated ("Merrill Lynch") on
              behalf of the Funds, dated December 31, 1997, is incorporated
              herein by reference to the Registrant's Post-Effective
              Amendment No. 15, filed June 30, 1998 ("PEA No. 15").

  (h)(19)     Financial Services Agreement between Registrant and Merrill
              Lynch on behalf of the Funds, dated December 31, 1997, is
              incorporated herein by reference to PEA No. 15.

  (h)(20)     License Agreement, dated January 1, 2003, between Standard &
              Poor's and BGI/3/ is incorporated herein by reference to PEA No.
              57.

  (h)(21)     Amended and Restated Securities Lending Agency Agreement
              between Registrant and BGI/3/, dated November 2, 2009, is
              incorporated herein by reference to PEA No. 81.

  (h)(22)     Schedule A, dated November 2, 2009, to the Amended and
              Restated Securities Lending Agency Agreement between
              Registrant and BGI/3/ is incorporated herein by reference to PEA
              No. 81.

  (h)(23)     Exhibit A, dated November 2, 2009, to the Amended and
              Restated Securities Lending Agency Agreement between
              Registrant and BGI/3/ is incorporated herein by reference to PEA
              No. 81.

  (h)(24)     Independent Expense Reimbursement Agreement among
              Registrant, Master Investment Portfolio ("MIP"), BGI/3/ and
              Barclays Global Fund Advisors/4/, dated November 13, 2009, is
              incorporated herein by reference to PEA No. 81.

  (h)(25)     Form of Bank Agency Agreement between Registrant and SEI
              is incorporated herein by reference to PEA No. 59.

  (h)(26)     Schedule I, dated March 26, 2008, to the Form of Bank Agency
              Agreement between Registrant and SEI is incorporated herein
              by reference to PEA No. 66.

  (h)(27)     Form of Sub-Distribution Agreement between Registrant and
              SEI is incorporated herein by reference to PEA No. 59.

  (h)(28)     Schedule I, dated March 26, 2008, to the Form of
              Sub-Distribution Agreement between Registrant and SEI is
              incorporated herein by reference to PEA No. 66.

  (h)(29)     Form of Administration Agreement between Registrant, with
              respect to the Funds set forth in Appendix A, and BlackRock
              Institutional Trust Company, N.A. dated February 22, 2010, is
              filed herein.

  (h)(30)     Form of Appendix A, dated February 22, 2010, to the
              Administration Agreement between Registrant and BlackRock
              Institutional Trust Company, N.A. dated February 22, 2010, is
              filed herein.

  (h)(31)     Form of Transfer Agency Agreement between the Registrant
              and PNC Global Investment Servicing (U.S.) Inc. is
              incorporated herein by reference to Exhibit 8(a) to Post-
              Effective Amendment No. 39 to the Registration Statement on
              Form N-1A of BlackRock Bond Fund, Inc. (formerly Merrill
              Lynch Bond Fund, Inc.) (File No. 2-62329), filed on
              September 15, 2006.

    (i)       Opinion and Consent of Counsel (Sidley Austin LLP) is filed
              herein.

    (j)       Consent of Independent Registered Public Accounting Firm
              (PricewaterhouseCoopers LLP) is filed herein.

    (k)       Not applicable.

    (l)       Not applicable.


  EXHIBIT                               DESCRIPTION
------------  -----------------------------------------------------------------

    (m)       Distribution Plan, dated February 22, 2010, is incorporated
              herein by reference to PEA No. 84.

   (n)(1)     Form of Amended and Restated Rule 18f-3 Multi-Class Plan,
              dated February 22, 2010, is filed herein.

   (n)(2)     Form of Appendix A, dated February 22, 2010, to the Rule
              18f-3 Multi-Class Plan is filed herein.

   (p)(1)     Registrant Code of Ethics is incorporated herein by reference to
              PEA No. 81.

   (p)(2)     Code of Ethics of SEI, dated January 2004, is incorporated
              herein by reference to the Registrant's Post-Effective
              Amendment No. 56, filed April 29, 2005.

   (p)(3)     Code of Ethics of BlackRock Investments, LLC is incorporated
              herein by reference to Exhibit 15(b) to Post-Effective
              Amendment No. 44 to the Registration Statement on Form
              N-1A of Ready Assets Prime Money Fund (File No. 2-52711),
              filed on April 29, 2009.

    (q)       Powers of Attorney, each dated December 3, 2009, for Richard
              S. Davis, Henry Gabbay, David O. Beim, Ronald W. Forbes,
              Dr. Matina S. Horner, Rodney D. Johnson, Herbert I. London,
              Cynthia A. Montgomery, Joseph P. Platt, Jr. , Robert C. Robb,
              Jr., Kenneth L. Urish, Toby Rosenblatt and Frederick W.
              Winter are incorporated herein by reference to PEA No. 84.

ITEM 29. PERSONS CONTROLLED BY OR UNDER COMMON CONTROL WITH REGISTRANT

The chart below identifies persons who, as of March 31, 2010, are controlled by or who are under common control with the Registrant. For purposes of the Investment Company Act of 1940, as amended (the "1940 Act"), any person who owns directly or through one or more controlled companies more than 25% of the voting securities of a company is presumed to "control" such company. Each of the companies listed below is organized under the laws of the State of Delaware.

                                                                                   PERCENTAGE OF
                                     PERSON CONTROLLED BY OR UNDER COMMON CONTROL     VOTING
        FUND OR FUND CLASS                       WITH THE REGISTRANT                SECURITIES
------------------------------------ --------------------------------------------  -------------
     BlackRock Bond Index Fund              Bond Index Master Portfolio                 100%
                                                 400 Howard Street
                                              San Francisco, CA 94105

 LifePath(R) Retirement Portfolio       LifePath Retirement Master Portfolio            52%
                                                 400 Howard Street
                                              San Francisco, CA 94105

    LifePath 2020 Portfolio(R)             LifePath 2020 Master Portfolio               55%
                                                 400 Howard Street
                                              San Francisco, CA 94105

    LifePath 2030 Portfolio(R)             LifePath 2030 Master Portfolio               53%
                                                 400 Howard Street
                                              San Francisco, CA 94105

    LifePath 2040 Portfolio(R)             LifePath 2040 Master Portfolio               54%
                                                 400 Howard Street
                                              San Francisco, CA 94105

    LifePath(R) 2050 Portfolio             LifePath 2050 Master Portfolio               55%
                                                 400 Howard Street
                                              San Francisco, CA 94105

 BlackRock Cash Funds: Government     Government Money Market Master Portfolio          100%
                                                 400 Howard Street
                                              San Francisco, CA 94105

BlackRock Cash Funds: Institutional        Money Market Master Portfolio                95%
                                                 400 Howard Street
                                              San Francisco, CA 94105

    BlackRock Cash Funds: Prime         Prime Money Market Master Portfolio             88%
                                                 400 Howard Street
                                              San Francisco, CA 94105

  BlackRock Cash Funds: Treasury       Treasury Money Market Master Portfolio           100%


                    PERSON CONTROLLED BY OR UNDER COMMON CONTROL    PERCENTAGE OF
FUND OR FUND CLASS              WITH THE REGISTRANT               VOTING SECURITIES
------------------  --------------------------------------------  -----------------
                                 400 Howard Street
                              San Francisco, CA 94105

ITEM 30. INDEMNIFICATION.

Section 10.02 of the Registrant's Amended and Restated Agreement and Declaration of Trust provides:

(a) Subject to the exceptions and limitations contained in paragraph
(b) below: (i) every Person who is, or has been, a Trustee or officer of the Trust (hereinafter referred to as a "Covered Person") shall be indemnified by the Trust to the fullest extent permitted by law against liability and against all expenses reasonably incurred or paid by him in connection with any claim, action, suit, or proceeding in which he or she becomes involved as a party or otherwise by virtue of his being or having been a Trustee or officer and against amounts paid or incurred by him or her in the settlement thereof; and (ii) the words "claim," "action," "suit," or "proceeding" shall apply to all claims, actions, suits, or proceedings (civil, criminal, or other, including appeals), actual or threatened, while in office or thereafter, and the words "liability" and "expenses" shall include, without limitation, attorney's fees, costs, judgments, amounts paid in settlement, fines, penalties, and other liabilities.

(b) No indemnification shall be provided hereunder to a Covered Person:
(i) who shall have been adjudicated by a court or body before which the proceeding was brought (A) to be liable to the Trust or its Shareholders by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of his office or (B) not to have acted in good faith in the reasonable belief that his action was in the best interest of the Trust; or (ii) in the event of a settlement, unless there has been a determination that such Trustee or officer did not engage in willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of his office: (A) by the court or other body approving the settlement; (B) by at least a majority of those Trustees who neither are Interested Persons of the Trust nor are parties to the matter based upon a review of readily-available facts (as opposed to a full trial-type inquiry); or (C) by written opinion of independent legal counsel based upon a review of readily-available facts (as opposed to a full trial-type inquiry); provided, however, that any Shareholder, by appropriate legal proceedings, may challenge any such determination by the Trustees or by independent counsel.

(c) The rights of indemnification herein provided may be insured against by policies maintained by the Trust, shall be severable, shall not be exclusive of or affect any other rights to which any Covered Person may now or hereafter be entitled, shall continue as to a person who has ceased to be a Covered Person and shall inure to the benefit of the heirs, executors, and administrators of such a person. Nothing contained herein shall affect any rights to indemnification to which Trust personnel, other than Covered Persons, and other persons may be entitled by contract or otherwise under law.

(d) To the maximum extent permitted by applicable law, expenses in connection with the preparation and presentation of a defense to any claim, action, suit, or proceeding of the character described in paragraph (a) of this Section 10.02 may be paid by the Trust or Series from time to time prior to final disposition thereof upon receipt of an undertaking by or on behalf of such Covered Person that such amount will be repaid by such Covered Person to the Trust or Series if it ultimately is determined that he or she is not entitled to indemnification under this Section 10.02; provided, however, that either (i) such Covered Person shall have provided a surety bond or some other appropriate security for such undertaking;
(ii) the Trust or Series thereof is insured against losses arising out of any such advance payments, or (iii) either a majority of the Trustees who are neither Interested Persons of the Trust nor parties to the matter, or independent legal counsel in a written opinion, shall have determined, based upon a review of readily-available facts (as opposed to a trial-type inquiry or full investigation), that there is a reason to believe that such Covered Person will be entitled to indemnification under this Section 10.02. In connection with any determination pursuant to clause (iii) of the preceding sentence, any Covered Person who is a Trustee and is not an Interested Person of the Trust and any Covered Person who has been a Trustee and at such time was not an Interested Person of the Trust shall be entitled to a rebuttable presumption that he or she has not engaged in willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of his or her office.

ITEM 31. BUSINESS AND OTHER CONNECTIONS OF INVESTMENT ADVISER.

The Funds currently do not retain an investment adviser. MIP, in which a given Fund invests, is advised by BlackRock Fund Advisors ("BFA"), a wholly-owned subsidiary of BlackRock Institutional Trust Company, N.A. ("BTC"), located at 400 Howard Street, San Francisco, California 94105. BFA's business is that of a registered investment adviser to certain open-end, management investment companies and various other institutional investors.


The information required by this Item 31 about officers and directors of BFA, together with information as to any other business profession, vocation or employment of a substantial nature engaged in by such officers and directors during the past two years, is incorporated by reference to Schedule A and D of Form ADV, filed by BFA pursuant to the Investment Advisers Act of 1940, as amended (File No. 801-22609).

ITEM 32. PRINCIPAL UNDERWRITERS.

(a) SEI, the distributor for certain Funds, acts as a principal underwriter, distributor or investment adviser for each of the following investment companies (other than the Registrant):

SEI Daily Income Trust
SEI Liquid Asset Trust
SEI Tax Exempt Trust
SEI Institutional Managed Trust SEI Institutional International Trust The Advisors' Inner Circle Fund The Advisors' Inner Circle Fund II Bishop Street Funds
SEI Asset Allocation Trust
SEI Institutional Investments Trust Oak Associates Funds
CNI Charter Funds
iShares, Inc.
iShares Trust
Optique Funds, Inc.
Causeway Capital Management Trust SEI Opportunity Fund, LP
The Arbitrage Funds
The Turner Funds
ProShares Trust
Community Reinvestment Act Qualified Investment Fund SEI Alpha Strategy Portfolios, LP TD Asset Management USA Funds SEI Structured Credit Fund, LP Wilshire Mutual Funds, Inc. Wilshire Variable Insurance Trust Forward Funds
Global X Funds
Faith Shares Trust
Schwab Strategic Trust

SEI provides numerous financial services to investment managers, pension plan sponsors, and bank trust departments. These services include portfolio evaluation, performance measurement and consulting services ("Funds Evaluation") and automated execution, clearing and settlement of securities transactions ("MarketLink").

BRIL, the distributor of certain Funds, acts as the principal underwriter or placement agent, as applicable, for each of the following open-end registered investment companies including certain Funds of the Registrant:

BlackRock Balanced Capital Fund, Inc.          BlackRock Short-Term Bond Series, Inc.
BlackRock Basic Value Fund, Inc.               BlackRock Utilities and Telecommunications Fund, Inc.
BlackRock Bond Allocation Target Shares        BlackRock Value Opportunities Fund, Inc.
BlackRock Bond Fund, Inc.                      BlackRock Variable Series Funds, Inc.
BlackRock California Municipal Series Trust    BlackRock World Income Fund, Inc.
BlackRock Equity Dividend Fund                 CMA Government Securities Fund
BlackRock EuroFund                             CMA Money Fund
BlackRock Financial Institutions Series Trust  CMA Multi-State Municipal Series Trust
BlackRock Focus Growth Fund, Inc.              CMA Tax-Exempt Fund
BlackRock Focus Value Fund, Inc.               CMA Treasury Fund
BlackRock Fundamental Growth Fund, Inc.        FDP Series, Inc.
BlackRock Funds                                Funds for Institutions Series
BlackRock Funds II                             Global Financial Services Master LLC
BlackRock Funds III                            Managed Account Series


BlackRock Global Allocation Fund, Inc.              Master Basic Value LLC
BlackRock Global Dynamic Equity Fund                Master Bond LLC
BlackRock Global Emerging Markets Fund, Inc.        Master Focus Growth LLC
BlackRock Global Financial Services Fund, Inc.      Master Government Securities LLC
BlackRock Global Growth Fund., Inc.                 Master Institutional Money Market LLC
BlackRock Global SmallCap Fund, Inc.                Master Investment Portfolio
BlackRock Healthcare Fund, Inc.                     Master Large Cap Series LLC
BlackRock Index Funds, Inc.                         Master Money LLC
BlackRock International Value Trust                 Master Tax-Exempt LLC
BlackRock Large Cap Series Funds, Inc.              Master Treasury LLC
BlackRock Latin America Fund, Inc.                  Master Value Opportunities LLC
BlackRock Liquidity Funds                           Quantitative Master Series LLC
BlackRock Master LLC                                Ready Assets Prime Money Fund
BlackRock Mid Cap Value Opportunities Series, Inc.  Ready Assets U.S.A. Government Money Fund
BlackRock Multi-State Municipal Series Trust        Ready Assets U.S. Treasury Money Fund
BlackRock Municipal Bond Fund, Inc.                 Retirement Series Trust
BlackRock Municipal Series Trust                    Short-Term Bond Master LLC
BlackRock Natural Resources Trust                   WCMA Government Securities Fund
BlackRock Pacific Fund, Inc.                        WCMA Money Fund
BlackRock Principal Protected Trust                 WCMA Tax-Exempt Fund
BlackRock Series Fund, Inc.                         WCMA Treasury Fund
BlackRock Series, Inc.

BRIL also acts as the principal underwriter or placement agent, as applicable, for each of the following closed-end registered investment companies:

BlackRock Fixed Income Value Opportunities  BlackRock Senior Floating Rate Fund II, Inc.
BlackRock Senior Floating Rate Fund, Inc.   Master Senior Floating Rate LLC

(b) Set forth below is information with respect to each director, officer or partner of SEI. The business address of each director or officer is One Freedom Valley Drive, Oaks, PA 19456.

                                                                  Positions and
                                                                  Offices with
Name                Position and Office with SEI                   Registrant
----                ----------------------------                  -------------
William M. Doran    Director                                               None
Edward D. Loughlin  Director                                               None
Wayne M. Withrow    Director                                               None
Kevin Barr          President & Chief Executive Officer                    None
Maxine Chou         Chief Financial Officer, Chief Operations
                      Officer & Treasurer                                  None
John Munch          General Counsel & Secretary                            None
Karen LaTourette    Chief Compliance Officer, Anti-Money
                      Laundering Officer & Assistant Secretary             None
Mark J. Held        Senior Vice President                                  None
Lori L. White       Vice President & Assistant Secretary                   None
Robert Silvestri    Vice President                                         None
John Coary          Vice President & Assistant Secretary                   None
John Cronin         Vice President                                         None

Set forth below is information concerning each director and officer of BRIL. The principal business address for each such person is 40 East 52nd Street, New York, New York 10022.

                     Position(s) and Office(s) with   Position(s) and Office(s)
Name                 BRIL                             with Registrant
-------------------  -------------------------------  -------------------------
Laurence Fink        Chairman and Director                    None

Francis Porcelli     Chief Executive Officer and
                       Managing Director                      None

Anne Ackerley        Managing Director                        President
                                                              and Chief
                                                              Executive
                                                              Officer

Robert Connolly      General Counsel, Secretary and
                       Managing Director                      None

                     Position(s) and Office(s) with   Position(s) and Office(s)
Name                 BRIL                             with Registrant
-------------------  -------------------------------  -------------------------
Paul Greenberg       Treasurer, Chief Financial
                       Officer and Managing Director       None

Rick Froio           Chief Compliance Officer,
                       Assistant Secretary and
                       Director                            None

Brian Schmidt        Managing Director                     Vice President

Brenda Sklar         Managing Director                     None

Stephen Hart         Associate                             None

John Blevins         Assistant Secretary and
                       Managing Director                   None

Robert Kapito        Director                              None

Daniel Waltcher      Director                              None

(c) Not applicable.

ITEM 33. LOCATION OF ACCOUNTS AND RECORDS.

(a) The Registrant maintains accounts, books and other documents required by
Section 31(a) of the 1940 Act and the rules thereunder (collectively, "Records") at the offices of State Street Bank and Trust Company ("State Street"), 200 Clarendon Street, Boston, Massachusetts 02116.

(b) BFA and BTC maintain all Records relating to their services as adviser and administrator, respectively, to the MIP at 400 Howard Street, San Francisco, California 94105.

(c) SEI maintains all Records relating to its services as distributor of certain Funds at One Freedom Valley Drive, Oaks, Pennsylvania 19456.

(d) BRIL maintains all Records relating to its services as distributor of certain Funds at 40 East 52nd Street, New York, New York 10022.

(e) State Street maintains all Records relating to its services as sub-administrator, transfer agent of certain Funds and custodian at 200 Clarendon Street, Boston, Massachusetts 02116.

(f) PNC Global Investment Servicing (U.S.) Inc. maintains all Records relating to its services as transfer agent of certain Funds at 301 Bellevue Parkway, Wilmington, Delaware 19809.

ITEM 34. MANAGEMENT SERVICES.

Other than as set forth under the caption "Management" in the Statements of Additional Information constituting Part B of this Registration Statement, the Registrant is not a party to any management-related service contract.

ITEM 35. UNDERTAKINGS.

Not applicable. /1/ Prior to December 1, 2009, BlackRock Funds III was known as Barclays Global Investors Funds.
/2/ On July 2, 2007, State Street Corporation acquired Investors Financial Services Corporation, the parent company of IBT which provides sub-administrative, custodial and transfer agency services for the Funds. /3/ Prior to December 1, 2009, BlackRock Institutional Trust Company, N.A. was known as BGI.
/4/ Prior to December 1, 2009, BlackRock Fund Advisors was known as Barclays Global Fund Advisors.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended
("Securities Act"), and the 1940 Act, BlackRock Funds III (the "Registrant")
certifies that it meets all of the requirements for the effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act and duly caused this Post-Effective Amendment No. 88 to the Registration Statement on Form N-1A of the Registrant, to be signed on behalf of the Registrant by the undersigned, thereto duly authorized, in the City of New York, State of New York on the 30th day of April 2010.

BLACKROCK FUNDS III

By  /s/ Anne F. Ackerley
    -----------------------------------
    Anne F. Ackerley
    President and Chief Executive Officer
    (Chief Executive Officer)

Pursuant to the requirements of the Securities Act, this Post-Effective Amendment No. 88 to the Registration Statement on Form N-1A of the Registrant has been signed below by the following persons in the capacities and on the dates indicated:

     Signature                 Title                          Date
     ---------                 -----                          ----

     /s/ Anne F. Ackerley      President and Chief Executive  April 30, 2010
     ------------------------  Officer (Chief Executive
     Anne F. Ackerley          Officer)

     /s/ Neal J. Andrews                                      April 30, 2010
     ------------------------  Chief Financial Officer
     Neal J. Andrews

     Richard S. Davis*                                        April 30, 2010
     ------------------------  Trustee
     Richard S. Davis

     Henry Gabbay*                                            April 30, 2010
     ------------------------  Trustee
     Henry Gabbay

     David O. Beim*                                           April 30, 2010
     ------------------------  Trustee
     David O. Beim

     Ronald W. Forbes*                                        April 30, 2010
     ------------------------  Trustee
     Ronald W. Forbes

     Dr. Matina S. Horner*                                    April 30, 2010
     ------------------------  Trustee
     Dr. Matina S. Horner

     Rodney D. Johnson*                                       April 30, 2010
     ------------------------  Trustee
     Rodney D. Johnson

     Herbert I. London*                                       April 30, 2010
     ------------------------  Trustee
     Herbert I. London

     Cynthia A. Montgomery*                                   April 30, 2010
     ------------------------  Trustee
     Cynthia A. Montgomery

     Joseph P. Platt, Jr.*                                    April 30, 2010
     ------------------------  Trustee
     Joseph P. Platt, Jr.

     Robert C. Robb, Jr.*                                     April 30, 2010
     ------------------------  Trustee
     Robert C. Robb, Jr.

      Signature                 Title                          Date
      ---------                 -----                          ----

      Toby Rosenblatt*
      ------------------------  Trustee                        April 30, 2010
      Toby Rosenblatt

      Kenneth L. Urish*
      ------------------------  Trustee                        April 30, 2010
      Kenneth L. Urish

      Frederick W. Winter*
      ------------------------  Trustee                        April 30, 2010
      Frederick W. Winter

*By:  /s/ Edward B. Baer
      ------------------------                                 April 30, 2010
      Edward B. Baer
      (Attorney-in-Fact)
--------
*  As Attorney-in-Fact pursuant to the power of attorney, dated December 3,
   2009, as incorporated herein by reference to PEA No. 84.


SIGNATURES

This Registration Statement on Form N-1A of BlackRock Funds III (the "Registrant") contains certain disclosures regarding series of the Master Investment Portfolio (the "Trust"). The Trust has, subject to the next sentence, duly caused this Registration Statement on Form N-1A of the Registrant to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York and the State of New York on April 30, 2010. The Trust is executing this Registration Statement only in respect of the disclosures contained herein specifically describing the Trust and hereby disclaims any responsibility or liability as to any other disclosures in this Registration Statement.

MASTER INVESTMENT PORTFOLIO

By  /s/ Anne F. Ackerley
    -----------------------------------
    Anne F. Ackerley
    President and Chief Executive Officer
    (Chief Executive Officer)

This Registration Statement on Form N-1A of the Registrant has been signed below by the following persons, solely in the capacities indicated and subject to the next sentence on April 30, 2010. Each of the following persons is signing this Registration Statement only in respect of the disclosures contained herein specifically describing the Trust and hereby disclaims any responsibility or liability as to any other disclosures in this Registration Statement.

Signature                 Title                          Date
---------                 -----                          ----

/s/ Anne F. Ackerley      President and Chief Executive  April 30, 2010
------------------------  Officer (Chief Executive
Anne F. Ackerley          Officer)

/s/ Neal J. Andrews                                      April 30, 2010
------------------------  Chief Financial Officer
Neal J. Andrews

Richard S. Davis*                                        April 30, 2010
------------------------  Trustee
Richard S. Davis

Henry Gabbay*                                            April 30, 2010
------------------------  Trustee
Henry Gabbay

David O. Beim*                                           April 30, 2010
------------------------  Trustee
David O. Beim

Ronald W. Forbes*                                        April 30, 2010
------------------------  Trustee
Ronald W. Forbes

Dr. Matina S. Horner*                                    April 30, 2010
------------------------  Trustee
Dr. Matina S. Horner

Rodney D. Johnson*                                       April 30, 2010
------------------------  Trustee
Rodney D. Johnson

Herbert I. London*                                       April 30, 2010
------------------------  Trustee
Herbert I. London

Cynthia A. Montgomery*                                   April 30, 2010
------------------------  Trustee
Cynthia A. Montgomery

Joseph P. Platt, Jr.*                                    April 30, 2010
------------------------  Trustee
Joseph P. Platt, Jr.

Robert C. Robb, Jr.*                                     April 30, 2010
------------------------  Trustee
Robert C. Robb, Jr.


      Signature                 Title                          Date
      ---------                 -----                          ----

      Toby Rosenblatt*
      ------------------------  Trustee                        April 30, 2010
      Toby Rosenblatt

      Kenneth L. Urish*
      ------------------------  Trustee                        April 30, 2010
      Kenneth L. Urish

      Frederick W. Winter*
      ------------------------  Trustee                        April 30, 2010
      Frederick W. Winter

*By:  /s/ Edward B. Baer
      ------------------------                                 April 30, 2010
      Edward B. Baer
      (Attorney-in-Fact)


* As Attorney-in-Fact pursuant to the power of attorney, dated December 3, 2009, as incorporated herein by reference to PEA No. 84.

EXHIBIT INDEX

(a)(3) Restated Certificate of Trust.

(h)(29) Form of Administration Agreement between Registrant, with respect to the Funds set forth in Appendix A, and BlackRock Institutional Trust Company, N.A.

(h)(30) Form of Appendix A, to the Administration Agreement between Registrant and BlackRock Institutional Trust Company, N.A.

(i) Opinion and Consent of Counsel (Sidley Austin LLP).

(j) Consent of Independent Registered Public Accounting Firm (PricewaterhouseCoopers LLP).

(n)(1) Form of Amended and Restated Rule 18f-3 Multi-Class Plan.

(n)(2) Form of Appendix A to the Amended and Restated Rule 18f-3 Multi-Class Plan.


EXHIBIT (A)(3)

RESTATED
CERTIFICATE OF TRUST
OF
BARCLAYS GLOBAL INVESTORS FUNDS

This RESTATED CERTIFICATE OF TRUST of Barclay Global Investors Funds (the "Trust"), has been duly executed and is being filed on behalf of the Trust by the undersigned as trustee to amend and restate the Certificate of Trust of a statutory trust under the Delaware Statutory Trust Act (12 Del, C.
Section 3801 et seq .) (the "Act"). The original Certificate of Trust of the Trust, which was filed with the Secretary of State of the State Delaware on December 4, 2001, is hereby amended and restated as follows:

1. Name. The name of the statutory trust is BlackRock Funds III.

2. Registered Office; Registered Agent. The business address of the registered office of the Trust in the State of Delaware is c/o The Corporation Trust Company, Corporation Trust Center, 1209 Orange Street, Wilmington, New Castle County, Delaware 19801. The name of the Trust's registered agent at such address is The Corporation Trust Company.

3. Notice of Series. Notice is hereby given that the Trust shall consist of one or more series. Notice is given pursuant to Section 3804 of the Act that the debts, liabilities, obligations and expenses incurred, contracted for or otherwise existing with respect to a particular series of the Trust shall be enforceable against the assets of such series only, and not against the assets of the Trust generally or any other series thereof, and none of the debts, liabilities, obligations and expenses incurred, contracted for or otherwise existing with respect to the Trust generally or any other series thereof shall be enforceable against the assets of such series.

4. Investment Company. The trust is a registered investment company under the Investment Company Act of 1940, as amended.

5. Effective Date. This Restated Certificate of Trust shall be effective upon its filing with the Secretary of the State of Delaware.

IN WITNESS WHEREOF, the undersigned Trustee of Barclays Global Investors Funds has executed this Restated Certificate of Trust in accordance with
Section 3811(a)(2) of the Act.

  /s/ Ronald W. Forbes
-----------------------------
 Ronald W. Forbes,
 Trustee



Exhibit (h)(29)

ADMINISTRATION AGREEMENT

BLACKROCK FUNDS III
(FORMERLY BARCLAYS GLOBAL INVESTORS FUNDS)

________, 2010

BlackRock Institutional Trust Company, N.A. 45 Fremont Street
San Francisco, CA 94105

Ladies and Gentlemen:

This Administration Agreement is made as of the above date between BlackRock Funds III (formerly Barclays Global Investors Funds) (the "Trust"), on behalf of its series listed in the attached Appendix A, as such Appendix may be amended from time to time (collectively, the "Funds"), and BlackRock Institutional Trust Company, N.A. (formerly Barclays Global Investors, N.A.) ("BTC"). Absent written notification to the contrary by either the Trust or BTC, each new "lifepath" fund of the Trust established in the future shall automatically become a "Fund" for all purposes hereunder and shall be added to Appendix A with the Administration Fee specified for the Fund in the Trust's then effective registration statement filed under the Investment Company Act of 1940, as amended (the "Act"), and the Securities Act of 1933, as amended (the "Registration Statement").

The parties agree as follows:

1. Trust. The Trust is a registered open-end, management investment company. The Trust engages in the business of investing and reinvesting the assets of each Fund in the manner and in accordance with the applicable investment objective, policies and restrictions specified in the Trust's currently effective prospectuses and statements of additional information incorporated therein relating to the Funds and the Trust (such prospectuses and such statements of additional information being collectively referred to as the "Prospectuses") included in the Registration Statement, as amended from time to time. The Funds are feeder funds that invest all of their assets in corresponding master portfolios of other registered investment companies (each a "Master Trust") and, accordingly, the Trust has not engaged an adviser to manage the investing and reinvesting of the assets of such Funds.

2. Administrator. The Trust is engaging BTC to provide, or cause to be provided, the administrative services specified elsewhere in this Agreement, subject to the overall supervision of the Trust's Board of Trustees.

3. Administrative Services. BTC agrees, at its expense (a) to supervise the administrative operations and undertake to provide, or cause to be provided, the services described on Appendix B, as such Appendix may be amended from time to time by the mutual consent of the parties (the provision of, and liability for, certain of such services to be allocated

1

on such Appendix) in connection with the operations of the Trust and the Funds, including without limitation those functions that the Trust has authorized BTC, as its Administrator, to perform pursuant to the Funds' Shareholder Servicing Plan with respect to the Funds; (b) to take all reasonable action in the performance of its obligations under this Agreement to assure that the necessary information is made available to other service providers, as such may be required by the Trust from time to time; and (c) to provide all other administrative services reasonably necessary for the operation of the Funds, other than those services that are to be provided by the Trust's transfer and dividend disbursing agent and custodian.

4. Expenses Borne by Administrator. Except as otherwise provided in this Agreement, BTC agrees to bear all costs of the operations of each Fund, including but not limited to governmental fees; interest charges; fees and expenses of its legal counsel (other than as set forth below) and its transfer agent and dividend disbursing agent; fees paid to shareholder servicing, shareholder servicing and processing, and other special purpose agents; expenses of preparing and printing any stock certificates, prospectuses, statements of additional information, shareholders' reports, notices, proxy statements and reports to regulatory agencies; office supplies; premiums for fidelity bonds and errors and omissions and/or officers and trustees liability insurance; trade association membership dues; pricing services, if any; fees and expenses of any custodian and fund accountant, including those for keeping books and accounts and calculating the net asset value per share in the Funds; expenses of shareholders' meetings; expenses relating to the issuance, registration, qualification and redemption of shares of the Funds; and organizational expenses. Notwithstanding anything to the contrary in this Agreement (but subject to the proviso to the first sentence of paragraph 5 below), BTC shall not be required to bear (a) any portion of brokerage or other expenses connected with the execution of portfolio securities transactions for a Master Trust, (b) fees payable to the investment adviser under its advisory contract with a Master Trust, (c) distribution or service fees payable as a result of any distribution and service plan adopted by the Board of Trustees pursuant to Rule 12b-1 under the 1940 Act, (d) each Fund's pro rata portion of the compensation of the Trustees who are not "interested persons" (as defined in the Act) of the Trust ("Independent Trustees"), (e) travel expenses of the Independent Trustees in connection with their attendance at Board and other meetings relating to the Trust, (f) fees and expenses of legal counsel for the Independent Trustees, (g) fees and expenses of the Fund's independent auditors,
(h) litigation expenses (including counsel fees and expenses in connection with litigation), (i) taxes (including income, excise, transfer and withholding taxes), or (j) any other cost or expense that a majority of the Independent Trustees deems to be an extraordinary expense.

5. Administration Fees. In consideration of the administration services to be provided by BTC under this Agreement, the Trust shall pay BTC a monthly fee on behalf of each Fund on the first business day of each month at the applicable annual rates specified as a percentage of daily net assets on Appendix A attached to this Agreement, provided that the amount of the fee payable on behalf of such Fund shall be reduced by an amount equal to the amounts payable by such Fund for expenses described in paragraph 4(d), (e),
(f) and (g) above. If the fees payable to BTC under this paragraph begin to accrue after the beginning of any month or if this Agreement terminates before the end of any month, the fee for the period from the effective date to the end of the month or from the beginning of the month to the termination date, respectively, shall be prorated according to the proportion that the period bears to the full month in which the

2

effectiveness or termination occurs. For purposes of calculating each such monthly fee, the value of each Fund's net assets shall be computed in the manner specified in each Fund's Prospectus, as supplemented from time to time, for the computation of the value of the Fund's net assets in connection with the determination of the net asset value of a Fund's shares. For purposes of this Agreement, a "business day" is any day the Fund is open for business.

6. Standard of Care. BTC shall exercise reasonable care and shall give the Trust the benefit of its best judgment and efforts in rendering services under this Agreement. As an inducement to BTC's undertaking to render services hereunder, the Trust agrees that BTC shall not be liable under this Agreement for any mistake in judgment or in any other event whatsoever, provided that nothing in this Agreement shall be deemed to protect or purport to protect BTC against any liability to the Trust or its shareholders to which BTC would otherwise be subject by reason of willful misfeasance, bad faith or negligence in the performance of BTC's duties under this Agreement or by reason of reckless disregard of its obligations and duties hereunder.

7. Term, etc. This Agreement shall become effective on its execution date and shall remain in full force and effect for a period of two years or until terminated pursuant to the provisions of this paragraph, and it may be reapproved at least annually thereafter by the Trust's Board of Trustees, including a majority of the Independent Trustees who are not parties to this Agreement. This Agreement may be terminated at any time without payment of any penalty, upon 60 days' written notice, by vote of the Board of Trustees of the Trust or by BTC. BTC will cooperate with and assist the Trust, its agents and any successor administrator or administrators in any substitution/conversion process. This Agreement shall extend to and shall be binding upon the parties hereto and their respective successors and assigns; provided, however, that this Agreement shall not be assignable without the written consent of the other party.

8. Non-Exclusivity. Except to the extent necessary to perform BTC's obligations under this Agreement, nothing herein shall be deemed to limit or restrict the right of BTC, or any affiliate or employee of BTC, to engage in any other business or to devote time and attention to the management or other aspects of any other business, whether of a similar or dissimilar nature, or to render services of any kind to any other corporation, firm, individual or association.

9. Governing Law. This Agreement shall be governed by and construed in accordance with the laws of the State of Delaware.

10. Delegation. The Trust hereby agrees and acknowledges that BTC may delegate responsibility for any or all of the services to be provided hereunder to [State Street Bank & Trust Company] as sub-administrator or to other service providers, provided that BTC agrees to remain fully liable to the Trust for the provision of any service that BTC delegates to any co-administrator or sub-administrator.

11. Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but such counterpart shall, together, constitute only one instrument.

3

If the foregoing correctly sets forth the agreement between the Trust and BTC, please so indicate by signing and returning to the Trust the enclosed copy hereof.

Very truly yours,

BLACKROCK FUNDS III
on behalf of the funds listed in
Appendix A

By: -----------------------------
Name:
Title:

ACCEPTED as of the date
set forth above:

BLACKROCK INSTITUTIONAL TRUST COMPANY, N.A.

By: -------------------------
Name:
Title:

4

                                                                Exhibit (h)(30)
                                  Appendix A

                                     FEES

           FUNDS OF THE TRUST WITH CLASS,                 ADMINISTRATION FEE
                   IF APPLICABLE                        (AS % OF NET ASSETS)/1/
-----------------------------------------------------   ----------------------
LifePath Retirement Portfolio     Class I                        0.50
                                  Class A                        0.50
                                  Class C                        0.50
                                  Class R                        0.50
                                  Class S                        0.15

LifePath 2020 Portfolio           Class I                        0.50
                                  Class A                        0.50
                                  Class C                        0.50
                                  Class R                        0.50
                                  Class S                        0.15

LifePath 2030 Portfolio           Class I                        0.50
                                  Class A                        0.50
                                  Class C                        0.50
                                  Class R                        0.50
                                  Class S                        0.15

LifePath 2040 Portfolio           Class I                        0.50
                                  Class A                        0.50
                                  Class C                        0.50
                                  Class R                        0.50
                                  Class S                        0.15

LifePath 2050 Portfolio           Class I                        0.50
                                  Class A                        0.50
                                  Class C                        0.50
                                  Class R                        0.50
                                  Class S                        0.15

Approved by the Board of Trustees of BlackRock Funds III on February 22, 2010. /1/ Expenses attributable to one or more, but not all, of the Funds or share classes (such as shareholder servicing expenses) shall be charged against the assets of the relevant Funds or share classes. Because of the differences in the expenses attributable to one or more, but not all, of the share classes of a particular Fund, a Fund may have different administration fees for different share classes.

                                                                     Exhibit (i)

[LOGO] SIDLEY AUSTIN LLP    SIDLEY AUSTIN LLP    BEIJING        NEW YORK
       -----------------    787 SEVENTH AVENUE   BRUSSELS       PALO ALTO
       SIDLEY               NEW YORK, NY 10019   CHICAGO        SAN FRANCISCO
                            (212) 839 5300       DALLAS         SHANGHAI
                            (212) 839 5599 FAX   FRANKFURT      SINGAPORE
                                                 GENEVA         SYDNEY
                                                 HONG KONG      TOKYO
                                                 LONDON         WASHINGTON, D.C.
                                                 LOS ANGELES

                                                 FOUNDED 1866

                                 April 28, 2010

BlackRock Funds III
400 Howard Street
San Francisco, CA  94105

Ladies and Gentlemen:

We have acted as counsel for BlackRock Funds III, a statutory trust organized under the laws of the State of Delaware (the "Trust"), in connection with the filing of Post-Effective Amendment No. 88 to its Registration Statement on Form N-1A under the Securities Act of 1933, as amended (the "Securities Act"), and the Investment Company Act of 1940, as amended (the "Investment Company Act") (File Nos. 33-54126 and 811-07332) (the "Registration Statement"). Included in the Registration Statement are the series of the Trust and the classes of shares of beneficial interest into which such series are divided (the "Shares") as set forth on Exhibit A.

As counsel to the Trust, we are familiar with the proceedings taken by it in connection with the authorization, issuance and sale of the Shares in the manner referred to in the Registration Statement. In addition, we have examined and are familiar with the Agreement and Declaration of Trust of the Trust, as amended, the By-Laws of the Trust, as amended, and such other documents as we have deemed relevant to the matters referred to in this opinion.

Based upon the foregoing, we are of the opinion that the Shares, upon issuance and sale in accordance with the terms, conditions, requirements and procedures set forth in the Registration Statement, will be validly issued, fully paid and non-assessable beneficial interests in the Trust.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the use of our name in the prospectuses and statements of additional information constituting parts thereof.

Very truly yours

SIDLEY AUSTIN LLP

Sidley Austin LLP is a limited liability partnership practicing in affiliation with other Sidley Austin partnerships


                                    EXHIBIT A
                                    ---------

SERIES                                CLASS
---------------------------------     ------------------------------------------
BlackRock Cash Funds:                 Capital Shares
    Treasury                          Institutional Shares
                                      Premium Shares
                                      Select Shares
                                      SL Agency Shares
                                      Trust Shares

BlackRock Cash Funds:                 Institutional Shares
    Government                        Select Shares
                                      SL Agency Shares
                                      Trust Shares

BlackRock Cash Funds:                 AON Captives Shares
    Institutional                     Capital Shares
                                      Institutional Shares
                                      Premium Shares
                                      Select Shares
                                      SL Agency Shares
                                      Trust Shares

BlackRock Cash Funds:                 Capital Shares
    Prime                             Institutional Shares
                                      Premium Shares
                                      Select Shares
                                      SL Agency Shares
                                      Trust Shares

LifePath (R) Retirement Portfolio     Institutional
                                      Investor A
                                      Investor C
                                      Class R
                                      Class K

LifePath 2020 (R) Portfolio           Institutional
                                      Investor A
                                      Investor C
                                      Class R
                                      Class K

LifePath 2030 (R) Portfolio           Institutional
                                      Investor A
                                      Investor C
                                      Class R
                                      Class K

LifePath 2040 (R) Portfolio           Institutional
                                      Investor A
                                      Investor C
                                      Class R
                                      Class K

LifePath 2050 (R) Portfolio           Institutional
                                      Investor A
                                      Investor C
                                      Class R
                                      Class K

Bond Index Fund                       N/A

S&P 500 Stock Fund                    N/A


Exhibit (j)

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form N-1A of our reports dated February 24, 2010, relating to the financial statements and financial highlights which appear in the December 31, 2009 Annual Reports to Shareholders of the LifePath Retirement Portfolio, LifePath 2020 Portfolio, LifePath 2030 Portfolio, LifePath 2040 Portfolio, LifePath 2050 Portfolio, BlackRock Bond Index Fund, BlackRock Cash Funds:
Government, BlackRock Cash Funds: Institutional, BlackRock Cash Funds: Prime, BlackRock S&P 500 Stock Fund and BlackRock Cash Funds: Treasury, each a series of BlackRock Funds III, which are also incorporated by reference into the Registration Statement.

We also consent to the incorporation by reference in this Registration Statement on Form N-1A of our reports dated February 24, 2010, relating to the financial statements which appear in the December 31, 2009 Annual Reports to Interestholders of the Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, LifePath Retirement Master Portfolio, LifePath 2020 Master Portfolio, LifePath 2030 Master Portfolio, LifePath 2040 Master Portfolio, LifePath 2050 Master Portfolio, Bond Index Master Portfolio, Money Market Master Portfolio, Government Money Market Master Portfolio, Prime Money Market Master Portfolio, S&P 500 Stock Master Portfolio and Treasury Money Market Master Portfolio, each a portfolio of Master Investment Portfolio, which are also incorporated by reference into the Registration Statement.

We also consent to the references to us under the headings "Financial Highlights" and "Independent Registered Public Accounting Firm" in such Registration Statement.

PricewaterhouseCoopers LLP
San Francisco, California
April 29, 2010


Exhibit (n)(1)

BLACKROCK FUNDS III
AMENDED AND RESTATED
RULE 18F-3 MULTI-CLASS PLAN

I. Introduction.

Pursuant to Rule 18f-3 under the Investment Company Act of 1940, as amended (the "1940 Act"), this Amended and Restated Rule 18f-3 Multi-Class Plan (the "Plan") sets forth the method for allocating fees and expenses among each class of shares in the separate investment portfolios (the "Funds") of BlackRock Funds III (the "Trust"). In addition, the Plan sets forth the distribution fees, administration fees (including shareholder servicing fees and processing fees), minimum investments, maximum initial sales charges, contingent deferred sales charges ("CDSCs"), conversion features, exchange privileges and other features applicable to each class of shares of the Funds.

The Trust is an open-end series investment company registered under the 1940 Act, the shares of which are registered on Form N-lA under the Securities Act of 1933, as amended. The Trust hereby elects to offer multiple classes of shares of the Funds pursuant to the provisions of Rule 18f-3 and the Plan. Appendix A, as it may be amended from time to time, lists the Funds that have approved the Plan and the classes of each such Fund. Each such Fund that has authorized the issuance of multiple classes of shares is referred to as a "Multi-Class Fund" hereunder.

II. Allocation of Expenses.

A. MANDATORY CLASS EXPENSES. Pursuant to Rule 18f-3 under the 1940 Act, the Trust allocates to each class of shares of a Multi-Class Fund: (i) any fees and expenses incurred by the Multi-Class Fund in connection with the distribution or servicing of such class of shares under a distribution plan or services plan adopted for such class of shares pursuant to Rule 12b-l under the 1940 Act; and (ii) any fees and expenses under the Multi-Class Fund's shareholder servicing plan or its shareholder servicing and processing plan in connection with the provision of shareholder servicing and/or processing services to the holders of such class of shares (which fees and expenses are payable by BlackRock Institutional Trust Company, N.A., the Multi-Class Fund's administrator ("BTC"), pursuant to the Trust's Amended and Restated Administration Agreement with BTC, effective May 1, 2006, as amended, or with respect to the LifePath Portfolios (as defined in Appendix A), the Administration Agreement dated as of [ ], 2010 (each, an "Administration Agreement").

B. DISCRETIONARY CLASS EXPENSES. In addition, pursuant to Rule 18f-3, the Trust may allocate the following fees and expenses to a particular class of shares of a Multi-Class Fund:

(i) transfer agent fees identified by the transfer agent as being attributable to such class of shares;

(ii) printing and postage expenses related to preparing and distributing materials such as shareholder reports, notices, prospectuses, reports, and


proxies to current shareholders of that class or to regulatory agencies with respect to such class of shares;

(iii) blue sky notification or other filing fees incurred with respect to such class of shares;

(iv) Securities and Exchange Commission registration fees incurred with respect to such class of shares;

(v) the expense of administrative personnel and services (including, but not limited to, those of a portfolio accountant, custodian or dividend paying agent charged with calculating net asset values or determining or paying dividends) as required to support the shareholders of such class of shares;

(vi) litigation or other legal expenses incurred with respect to such class of shares;

(vii) fees of the Trust's Trustees incurred with respect to matters affecting such class of shares;

(viii) independent accountants' fees incurred with respect to such class of shares; and

(ix) any other fees and expenses, not including advisory or custodial fees or other expenses related to the management of the Multi-Class Fund's assets, incurred with respect to such class of shares.

For all purposes under this Plan, fees and expenses incurred "with respect to" a class of shares are those fees and expenses that are actually incurred in a different amount by the class or that relate to a different kind or degree of services provided to the class.

Notwithstanding any other provision of this Plan, the Trust, as contemplated by Subsection II.B, allocates to each class of shares of a Multi-Class Fund administration fees incurred pursuant to the Administration Agreement with respect to such class based on fees and expenses that are actually incurred in a different amount by the class or that relate to a different kind or degree of services provided to the class, as described in
Section III below.

C. RELATIVE NET ASSET VALUE ALLOCATION. Income, realized and unrealized capital gains and losses, and any expenses of a Multi-Class Fund not allocable to a particular class of the Multi-Class Fund pursuant to this Plan shall be allocated to each class of the Multi-Class Fund based upon the relative net asset value of that class in relation to the aggregate net asset value of the Multi-Class Fund.

D. WAIVERS AND REIMBURSEMENTS. In certain cases, a service provider for a Multi-Class Fund may waive or reimburse all or a portion of the expenses of a specific class of shares of the Multi-Class Fund. The Board of Trustees of the Trust will monitor any such waivers or reimbursements to ensure that they do not generate inappropriate cross-subsidization between classes.

III. Class Arrangements.

Appendix A summarizes the various features applicable to a particular class of shares of each Multi-Class Fund, including, where applicable, Rule 12b-l distribution fees, administration fees (including shareholder servicing fees and processing fees), investment minimums, maximum initial sales charges, CDSCs, conversion features and exchange privileges. In view of


the different scale and cost of meeting servicing demands for accounts that vary by size or type (e.g., retirement plans) and differing arrangements offered by intermediaries for different types of accounts (e.g., omnibus v. direct accounts), the administration fees (including shareholder servicing fees and processing fees) and minimum initial investments vary among the classes of the Multi-Class Funds. In addition, in view of the distribution arrangements applicable to certain classes of the Multi-Class Funds (e.g., distribution to the retirement market), those classes of the Multi-Class Funds are subject to 12b-l fees as set forth in Appendix A. Additional details and restrictions regarding such fees, features, services and distribution arrangements are set forth in the relevant Multi-Class Fund's current Prospectus and Statement of Additional Information. Except as set forth in this Plan or, with respect to voting, in the Trust's Declaration of Trust, each class of shares of a Multi-Class Fund will have the same relative rights and privileges and be subject to the same fees and expenses.

IV. Board Review.

The Board of Trustees of the Trust shall review the Plan as it deems necessary. Prior to any material amendment(s) to the Plan with respect to any Multi-Class Fund's shares, the Trust's Board of Trustees, including a majority of the Trustees that are not "interested persons" of the Trust (as defined in the 1940 Act), shall find that the Plan, as proposed to be amended (including any proposed amendments to the method of allocating class and/or fund expenses), is in the best interest of each class of shares of the Multi-Class Fund individually and the Multi-Class Fund as a whole. In considering whether to approve any proposed amendment(s) to the Plan, the Trustees of the Trust shall request and evaluate such information as they consider reasonably necessary to evaluate the proposed amendment(s) to the Plan.

Amended and approved by the Board of Trustees of BlackRock Funds III on February 22, 2010.


Exhibit (n)(2)

APPENDIX A

                                                                                                                       CONVERSION
                                                                 MAXIMUM       MAXIMUM                    MAXIMUM      FEATURES/
BLACKROCK FUNDS III                  MAXIMUM  ADMINISTRATION   SHAREHOLDER    PROCESSING   MINIMUM     INITIAL SALES    EXCHANGE
MULTI-CLASS MONEY MARKET FUNDS      12B-1 FEE      FEE       SERVICING FEE/1/   FEE/1/    INVESTMENT    CHARGE/CDSC    PRIVILEGES
----------------------------------  --------- -------------- ---------------  ---------- ------------ ---------------  ----------
a.   INSTITUTIONAL MONEY MARKET
     FUND
     Aon Captives Share Class         0.10%        0.05%          0.05%          None      $500,000        None           None
     Institutional Class              None         0.05%          0.05%          None    $100 million      None           None
     Capital Share Class              None         0.07%          0.07%          None    $25 million       None           None
     Premium Class                    None         0.10%          0.10%          None    $10 million       None           None
     Select Class                     None         0.15%          0.15%          None     $1 million       None           None
     SL Agency Share Class            None         0.02%          None           None       N/A/2/         None           None
     Trust Class                      None         0.38%          0.25%          0.13%     $100,000        None           None

b.   PRIME MONEY MARKET FUND
     Institutional Class              None         0.05%          0.05%          None    $100 million      None           None
     Capital Share Class              None         0.07%          0.07%          None    $25 million       None           None
     Premium Class                    None         0.10%          0.10%          None    $10 million       None           None
     Select Class                     None         0.15%          0.15%          None     $1 million       None           None
     SL Agency Share Class            None         0.02%          None           None       N/A/2/         None           None
     Trust Class                      None         0.38%          0.25%          0.13%     $100,000        None           None

c.   GOVERNMENT MONEY MARKET FUND
     Institutional Class              None         0.05%          0.05%          None    $100 million      None           None
     Capital Share Class              None         0.07%          0.07%          None    $25 million       None           None
     Premium Class                    None         0.10%          0.10%          None    $10 million       None           None
     Select Class                     None         0.15%          0.15%          None     $1 million       None           None
     SL Agency Share Class            None         0.02%          None           None       N/A/2/         None           None
     Trust Class                      None         0.38%          0.25%          0.13%     $100,000        None           None

d.   TREASURY MONEY MARKET FUND
     Institutional Class              None         0.05%          0.05%          None    $100 million      None           None
     Capital Share Class              None         0.07%          0.07%          None    $25 million       None           None
     Premium Class                    None         0.10%          0.10%          None    $10 million       None           None
     Select Class                     None         0.15%          0.15%          None     $1 million       None           None
     SL Agency Share Class            None         0.02%          None           None       N/A/2/         None           None
     Trust Class                      None         0.38%          0.25%          0.13%     $100,000        None           None


/1/ All shareholder servicing fees and processing fees will be paid by the Funds' administrator; so shareholders will not bear any of these fees in addition to the administration fee.
/2/ Although the Class SL Agency shares do not have a minimum investment, they shall only be made available to clients of BlackRock Fund Advisors and its affiliates for the investment of securities lending collateral.

SHARE CLASSES OF THE LIFEPATH PORTFOLIOS

Each of LifePath Retirement Portfolio, LifePath 2020 Portfolio, LifePath 2030 Portfolio, LifePath 2040 Portfolio and LifePath 2050 Portfolio (collectively, the "LifePath Portfolios") may offer any of the following classes of shares:
Class A Shares, Class C Shares, Class I Shares, Class R Shares, and Class K Shares. The different classes of the LifePath Portfolios are differentiated as follows:

CLASS A SHARES

Class A Shares shall be available for purchase through securities brokers, dealers or financial institutions or through the Fund's transfer agent, subject to restrictions described in their prospectus.

Class A Shares shall be subject to a front-end sales charge at the rates (and subject to the reductions and exemptions) described in their prospectus. When the aggregate offering price of Class A Shares of the


LifePath Portfolios purchased by an investor qualifies the investor to purchase such shares without paying a front-end sales charge, a contingent deferred sales charge may be imposed at the rates (and subject to the reductions and exemptions) described in the prospectus.

Class A Shares of a LifePath Portfolio shall bear the expense of distribution, shareholder servicing and administration fees described in the prospectus, if any.

Distribution fees shall be payable to the Fund's distributor and/or to BlackRock Fund Advisors or any other affiliate of PNC Bank, National Association or Merrill Lynch & Co., Inc. (collectively, "BlackRock Advisors") primarily: (i) to compensate the distributor for distribution and sales support services and to reimburse the distributor for related expenses, including payments to brokers, dealers, other financial institutions or other industry professionals (collectively, "Selling Agents") for sales support services; and
(ii) to compensate BlackRock Advisors for sales support services and to reimburse BlackRock Advisors for related expenses, including payments to Selling Agents for sales support services. The Fund's distributor, BlackRock Advisors and other parties may each make payments without limitation as to amount in connection with distribution or sales support activities relating to A Shares out of its past profits or any additional sources (other than distribution fees) which are available to it.

Shareholder servicing fees shall be payable to brokers, dealers, other financial institutions or other industry professionals (including BlackRock Advisors) (collectively, "Service Agents") for general shareholder liaison services.

Administration fees shall be payable to the Fund's administrator for supervising the Fund's administrative operations and providing certain other administrative services reasonably necessary for the operation of the Fund. The Fund's administrator may also pay third parties to provide such services.

CLASS C SHARES

Class C Shares shall be available for purchase through securities brokers, dealers or financial institutions or through the Fund's transfer agent, subject to restrictions described in their prospectus. Class C Shares of the LifePath Portfolios generally shall be subject to a contingent deferred sales charge at the rates (and subject to the reductions and exemptions) described in their prospectus.

Class C Shares of a LifePath Portfolio shall bear the expense of distribution, shareholder servicing and administration fees described in the prospectus, if any.

Distribution fees shall be payable to the Fund's distributor and/or to BlackRock Advisors primarily: (i) to compensate the distributor for distribution and sales support services and to reimburse the distributor for related expenses, including payments to Selling Agents for sales support services; and (ii) to compensate BlackRock Advisors for sales support services and to reimburse BlackRock Advisors for related expenses, including payments to Selling Agents for sales support services. The Fund's distributor, BlackRock Advisors and other parties may each make payments without limitation as to amount in connection with distribution or sales support activities relating to C Shares out of its past profits or any additional sources (other than distribution fees) which are available to it.

Shareholder servicing fees shall be payable to Service Agents for general shareholder liaison services.

Administration fees shall be payable to the Fund's administrator for supervising the Fund's administrative operations and providing certain other administrative services reasonably necessary for the operation of the Fund. The Fund's administrator may also pay third parties to provide such services.

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CLASS I SHARES

Class I Shares shall be available from the distributor for purchase by institutional investors, individuals, registered investment advisers and others meeting certain minimum investment and other requirements described in the prospectus. Class I Shares shall not be subject to a sales charge or a separate fee payable pursuant to any distribution plan or shareholder servicing plan. The Fund's distributor, BlackRock Advisors and other parties may each make payments without limitation as to amount in connection with distribution or sales support activities relating to Class I Shares out of its past profits or any sources which are available to it.

Class I Shares shall bear the expense of administration fees described in the prospectus, if any. Administration fees shall be payable to the Fund's administrator for supervising the Fund's administrative operations and providing certain other administrative services reasonably necessary for the operation of the Fund. The Fund's administrator may also pay third parties to provide such services.

CLASS R SHARES

Class R Shares shall be available for purchase only through certain retirement plans, subject to restrictions described in their prospectus. Class R Shares of a Portfolio shall not be subject to a sales charge.

Class R Shares of a Portfolio shall bear the expense of distribution, shareholder servicing and administration fees described in the prospectus, if any.

Distribution fees shall be payable to the Fund's distributor and/or to BlackRock Advisors primarily: (i) to compensate the distributor for distribution and sales support services and to reimburse the distributor for related expenses, including payments to Selling Agents for sales support services; and (ii) to compensate BlackRock Advisors for sales support services and to reimburse BlackRock Advisors for related expenses, including payments to Selling Agents for sales support services. The Fund's distributor, BlackRock Advisors and other parties may each make payments without limitation as to amount in connection with distribution or sales support activities relating to R Shares out of its past profits or any additional sources (other than distribution fees) which are available to it.

Shareholder servicing fees shall be payable to Service Agents for general shareholder liaison services.

Administration fees shall be payable to the Fund's administrator for supervising the Fund's administrative operations and providing certain other administrative services reasonably necessary for the operation of the Fund. The Fund's administrator may also pay third parties to provide such services.

CLASS K SHARES

Class K shares shall be available only to (i) qualified recordkeepers with a distribution and/or fund servicing agreement (establishing an omnibus trading relationship) maintained with the Funds' distributor, (ii) defined benefit plans, defined contribution plans, endowments and foundations with greater than $100 million in a qualified tax-exempt plan, and (iii) employers with greater than $100 million in the aggregate between qualified and non- qualified plans that they sponsor.

Class K shares are not subject to sales charges or distribution fees.

Amended and approved by the Board of Trustees of BlackRock Funds III on February 22, 2010.

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