About Your Investment

Buying Shares from a Registered Investment Professional

B lackRock Funds believes that investors can benefit from the advice and ongoing assistance of a registered investment professional. Accordingly, when you buy or sell BlackRock Funds Investor A Shares, you may pay a sales charge, which is used to compensate your investment professional for services provided to you. An investment professional who is compensated for selling shares may receive a different amount for each class.

As a shareholder you pay certain fees and expenses. Shareholder fees are paid directly from your investment and annual fund operating expenses are paid out of fund assets and are reflected in the fund’s net asset value.

Your registered representative can help you to buy shares by telephone. Before you place your order make sure that you have read the Prospectus and have a discussion with your registered representative about the details of your investment.

What Price Per Share Will You Pay?

T he price of mutual fund shares generally changes every day the New York Stock Exchange (NYSE) is open (business day). A mutual fund is a pool of investors’ money that is used to purchase a portfolio of securities, which in turn is owned in common by the investors. Investors put money into a mutual fund by buying shares. If a mutual fund has a portfolio worth $50 million and has 5 million shares outstanding, the net asset value (NAV) per share is $10. When you buy Investor A Shares you pay the NAV per share plus the applicable front-end sales charge.

PFPC Inc. (PFPC), the Fund’s transfer agent, will probably receive your order from your registered representative, who takes your order. However, you can also fill out a purchase application and mail it to the transfer agent with your check. Please call (800) 441-7762 for a purchase application. Purchase orders received by the transfer agent before the close of regular trading on the NYSE (currently 4 p.m. (Eastern time)) on each day the NYSE is open will be priced based on the NAV calculated at the close of trading on that day plus any applicable sales charge. NAV is calculated separately for each class of shares of the fund as of the close of business on the NYSE, generally 4 p.m. (Eastern time), each day the NYSE is open. Shares will not be priced on days the NYSE is closed. Purchase orders received after the close of trading will be priced based on the next calculation of NAV. Non-U.S. securities and certain other securities held by the fund may trade on days

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when the NYSE is closed. In these cases, net asset value of shares may change when fund shares cannot be bought or sold.

Since the NAV changes daily, the price of your shares depends on the time that your order is received by the Fund’s transfer agent, whose job it is to keep track of shareholder records.

The fund’s assets are valued primarily on the basis of market quotations. Certain short-term debt securities are valued on the basis of amortized cost. When a determination is made that market quotations are not readily available, including, but not limited to, when (i) the exchange or market on which a security is traded does not open for trading for an entire trading day and no other market prices are available, (ii) a particular security does not trade regularly or has had its trading halted, (iii) a security does not have a price source due to its lack of liquidity, (iv) BlackRock believes a market quotation from a broker-dealer is unreliable (e.g., where it varies significantly from a recent trade), (v) the security is thinly traded or (vi) there has been a significant subsequent event, the fund values the affected securities at fair value as determined by BlackRock pursuant to procedures adopted by the Fund’s Board of Trustees. For example, the fund will value a security that trades principally on a foreign market using the most recent closing market price from the market on which the security principally trades, unless, in BlackRock’s judgment, a significant event subsequent to the market close has rendered such market closing price unreliable. Because significant events could affect the value of a foreign security between the close of the foreign market where the security is principally traded and the time the fund calculates its NAV, such closing price may not be reflective of current market conditions. In this case, the fund will use what it believes to be the fair value of the security as of the time the fund calculates its NAV.

Fair value represents a good faith approximation of the value of a security. A security’s valuation may differ depending on the method used for determining value. Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. The fair value of one or more securities may not, in retrospect, be the prices at which those assets could have been sold during the period in which the particular fair values were used in determining the fund’s NAV. As a result, the fund’s sale or redemption of its shares at NAV, at a time when a holding or holdings are valued at

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fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

When Must You Pay?

P ayment for an order must be made in Federal funds or other immediately available funds by the time specified by your registered representative or other financial intermediary, but in no event later than 4 p.m. (Eastern time) on the third business day following PFPC’s receipt of the order. If payment is not received by this time, the order will be cancelled and you and your registered representative or other financial intermediary will be responsible for any loss to the Fund. For shares purchased directly from the transfer agent, 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 transfer agent to purchase shares, but you must call the Fund at (800) 441-7762 before doing so to confirm the wiring instructions.

To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions, including the Fund, to obtain, verify and record information that identifies each person who opens an account. When opening an account, you will be asked for your name, address, date of birth and other information that will allow the Fund to identify you. The Fund may also ask to see other identifying documents such as a driver’s license (for individuals) or Articles of Incorporation or other formation documents (for institutions). The Fund may use a third party to obtain and verify this information. The Fund may not be able to establish an account, or it may close your existing account and/or redeem your shares involuntarily, if you do not provide sufficient information within the relevant time periods.

How Much is the Minimum Investment?

T he minimum investment for the initial purchase of Investor A Shares is $1,000. The Fund permits a lower initial investment for employees of the Fund or one of its service providers and through certain fee-based programs, retirement plans and the Automatic Investment Plan (AIP) in which shareholders make regular, periodic investments through a savings or checking account. See “Automatic Investment Plan” below.

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There is a $50 minimum for all subsequent investments, subject to certain exclusions.

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

Which Pricing Option Should You Choose?

B lackRock Funds offers different pricing options to investors in the form of different share classes. Your registered representative can help you decide which option works best for you.

Investor A Shares (Front-End Load)

A portion of the front-end sales charge on Investor A Shares is reallowed to your registered representative, as described in the SAI. Please contact your registered representative for details about compensation he or she receives for selling you shares of the Fund. To receive information about sales charges and payments to registered representatives free of charge, please see the SAI or go to www.blackrock.com/funds .

How Much is the Sales Charge?

T he table below shows the schedules of sales charges that you may pay if you buy and sell Investor A Shares of the fund.

Purchase of Investor A Shares

T he 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

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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). Additionally, the front-end sales charge can be reduced or eliminated through one or a combination of the following: the right of accumulation, a Letter of Intent, the reinstatement privilege, quantity discounts or a waiver of the sales charge (described below). In order to receive a reduction in your Investor A sales charge, you must contact your financial adviser or the Fund at the time of your purchase to let them know that you qualify for such a reduction. If you do not notify your financial adviser or the Fund, you may not receive the sales charge to which you are otherwise entitled.

The following schedule of front-end sales charges and quantity discounts applies to the Long Duration Bond Portfolio.

The Fund’s distributor retains .25% of the sales charge on all purchases of Investor A Shares. When an investor purchases Investor A Shares directly from the Fund (and not through a broker), the distributor retains the entire front-end sales charge.

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Can the Sales Charge be Reduced or Eliminated?

T here 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 “Purchase of Investor A Shares” section). Additionally, the front-end sales charge can be reduced or eliminated through one or a combination of the following: the right of accumulation, a Letter of Intent, the reinstatement privilege, quantity discounts or a waiver of the sales charge (described below). You may be required to provide PFPC and/or your registered representative with certain records and information in connection with the exercise of these rights, including information or records regarding shares of the fund held (i) in other accounts at your registered representative, (ii) at any other financial intermediary and (iii) at any financial intermediary by your related parties, such as members of your family or household. For more information, see the SAI or contact your investment professional.

Right of Accumulation

I nvestors have a “right of accumulation” under which the current value of an investor’s existing Investor A, A1, B, B1, B2, C, C1, C2 and Institutional Shares in most BlackRock funds 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. Service Organizations 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 Service Organization will be treated similarly. In order to use this right, the investor must alert PFPC to the existence of any previously purchased shares.

Letter of Intent

A n 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, B, C or Institutional Shares in one or more 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 PFPC, and the investor must tell PFPC that later purchases are subject to the Letter of Intent. During the term of

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the Letter of Intent, PFPC 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, PFPC will redeem enough of the Investor A Shares held in escrow to pay the difference.

Reinstatement Privilege

U pon redemption of Institutional and Investor A, A1, B, B1, B2, C, C1 and C2 Shares, shareholders may reinvest their redemption proceeds (after paying any applicable CDSC or redemption fee) in Investor A Shares of the SAME fund without paying a front-end sales charge. This right may be exercised once a year and within 60 days of the redemption, provided that the 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 NAV calculated at the close of trading on the day the request is received. To exercise this privilege, PFPC must receive written notification from the shareholder of record or the registered representative of record, at the time of purchase. Investors should consult a tax adviser concerning the tax consequences of exercising this reinstatement privilege.

Quantity Discounts

I n addition to quantity discounts for individuals which we discussed above, there are ways for you to qualify for breakpoints and therefore reduce the front-end sales charge by combining your order with the orders of (a) your spouse and any of your children under the age of 21, or (b) a trustee or fiduciary of a single trust estate or single fiduciary account. All orders must be placed at one time and certain restrictions apply. Investors must tell PFPC or their broker, at the time of purchase, that they are aggregating their purchases. For more information, please contact the Fund at (800) 441-7762 or see the SAI.

Waiving the Sales Charge

T he following investors may buy Investor A Shares without paying a front-end sales charge: (a) authorized qualified employee benefit plans or savings plans and rollovers of current investments in the Fund through such plans; (b) persons investing

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through an authorized payroll deduction plan; (c) persons investing through an authorized investment plan for organizations which operate under Section 501(c)(3) of the Internal Revenue Code; (d) registered investment advisers, trust companies and bank trust departments exercising discretionary investment authority with respect to amounts to be invested in the fund; (e) persons participating in selected fee-based programs 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; and (f) employees of MetLife. Investors who qualify for any of these exemptions from the sales charge must purchase Investor A Shares. Additionally, some people associated with the Fund and its service providers may buy Investor A Shares without paying a sales charge. The front-end sales charge is not applied on Investor A Shares acquired through the reinvestment of dividends or distributions. There is no initial sales charge on purchases of $1,000,000 or more of Investor A Shares; however, you may pay a CDSC as described in “Purchase of Investor A Shares.” The applicable CDSC on Investor A Shares is not charged in connection with: (a) redemptions of Investor A Shares purchased through authorized qualified employee benefit plans or savings plans and rollovers of current investments in the Fund through such plans; (b) exchanges described in “Exchange Privilege” below; (c) redemptions made in connection with minimum required distributions due to the shareholder reaching age 70  ¹ / 2 from IRA and 403(b)(7) accounts; (d) redemptions made with respect to certain retirement plans sponsored by the Fund, BlackRock or its affiliates; (e) redemptions (i) within one year of a shareholder’s death or, if later, the receipt of a certified probate settlement (including in connection with the distribution of account assets to a beneficiary of the decedent) or (ii) in connection with a shareholder’s disability (as defined in the Internal Revenue Code) subsequent to the purchase of Investor A Shares; (f) involuntary redemptions of Investor A Shares in accounts with low balances; (g) certain redemptions made pursuant to the Systematic Withdrawal Plan (described below); (h) redemptions related to the payment of PFPC custodial IRA fees; and (i) redemptions when a shareholder can demonstrate hardship, in the absolute discretion of the Fund. For more information on the waivers, please contact the Fund at (800) 441-7762 or see the SAI.

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Distribution and Service Plan

T he Fund has adopted a plan (the Plan) that allows the Fund to pay distribution fees for the sale of its shares under Rule 12b-1 of the Investment Company Act and shareholder servicing fees for certain services provided to its shareholders. Investor A Shares do not pay a distribution fee.

Under the Plan, the Fund pays shareholder servicing fees to brokers, dealers, financial institutions and industry professionals (including BlackRock, PNC Bank, Merrill Lynch & Co., Inc. (Merrill Lynch) and their affiliates) (Service Organizations) whereby the Service Organizations provide support services to their customers who own Investor A Shares in return for these fees. The Fund may pay a shareholder servicing fee of up to .25% per year of the average daily net asset value of Investor A Shares of the fund. All Investor A Shares pay this shareholder servicing fee.

In return for the shareholder servicing fee, Service Organizations (including BlackRock) may provide one or more of the following services to their customers who own Investor A Shares:

The shareholder servicing fees payable pursuant to the Plan are fees payable for the administration and servicing of shareholder accounts and 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 Fund assets on an on-going basis, over time these fees will increase the cost of your investment.

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For more information on the Plan including a complete list of services provided thereunder, see the SAI.

In addition to, rather than in lieu of, distribution and shareholder servicing fees that the Fund may pay to a Service Organization pursuant to the Plan and fees the Fund pays to its transfer agent, the Fund may enter into non-Plan agreements with Service Organizations pursuant to which the Fund will pay a Service Organization 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 Service Organization or (2) a fixed dollar amount for each account serviced by a Service Organization. The aggregate amount of these payments may be substantial.

The Plan permits BlackRock, 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 Fund). From time to time, BlackRock, 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. BlackRock, the Distributor and their affiliates may compensate affiliated and unaffiliated Service Organizations for the sale and distribution of shares of the Fund or 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 Service Organization, or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization. The aggregate amount of these payments by BlackRock, the Distributor and their affiliates may be substantial. Payments by BlackRock 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 Service Organization, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Service Organization for details about payments it may receive from the Fund or from BlackRock, the Distributor or their affiliates. For more information, see the SAI.

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Selling Shares

Y ou can redeem shares at any time. The Fund will redeem your shares at the next NAV calculated after your order is received by the fund’s transfer agent minus any applicable CDSC and/or redemption fee. Each of the CDSC and redemption fee is assessed without regard to the other. See “Market Timing and Redemption Fees” below. Shares may be redeemed by sending a written redemption request to BlackRock Funds, c/o PFPC Inc., P.O. Box 9819, Providence, RI 02940-8019. Shares may also be redeemed by telephone request by calling (800) 441-7762. Redemption proceeds may be paid by check or, if the Fund has verified banking information on file, through the Automated Clearing House Network (ACH) or by wire transfer. Redemption requests in excess of $100,000 (for checks) and $250,000 (for ACH and wire transfers) must be in writing with a medallion signature guarantee. Shares may also be redeemed by use of the Fund’s automated voice response unit service (VRU). Payment for shares redeemed by VRU or Internet may be made for non-retirement accounts in amounts up to $25,000, either through check, ACH or wire. You will be charged a fee of $7.50 for each redemption payment made by wire transfer and $15 for redemptions by check sent via overnight mail.

You can also make redemption requests through your registered investment professional, who may charge for this service.

Unless another option is requested, payment for redeemed shares is normally made by check mailed within seven days after PFPC receives the redemption request. If the shares to be redeemed have been recently purchased by check, PFPC may delay the payment of redemption proceeds for up to 10 business days after the purchase date until the check has cleared.

Market Timing and Redemption Fees

T he Board of Trustees of the Fund has 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. The exchange privilege for Investor, Institutional and R Shares 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

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an adverse effect on the performance of a 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 NAV 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 “What Price Per Share Will You Pay?” above.

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 Board of Trustees has approved the policies discussed below to seek to deter market timing activity. The Board has not adopted any specific numerical restrictions on purchases, sales and exchanges of fund shares because legitimate strategies, such as asset allocation, dollar cost averaging or similar activities, may result in frequent trading of fund shares. It is not expected that shareholders would be harmed by such legitimate activities.

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

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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 are not 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 funds. 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.

Each of the Fund’s High Yield Bond, International Bond, Aurora, Small/Mid-Cap Growth, Small Cap Value Equity, Small Cap Core Equity, Small Cap Growth Equity, Health Sciences Opportunities, Global Science & Technology Opportunities, Global Resources, All-Cap Global Resources, Global Opportunities, International Opportunities and U.S. Opportunities Portfolios will automatically assess and retain a fee of 2% of the current NAV, 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). A new 30-day period begins with each acquisition of shares through a purchase or exchange. For example, a series of transactions in which shares of Portfolio A are exchanged for shares of Portfolio B 20 days after the purchase of the Portfolio A shares, followed in 20 days by an exchange of the Portfolio B shares for shares of Portfolio C, will be subject to two redemption fees (one on each exchange).

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The redemption fee is for the benefit of the remaining shareholders of a fund and is intended to encourage long-term investment, to compensate for transaction and other expenses caused by early redemptions and exchanges, and to facilitate portfolio management. The “first-in, first-out” method is used to determine the holding period. Under this method, the date of redemption or exchange will be compared with the earliest purchase date of shares held in the account. The Fund sells shares to some 401(k) plans, 403(b) plans, bank or trust company accounts, and accounts of certain financial institutions or intermediaries that do not apply the redemption fee to underlying shareholders, often because of administrative or systems limitations. From time to time, with the approval of the Fund, the redemption fee will not be assessed on redemptions or exchanges by: (i) accounts of asset allocation programs or wrap programs whose trading practices are determined by the Fund not to be detrimental to a fund or long-term shareholders ( e.g. , model driven programs with periodic automatic portfolio rebalancing that prohibit participant-directed trading and other programs with similar characteristics); (ii) accounts of shareholders who have died or become disabled; (iii) shareholders redeeming or exchanging shares through the Fund’s Systematic Withdrawal Plan, Systematic Exchange Plan or in connection with required distributions from an IRA, 401(k) plan, 403(b) plan or any other Internal Revenue Code Section 401 qualified retirement plan or account, or distribution from a 529 plan; (iv) shareholders executing rollovers of current investments in the Fund through qualified employee benefit plans; and (v) certain other accounts in the absolute discretion of the Fund when a shareholder can demonstrate hardship. The Fund reserves the right to modify or eliminate these waivers at any time.

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.

Expedited Redemptions

I f a shareholder has given authorization for expedited redemption, shares can be redeemed by telephone and the proceeds sent by check to the shareholder or by Federal wire

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transfer to a single previously designated bank account. Shareholders will pay $15 for redemption proceeds sent by check via overnight mail and $7.50 for redemption proceeds sent by Federal wire transfer. You are responsible for any additional charges imposed by your bank for this service. Once authorization for expedited redemptions is on file, the Fund will honor requests by telephone at (800) 441-7762. The Fund is not responsible for the efficiency of the Federal wire system or the shareholder’s firm or bank. The Fund may refuse a telephone redemption request if it believes it is advisable to do so and may use reasonable procedures to make sure telephone instructions are genuine. The Fund and its service providers will not be liable for any loss that results from acting upon telephone instructions that they reasonably believed to be genuine in accordance with those procedures. The Fund may alter the terms of or terminate this expedited redemption privilege at any time for any reason.

The Fund's Rights

T he Fund may:

Accounts with Low Balances

T he Fund may redeem a shareholder’s account in the fund at any time if the net asset value of the account in the fund falls below $500 as the result of a redemption or an exchange request. This minimum does not apply to accounts of authorized qualified employee benefit plans, selected fee-based programs and accounts established under the Uniform Gifts to Minors or Uniform Transfers to Minors Acts. The shareholder will be notified in writing that the value of the account is less than the required

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amount and the shareholder will be allowed 60 days to make additional investments before the redemption is processed.

Purchases and Redemptions

Call your registered representative or (800) 441-7762.

World Wide Web

Access general fund information and specific fund

performance, including SAI and annual/semi-annual reports, free of charge. Request mutual fund prospectuses and literature. Forward mutual fund inquiries. www.blackrock.com/funds

Written Correspondence

BlackRock Funds

c/o PFPC Inc.

PO Box 9819

Providence, RI 02940-8019

Overnight Mail

BlackRock Funds

c/o PFPC Inc.

101 Sabin Street

Pawtucket, RI 02860

Internal Wholesalers/Broker Dealer Support

Available to support investment professionals

8:30 a.m. to 6:00 p.m. (Eastern time), Monday-Friday.

Call: (800) 882-0052.

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) 441-7762.

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 Web site (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 Section of the SEC, Washington, D.C. 20549.

INVESTMENT COMPANY ACT FILE NO. 811-05742

PRO-LG-INV 1006

BlackRock Funds

Long Duration Bond Portfolio

Institutional Shares

Prospectus

October 13, 2006

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.

How to Find the

Information You Need

About BlackRock Funds

T his is the BlackRock Long Duration Bond Portfolio (Institutional Shares) Prospectus. It has been written to provide you with the information you need to make an informed decision about whether to invest in BlackRock Funds (the Fund). The Fund’s investment adviser is BlackRock Advisors, LLC (BlackRock).

This Prospectus contains information on the Long Duration Bond Portfolio (Institutional Shares). The Prospectus has been organized so that the fund has a short section with important fund facts. Also included are sections that tell you about buying and selling shares, certain fees and expenses, shareholder features of the fund and your rights as a shareholder.

If you have questions after reading the Prospectus, ask your registered representative for assistance. Your investment professional has been trained to help you decide which investments are right for you.

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BlackRock

Long Duration Bond Portfolio

IMPORTANT DEFINITIONS

Asset-Backed Securities: Bonds that are backed by a pool of assets, usually loans such as installment sale contracts or credit card receivables.

Bonds: Debt obligations such as bonds and debentures, U.S. Government securities, debt obligations of domestic and non-U.S. corporations, debt obligations of non-U.S. governments and their political subdivisions, asset-backed securities, various mortgage-backed securities (both residential and commercial), other floating or variable rate obligations, municipal obligations and zero coupon debt securities.

Collateralized Mortgage Obligations (CMO): Bonds that are backed by cash flows from pools of mortgages. CMOs may have multiple classes with different payment rights and protections.

Commercial Mortgage-Backed Securities (CMBS): Bonds that are backed by a mortgage loan or pools of loans secured by commercial property, not residential mortgages.

Credit Default Swaps: In entering into a credit default swap, one party would pay a counterparty a periodic stream of payments over the term of the contract, provided that no event of default on a specific bond has occurred. In return, upon any event of default on such bond, the first party would receive from the counterparty a payment equal to the par (or other agreed-upon) value of such bond.

Dollar Rolls: A dollar roll transaction involves a sale by the fund of a mortgage-backed or other security concurrently with an agreement by the fund to repurchase a similar security at a later date at an agreed-upon price. The securities that are repurchased will bear the same interest rate and stated maturity as those sold, but pools of mortgages collateralizing those securities may have different prepayment histories than those sold.

About Your Investment

Buying Shares

I nstitutional Shares are offered without a sales charge to:

Purchase orders may be placed by calling (800) 441-7762.

Investors who currently own Institutional Shares of the fund may make additional purchases of Institutional Shares of the fund except for investors holding shares through certain client accounts at financial intermediaries that are omnibus with the Fund and do not meet applicable minimums.

What Price Per Share Will You Pay?

T he price of mutual fund shares generally changes every day the New York Stock Exchange (NYSE) is open (business day). A mutual fund is a pool of investors’ money that is used to purchase a portfolio of securities, which in turn is owned in common by the investors. Investors put money into a mutual fund by buying shares. If a mutual fund has a portfolio worth $50 million and has 5 million shares outstanding, the net asset value (NAV) per share is $10.

Purchase orders received by the close of regular trading on the NYSE (currently 4 p.m. (Eastern time)) on each day the NYSE is open will be priced based on the NAV calculated at the close of trading on that day. NAV is calculated separately for each class of shares of the fund as of the close of business on the NYSE, generally 4 p.m. (Eastern time), each day the NYSE is open.

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Shares will not be priced on days the NYSE is closed. Purchase orders received after the close of trading will be priced based on the next calculation of NAV. Non-U.S. securities and certain other securities held by the fund may trade on days when the NYSE is closed. In these cases, net asset value of shares may change when fund shares cannot be bought or sold.

Since the NAV changes daily, the price of your shares depends on the time that your order is received.

The fund’s assets are valued primarily on the basis of market quotations. Certain short-term debt securities are valued on the basis of amortized cost. When a determination is made that market quotations are not readily available, including, but not limited to, when (i) the exchange or market on which a security is traded does not open for trading for an entire trading day and no other market prices are available, (ii) a particular security does not trade regularly or has had its trading halted, (iii) a security does not have a price source due to its lack of liquidity, (iv) BlackRock believes a market quotation from a broker-dealer is unreliable (e.g., where it varies significantly from a recent trade), (v) the security is thinly traded or (vi) there has been a significant subsequent event, the fund values the affected securities at fair value as determined by BlackRock pursuant to procedures adopted by the Fund’s Board of Trustees. For example, the fund will value a security that trades principally on a foreign market using the most recent closing market price from the market on which the security principally trades, unless, in BlackRock’s judgment, a significant event subsequent to the market close has rendered such market closing price unreliable. Because significant events could affect the value of a foreign security between the close of the foreign market where the security is principally traded and the time the fund calculates its NAV, such closing price may not be reflective of current market conditions. In this case, the fund will use what it believes to be the fair value of the security as of the time the fund calculates its NAV.

Fair value represents a good faith approximation of the value of a security. A security’s valuation may differ depending on the method used for determining value. Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. The fair value of one or more securities may not, in retrospect, be the prices at which those assets could have been sold during the period in which the particular fair values were used in determining the

9

fund’s NAV. As a result, the fund’s sale or redemption of its shares at NAV, 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.

Certain financial institutions may buy and sell Institutional Shares on behalf of their customers. The institutions may charge a fee for this service and may impose additional conditions on owning fund shares. Shareholders should contact their institutions for more information.

Paying for Shares

P ayment for Institutional Shares must normally be made in Federal funds or other funds immediately available by 4 p.m. (Eastern time) on the first business day following receipt of the order. Payment may also, at the discretion of the Fund, be made in the form of securities that are permissible investments for the fund. If payment is not received by this time, you will be responsible for any loss to the Fund.

To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions, including the Fund, to obtain, verify and record information that identifies each person who opens an account. When opening an account, you will be asked for your name, address, date of birth and other information that will allow the Fund to identify you. The Fund may also ask to see other identifying documents such as a driver’s license (for individuals) or Articles of Incorporation or other formation documents (for institutions). The Fund may use a third party to obtain and verify this information. The Fund may not be able to establish an account, or it may close your existing account and/or redeem your shares involuntarily, if you do not provide sufficient information within the relevant time periods.

How Much is the Minimum Investment?

T he minimum investment for the initial purchase of Institutional Shares is:

The Fund has lower investment minimums for other categories of shareholders eligible to purchase Institutional Shares, including selected fee-based programs, as set forth in the “Buying Shares” section.

The Fund does not accept third party checks as payment for shares.

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The Fund may permit a lower initial investment for certain investors if their purchase, combined with purchases by other investors received together by the Fund, meets the minimum investment requirement. The Fund may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholder and suspend and resume the sale of any share class of the fund at any time for any reason.

Distribution and Service Plan

T he Fund has adopted a plan (the Plan) that allows the Fund to pay distribution fees for the sale of its shares under Rule 12b-1 of the Investment Company Act and shareholder servicing fees for certain services provided to its shareholders.

In accordance with the Plan, Institutional shares currently do not make such payments. The Fund, however, may enter into non-Plan agreements with brokers, dealers, financial institutions and industry professionals (including PNC Bank, Merrill Lynch & Co., Inc. (Merrill Lynch), BlackRock and their affiliates) (Service Organizations) pursuant to which the Fund will pay a Service Organization for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan payments are in addition to, rather than in lieu of, fees the Fund pays to its transfer agent and are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Service Organization or (2) a fixed dollar amount for each account serviced by a Service Organization. The aggregate amount of these payments may be substantial.

The Plan permits BlackRock, BlackRock Distributors, Inc. (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 Fund). From time to time, BlackRock, 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. BlackRock, the Distributor and their affiliates may compensate affiliated and unaffiliated Service Organizations for the sale and distribution of shares of the Fund or for these other services to the Fund and shareholders. These payments may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Service Organization, or may be based on a percentage of the value of shares sold to, or held by, customers of the Service

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Organization. The aggregate amount of these payments by BlackRock, the Distributor and their affiliates may be substantial. Payments by BlackRock 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 Service Organization, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Service Organization for details about payments it may receive from the Fund or from BlackRock, the Distributor or their affiliates. For more information, see the SAI.

Selling Shares

S hareholders may place redemption orders by telephoning (800) 441-7762. Shares are redeemed at the NAV per share next determined after receipt of the redemption order, minus any applicable redemption fee. See “Market Timing and Redemption Fees” below. The Fund, its administrators 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.

Payment for redeemed shares for which a redemption order is received before 4 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 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 judgement of the Fund, an earlier payment could adversely affect the fund. No charge for wiring redemption payments is imposed by the Fund.

During periods of substantial economic or market change, telephone redemptions may be difficult to complete. Redemption requests may also be mailed to BlackRock Funds, c/o PFPC Inc., P.O. Box 9819, Providence, RI 02940.

The Fund is not responsible for the efficiency of the Federal wire system or the shareholder’s firm or bank. The Fund does not currently charge for wire transfers. The shareholder is responsible

12

for any charges imposed by the shareholder’s 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 BlackRock Funds, c/o PFPC Inc., P.O. Box 9819, Providence, RI 02940.

The Fund may refuse a telephone redemption request if it believes it is advisable to do so.

Market Timing and Redemption Fees

T he Board of Trustees of the Fund has 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. The exchange privilege for Investor, Institutional and R Shares 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 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 NAV 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 “What Price Per Share Will You Pay?” above.

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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 Board of Trustees has approved the policies discussed below to seek to deter market timing activity. The Board has not adopted any specific numerical restrictions on purchases, sales and exchanges of fund shares because legitimate strategies, such as asset allocation, dollar cost averaging or similar activities, may result in frequent trading of fund shares. It is not expected that shareholders would be harmed by such legitimate activities.

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 are not 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. 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.

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Each of the Fund’s High Yield Bond, International Bond, Aurora, Small/Mid-Cap Growth, Small Cap Value Equity, Small Cap Core Equity, Small Cap Growth Equity, Health Sciences Opportunities, Global Science & Technology Opportunities, Global Resources, All-Cap Global Resources, U.S. Opportunities, Global Opportunities and International Opportunities Portfolios will automatically assess and retain a fee of 2% of the current NAV, 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). A new 30-day period begins with each acquisition of shares through a purchase or exchange. For example, a series of transactions in which shares of Portfolio A are exchanged for shares of Portfolio B 20 days after the purchase of the Portfolio A shares, followed in 20 days by an exchange of the Portfolio B shares for shares of Portfolio C, will be subject to two redemption fees (one on each exchange).

The redemption fee is for the benefit of the remaining shareholders of a fund and is intended to encourage long-term investment, to compensate for transaction and other expenses caused by early redemptions and exchanges, and to facilitate portfolio management. The “first-in, first-out” method is used to determine the holding period. Under this method, the date of redemption or exchange will be compared with the earliest purchase date of shares held in the account. The Fund sells shares to some 401(k) plans, 403(b) plans, bank or trust company accounts, and accounts of certain financial institutions or intermediaries that do not apply the redemption fee to underlying shareholders, often because of administrative or systems limitations. From time to time, with the approval of the Fund, the redemption fee will not be assessed on redemptions or exchanges by: (i) accounts of asset allocation programs or wrap programs whose trading practices are determined by the Fund not to be detrimental to a fund or long-term shareholders ( e.g. , model driven programs with periodic automatic portfolio rebalancing that prohibit participant-directed trading and other programs with similar characteristics); (ii) accounts of shareholders who have died or become disabled; (iii) shareholders redeeming or exchanging shares through the Fund’s Systematic Withdrawal Plan, Systematic Exchange Plan or in connection with required distributions from an IRA, 401(k) plan, 403(b) plan or any other Internal Revenue Code Section 401 qualified retirement plan or account, or distribution from a 529 plan; (iv) shareholders executing rollovers of current investments in the Fund through qualified employee benefit plans; and (v) certain other accounts in

15

the absolute discretion of the Fund when a shareholder can demonstrate hardship. The Fund reserves the right to modify or eliminate these waivers at any time.

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.

The Fund's Rights

T he Fund may:

Accounts with Low Balances

T he Fund may redeem a shareholder’s account in the fund at any time if the net asset value of the account in the fund falls below the required minimum investment as the result of a

redemption or exchange request. The shareholder will be notified in writing that the value of the account is less than the required amount and the shareholder will be allowed 60 days to make additional investments before the redemption is processed.

Statements

E very shareholder automatically receives quarterly account statements. In addition, for tax purposes, shareholders also receive a yearly statement describing the characteristics of any dividends or other distributions received.

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IMPORTANT DEFINITIONS

Adviser: The adviser of a mutual fund is responsible for the overall investment management of the fund. The adviser for BlackRock Funds is BlackRock Advisors, LLC.

Sub-Adviser: The sub-adviser of a fund is responsible for its day-to-day management and will generally make all buy and sell decisions. Sub-advisers also provide research and credit analysis. The sub-adviser for the fund is BlackRock Financial Management, Inc.

Purchases and Redemptions

Call your registered representative or (800) 441-7762.

World Wide Web

Access general fund information and specific fund

performance, including SAI and annual/semi-annual reports, free of charge. Request mutual fund prospectuses and literature. Forward mutual fund inquiries. www.blackrock.com/funds

Written Correspondence

BlackRock Funds

c/o PFPC Inc.

PO Box 9819

Providence, RI 02940-8019

Overnight Mail

BlackRock Funds

c/o PFPC Inc.

101 Sabin Street

Pawtucket, RI 02860

Internal Wholesalers/Broker Dealer Support

Available to support investment professionals

8:30 a.m. to 6:00 p.m. (Eastern time), Monday-Friday.

Call: (800) 882-0052

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 Web site (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 Section of the SEC, Washington, D.C. 20549.

INVESTMENT COMPANY ACT FILE NO. 811-05742

PRO-LG- I 1006

BlackRock Funds

Long Duration Bond Portfolio

BlackRock Shares

Prospectus

October 13, 2006

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.

How to Find the

Information You Need

About BlackRock Funds

T his is the BlackRock Long Duration Bond Portfolio (BlackRock Shares) Prospectus. It has been written to provide you with the information you need to make an informed decision about whether to invest in BlackRock Funds (the Fund). The Fund’s investment adviser is BlackRock Advisors, LLC (BlackRock).

This Prospectus contains information on the Long Duration Bond Portfolio (BlackRock Shares). The Prospectus has been organized so that the fund has a short section with important fund facts. Also included are sections that tell you about buying and selling shares, certain fees and expenses, shareholder features of the fund and your rights as a shareholder.

1

BlackRock

Long Duration Bond Portfolio

IMPORTANT DEFINITIONS

Asset-Backed Securities: Bonds that are backed by a pool of assets, usually loans such as installment sale contracts or credit card receivables.

Bonds: Debt obligations such as bonds and debentures, U.S. Government securities, debt obligations of domestic and non-U.S. corporations, debt obligations of non-U.S. governments and their political subdivisions, asset-backed securities, various mortgage-backed securities (both residential and commercial), other floating or variable rate obligations, municipal obligations and zero coupon debt securities.

Collateralized Mortgage Obligations (CMO): Bonds that are backed by cash flows from pools of mortgages. CMOs may have multiple classes with different payment rights and protections.

Commercial Mortgage-Backed Securities (CMBS): Bonds that are backed by a mortgage loan or pools of loans secured by commercial property, not residential mortgages.

Credit Default Swaps: In entering into a credit default swap, one party would pay a counterparty a periodic stream of payments over the term of the contract, provided that no event of default on a specific bond has occurred. In return, upon any event of default on such bond, the first party would receive from the counterparty a payment equal to the par (or other agreed-upon) value of such bond.

Dollar Rolls: A dollar roll transaction involves a sale by the fund of a mortgage-backed or other security concurrently with an agreement by the fund to repurchase a similar security at a later date at an agreed-upon price. The securities that are repurchased will bear the same interest rate and stated maturity as those sold, but pools of mortgages collateralizing those securities may have different prepayment histories than those sold.

About Your Investment

Buying Shares

B lackRock Shares are offered without a sales charge to institutional investors, registered investment advisers and certain fee-based programs.

Purchase orders may be placed by calling (800) 441-7762.

Price Per Share

T he price of mutual fund shares generally changes every day the New York Stock Exchange (NYSE) is open (business day). A mutual fund is a pool of investors’ money that is used to purchase a portfolio of securities, which in turn is owned in common by the investors. Investors put money into a mutual fund by buying shares. If a mutual fund has a portfolio worth $50 million and has 5 million shares outstanding, the net asset value (NAV) per share is $10.

Purchase orders received before the close of regular trading on the NYSE (currently 4 p.m. (Eastern time)) on each day the NYSE is open will be priced based on the NAV calculated at the close of trading on that day. NAV is calculated separately for each class of shares of the fund as of the close of business on the NYSE, generally 4 p.m. (Eastern time), each day the NYSE is open. Shares will not be priced on days the NYSE is closed. Purchase orders received after the close of trading will be priced based on the next calculation of NAV. Non-U.S. securities and certain other securities held by the fund may trade on days when the NYSE is closed. In these cases, net asset value of shares may change when fund shares cannot be bought or sold.

Since the NAV changes daily, the price of your shares depends on the time that your order is received.

The fund’s assets are valued primarily on the basis of market quotations. Certain short-term debt securities are valued on the basis of amortized cost. When a determination is made that market quotations are not readily available, including, but not limited to, when (i) the exchange or market on which a security is traded does not open for trading for an entire trading day and no other market prices are available, (ii) a particular security does not trade regularly or has had its trading halted, (iii) a security does not have a price source due to its lack of liquidity, (iv) BlackRock believes a market quotation from a broker-dealer is unreliable (e.g., where it varies significantly from a recent trade), (v) the security is thinly traded or (vi) there has been a significant subsequent event, the fund values the affected securities at fair

8

value as determined by BlackRock pursuant to procedures adopted by the Fund’s Board of Trustees. For example, the fund will value a security that trades principally on a foreign market using the most recent closing market price from the market on which the security principally trades, unless, in BlackRock’s judgment, a significant event subsequent to the market close has rendered such market closing price unreliable. Because significant events could affect the value of a foreign security between the close of the foreign market where the security is principally traded and the time the fund calculates its NAV, such closing price may not be reflective of current market conditions. In this case, the fund will use what it believes to be the fair value of the security as of the time the fund calculates its NAV.

Fair value represents a good faith approximation of the value of a security. A security’s valuation may differ depending on the method used for determining value. Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. The fair value of one or more securities may not, in retrospect, be the prices at which those assets could have been sold during the period in which the particular fair values were used in determining the fund’s NAV. As a result, a fund’s sale or redemption of its shares at NAV, 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.

Certain financial institutions may buy and sell BlackRock Shares on behalf of their customers. The institutions may charge a fee for this service and may impose additional conditions on owning fund shares. Shareholders should contact their institutions for more information.

Paying for Shares

P ayment for BlackRock Shares must normally be made in Federal funds or other funds immediately available by 4 p.m. (Eastern time) on the first business day following receipt of the order. Payment may also, at the discretion of the Fund, be made in the form of securities that are permissible investments for the respective fund. If payment is not received by this time, you will be responsible for any loss to the Fund.

To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions,

9

including the Fund, to obtain, verify and record information that identifies each person who opens an account. When opening an account, you will be asked for your name, address, date of birth and other information that will allow the Fund to identify you. The Fund may also ask to see other identifying documents such as a driver’s license (for individuals) or Articles of Incorporation or other formation documents (for institutions). The Fund may use a third party to obtain and verify this information. The Fund may not be able to establish an account, or it may close your existing account and/or redeem your shares involuntarily, if you do not provide sufficient information within the relevant time periods.

How Much is the Minimum Investment?

T he minimum investment for the initial purchase of BlackRock Shares is generally $5,000,000. The minimum initial investment for registered investment advisers is $250,000, and there is no minimum initial investment requirement for fee-based programs with an annual fee of at least .50%. There is no minimum requirement for later investments. The Fund does not accept third party checks as payment for shares.

The Fund may permit a lower initial investment for certain investors if their purchase, combined with purchases by other investors received together by the Fund, meets the minimum investment requirement. The Fund may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholder and suspend and resume the sale of any share class of the fund at any time for any reason.

Distribution and Service Plan

T he Fund has adopted a plan (the Plan) that allows the Fund to pay distribution fees for the sale of its shares under Rule 12b-1 of the Investment Company Act and shareholder servicing fees for certain services provided to its shareholders.

In accordance with the Plan, with the exception of the Small Cap Value Equity Portfolio, BlackRock shares currently do not make such payments. The Fund, however, may enter into non-Plan agreements with brokers, dealers, financial institutions and industry professionals (including PNC Bank, Merrill Lynch & Co., Inc. (Merrill Lynch), BlackRock and their affiliates) (Service Organizations) pursuant to which the Fund will pay a Service Organization for administrative, networking, recordkeeping, sub-transfer agency and shareholder services. These non-Plan

10

payments are in addition to, rather than in lieu of, fees the Fund pays to its transfer agent and are generally based on either (1) a percentage of the average daily net assets of Fund shareholders serviced by a Service Organization or (2) a fixed dollar amount for each account serviced by a Service Organization. The aggregate amount of these payments may be substantial.

The Plan permits BlackRock, BlackRock Distributors, Inc. (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 Fund). From time to time, BlackRock, 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. BlackRock, the Distributor and their affiliates may compensate affiliated and unaffiliated Service Organizations for the sale and distribution of shares of the Fund or for these other services to the Fund and shareholders. These payments may be a fixed dollar amount, may be based on the number of customer accounts maintained by the Service Organization, or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization. The aggregate amount of these payments by BlackRock, the Distributor and their affiliates may be substantial. Payments by BlackRock 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 Service Organization, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Service Organization for details about payments it may receive from the Fund or from BlackRock, the Distributor or their affiliates. For more information, see the SAI.

Selling Shares

S hareholders may place redemption orders by telephoning (800) 441-7762. Shares are redeemed at the NAV per share next determined after receipt of the redemption order, minus any applicable redemption fee. See “Market Timing and Redemption Fees” below. The Fund, its administrators 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

11

for acting upon telephone instructions that are reasonably believed to be genuine in accordance with such procedures.

Payment for redeemed shares for which a redemption order is received before 4 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 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 judgement of the Fund, an earlier payment could adversely affect the fund. No charge for wiring redemption payments is imposed by the Fund.

During periods of substantial economic or market change, telephone redemptions may be difficult to complete. Redemption requests may also be mailed to BlackRock Funds, c/o PFPC, Inc., P.O. Box 9819, Providence, RI 02940.

The Fund may refuse a telephone redemption request if it believes it is advisable to do so.

Market Timing and Redemption/Exchange Fees

T he Board of Trustees of the Fund has 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. The exchange privilege for Investor, Institutional and R Shares 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 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

12

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 NAV 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 “What Price Per Share Will You Pay?” above.

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 Board of Trustees has approved the policies discussed below to seek to deter market timing activity. The Board has not adopted any specific numerical restrictions on purchases, sales and exchanges of fund shares because legitimate strategies, such as asset allocation, dollar cost averaging or similar activities, may result in frequent trading of fund shares. It is not expected that shareholders would be harmed by such legitimate activities.

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

13

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 are not 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. 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.

Each of the Fund’s High Yield Bond, International Bond, Aurora, Small/Mid-Cap Growth, Small Cap Value Equity, Small Cap Core Equity, Small Cap Growth Equity, Health Sciences Opportunities, Global Science & Technology Opportunities, Global Resources, All-Cap Global Resources, U.S. Opportunities, Global Opportunities and International Opportunities Portfolios will automatically assess and retain a fee of 2% of the current NAV, 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). A new 30-day period begins with each acquisition of shares through a purchase or exchange. For example, a series of transactions in which shares of Portfolio A are exchanged for shares of Portfolio B 20 days after the purchase of the Portfolio A shares, followed in 20 days by an exchange of the Portfolio B shares for shares of Portfolio C, will be subject to two redemption fees (one on each exchange).

The redemption fee is for the benefit of the remaining shareholders of a fund and is intended to encourage long-term investment, to compensate for transaction and other expenses caused by early redemptions and exchanges, and to facilitate portfolio management. The “first-in, first-out” method is used to determine the holding period. Under this method, the date of

14

redemption or exchange will be compared with the earliest purchase date of shares held in the account. The Fund sells shares to some 401(k) plans, 403(b) plans, bank or trust company accounts, and accounts of certain financial institutions or intermediaries that do not apply the redemption fee to underlying shareholders, often because of administrative or systems limitations. From time to time, with the approval of the Fund, the redemption fee will not be assessed on redemptions or exchanges by: (i) accounts of asset allocation programs or wrap programs whose trading practices are determined by the Fund not to be detrimental to a fund or long-term shareholders ( e.g. , model driven programs with periodic automatic portfolio rebalancing that prohibit participant-directed trading and other programs with similar characteristics); (ii) accounts of shareholders who have died or become disabled; (iii) shareholders redeeming or exchanging shares through the Fund’s Systematic Withdrawal Plan, Systematic Exchange Plan or in connection with required distributions from an IRA, 401(k) plan, 403(b) plan, or any other Internal Revenue Code Section 401 qualified retirement plan or account, or distribution from a 529 plan; (iv) shareholders executing rollovers of current investments in the Fund through qualified employee benefit plans; and (v) certain other accounts in the absolute discretion of the Fund when a shareholder can demonstrate hardship. The Fund reserves the right to modify or eliminate these waivers at any time.

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.

The Fund's Rights

T he Fund may:

15

Accounts with Low Balances

T he Fund may redeem a shareholder’s account in the fund at any time the net asset value of the account in the fund falls below the applicable minimum initial investment as the result of a redemption. The shareholder will be notified in writing that the value of the account is less than the required amount and the shareholder will be allowed 60 days to make additional investments before the redemption is processed.

Statements

E very shareholder automatically receives quarterly account statements. In addition, for tax purposes, shareholders also receive a yearly statement describing the characteristics of any dividends or other distributions received.

About Your Investment

Buying Shares

R Shares are available only to certain authorized qualified employee benefit plans. If you buy 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 shareholder servicing fee of 0.25% per year.

What Price Per Share Will You Pay?

T he price of mutual fund shares generally changes every day the New York Stock Exchange (NYSE) is open (business day). A mutual fund is a pool of investors’ money that is used to purchase a portfolio of securities, which in turn is owned in common by the investors. Investors put money into a mutual fund by buying shares. If a mutual fund has a portfolio worth $50 million and has 5 million shares outstanding, the net asset value (NAV) per share is $10. When you buy R Shares you pay the NAV per share.

Purchase orders received by the close of regular trading on the NYSE (currently 4 p.m. (Eastern time)) on each day the NYSE is open will be priced based on the NAV calculated at the close of trading on that day. NAV is calculated separately for each class of shares of the fund as of the close of business on the NYSE, generally 4 p.m. (Eastern time), each day the NYSE is open. Shares will not be priced on days the NYSE is closed. Purchase orders received after the close of trading will be priced based on the next calculation of NAV. The non-U.S. securities and certain other securities held by the fund may trade on days when the NYSE is closed. In these cases, net asset value of shares may change when fund shares cannot be bought or sold.

Since the NAV changes daily, the price you pay for your shares depends on the time that your order is received by the Fund’s transfer agent, whose job it is to keep track of shareholder records.

The fund’s assets are valued primarily on the basis of market quotations. Certain short-term debt securities are valued on the basis of amortized cost. When a determination is made that market quotations are not readily available, including, but not limited to, when (i) the exchange or market on which a security is traded does not open for trading for an entire trading day and no other market prices are available, (ii) a particular security does not trade regularly or has had its trading halted, (iii) a security does not have a price source due to its lack of liquidity, (iv) BlackRock

9

believes a market quotation from a broker-dealer is unreliable (e.g., where it varies significantly from a recent trade), (v) the security is thinly traded or (vi) there has been a significant subsequent event, the fund values the affected securities at fair value as determined by BlackRock pursuant to procedures adopted by the Fund’s Board of Trustees. For example, the fund will value a security that trades principally on a foreign market using the most recent closing market price from the market on which the security principally trades, unless, in BlackRock’s judgment, a significant event subsequent to the market close has rendered such market closing price unreliable. Because significant events could affect the value of a foreign security between the close of the foreign market where the security is principally traded and the time the fund calculates its NAV, such closing price may not be reflective of current market conditions. In this case, the fund will use what it believes to be the fair value of the security as of the time the fund calculates its NAV.

Fair value represents a good faith approximation of the value of a security. A security’s valuation may differ depending on the method used for determining value. Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. The fair value of one or more securities may not, in retrospect, be the prices at which those assets could have been sold during the period in which the particular fair values were used in determining the fund’s NAV. As a result, the fund’s sale or redemption of its shares at NAV, 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.

Paying for Shares

P ayment for an order must normally be made in Federal funds or other funds immediately available by 4 p.m. (Eastern time) on the first business day following receipt of the order. If payment is not received by this time, the order will be cancelled and you and your financial intermediary will be responsible for any loss to the Fund.

To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions, including the Fund, to obtain, verify and record information that identifies each person who opens an account. When opening an account, you will be asked for your name, address, date of birth

10

and other information that will allow the Fund to identify you. The Fund may also ask to see other identifying documents such as a driver’s license (for individuals) or Articles of Incorporation or other formation documents (for institutions). The Fund may use a third party to obtain and verify this information. The Fund may not be able to establish an account, or it may close your existing account and/or redeem your shares involuntarily, if you do not provide sufficient information within the relevant time periods.

How Much is the Minimum Investment?

T he minimum investment for the initial purchase of R Shares is $100. There is a $50 minimum for all subsequent investments. The Fund may reject any purchase order, modify or waive the minimum initial or subsequent investment requirements for any shareholder and suspend and resume the sale of any share class of any fund at any time for any reason.

Distribution and Service Plan

The Fund has adopted a plan (the Plan) that allows the Fund to pay distribution fees for the sale of its shares under Rule 12b-1 of the Investment Company Act and shareholder servicing fees for certain services provided to its shareholders.

Under the Plan, R Shares pay a fee (distribution fees) to BlackRock Distributors, Inc. (the Distributor) and/or affiliates of PNC Bank or Merrill Lynch & Co., Inc. (Merrill Lynch) (including BlackRock) 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 PNC Bank or Merrill Lynch (including BlackRock) for sales support services provided in connection with the sale of R Shares. The distribution fees may also be used to pay brokers, dealers, financial institutions and industry professionals (including BlackRock, PNC Bank, Merrill Lynch and their affiliates) (Service Organizations) for sales support services and related expenses. All R Shares pay a maximum distribution fee of .25% per year of the average daily net asset value of each fund attributable to R Shares.

Under the Plan, the Fund also pays shareholder servicing fees to Service Organizations whereby the Service Organizations provide support services to their customers who own R Shares in return for these fees. The Fund may pay a shareholder servicing fee of up to .25% per year of the average daily net asset value of R Shares of the fund. All R Shares pay this shareholder servicing fee.

11

In return for the shareholder servicing fee, Service Organizations (including BlackRock) may provide one or more of the following services to their customers who own R Shares:

The shareholder servicing fees payable pursuant to the Plan are fees payable for the administration and servicing of shareholder accounts and 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 Fund assets on an on-going basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of sales charges.

For more information on the Plan, including a complete list of services provided thereunder, see the SAI.

In addition to, rather than in lieu of, distribution and shareholder servicing fees that the Fund may pay to a Service Organization pursuant to the Plan and fees the Fund pays to its transfer agent, the Fund may enter into non-Plan agreements with Service Organizations pursuant to which the Fund will pay a Service Organization 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 Service Organization or (2) a fixed dollar amount for each account serviced by a Service Organization. The aggregate amount of these payments may be substantial.

The Plan permits BlackRock, 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 Fund). From time to time, BlackRock, 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. BlackRock, the Distributor and their affiliates may compensate

12

affiliated and unaffiliated Service Organizations for the sale and distribution of shares of the Fund or 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 Service Organization, or may be based on a percentage of the value of shares sold to, or held by, customers of the Service Organization. The aggregate amount of these payments by BlackRock, the Distributor and their affiliates may be substantial. Payments by BlackRock 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 Service Organization, its employees or associated persons to recommend or sell shares of the Fund to you. Please contact your Service Organization for details about payments it may receive from the Fund or from BlackRock, the Distributor or their affiliates. For more information, see the SAI.

Selling Shares

Authorized qualified employee benefit plan participants may redeem R Shares in accordance with the procedures applicable to their plan accounts. These procedures will vary according to the type of account and the plan involved and customers should consult their account managers in this regard. Authorized qualified employee benefit plans are responsible for transmitting redemption orders to PFPC and crediting their customers’ accounts with redemption proceeds on a timely basis.

Authorized qualified employee benefit plans may place redemption orders by telephoning (800) 441-7762. Shares are redeemed at the NAV per share next determined after receipt of the redemption order minus any applicable redemption fee. See “Market Timing and Redemption Fees” below. The Fund, its administrators 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.

Payment for redeemed shares for which a redemption order is received before 4 p.m. (Eastern time) on a business day is normally made in Federal funds wired to the redeeming plan on the next business day, provided that the fund’s custodian is also open for

13

business. Payment for redemption orders received after 4 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 a fund. No charge for wiring redemption payments is imposed by the Fund, 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.

During periods of substantial economic market change telephone redemptions may be difficult to complete. Redemption requests may also be mailed to BlackRock Funds, c/o PFPC, Inc., P.O. Box 9819, Providence, RI 02940.

The Fund is not responsible for the efficiency of the Federal wire system or the shareholder’s firm or bank. The Fund does not currently charge for wire transfers. The shareholder is responsible for any charges imposed by the shareholder’s 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 BlackRock Funds, c/o PFPC, Inc., P.O. Box 9819, Providence, RI 02940.

The Fund may refuse a telephone redemption request if it believes it is advisable to do so.

Market Timing and Redemption/Exchange Fees

T he Board of Trustees of the Fund has 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. The exchange privilege for Investor, Institutional and R Shares 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 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

14

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 NAV 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 “What Price Per Share Will You Pay?” above.

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 Board of Trustees has approved the policies discussed below to seek to deter market timing activity. The Board has not adopted any specific numerical restrictions on purchases, sales and exchanges of fund shares because legitimate strategies, such as asset allocation, dollar cost averaging or similar activities, may result in frequent trading of fund shares. It is not expected that shareholders would be harmed by such legitimate activities.

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

15

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 are not 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 funds. 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.

Each of the Fund’s High Yield Bond, International Bond, Aurora, Small/Mid-Cap Growth, Small Cap Value Equity, Small Cap Core Equity, Small Cap Growth Equity, Health Sciences Opportunities, Global Science & Technology Opportunities, Global Resources, All-Cap Global Resources, U.S. Opportunities, Global Opportunities and International Opportunities Portfolios will automatically assess and retain a fee of 2% of the current NAV, 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). A new 30-day period begins with each acquisition of shares through a purchase or exchange. For example, a series of transactions in which shares of Portfolio A are exchanged for shares of Portfolio B 20 days after the purchase of the Portfolio A shares, followed in 20 days by an exchange of the Portfolio B shares for shares of Portfolio C, will be subject to two redemption fees (one on each exchange).

The redemption fee is for the benefit of the remaining shareholders of a fund and is intended to encourage long-term investment, to compensate for transaction and other expenses caused by early redemptions and exchanges, and to facilitate

16

portfolio management. The “first-in, first-out” method is used to determine the holding period. Under this method, the date of redemption or exchange will be compared with the earliest purchase date of shares held in the account. The Fund sells shares to some 401(k) plans, 403(b) plans, bank or trust company accounts, and accounts of certain financial institutions or intermediaries that do not apply the redemption fee to underlying shareholders, often because of administrative or systems limitations. From time to time, with the approval of the Fund, the redemption fee will not be assessed on redemptions or exchanges by: (i) accounts of asset allocation programs or wrap programs whose trading practices are determined by the Fund not to be detrimental to a fund or long-term shareholders ( e.g. , model driven programs with periodic automatic portfolio rebalancing that prohibit participant-directed trading and other programs with similar characteristics); (ii) accounts of shareholders who have died or become disabled; (iii) shareholders redeeming or exchanging shares through the Fund’s Systematic Withdrawal Plan, Systematic Exchange Plan or in connection with required distributions from an IRA, 401(k) plan, 403(b) plan or any other Internal Revenue Code Section 401 qualified retirement plan or account, or distribution from a 529 plan; (iv) shareholders executing rollovers of current investments in the Fund through qualified employee benefit plans; and (v) certain other accounts in the absolute discretion of the Fund when a shareholder can demonstrate hardship. The Fund reserves the right to modify or eliminate these waivers at any time.

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.

The Fund's Rights

T he Fund may:

17

Accounts with Low Balances

T he Fund may redeem a shareholder’s account in the fund at any time if the net asset value of the account in the fund falls below the required minimum initial investment as the result of a redemption or an exchange request. The shareholder will be notified in writing that the value of the account is less than the required amount and the shareholder will be allowed 60 days to make additional investments before the redemption is processed.

Purchases and Redemptions

Call your registered representative or (800) 441-7762.

World Wide Web

Access general fund information and specific fund performance, including SAI and annual/semi-annual reports, free of charge. Request mutual fund prospectuses and literature. Forward mutual fund inquiries. www.blackrock.com/funds

Written Correspondence

BlackRock Funds

c/o PFPC Inc.

PO Box 9819

Providence, RI 02940-8019

Overnight Mail

BlackRock Funds

c/o PFPC Inc.

101 Sabin Street

Pawtucket, RI 02860

Internal Wholesalers/Broker Dealer Support

Available to support investment professionals 8:30 a.m. to 6:00 p.m. (Eastern time), Monday - Friday. Call: (800) 882-0052.

Portfolio Characteristics and Holdings

A description of the Funds’ 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 Web site (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 Section of the SEC, Washington, D.C. 20549.

INVESTMENT COMPANY ACT FILE NO. 811-05742

PRO-LG-R 1006

BLACKROCK FUNDS ^SM