INVESTMENT OBJECTIVES AND STRATEGIES

The following supplements the investment objectives, strategies and risks of the Portfolios as set forth in the Prospectus. The investment objective of the Prime Obligations Portfolio may be changed without shareholder approval. The investment objective of the U.S. Government Select Portfolio may not be changed without the vote of the majority of the Portfolio’s outstanding shares. Except as expressly noted below, however, each Portfolio’s investment strategies may be changed without shareholder approval. In addition to the instruments discussed below and in the Prospectus, each Portfolio may purchase other types of financial instruments, however designated, whose investment and credit quality characteristics are determined by Northern Trust Investments, Inc. (“NTI” or the “Investment Adviser,” and NTI and TNTC are collectively referred to herein as “Northern Trust”) to be substantially similar to those of any other investment otherwise permitted by a Portfolio’s investment strategies.

Prime Obligations Portfolio seeks to maximize current income to the extent consistent with the preservation of capital and maintenance of liquidity by investing exclusively in high quality money market instruments. The Portfolio seeks to achieve its objective by investing in a broad range of high quality, U.S. dollar-denominated government, bank and commercial obligations that are available in the money markets.

U.S. Government Select Portfolio seeks to achieve its objective by investing, under normal circumstances, substantially all (and at least 80%) of its net assets in securities issued or guaranteed as to principal and interest by the U.S. government or by its agencies, instrumentalities or sponsored enterprises. Under normal circumstances, the Portfolio will seek to acquire only those U.S. government securities paying interest that generally is exempt from state income taxation. These securities include obligations issued by the U.S. Treasury and certain U.S. government agencies, instrumentalities or sponsored enterprises, such as the Federal Home Loan Bank and the Federal Farm Credit Banks Funding Corp. To the extent required by the Securities and Exchange Commission (“SEC”) regulations, shareholders will be provided with sixty days’ notice in the manner prescribed by the SEC before any change in the Portfolio’s policy stated in the Prospectus to invest at least 80% of its net assets in the particular type of investment suggested by its name. For this purpose, “net assets” include the amount of any borrowings for investment purposes and the amount of “net assets” is measured at the time of purchase.

ASSET-BACKED (INCLUDING MORTGAGE-BACKED) SECURITIES. To the extent described in the Prospectus, the Portfolios may purchase asset-backed securities, which are securities backed by mortgages, installment contracts, credit card receivables, municipal securities or other financial assets. The investment characteristics of asset-backed securities differ from those of traditional fixed-income securities. Asset-backed securities represent interests in “pools” of assets in which payments of both interest and principal on the securities are made periodically, thus in effect “passing through” such payments made by the individual borrowers on the assets that underlie the securities, net of any fees paid to the issuer or guarantor of the securities. The average life of asset-backed securities varies with the maturities of the underlying instruments,

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and the average life of a mortgage-backed instrument, in particular, is likely to be substantially less than the original maturity of the mortgage pools underlying the securities as a result of mortgage prepayments. For this and other reasons, an asset-backed security normally is subject to both call risk and extension risk, and an asset-backed security’s stated maturity may be shortened. In addition, the security’s total return may be difficult to predict precisely. These differences can result in significantly greater price and yield volatility than is the case with traditional fixed-income securities.

If an asset-backed security is purchased at a premium, a prepayment rate that is faster than expected will reduce yield to maturity, while a prepayment rate that is slower than expected will have the opposite effect of increasing yield to maturity. Conversely, if an asset-backed security is purchased at a discount, faster than expected prepayments will increase, while slower than expected prepayments will decrease, yield to maturity. Prepayments on asset-backed securities generally increase with falling interest rates and decrease with rising interest rates; furthermore, prepayment rates are influenced by a variety of economic and social factors. In general, the collateral supporting non-mortgage asset-backed securities is of shorter maturity than mortgage loans and is less likely to experience substantial prepayments.

Asset-backed securities acquired by certain Portfolios may include collateralized mortgage obligations (“CMOs”). CMOs provide the holder with a specified interest in the cash flow of a pool of underlying mortgages or other mortgage-backed securities. Issuers of CMOs ordinarily elect to be taxed as pass-through entities known as real estate mortgage investment conduits (“REMICs”). CMOs are issued in multiple classes, each with a specified fixed or floating interest rate and a final distribution date. The relative payment rights of the various CMO classes may be structured in a variety of ways, and normally are considered derivative securities. In some cases CMOs may be highly leveraged and very speculative. The Portfolios will not purchase “residual” CMO interests, which normally exhibit greater price volatility.

There are a number of important differences among the agencies, instrumentalities and sponsored enterprises of the U.S. government that issue mortgage-related securities and among the securities that they issue. Mortgage-related securities guaranteed by the Government National Mortgage Association (“Ginnie Mae”) include Ginnie Mae Mortgage Pass-Through Certificates, which are guaranteed as to the timely payment of principal and interest by Ginnie Mae and backed by the full faith and credit of the United States, which means that the U.S. government guarantees that the interest and principal will be paid when due. Ginnie Mae is a wholly-owned U.S. government corporation within the Department of Housing and Urban Development. Ginnie Mae certificates also are supported by the authority of Ginnie Mae to borrow funds from the U.S. Treasury to make payments under its guarantee.

Mortgage-backed securities issued by the Federal National Mortgage Association (“Fannie Mae”) include Fannie Mae Guaranteed Mortgage Pass-Through Certificates, which are solely the obligations of Fannie Mae and are not backed by or entitled to the full faith and credit of the United States, except as described below, but are supported by the right of the issuer to borrow from the U.S. Treasury. Fannie Mae is a stockholder-owned corporation chartered under an Act of the U.S. Congress. Fannie Mae certificates are guaranteed as to timely payment of the principal and interest by Fannie Mae. Mortgage-related securities issued by the Federal Home Loan Mortgage Corporation (“Freddie Mac”) include Freddie Mac Mortgage Participation Certificates. Freddie Mac is a corporate instrumentality of the United States, created pursuant to an Act of Congress. Freddie Mac certificates are not guaranteed by the United States or by any Federal Home Loan Banks and do not constitute a debt or obligation of the United States or of any Federal Home Loan Bank. Freddie Mac certificates entitle the holder to timely payment of interest, which is guaranteed by Freddie Mac. Freddie Mac guarantees either ultimate collection or timely payment of all principal payments on the underlying mortgage loans. When Freddie Mac does not guarantee timely payment of principal, Freddie Mac may remit the amount due on account of its guarantee of ultimate payment of principal after default.

From time to time, proposals have been introduced before Congress for the purpose of restricting or eliminating federal sponsorship of Fannie Mae and Freddie Mac. The Trust cannot predict what legislation, if

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any, may be proposed in the future in Congress with regard to such sponsorship or which proposals, if any, might be enacted. Such proposals, if enacted, might materially and adversely affect the availability of government guaranteed mortgage-backed securities and the Portfolios’ liquidity and value.

There is risk that the U.S. government will not provide financial support to its agencies, authorities, instrumentalities or sponsored enterprises. A Portfolio may purchase U.S. government securities that are not backed by the full faith and credit of the United States, such as those issued by Fannie Mae and Freddie Mac. The maximum potential liability of the issuers of some U.S. government securities held by a Portfolio may greatly exceed their current resources, including their legal right to support from the U.S. Treasury. It is possible that these issuers will not have the funds to meet their payment obligations in the future.

The volatility and disruption that impacted the capital and credit markets during late 2008 and into 2009 have led to increased market concerns about Freddie Mac’s and Fannie Mae’s ability to withstand future credit losses associated with securities held in their investment portfolios, and on which they provide guarantees, without the direct support of the federal government. On September 7, 2008, both Freddie Mac and Fannie Mae were placed under the conservatorship of the Federal Housing Finance Agency (“FHFA”). Under the plan of conservatorship, the FHFA has assumed control of, and generally has the power to direct, the operations of Freddie Mac and Fannie Mae, and is empowered to exercise all powers collectively held by their respective shareholders, directors and officers, including the power to: (1) take over the assets of and operate Freddie Mac and Fannie Mae with all the powers of the shareholders, the directors, and the officers of Freddie Mac and Fannie Mae and conduct all business of Freddie Mac and Fannie Mae; (2) collect all obligations and money due to Freddie Mac and Fannie Mae; (3) perform all functions of Freddie Mac and Fannie Mae which are consistent with the conservator’s appointment; (4) preserve and conserve the assets and property of Freddie Mac and Fannie Mae; and (5) contract for assistance in fulfilling any function, activity, action or duty of the conservator. In addition, in connection with the actions taken by the FHFA, the U.S. Treasury Department (the “Treasury”) entered into certain preferred stock purchase agreements with each of Freddie Mac and Fannie Mae which established the Treasury as the holder of a new class of senior preferred stock in each of Freddie Mac and Fannie Mae, which stock was issued in connection with financial contributions from the Treasury to Freddie Mac and Fannie Mae.

The conditions attached to the financial contribution made by the Treasury to Freddie Mac and Fannie Mae and the issuance of this senior preferred stock placed significant restrictions on the activities of Freddie Mac and Fannie Mae. Freddie Mac and Fannie Mae must obtain the consent of the Treasury to, among other things: (i) make any payment to purchase or redeem its capital stock or pay any dividend other than in respect of the senior preferred stock issued to the Treasury, (ii) issue capital stock of any kind, (iii) terminate the conservatorship of the FHFA except in connection with a receivership, or (iv) increase its debt beyond certain specified levels. In addition, significant restrictions were placed on the maximum size of each of Freddie Mac’s and Fannie Mae’s respective portfolios of mortgages and mortgage-backed securities portfolios, and the purchase agreements entered into by Freddie Mac and Fannie Mae provide that the maximum size of their portfolios of these assets must decrease by a specified percentage each year. The future status and role of Freddie Mac and Fannie Mae could be impacted by (among other things): the actions taken and restrictions placed on Freddie Mac and Fannie Mae by the FHFA in its role as conservator; the restrictions placed on Freddie Mac’s and Fannie Mae’s operations and activities as a result of the senior preferred stock investment made by the Treasury; market responses to developments at Freddie Mac and Fannie Mae; and future legislative and regulatory action that alters the operations, ownership, structure and/or mission of these institutions, each of which may, in turn, impact the value of, and cash flows on, any mortgage-backed securities guaranteed by Freddie Mac and Fannie Mae, including any such mortgage-backed securities held by the Portfolios.

As a result of the economic recession that commenced in the U.S. in 2008, there is a heightened risk that the receivables and loans underlying the asset-backed securities purchased by the Portfolios may suffer greater levels of default than was historically experienced.

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In addition, privately issued mortgage-backed securities (as well as other types of asset-backed securities) do not have the backing of any U.S. government agency, instrumentality or sponsored enterprise. The seller or servicer of the underlying mortgage obligations generally will make representations and warranties to certificate-holders as to certain characteristics of the mortgage loans and as to the accuracy of certain information furnished to the trustee in respect of each such mortgage loan. Upon a breach of any representation or warranty that materially and adversely affects the interests of the related certificate-holders in a mortgage loan, the seller or servicer generally will be obligated either to cure the breach in all material respects, to repurchase the mortgage loan or, if the related agreement so provides, to substitute in its place a mortgage loan pursuant to the conditions set forth therein. Such a repurchase or substitution obligation may constitute the sole remedy available to the related certificate-holders or the trustee for the material breach of any such representation or warranty by the seller or servicer. To provide additional investor protection, some mortgage-backed securities may have various types of credit enhancements, reserve funds, subordination provisions or other features. Non-mortgage asset-backed securities involve certain risks that are not presented by mortgage-backed securities. Primarily, these securities do not have the benefit of the same security interest in the underlying collateral. Credit card receivables generally are unsecured and the debtors are entitled to the protection of a number of state and federal consumer credit laws, many of which have given debtors the right to set off certain amounts owed on the credit cards, thereby reducing the balance due. Most issuers of automobile receivables permit the servicers to retain possession of the underlying obligations. If the servicer were to sell these obligations to another party, there is a risk that the purchaser would acquire an interest superior to that of the holders of the related automobile receivables. In addition, because of the large number of vehicles involved in a typical issuance and technical requirements under state laws, the trustee for the holders of the automobile receivables may not have an effective security interest in all of the obligations backing such receivables. Therefore, there is a possibility that recoveries on repossessed collateral may not, in some cases, be able to support payments on these securities.

The disruption in the residential mortgage-backed securities market (and in particular, the “subprime” residential mortgage market), the broader mortgage-backed securities market and the asset-backed securities market in 2008-2009 has resulted, and continues to result, in downward price pressures and increasing foreclosures and defaults in residential and commercial real estate. Concerns over inflation, energy costs, geopolitical issues, the availability and cost of credit, the mortgage market and a depressed real estate market have contributed to increased volatility and diminished expectations for the economy and markets going forward, and have contributed to dramatic declines in the housing market, with falling home prices and increasing foreclosures and unemployment, and significant asset write-downs by financial institutions. These conditions have prompted a number of financial institutions to seek additional capital, to merge with other institutions and, in some cases, to fail. The continuation or worsening of this general economic downturn may lead to further declines in income from, or the value of, real estate, including the real estate which secures the mortgage-backed securities held by certain Portfolios. Additionally, a lack of credit availability, higher mortgage rates and decreases in the value of real property have occurred and may continue to occur or worsen, and potentially prevent borrowers from refinancing their mortgages, which may increase the likelihood of default on their mortgage loans. These economic conditions, coupled with high levels of real estate inventory and elevated incidence of underwater mortgages, may also adversely affect the amount of proceeds the holder of a mortgage loan or mortgage-backed securities (including the mortgage-backed securities in which certain of the Portfolios may invest) would realize in the event of a foreclosure or other exercise of remedies. Moreover, even if such mortgage-backed securities are performing as anticipated, the value of such securities in the secondary market may nevertheless fall or continue to fall as a result of deterioration in general market conditions for such mortgage-backed securities or other asset-backed or structured products. Trading activity associated with market indices may also drive spreads on those indices wider than spreads on mortgage-backed securities, thereby resulting in a decrease in value of such mortgage-backed securities, including the mortgage-backed securities owned by the Portfolios.

Asset-backed securities acquired by the Portfolios may also include collateralized debt obligations (“CDOs”). CDOs include collateralized bond obligations (“CBOs”) and collateralized loan obligations (“CLOs”) and other similarly structured securities.

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A CBO is a trust or other special purpose entity (“SPE”) that is typically backed by a diversified pool of fixed-income securities (which may include high risk, below investment grade securities). A CLO is a trust or other SPE that is typically collateralized by a pool of loans, which may include, among others, domestic and non-U.S. senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans. Although certain CDOs may receive credit enhancement in the form of a senior-subordinate structure, over-collateralization or bond insurance, such enhancement may not always be present and may fail to protect a Portfolio against the risk of loss on default of the collateral. Certain CDOs may use derivatives contracts to create “synthetic” exposure to assets rather than holding such assets directly, which entails the risks of derivative instruments described elsewhere in this SAI. CDOs may charge management fees and administrative expenses, which are in addition to those of a Portfolio.

For both CBOs and CLOs, the cashflows from the SPE are split into two or more portions, called tranches, varying in risk and yield. The riskiest portion is the “equity” tranche, which bears the first loss from defaults from the bonds or loans in the SPE and serves to protect the other, more senior tranches from default (though such protection is not complete). Since it is partially protected from defaults, a senior tranche from a CBO or CLO typically has higher ratings and lower yields than its underlying securities, and may be rated investment grade. Despite the protection from the equity tranche, CBO or CLO tranches can experience substantial losses due to actual defaults, increased sensitivity to defaults due to collateral default and disappearance of protecting tranches, market anticipation of defaults, as well as investor aversion to CBO or CLO securities as a class. Interest on certain tranches of a CDO may be paid in kind (paid in the form of obligations of the same type rather than cash), which involves continued exposure to default risk with respect to such payments.

The risks of an investment in a CDO depend largely on the type of the collateral securities and the class of the CDO in which a Portfolio invests. Normally, CBOs, CLOs and other CDOs are privately offered and sold, and thus are not registered under the securities laws. As a result, investments in CDOs may be characterized by a Portfolio as illiquid securities. However, an active dealer market may exist for CDOs, allowing a CDO to qualify for Rule 144A transactions. In addition to the normal risks associated with fixed-income securities and asset-backed securities generally discussed elsewhere in this SAI, CDOs carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the quality of the collateral may decline in value or default; (iii) a Portfolio may invest in tranches of CDOs that are subordinate to other tranches; (iv) the complex structure of the security may not be fully understood at the time of investment and may produce disputes with the issuer or unexpected investment results; and (v) the CDO’s manager may perform poorly or default.

COMMERCIAL PAPER, BANKERS’ ACCEPTANCES, CERTIFICATES OF DEPOSIT, TIME DEPOSITS AND BANK NOTES. To the extent consistent with their respective investment objectives and strategies, the Portfolios may invest in commercial paper. Commercial paper represents short-term unsecured promissory notes issued in bearer form by banks or bank holding companies, corporations and finance companies. Certificates of deposit are negotiable certificates issued against funds deposited in a commercial bank for a definite period of time and earning a specified return. Bankers’ acceptances are negotiable drafts or bills of exchange, normally drawn by an importer or exporter to pay for specific merchandise, which are “accepted” by a bank, meaning, in effect, that the bank unconditionally agrees to pay the face value of the instrument on maturity. Fixed time deposits are bank obligations payable at a stated maturity date and bearing interest at a fixed rate. Fixed time deposits may be withdrawn on demand by the investor, but may be subject to early withdrawal penalties that vary depending upon market conditions and the remaining maturity of the obligation. There are no contractual restrictions on the right to transfer a beneficial interest in a fixed time deposit to a third party. Bank notes generally rank junior to deposit liabilities of banks and pari passu with other senior, unsecured obligations of the bank. Bank notes are classified as “other borrowings” on a bank’s balance sheet, while deposit notes and certificates of deposit are classified as deposits. Bank notes are not insured by the FDIC or any other insurer. Deposit notes are insured by the FDIC only to the extent of $250,000 per depositor per bank.

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To the extent such obligations are U.S. dollar-denominated, the Prime Obligations Portfolio may invest a portion of its assets in the obligations of foreign banks and foreign branches of domestic banks. Such obligations include Eurodollar Certificates of Deposit (“ECDs”), which are U.S. dollar-denominated certificates of deposit issued by offices of foreign and domestic banks located outside the United States; Eurodollar Time Deposits (“ETDs”), which are U.S. dollar-denominated deposits in a foreign branch of a U.S. bank or a foreign bank; Canadian Time Deposits (“CTDs”), which are essentially the same as ETDs except they are issued by Canadian offices of major Canadian banks; Schedule Bs, which are obligations issued by Canadian branches of foreign or domestic banks; Yankee Certificates of Deposit (“Yankee CDs”), which are U.S. dollar-denominated certificates of deposit issued by a U.S. branch of a foreign bank and held in the United States; and Yankee Bankers’ Acceptances (“Yankee BAs”), which are U.S. dollar-denominated bankers’ acceptances issued by a U.S. branch of a foreign bank and held in the United States.

Commercial paper purchased by certain Portfolios may include asset-backed commercial paper. Asset-backed commercial paper is issued by a SPE that is organized to issue the commercial paper and to purchase trade receivables or other financial assets. The credit quality of asset-backed commercial paper depends primarily on the quality of these assets and the level of any additional credit support.

CUSTODIAL RECEIPTS FOR TREASURY SECURITIES. To the extent consistent with its investment objective and strategies, the Prime Obligations Portfolio may acquire U.S. government obligations and their unmatured interest coupons that have been separated (“stripped”) by their holder, typically a custodian bank or investment brokerage firm. Having separated the interest coupons from the underlying principal of the U.S. government obligations, the holder will resell the stripped securities in custodial receipt programs with a number of different names, including “Treasury Income Growth Receipts” (“TIGRs”) and “Certificate of Accrual on Treasury Securities” (“CATS”). The stripped coupons are sold separately from the underlying principal, which usually is sold at a deep discount because the buyer receives only the right to receive a future fixed payment on the security and does not receive any rights to periodic interest (cash) payments. The underlying U.S. Treasury bonds and notes themselves are held in book-entry form at the Federal Reserve Bank or, in the case of bearer securities (i.e., unregistered securities which are ostensibly owned by the bearer or holder), in trust on behalf of the owners. Counsel to the underwriters of these certificates or other evidences of ownership of U.S. Treasury securities have stated that, in their opinion, purchasers of the stripped securities most likely will be deemed the beneficial holders of the underlying U.S. government obligations for federal tax purposes. The Trust is unaware of any binding legislative, judicial or administrative authority on this issue.

CYBER SECURITY ISSUES . With the increased use of technologies such as the Internet to conduct business, each Portfolio is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber attacks include, but are not limited to, gaining unauthorized access to digital systems for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of service attacks on websites. Cyber security failures or breaches by a Portfolio’s third party service providers (including, but not limited to, fund accountants and transfer agents, third party intermediaries and the issuers of securities in which the Portfolios invest) have the ability to cause disruptions and impact business operations potentially resulting in financial losses, the inability of Portfolio shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. While the Portfolios’ primary service providers have established business continuity plans in the event of, and risk management systems to prevent, such cyber attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. Furthermore, the Portfolios cannot control the cyber security plans and systems put in place by issuers in which the Portfolios invest or third party intermediaries. The Portfolios and their shareholders could be negatively impacted as a result.

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DEMAND FEATURES AND GUARANTEES. To the extent consistent with its investment objective and strategies, each Portfolio may invest a significant percentage of its assets in securities that have demand features, guarantees or similar credit and liquidity enhancements. A demand feature permits the holder of the security to sell the security within a specified period of time at a stated price and entitles the holder of the security to receive an amount equal to the approximate amortized cost of the security plus accrued interest. A guarantee permits the holder of the security to receive, upon presentment to the guarantor, the principal amount of the underlying security plus accrued interest when due or upon default. A guarantee is the unconditional obligation of an entity other than the issuer of the security. Demand features and guarantees can effectively:

The aggregate price for a security subject to a demand feature or a guarantee may be higher than the price that would otherwise be paid for the security without the guarantee or the demand feature. When a Portfolio purchases securities subject to guarantees or demand features, there is an increase in the cost of the underlying security and a corresponding reduction in its yield. Because each Portfolio invests in securities backed by banks and other financial institutions, changes in the credit quality of these institutions could cause losses to the Portfolio.

FOREIGN INVESTMENTS. To the extent consistent with its investment objective and strategies, each Portfolio may invest in U.S. dollar-denominated foreign securities, including bonds and other fixed-income securities of foreign issuers. Foreign fixed-income securities may include eurodollar convertible securities, which are fixed-income securities that are issued in U.S. dollars outside the United States and are convertible into or exchangeable for equity securities of the same or a different issuer. The Prime Obligations Portfolio also may invest in U.S. dollar-denominated obligations issued or guaranteed by one or more foreign governments or any of their political subdivisions, agencies, instrumentalities or sponsored enterprises, as well as other foreign issuers. These obligations may be issued by supranational entities, including international organizations (such as the European Coal and Steel Community) designed or supported by governmental entities to promote economic reconstruction or development and international banking institutions and related government agencies.

Investment in foreign securities involves special risks. These include market risk, interest rate risk and the risks of investing in securities of foreign issuers and of companies whose securities are principally traded outside the United States on foreign exchanges or foreign over-the-counter markets. Market risk involves the possibility that security prices will decline over short or even extended periods. The markets tend to be cyclical, with periods of generally rising prices and periods of generally declining prices. These cycles will affect the value of a Portfolio to the extent that it invests in foreign securities. The holdings of the Portfolios, to the extent that they invest in fixed-income securities, will be sensitive to changes in interest rates and the interest rate environment. Generally, the prices of bonds and debt securities fluctuate inversely with interest rate changes.

There are other risks and costs involved in investing in foreign securities which are in addition to the usual risks inherent in domestic investments. Investment in foreign securities involves higher costs than investment in U.S. securities, including higher transaction and custody costs as well as the imposition of additional taxes by foreign governments. Foreign investments also involve risks associated with less complete financial information about the issuers, less market liquidity, more market volatility and political instability. Future political and economic developments, the possible imposition of withholding taxes on dividend income, the possible seizure or nationalization of foreign holdings, the possible establishment of exchange controls, or the adoption of other governmental restrictions might adversely affect an investment in foreign securities. Additionally, foreign banks and foreign branches of domestic banks are subject to less stringent reserve requirements, and to different accounting, auditing and recordkeeping requirements. Also, the legal remedies for investors may be more limited than the remedies available in the U.S. Additionally, many countries throughout the world are dependent on a healthy U.S. economy and are adversely affected when the U.S. economy weakens or its markets decline.

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For example, the decline in the U.S. subprime mortgage market quickly spread throughout global credit markets, triggering a liquidity crisis that affected fixed-income and equity markets around the world.

European countries can be significantly affected by the tight fiscal and monetary controls that the European Economic and Monetary Union (“EMU”) imposes for membership. Europe’s economies are diverse, its governments are decentralized, and its cultures vary widely. Several EU countries, including Greece, Ireland, Italy, Spain and Portugal, have faced budget issues, some of which may have negative long-term effects for the economies of those countries and other EU countries. There is continued concern about national-level support for the euro and the accompanying coordination of fiscal and wage policy among EMU member countries. Member countries are required to maintain tight control over inflation, public debt, and budget deficit to qualify for membership in the EMU. These requirements can severely limit the ability of EMU member countries to implement monetary policy to address regional economic conditions.

To the extent consistent with its investment objective and strategies, the Prime Obligations Portfolio may invest in foreign debt, including the securities of foreign governments. Several risks exist concerning such investments, including the risk that foreign governments may default on their obligations, may not respect the integrity of such debt, may attempt to renegotiate the debt at a lower rate, and may not honor investments by U.S. entities or citizens.

Dividends and interest payable on a Portfolio’s foreign portfolio securities may be subject to foreign withholding taxes. To the extent such taxes are not offset by credits or deductions allowed to investors under U.S. federal income tax law, they may reduce the net return to the shareholders. See “Taxes” on page 51.

The Portfolios’ income and, in some cases, capital gains from foreign stocks and securities will be subject to applicable taxation in certain of the countries in which they invest, and treaties between the U.S. and such countries may not be available in some cases to reduce the otherwise applicable tax rates. See “Taxes” on page 51.

Foreign markets also have different clearance and settlement procedures, and in certain markets there have been times when settlements have been unable to keep pace with the volume of securities transactions, making it difficult to conduct such transactions. Such delays in settlement could result in temporary periods when a portion of the assets of a Portfolio remain uninvested and no return is earned on such assets. The inability of a Portfolio to make intended security purchases or sales due to settlement problems could result in missed attractive investment opportunities, losses to the Portfolio due to subsequent declines in value of the portfolio securities or, if the Portfolio has entered into a contract to sell the securities, possible liability to the purchaser.

The Prime Obligations Portfolio may invest a significant percentage of its assets in the securities of issuers located in geographic regions with securities markets that are highly developed, liquid and subject to extensive regulation, including Japan. In recent years, Japan’s economic growth has been substantially below the level of earlier decades, and its economy has experienced periods of recession. Similar to many European countries, Japan is experiencing a deterioration of its competitiveness. Although Japan is attempting to reform its political process and deregulate its economy to address the situation, there is no guarantee that these efforts will succeed.

FORWARD COMMITMENTS, WHEN-ISSUED SECURITIES AND DELAYED-DELIVERY TRANSACTIONS. Each Portfolio may purchase securities on a when-issued basis or purchase or sell securities on a forward commitment (sometimes called delayed-delivery) basis. These transactions involve a commitment by the Portfolio to purchase or sell securities at a future date. The price of the underlying securities (usually expressed in terms of yield) and the date when the securities will be delivered and paid for (the settlement date) are fixed at the time the transaction is negotiated. When-issued purchases and forward commitment transactions normally are negotiated directly with the other party.

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A Portfolio will purchase securities on a when-issued basis or purchase or sell securities on a forward commitment basis only with the intention of completing the transaction and actually purchasing or selling the securities. If deemed advisable as a matter of investment strategy, however, a Portfolio may dispose of or negotiate a commitment after entering into it. A Portfolio also may sell securities it has committed to purchase before those securities are delivered to the Portfolio on the settlement date. The Portfolio may realize a capital gain or loss in connection with these transactions.

When a Portfolio purchases securities on a when-issued, delayed-delivery or forward commitment basis, the Portfolio will segregate liquid assets having a value (determined daily) at least equal to the amount of the Portfolio’s purchase commitments until three days prior to the settlement date, or will otherwise cover its position. These procedures are designed to ensure that the Portfolio will maintain sufficient assets at all times to cover its obligations under when-issued purchases, forward commitments and delayed-delivery transactions. For purposes of determining a Portfolio’s average dollar-weighted maturity, the maturity of when-issued, delayed-delivery or forward commitment securities will be calculated from the commitment date.

ILLIQUID OR RESTRICTED SECURITIES. Each Portfolio may invest up to 5% of its net assets in securities that are illiquid. The Portfolios may purchase commercial paper issued pursuant to Section 4(2) of the Securities Act of 1933, as amended (the “1933 Act”) and securities that are not registered under the 1933 Act, but can be sold to “qualified institutional buyers” in accordance with Rule 144A under the 1933 Act. These securities will not be considered illiquid so long as the Investment Adviser determines, under guidelines approved by the Trust’s Board of Trustees, that an adequate trading market exists. This practice could increase the level of illiquidity during any period that qualified institutional buyers become uninterested in purchasing these securities.

INFLATION-INDEXED SECURITIES. The Portfolios may invest in inflation-indexed securities, which are fixed-income securities whose value is periodically adjusted according to the rate of inflation. Two structures are common: the U.S. Treasury and some other issuers utilize a structure that accrues inflation into the principal value of the security; most other issuers pay out the Consumer Price Index (“CPI”) accruals as part of a semiannual coupon.

Inflation-indexed securities issued by the U.S. Treasury have varying maturities and pay interest on a semi-annual basis equal to a fixed percentage of the inflation-adjusted principal amount. If the periodic adjustment rate measuring inflation falls, the principal value of inflation-indexed bonds will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-indexed bonds, even during a period of deflation. However, the current market value of the bonds is not guaranteed and will fluctuate. A Portfolio also may invest in other inflation-related bonds which may or may not provide a similar guarantee. If a guarantee of principal is not provided, the adjusted principal value of the bond repaid at maturity may be less than the original principal amount.

The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates in turn are tied to the relationship between nominal interest rates and the rate of inflation. Therefore, if the rate of inflation rises at a faster rate than nominal interest rates, real interest rates might decline, leading to an increase in value of inflation-indexed bonds. In contrast, if nominal interest rates increase at a faster rate than inflation, real interest rates might rise, leading to a decrease in value of inflation-indexed bonds. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity.

While these securities are expected to be protected from long-term inflationary trends, short-term increases in inflation may lead to a decline in value. If interest rates rise due to reasons other than inflation (for example, due to changes in currency exchange rates), investors in these securities may not be protected to the extent that the increase is not reflected in the bond’s inflation measure.

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The periodic adjustment of U.S. inflation-indexed bonds is tied to the Consumer Price Index for All Urban Consumers (“CPI-U”), which is calculated monthly by the U.S. Bureau of Labor Statistics. The CPI-U is a measurement of changes in the cost of living, made up of components such as housing, food, transportation and energy. Inflation-indexed bonds issued by a foreign government are generally adjusted to reflect a comparable inflation index calculated by that government. There can be no assurance that the CPI-U or any foreign inflation index will accurately measure the real rate of inflation in the prices of goods and services. Moreover, there can be no assurance that the rate of inflation in a foreign country will be correlated to the rate of inflation in the United States.

The taxation of inflation-indexed Treasury securities is similar to the taxation of conventional bonds. Both interest payments and the difference between original principal and the inflation-adjusted principal will be treated as interest income subject to taxation. Interest payments are taxable when received or accrued. The inflation adjustment to the principal is subject to tax in the year the adjustment is made, not at maturity of the security when the cash from the repayment of principal is received. If an upward adjustment has been made (which typically should happen), investors in non-tax-deferred accounts will pay taxes on this amount currently. Decreases in the indexed principal can be deducted only from current or previous interest payments reported as income. Inflation-indexed Treasury securities therefore have a potential cash flow mismatch to an investor, because investors must pay taxes on the inflation-adjusted principal before the repayment of principal is received. It is possible that, particularly for high income tax bracket investors, inflation-indexed Treasury securities would not generate enough income in a given year to cover the tax liability they could create. This is similar to the current tax treatment for zero-coupon bonds and other discount securities. If inflation-indexed Treasury securities are sold prior to maturity, capital losses or gains are realized in the same manner as traditional bonds. The Portfolios, however, distribute income on a monthly basis. Portfolio investors will receive dividends that represent both the interest payments and the principal adjustments of the inflation-indexed securities held in the Portfolio.

INSURANCE FUNDING AGREEMENTS. To the extent consistent with their respective investment objectives and strategies, the Portfolios may invest in insurance funding agreements (“IFAs”). An IFA is normally a general obligation of the issuing insurance company and not a separate account. The purchase price paid for an IFA becomes part of the general assets of the insurance company, and the contract is paid from the company’s general assets. Generally, IFAs are not assignable or transferable without the permission of the issuing insurance companies, and an active secondary market in IFAs may not exist. Therefore, IFAs will be subject to a Portfolio’s limitation on illiquid investments when the Portfolio may not demand payment of the principal amount within seven days and a reliable trading market is absent.

INVESTMENT COMPANIES. With respect to the investments of the Portfolios in the securities of other affiliated and unaffiliated investment companies, such investments will be limited so that, as determined after a purchase is made, either: (a) not more than 3% of the total outstanding stock of such investment company will be owned by a Portfolio, the Trust as a whole and its affiliated persons (as defined in the 1940 Act); or (b) (i) not more than 5% of the value of the total assets of a Portfolio will be invested in the securities of any one investment company, (ii) not more than 10% of the value of its total assets will be invested in the aggregate securities of investment companies as a group and (iii) not more than 3% of the outstanding voting stock of any one investment company will be owned by the Portfolio. These limits will not apply to the investment of uninvested cash balances in shares of registered or unregistered money market portfolios whether affiliated or unaffiliated. The foregoing exemption, however, only applies to an unregistered money market portfolio that (i) limits its investments to those in which a money market portfolio may invest under Rule 2a-7 of the 1940 Act, and (ii) undertakes to comply with all the other provisions of Rule 2a-7.

Investments by the Portfolios in other investment companies, including exchange-traded funds (“ETFs”), will be subject to the limitations of the 1940 Act except as permitted by SEC orders. The Portfolios may rely on SEC orders that permit them to invest in certain ETFs beyond the limits contained in the 1940 Act, subject to certain terms and conditions. Generally, these terms and conditions require the Board to approve policies and

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procedures relating to certain of the Portfolios’ investments in ETFs. These policies and procedures require, among other things, that (i) the Investment Adviser conducts the Portfolios’ investment in ETFs without regard to any consideration received by the Portfolios or any of their affiliated persons and (ii) the Investment Adviser certifies to the Board quarterly that it has not received any consideration in connection with an investment by the Portfolios in an ETF, or if it has, the amount and purpose of the consideration will be reported to the Board and an equivalent amount of advisory fees shall be waived by the Investment Adviser.

Certain investment companies whose securities are purchased by the Portfolios may not be obligated to redeem such securities in an amount exceeding 1% of the investment company’s total outstanding securities during any period of less than 30 days. Therefore, such securities that exceed this amount may be illiquid.

If required by the 1940 Act, each Portfolio expects to vote the shares of other investment companies that are held by it in the same proportion as the vote of all other holders of such securities.

To the extent consistent with its investment objective and strategies, a Portfolio may invest all or substantially all of its assets in a single open-end investment company or series thereof with substantially the same investment objective, strategy and restrictions as the Portfolio. However, each Portfolio currently intends to limit its investments in securities issued by other investment companies to the extent described above. A Portfolio may adhere to other limitations with respect to its investments in securities issued by other investment companies if required or permitted by the SEC or deemed to be in the best interests of the Trust.

MUNICIPAL INSTRUMENTS. To the extent consistent with their investment objectives and strategies, the Portfolios may invest in municipal instruments. Opinions relating to the validity of municipal instruments and to federal and state tax issues relating to these securities are rendered by bond counsel to the respective issuing authorities at the time of issuance. Such opinions may contain various assumptions, qualifications or exceptions that are reasonably acceptable to the Investment Adviser. Neither the Trust nor the Investment Adviser will review the proceedings relating to the issuance of municipal instruments or the bases for such opinions.

Municipal instruments generally are issued to finance public works, such as airports, bridges, highways, housing, health-related entities, transportation-related projects, educational programs, water and pollution control and sewer works. They also are issued to repay outstanding obligations, to raise funds for general operating expenses and to make loans to other public institutions and for other facilities. Municipal instruments include private activity bonds issued by or on behalf of public authorities. Private activity bonds are or have been issued to obtain funds to provide, among other things, privately operated housing facilities, pollution control facilities, convention or trade show facilities, mass transit, airport, port or parking facilities and certain local facilities for water supply, gas, electricity or sewage or solid waste disposal. Private activity bonds also are issued to privately held or publicly owned corporations in the financing of commercial or industrial facilities.

State and local governments are authorized in most states to issue private activity bonds for such purposes in order to encourage corporations to locate within their communities. The principal and interest on these obligations may be payable from the general revenues of the users of such facilities.

Municipal instruments include both “general” and “revenue” obligations. General obligations are secured by the issuer’s pledge of its full faith, credit and taxing power for the payment of principal and interest. Revenue obligations are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source such as lease revenue payments from the user of the facility being financed. Industrial development bonds are in most cases revenue securities and are not payable from the unrestricted revenues of the issuer. Consequently, the credit quality of an industrial revenue bond usually is directly related to the credit standing of the private user of the facility involved.

Within the principal classifications of municipal instruments described above there are a variety of categories, including municipal bonds, municipal notes, municipal leases, asset-backed securities such as

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custodial receipts and participation certificates. Municipal notes include tax, revenue and bond anticipation notes of short maturity, generally less than three years, which are issued to obtain temporary funds for various public purposes. Municipal leases and participation certificates are obligations issued by state and local governments or authorities to finance the acquisition of equipment and facilities. Participation certificates may represent participation in a lease, an installment purchase contract, or a conditional sales contract. Certain municipal lease obligations (and related participation certificates) may include “non-appropriation” clauses which provide that the municipality has no obligation to make lease or installment purchase payments in future years unless money is appropriated for such purpose on a yearly basis. Custodial receipts are underwritten by securities dealers or banks and evidence ownership of future interest payments, principal payments or both on certain municipal securities. Municipal leases (and participations in such leases) present the risk that a municipality will not appropriate funds for the lease payments. The Investment Adviser will determine the credit quality of any unrated municipal leases on an ongoing basis, including an assessment of the likelihood that the leases will not be canceled.

To the extent consistent with their respective investment objectives and strategies, the Portfolios also may invest in “moral obligation” bonds, which normally are issued by special purpose public authorities. If the issuer of a moral obligation bond is unable to meet its debt service obligations from current revenues, it may draw on a reserve fund (if such a fund has been established), the restoration of which is a moral commitment, but not a legal obligation of the state or municipality which created the issuer.

Municipal bonds with a series of maturity dates are called serial bonds. The Portfolios may purchase serial bonds and other long-term securities provided that they have remaining maturities meeting the Portfolios’ maturity requirements. The Portfolios also may purchase long-term variable and floating rate bonds (sometimes referred to as “put bonds”) where a Portfolio obtains at the time of purchase the right to put the bond back to the issuer or a third party at par at least every thirteen months. Put bonds with conditional puts (that is, puts which cannot be exercised if the issuer defaults on its payment obligations) will present risks that are different than those of other municipal instruments because of the possibility that the Portfolios might hold long-term put bonds on which defaults occur following acquisition by the Portfolios.

To the extent consistent with their respective investment objectives and strategies, the Portfolios may acquire securities in the form of custodial receipts evidencing rights to receive a specific future interest payment, principal payment or both on certain municipal obligations. Such obligations are held in custody by a bank on behalf of the holders of the receipts. These custodial receipts are known by various names, including “Municipal Receipts,” “Municipal Certificates of Accrual on Tax-Exempt Securities” (“M-CATS”) and “Municipal Zero- Coupon Receipts.” The Portfolios also may purchase certificates of participation that, in the opinion of counsel to the issuer, are exempt from regular federal income tax. Certificates of participation are a type of floating or variable rate of obligation that represents interests in a pool of municipal obligations held by a bank.

To the extent consistent with their respective investment objectives and strategies, the Portfolios also may invest in “tax credit bonds.” A tax credit bond is defined in the Code, as a “qualified tax credit bond” (which includes a qualified forestry conservation bond, a new clean renewable energy bond, a qualified energy conservation bond, and a qualified zone academy bond, each of which must meet certain requirements specified in the Code), a “build America bond” (which includes certain qualified bonds issued before January 1, 2011) or certain other specified bonds.

An issuer’s obligations under its municipal instruments are subject to the provisions of bankruptcy, insolvency and other laws affecting the rights and remedies of creditors, such as the Federal Bankruptcy Code, and laws, if any, which may be enacted by federal or state legislatures extending the time for payment of principal or interest, or both, or imposing other constraints upon enforcement of such obligations or upon the ability of municipalities to levy taxes. The power or ability of an issuer to meet its obligations for the payment of interest on and principal of its municipal instruments may be materially adversely affected by litigation or other conditions.

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From time to time, proposals have been introduced before Congress for the purpose of restricting or eliminating the federal income tax exemption for interest on municipal instruments. For example, under the Tax Reform Act of 1986, interest on certain private activity bonds must be included in an investor’s federal alternative minimum taxable income, and corporate investors must include all tax-exempt interest in their federal alternative minimum taxable income. The Trust cannot predict what legislation, if any, may be proposed in the future in Congress as regards the federal income tax status of interest on municipal instruments or which proposals, if any, might be enacted.

Certain of the municipal instruments held by a Portfolio may be insured as to the timely payment of principal and interest. The insurance policies usually will be obtained by the issuer of the municipal instrument at the time of its original issuance. In the event that the issuer defaults on an interest or principal payment, the insurer will be notified and will be required to make payment to the bondholders. There is, however, no guarantee that the insurer will meet its obligations. In addition, such insurance will not protect against market fluctuations caused by changes in interest rates and other factors. Moreover, the insurers’ exposure to securities involving subprime mortgages may cause a municipal bond insurer’s rating to be downgraded or may cause the bond insurer to become insolvent, which may affect the prices and liquidity of municipal obligations insured by the insurance company. A Portfolio may invest more than 25% of its total assets in municipal instruments covered by insurance policies.

In addition, a single enhancement provider may provide credit enhancement to more than one of a Portfolio’s investments. Having multiple securities’ credit enhanced by the same enhancement provider will increase the adverse effects on a Portfolio that are likely to result from a downgrading of, or a default by, such an enhancement provider. Adverse developments in the banking or bond insurance industries also may negatively affect a Portfolio. Bond insurers that provide credit enhancement for large segments of the fixed-income markets, particularly the municipal bond market, may be more susceptible to being downgraded or defaulting during recessions or similar period of economic stress. Municipal bonds may be covered by insurance that guarantees timely interest payments and repayment of principal on maturity. If a bond’s insurer fails to fulfill its obligations or loses its credit rating, the value of the bond could drop. Insurance does not protect a Portfolio or its shareholders from losses caused by declines in a bond’s market value.

Municipal instruments purchased by the Portfolios may be backed by letters of credit or other forms of credit enhancement issued by foreign (as well as domestic) banks and other financial institutions. A change in the credit quality of these banks and financial institutions could, therefore, cause loss to a Portfolio that invests in municipal instruments. Letters of credit and other obligations of foreign financial institutions may involve certain risks in addition to those of domestic obligations.

The Portfolios may invest in municipal leases, which may be considered liquid under guidelines established by the Trust’s Board of Trustees. The guidelines will provide for determination of the liquidity of a municipal lease obligation based on factors including the following: (i) the frequency of trades and quotes for the obligation; (ii) the number of dealers willing to purchase or sell the security and the number of other potential buyers; (iii) the willingness of dealers to undertake to make a market in the security; and (iv) the nature of the marketplace trades, including the time needed to dispose of the security, the method of soliciting offers and the mechanics of transfer. The Investment Adviser, under guidelines approved by the Trust’s Board of Trustees, also will consider the marketability of a municipal lease obligation based upon an analysis of the general credit quality of the municipality issuing the obligation and the essentiality to the municipality of the property covered by the lease.

Currently, it is not the intention of the Prime Obligations Portfolio to invest more than 25% of the value of its respective total assets in municipal instruments whose issuers are located in the same state.

OPERATIONAL RISK . The Investment Adviser and other Portfolio service providers may experience disruptions or operating errors that could negatively impact the Portfolios. While service providers are required

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to have appropriate operational risk management policies and procedures, their methods of operational risk management may differ from those of the Portfolios in the setting of priorities, the personnel and resources available or the effectiveness of relevant controls. The Investment Adviser, through its monitoring and oversight of service providers, seeks to ensure that service providers take appropriate precautions to avoid and mitigate risks that could lead to disruptions and operating errors. However, it is not possible for the Investment Adviser or other Portfolio service providers to identify all of the operational risks that may affect a Portfolio or to develop processes and controls to completely eliminate or mitigate their occurrence or effects.

REPURCHASE AGREEMENTS. Each Portfolio may agree to purchase portfolio securities from domestic and foreign financial institutions subject to the seller’s agreement to repurchase them at a mutually agreed upon date and price (“repurchase agreements”). Repurchase agreements are considered to be loans under the 1940 Act. Although the securities subject to a repurchase agreement may bear maturities exceeding one year, settlement for the repurchase agreement will never be more than one year after the Portfolio’s acquisition of the securities and normally will be within a shorter period of time. Securities subject to repurchase agreements normally are held either by the Trust’s custodian or subcustodian (if any), or in the Federal Reserve/Treasury Book-Entry System. The seller under a repurchase agreement will be required to maintain the value of the securities subject to the agreement in an amount exceeding the repurchase price (including accrued interest). Default by the seller would, however, expose the Portfolio to possible loss because of adverse market action or delay in connection with the disposition of the underlying obligations. In addition, in the event of a bankruptcy, a Portfolio could suffer additional losses if a court determines that the Portfolio’s interest in the collateral is unenforceable. If a Portfolio enters into a repurchase agreement with a foreign financial institution, it may be subject to the same risks associated with foreign investments (see “Foreign Investments” above).

REVERSE REPURCHASE AGREEMENTS. Each Portfolio may borrow funds by selling portfolio securities to financial institutions such as banks and broker/dealers and agreeing to repurchase them at a mutually specified date and price (“reverse repurchase agreements”). The Portfolios may use the proceeds of reverse repurchase agreements to purchase other securities either maturing, or under an agreement to resell, on a date simultaneous with or prior to the expiration of the reverse repurchase agreement. Reverse repurchase agreements are considered to be borrowings under the 1940 Act. Reverse repurchase agreements involve the risk that the market value of the securities sold by the Portfolios may decline below the repurchase price. The Portfolios will pay interest on amounts obtained pursuant to a reverse repurchase agreement. While reverse repurchase agreements are outstanding, the Portfolios will segregate liquid assets in an amount at least equal to the market value of the securities, plus accrued interest, subject to the agreement.

STRIPPED SECURITIES. To the extent consistent with its investment objective and strategies, each Portfolio, including the U.S. Government Select Portfolio to the extent such stripped securities are Treasury Department strips, may purchase stripped securities. The Treasury Department has facilitated transfers of ownership of zero coupon securities by accounting separately for the beneficial ownership of particular interest coupon and principal payments on Treasury securities through the Federal Reserve book-entry record-keeping system. The Federal Reserve program as established by the Treasury Department is known as “Separate Trading of Registered Interest and Principal of Securities” or “STRIPS.” The Portfolios may purchase securities registered in the STRIPS program. Under the STRIPS program, a Portfolio will be able to have its beneficial ownership of zero coupon securities recorded directly in the book-entry record-keeping system in lieu of having to hold certificates or other evidences of ownership of the underlying U.S. Treasury securities.

Other types of stripped securities may be purchased by the Prime Obligations Portfolio, including stripped mortgage-backed securities (“SMBS”). SMBS usually are structured with two or more classes that receive different proportions of the interest and principal distributions from a pool of mortgage-backed obligations. A common type of SMBS will have one class receiving all of the interest, while the other class receives all of the principal. However, in some instances, one class will receive some of the interest and most of the principal while the other class will receive most of the interest and the remainder of the principal. If the underlying obligations experience greater than anticipated prepayments of principal, a Portfolio may fail to recoup fully its initial

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investment in these securities. The market value of the class consisting entirely of principal payments generally is extremely volatile in response to changes in interest rates. The yields on a class of SMBS that receives all or most of the interest generally are higher than prevailing market yields on other mortgage-backed obligations because their cash flow patterns also are volatile and there is a risk that the initial investment will not be recouped fully. SMBS issued by the U.S. government (or a U.S. government agency, instrumentality or sponsored enterprise) may be considered liquid under guidelines established by the Trust’s Board of Trustees if they can be disposed of promptly in the ordinary course of business at a value reasonably close to that used in the calculation of the NAV per share.

STRUCTURED SECURITIES. To the extent consistent with its investment objective and strategies, each Portfolio may purchase structured securities. These fixed-income instruments are structured to recast the investment characteristics of the underlying security or reference asset. If the issuer is a unit investment trust or other special purpose vehicle, the structuring will typically involve the deposit with or purchase by such issuer of specified instruments (such as commercial bank loans or securities) and/or the execution of various derivative transactions, and the issuance by that entity of one or more classes of securities (structured securities) backed by, or representing interests in, the underlying instruments. The cash flow on the underlying instruments may be apportioned among the newly issued structured securities to create securities with different investment characteristics, such as varying maturities, payment priorities and interest rate provisions, and the extent of such payments made with respect to structured securities is dependent on the extent of the cash flow on the underlying instruments. Investments in these securities may be structured as a class that is either subordinated or unsubordinated to the right of payment of another class. Subordinated structured securities typically have higher rates of return and present greater risks than unsubordinated structured products.

A Portfolio’s investments in these instruments are indirectly subject to the risks associated with derivative instruments, including, among others, credit risk, default or similar event risk, counterparty risk, interest rate risk, leverage risk and management risk. Because structured securities typically involve no credit enhancement, their credit risk generally will be equivalent to that of the underlying instruments. These securities generally are exempt from registration under the 1933 Act. Accordingly, there may be no established trading market for the securities and they may constitute illiquid investments. Structured securities may entail a greater degree of market risk than other types of debt securities because the investor bears the risk of the underlying security or reference asset. Structured securities may also be more volatile, less liquid, and more difficult to price accurately than less complex securities or more traditional debt securities.

SUPRANATIONAL BANK OBLIGATIONS. Each Portfolio, to the extent consistent with its investment objective and strategies, may invest in obligations of supranational banks. Supranational banks are international banking institutions designed or supported by national governments to promote economic reconstruction, development or trade among nations (e.g., the World Bank). Obligations of supranational banks may be supported by appropriated but unpaid commitments of their member countries and there is no assurance that these commitments will be undertaken or met in the future.

U.S. GOVERNMENT OBLIGATIONS. Examples of the types of U.S. government obligations that may be acquired by the Portfolios include U.S. Treasury Bills, Treasury Notes and Treasury Bonds and the obligations of Federal Home Loan Banks, Federal Farm Credit Banks, Federal Land Banks, the Federal Housing Administration, Farmers Home Administration, Export-Import Bank of the United States, Small Business Administration, Fannie Mae, Ginnie Mae, General Services Administration, Central Bank for Cooperatives, Freddie Mac, Federal Intermediate Credit Banks and the Maritime Administration.

Securities guaranteed as to principal and interest by the U.S. government or by its agencies, instrumentalities or sponsored enterprises also are deemed to include (i) securities for which the payment of principal and interest is backed by an irrevocable letter of credit issued by the U.S. government or by any agency, instrumentality or sponsored enterprise thereof, and (ii) participations in loans made to foreign governments or their agencies that are so guaranteed.

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The Portfolios may invest in a variety of U.S. Treasury obligations and obligations issued by or guaranteed by the U.S. government or by its agencies, instrumentalities or sponsored enterprises. Not all government obligations carry the same credit support. No assurance can be given that the U.S. government would provide financial support to its agencies, instrumentalities or sponsored enterprises if it were not obligated to do so by law. There is no assurance that these commitments will be undertaken or complied with in the future. In addition, the secondary market for certain participations in loans made to foreign governments or their agencies may be limited. In the absence of a suitable secondary market, such participations are generally considered illiquid.

VARIABLE AND FLOATING RATE INSTRUMENTS. Variable and floating rate instruments have interest rates that periodically are adjusted either at set intervals or that float at a margin in relation to a generally recognized index rate. These instruments include long-term variable and floating rate bonds (sometimes referred to as “put bonds”) where the Portfolio obtains at the time of purchase the right to put the bond back to the issuer or a third party at par at a specified date.

With respect to the variable and floating rate instruments that may be acquired by the Portfolios, the Investment Adviser will consider the earning power, cash flows and other liquidity ratios of the issuers and guarantors of such instruments and, if the instruments are subject to demand features, will monitor their financial status and ability to meet payment on demand. Where necessary to ensure that a variable or floating rate instrument meets the Portfolios’ quality requirements, the issuer’s obligation to pay the principal of the instrument will be backed by an unconditional bank letter or line of credit, guarantee or commitment to lend.

The Portfolios will invest in variable and floating rate instruments only when the Investment Adviser deems the investment to involve minimal credit risk. Unrated variable and floating rate instruments will be determined by the Investment Adviser to be of comparable quality at the time of the purchase to rated instruments that may be purchased by the Portfolios. In determining weighted average portfolio maturity, an instrument may, subject to the SEC’s regulations, be deemed to have a maturity shorter than its nominal maturity based on the period remaining until the next interest rate adjustment or the time the Portfolio involved can recover payment of principal as specified in the instrument. Variable and floating rate instruments eligible for purchase by the Portfolio include variable amount master demand notes, which permit the indebtedness thereunder to vary in addition to providing for periodic adjustments in the interest rate.

Variable and floating rate instruments that may be purchased by the Portfolios include variable amount master demand notes, which permit the indebtedness thereunder to vary in addition to providing for periodic adjustments in the interest rate. Variable and floating rate instruments held by a Portfolio will be subject to the Portfolio’s limitation on illiquid investments, absent a reliable trading market, when the Portfolio may not demand payment of the principal amount within seven days. Because there is no active secondary market for certain variable and floating rate instruments, they may be more difficult to sell if the issuer defaults on its payment obligations or during periods when the Portfolio is not entitled to exercise its demand rights. As a result, the Portfolio could suffer a loss with respect to these instruments.

YIELDS AND RATINGS. The yields on certain obligations, including the instruments in which the Portfolios may invest, are dependent on a variety of factors, including general market conditions, conditions in the particular market for the obligation, financial condition of the issuer, size of the offering, maturity of the obligation and ratings of the issue. The ratings of Standard & Poor’s ^® Ratings Services (“S&P”), Dominion Bond Rating Service Limited (“Dominion”), Moody’s Investors Service, Inc. (“Moody’s”) and Fitch Ratings (“Fitch”) represent their respective opinions as to the quality of the obligations they undertake to rate. Ratings, however, are general and are not absolute standards of quality. Consequently, obligations with the same rating, maturity and interest rate may have different market prices. For a more complete discussion of ratings, see Appendix A to this SAI.

Subject to the limitations stated in the Prospectus, if a security held by a Portfolio undergoes a rating revision, the Portfolio may continue to hold the security if the Investment Adviser determines such retention is warranted.

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ZERO COUPON BONDS. To the extent consistent with their respective investment objectives and strategies, the Portfolios may invest in zero coupon bonds. Zero coupon bonds are debt securities issued or sold at a discount from their face value and which do not entitle the holder to any periodic payment of interest prior to maturity or a specified date. The original issue discount varies depending on the time remaining until maturity or cash payment date, prevailing interest rates, the liquidity of the security and the perceived credit quality of the issuer. These securities also may take the form of debt securities that have been stripped of their unmatured interest coupons, the coupons themselves or receipts or certificates representing interests in such stripped debt obligations or coupons. The market prices of zero coupon bonds generally are more volatile than the market prices of interest bearing securities and are likely to respond to a greater degree to changes in interest rates than interest bearing securities having similar maturities and credit quality.

Zero coupon bonds involve the additional risk that, unlike securities that periodically pay interest to maturity, the Portfolio will realize no cash until a specified future payment date unless a portion of such securities is sold and, if the issuer of such securities defaults, the Portfolio may obtain no return at all on its investment. In addition, even though such securities do not provide for the payment of current interest in cash, the Portfolio is nonetheless required to accrue income on such investments for each taxable year and generally is required to distribute such accrued amounts (net of deductible expenses, if any) to avoid being subject to tax. Because no cash generally is received at the time of the accrual, the Portfolio may be required to liquidate other portfolio securities to obtain sufficient cash to satisfy federal tax distribution requirements applicable to the Portfolio.

INVESTMENT RESTRICTIONS

Each Portfolio is subject to the fundamental investment restrictions enumerated below which may be changed with respect to a particular Portfolio only by a vote of the holders of a majority of such Portfolio’s outstanding shares as described in “Description of Shares” on page 53.

No Portfolio may:

(1) Make loans, except through (a) the purchase of debt obligations in accordance with the Portfolio’s investment objective and strategies, (b) repurchase agreements with banks, brokers, dealers and other financial institutions, (c) loans of securities, and (d) loans to affiliates of the Portfolio to the extent permitted by law.

(2) Purchase or sell real estate or securities issued by real estate investment trusts but this restriction shall not prevent a Portfolio from investing directly or indirectly in portfolio instruments secured by real estate or interests therein.

(3) Invest in commodities or commodity contracts, except that each Portfolio may invest in currency and financial instruments and contracts that are commodities or commodity contracts.

(4) Invest in companies for the purpose of exercising control or management.

(5) Act as underwriter of securities, except as a Portfolio may be deemed to be an underwriter under the 1933 Act in connection with the purchase and sale of portfolio instruments in accordance with its investment objective and portfolio management policies.

(6) Make any investment inconsistent with the Portfolio’s classification as a diversified investment company under the 1940 Act.

(7) Purchase securities if such purchase would cause more than 25% in the aggregate of the market value of the total assets of a Portfolio to be invested in the securities of one or more issuers having their principal business activities in the same industry, provided that there is no limitation with respect to, and each Portfolio reserves freedom of action, when otherwise consistent with its investment strategies, to concentrate its investments in obligations issued or guaranteed by the U.S. government, its agencies or

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instrumentalities, obligations (other than commercial paper) issued or guaranteed by U.S. banks and U.S. branches of foreign banks and repurchase agreements and securities loans collateralized by such U.S. government obligations or such bank obligations. For the purpose of this restriction, state and municipal governments and their agencies and authorities are not deemed to be industries; as to utility companies, the gas, electric, water and telephone businesses are considered separate industries; personal credit finance companies and business credit finance companies are deemed to be separate industries; and wholly-owned finance companies are considered to be in the industries of their parents if their activities are primarily related to financing the activities of their parents.

(8) Borrow money, except that to the extent permitted by applicable law (a) a Portfolio may borrow from banks, other affiliated investment companies and other persons, and may engage in reverse repurchase agreements and other transactions which involve borrowings, in amounts up to 33-1/3% of its total assets (including the amount borrowed) or such other percentage permitted by law, (b) a Portfolio may borrow up to an additional 5% of its total assets for temporary purposes, (c) a Portfolio may obtain such short-term credits as may be necessary for the clearance of purchases and sales of portfolio securities, and (d) a Portfolio may purchase securities on margin. If due to market fluctuations or other reasons a Portfolio’s borrowings exceed the limitations stated above, the Trust will promptly reduce the borrowings of such Portfolio in accordance with the 1940 Act. In addition, as a matter of fundamental policy, a Portfolio will not issue senior securities to the extent such issuance would violate applicable law.

(9) Notwithstanding any of the Trust’s other fundamental investment restrictions (including, without limitation, those restrictions relating to issuer diversification, industry concentration and control), each Portfolio may: (a) purchase securities of other investment companies to the full extent permitted under Section 12 or any other provision of the 1940 Act (or any successor provision thereto) or under any regulation or order of the SEC; and (b) invest all or substantially all of its assets in a single open-end investment company or series thereof with substantially the same investment objective, strategies and fundamental restrictions as the Portfolio.

For the purposes of Investment Restriction Nos. 1 and 8 above, the Portfolios have received an exemptive order from the SEC permitting them to participate in lending and borrowing arrangements with affiliates.

In applying Investment Restriction No. 6 above, a security is considered to be issued by the entity, or entities, whose assets and revenues back the security. A guarantee of a security is not deemed to be a security issued by the guarantor when the value of all securities issued and guaranteed by the guarantor, and owned by a Portfolio, does not exceed 10% of the value of the Portfolio’s total assets.

The freedom of action reserved in Investment Restriction No. 7 with respect to U.S. branches of foreign banks is subject to the requirement that they are subject to the same regulation as domestic branches of U.S. banks. The freedom of action reserved with respect to foreign branches of U.S. banks is subject to the requirement that the domestic parent of the foreign branch be unconditionally liable in the event that the foreign branch failed to pay on its instruments for any reason. Obligations of U.S. branches of foreign banks may include certificates of deposit, bank and deposit notes, bankers’ acceptances and fixed time deposits. These obligations may be general obligations of the parent bank or may be limited to the issuing branch. Such obligations will meet the criteria for “Eligible Securities” as described in the Prospectus.

Except to the extent otherwise provided in Investment Restriction No. 7, for the purpose of such restriction in determining industry classification, a Portfolio may use any one of the following: the Bloomberg Industry Group Classification, S&P, J.J. Kenny Municipal Purpose Codes, FT Interactive Industrial Codes, Securities Industry Classification Codes or the Global Industry Classification Standard. For the purpose of determining the percentage of a Portfolio’s total assets invested in securities of issuers having their principal business activities in a particular industry, an asset-backed security will be classified separately based on the nature of its underlying assets.

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Securities held in escrow or separate accounts in connection with a Portfolio’s investment practices described in this SAI and the applicable Prospectus are not deemed to be mortgaged, pledged or hypothecated for purposes of the foregoing restrictions.

Notwithstanding Investment Restriction No. 8, each Portfolio intends, as a non-fundamental policy, to limit all borrowings to no more than 25% of its total assets (including the amount borrowed).

The Portfolios intend, as a non-fundamental policy, to diversify their investments in accordance with current SEC regulations. Investments in the securities of any single issuer (excluding cash, cash items, certain repurchase agreements, U.S. government securities and securities of other investment companies) will be limited to not more than 5% of the value of a Portfolio’s total assets at the time of purchase, except that 25% of the value of the total assets of each Portfolio may be invested in the securities of any one issuer for a period of up to three Business Days. Subject to certain exceptions, immediately after the acquisition of any demand features or guarantees (i.e., generally, the right to sell the security at a price equal to its approximate amortized cost (for a demand feature) or principal amount (for a guarantee) plus accrued interest), with respect to 75% of the assets of a Portfolio, no more than 10% of the Portfolio’s total assets may be invested in securities issued by or subject to demand features or guarantees issued by the same issuer. In accordance with SEC regulations, each Portfolio will limit its investments in securities that are rated in the two highest short-term rating categories as determined by at least two NRSROs (or one NRSRO if the security is rated by only one NRSRO) but which are not First Tier Securities (as defined in Rule 2a-7 under the 1940 Act) or, if unrated, are not of comparable quality to First Tier Securities (“Second Tier Securities”) to 3% of its total assets, with investments in any one issuer being limited to no more than one-half of one percent of its total assets.

Any Investment Restriction which involves a maximum percentage (other than the restriction set forth in Investment Restriction No. 8) will not be considered violated unless an excess over the percentage occurs immediately after, and is caused by, an acquisition of securities or assets of, or borrowings by, a Portfolio. The 1940 Act requires that if the asset coverage for borrowings at any time falls below the limits described in Investment Restriction No. 8, the Portfolio will, within three days thereafter (not including Sundays and holidays), reduce the amount of its borrowings to an extent that the net asset coverage of such borrowings shall conform to such limits.

Although the foregoing Investment Restrictions would permit the Portfolios to acquire options, enter into forward currency contracts and engage in short sales and interest rate and currency swaps, they are not currently permitted to engage in these transactions under SEC regulations.

DISCLOSURE OF PORTFOLIO HOLDINGS

The Board of Trustees of the Trust has adopted a policy on disclosure of portfolio holdings, which it believes is in the best interest of each Portfolio’s shareholders. The policy provides that neither the Portfolios nor their Investment Adviser, Distributor or any agent, or any employee thereof (“Portfolio Representative”) will disclose a Portfolio’s portfolio holdings information to any person other than in accordance with the policy. For purposes of the policy, “portfolio holdings information” means a Portfolio’s actual portfolio holdings, as well as non-public information about its trading strategies or pending transactions including the portfolio holdings, trading strategies or pending transactions of any actively managed commingled fund portfolio which contains identical holdings as the Portfolio. Under the policy, neither a Portfolio nor any Portfolio Representative may solicit or accept any compensation or other consideration in connection with the disclosure of portfolio holdings information. A Portfolio Representative may provide portfolio holdings information to third parties if such information has been included in a Portfolio’s public filings with the SEC or is disclosed on the Trust’s publicly accessible web site. Information posted on the Trust’s web site may be separately provided to any person commencing the day after it is first published on the Trust’s web site.

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Portfolio holdings information that is not filed with the SEC or posted on the publicly available web site may be provided to third parties only if the third party recipients are required to keep all portfolio holdings information confidential and are prohibited from trading on the information they receive. Disclosure to such third parties must be approved in advance by the Trust’s Chief Compliance Officer (“CCO”). Disclosure to providers of auditing, custody, proxy voting and other similar services for the Portfolios, as well as rating and ranking organizations, will generally be permitted; however, information may be disclosed to other third parties (including, without limitation, individuals, institutional investors, and intermediaries that sell shares of a Portfolio) only upon approval by the CCO, who must first determine that the Portfolio has a legitimate business purpose for doing so. In general, each recipient of non-public portfolio holdings information must sign a confidentiality and non-trading agreement, although this requirement will not apply when the recipient is otherwise subject to a duty of confidentiality as determined by the CCO. In accordance with the policy, the recipients who receive non-public portfolio holdings information on an ongoing basis are as follows: the Investment Adviser and its affiliates, the Portfolios’ independent registered public accounting firm, the Portfolios’ custodian, the Portfolios’ legal counsel, the Portfolios’ financial printer (R.R. Donnelley); the Portfolios’ proxy voting service (RiskMetrics Group); certain rating and ranking organizations, S&P and Moody’s; and the following vendors that provide portfolio analytical tools, Vestek (aka Thomson Financial), Citigroup, Barclays Capital and FactSet. These entities are obligated to keep such information confidential. Third-party providers of custodial or accounting services to a Portfolio may release non-public portfolio holdings information of the Portfolio only with the permission of Portfolio Representatives. From time to time, portfolio holdings information may be provided to broker-dealers solely in connection with a Portfolio seeking portfolio securities trading recommendations. In providing this information reasonable precautions, including limitations on the scope of the portfolio holdings information disclosed, are taken in an effort to avoid any potential misuse of the disclosed information.

The Portfolios currently publish on the Trust’s web site, northerninstitutionalfunds.com, complete month-end portfolio holdings for each Portfolio subject to at least a ten (10) calendar day lag between the date of the information and the date on which the information is disclosed. The Portfolios also publish on the Trust’s website, no later than the fifth business day of each month and for a period of not less than six months, certain information regarding each Portfolio’s portfolio holdings as of the last business day of the prior month. A Portfolio may publish on the web site complete portfolio holdings information more frequently if it has a legitimate business purpose for doing so.

Portfolio holdings also are currently disclosed through required filings with the SEC. Each Portfolio files its portfolio holdings with the SEC for each fiscal quarter on Form N-CSR (with respect to each annual period and semiannual period) and Form N-Q (with respect to the first and third quarters of the Portfolio’s fiscal year). Certain portfolio information with respect to the Portfolios will be provided in monthly holdings reports to the SEC on Form N-MFP. Form N-MFP will be made available to the public by the SEC 60 days after the end of the month to which the information pertains, and a link to each of the most recent 12 months of filings on Form N-MFP will be provided on the Trust’s web site. Shareholders may obtain a Portfolio’s Forms N-CSR, N-Q and N-MFP filings on the SEC’s web site at sec.gov. In addition, the Portfolios’ Forms N-CSR, N-Q and N-MFP filings may be reviewed and copied at the SEC’s public reference room in Washington, DC. You may call the SEC at 1-800-SEC-0330 for information about the SEC’s web site or the operation of the public reference room.

Under the policy, the Board of Trustees is to receive information, on a quarterly basis, regarding any other disclosures of non-public portfolio holdings information that were permitted during the preceding quarter.

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ADDITIONAL TRUST INFORMATION