PROSPECTUS May 1, Agency Shares

Transcription

1 Dreyfus Institutional Reserves Funds Dreyfus Institutional Reserves Money Fund Class/Tiker Ageny shares DRGXX Dreyfus Institutional Reserves Treasury Fund Class/Tiker Ageny shares DGYXX Dreyfus Institutional Reserves Treasury Prime Fund Class/Tiker Ageny shares DANXX PROSPECTUS May 1, 2010 Ageny Shares As with all mutual funds, the Seurities and Exhange Commission has not approved or disapproved these seurities or passed upon the adequay of this prospetus. Any representation to the ontrary is a riminal offense.

2 June 1, 2010 DREYFUS CASH MANAGEMENT FUNDS Supplement to the Current Prospetus The Seurities and Exhange Commission has reently amended its regulations with respet to money market funds. Beginning June 30, 2010, a money market fund will be required to limit its weighted average maturity (WAM) to 60 days or less, and its weighted average life to maturity (WAL) to 120 days. Prior to then, eah fund is subjet to a 90-day maximum WAM and is not subjet to a maximum WAL requirement. CMGT-S0610

3 May 3, 2010 DREYFUS MONEY MARKET FUNDS Supplement to the Current Prospetus The Seurities and Exhange Commission has reently amended its regulations with respet to money market funds. Beginning May 28, 2010, all money market funds will be required to omply with SEC requirements with respet to the liquidity of the funds investments. Speifially, taxable money market funds will be required to hold at least 10% of their total assets in daily liquid assets and all money market funds will be required to hold at least 30% of their total assets in weekly liquid assets. Daily liquid assets inlude ash (inluding demand deposits), diret obligations of the U.S. Government and seurities (inluding repurhase agreements) that will mature or are subjet to a demand feature that is exerisable and payable within one business day. Weekly liquid assets inlude ash (inluding demand deposits), diret obligations of the U.S. Government, ageny disount notes with remaining maturities of 60 days or less, and seurities (inluding repurhase agreements) that will mature or are subjet to a demand feature that is exerisable and payable within five business days. Also beginning May 28, 2010, new limits will be plaed on the ability of a money market fund to aquire seond-tier seurities. Speifially, money market funds will be prohibited from (i) investing more than 3% of total assets in seond-tier seurities, (ii) investing more than 1 2 of 1% of total assets in seond-tier seurities issued by any single issuer, and (iii) aquiring seond-tier seurities with a remaining maturity of more than 45 days. In addition, beginning June 30, 2010, a money market fund will be required to limit its dollar-weighted average portfolio maturity to 60 days or less, and its dollar-weighted average life (portfolio maturity measured without referene to any maturity shortening provisions of adjustable rate seurities by referene to their interest rate reset dates) to 120 days. DRY-MMF-0510

4 Contents Fund Summary Dreyfus Institutional Reserves Money Fund 1 Dreyfus Institutional Reserves Treasury Fund 4 Dreyfus Institutional Reserves Treasury Prime Fund 7 Fund Details Goal and Approah 10 Investment Risks 12 Management 15 Shareholder Guide Buying and Selling Shares 16 Distributions and Taxes 19 Servies for Fund Investors 20 Finanial Highlights 21 For More Information See bak over.

5 Dreyfus Institutional Reserves Money Fund INVESTMENT OBJECTIVE Fund Summary The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. FEES AND EXPENSES This table desribes the fees and expenses that you may pay if you buy and hold shares of the fund. The Dreyfus Corporation (Dreyfus) has agreed to pay all of the fund expenses, exept management fees, Rule 12b-1 fees, and ertain other expenses, inluding the fees and expenses of the non-interested Board members and their ounsel. Annual fund operating expenses (expenses that you pay eah year as perentage of the value of your investment) Management fees 0.14 Rule 12b-1 fee 0.15 Other expenses * 0.00 Total annual fund operating expenses * 0.29 * Amounts do not reflet the fee paid by the fund to the U.S. Treasury Department in onnetion with the fund s partiipation under the Treasury Department s Temporary Guarantee Program for Money Market Funds (the Program). If the Program fee had been refleted, Other expenses would have been 0.03% and Total annual fund operating expenses would have been 0.32%. These fees would have refleted the fund s partiipation in the Program for the period from Deember 19, 2008 through September 18, 2009 (the termination date of the fund s partiipation in the Program). EXAMPLE The Example is intended to help you ompare the ost of investing in the fund with the ost of investing in other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indiated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return eah year and that the fund s operating expenses remain the same. Although your atual osts may be higher or lower, based on these assumptions your osts would be: 1 Year 3 Years 5 Years 10 Years $30 $93 $163 $368 PRINCIPAL INVESTMENT STRATEGY As a money market fund, the fund is subjet to maturity, quality and diversifiation requirements designed to help it maintain a stable share prie. To pursue its goal, the fund normally invests in a diversified portfolio of highquality, dollar-denominated short-term debt seurities, inluding: seurities issued or guaranteed as to prinipal and interest by the U.S. government or its agenies or instrumentalities; ertifiates of deposit, time deposits, bankers aeptanes and other short-term seurities issued by domesti or foreign banks or thrifts or their subsidiaries or branhes; repurhase agreements, inluding tri-party repurhase agreements; asset-baked seurities; muniipal seurities; domesti and foreign ommerial paper, and other short-term orporate obligations, inluding those with floating or variable rates of interest; and obligations issued or guaranteed by one or more foreign governments or any of their politial subdivisions or agenies. The fund may invest more than 25% of its net assets in domesti or dollar-denominated foreign bank obligations. 1

6 PRINCIPAL RISKS An investment in the fund is not insured or guaranteed by the Federal Deposit Insurane Corporation (FDIC) or any other government ageny. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. The fund s yield will flutuate as the short-term seurities in its portfolio mature and the proeeds are reinvested in seurities with different interest rates. Additionally, while the fund has maintained a onstant share prie sine ineption, and will ontinue to try to do so, neither The Dreyfus Corporation nor its affiliates are required to make a apital infusion, enter into a apital support agreement or take other ations to prevent the fund s share prie from falling below $1.00. The following are the prinipal risks that ould redue the fund s inome level and/or share prie: Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. Credit risk. Failure of an issuer to make timely interest or prinipal payments, or a deline or pereption of a deline in the redit quality of a seurity, an ause the seurity s prie to fall, potentially lowering the fund s share prie. The redit quality of the seurities held by the fund an hange rapidly in ertain market environments, and the default of a single holding ould have the potential to ause signifiant deterioration of the fund s net asset value. Liquidity risk. When there is little or no ative trading market for speifi types of seurities, it an beome more diffiult to sell the seurities at or near their pereived value. In suh a market, the value of suh seurities may fall dramatially, potentially lowering the fund s share prie, even during periods of delining interest rates. Also, during suh periods, redemptions by a few large investors in the fund may have a signifiant adverse effet on the fund s net asset value and remaining fund shareholders. Banking industry risk. The risks generally assoiated with onentrating investments in the banking industry, suh as interest rate risk, redit risk, and regulatory developments relating to the banking industry. Foreign investment risk. The risks generally assoiated with dollar-denominated foreign investments, suh as eonomi and politial developments, seizure or nationalization of deposits, imposition of taxes or other restritions on payment of prinipal and interest. Government seurities risk. Not all obligations of the U.S. government, its agenies and instrumentalities are baked by the full faith and redit of the U.S. Treasury. Some obligations are baked only by the redit of the issuing ageny or instrumentality, and in some ases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agenies or instrumentalities of a seurity held by the fund does not apply to the market value of suh seurity or to shares of the fund itself. Counterparty risk. The risk that a ounterparty in a repurhase agreement ould fail to honor the terms of its agreement. PERFORMANCE The following bar hart and table provide some indiation of the risks of investing in the fund. The bar hart shows hanges in the performane of the fund s Ageny shares from year to year. The table shows the fund s average annual total returns over time. Of ourse, past performane (before and after taxes) is no guarantee of future results. More reent performane information may be available at The performane figures for the fund s Ageny shares prior to September 13, 2008 represent the performane of the predeessor fund s Ageny shares. Year-by-year total returns as of 12/31 eah year (%) 2

7 Ageny Shares Best Quarter (Q3, 2007): 1.30%. Worst Quarter (Q4, 2009): 0.00%. Average annual total returns (as of 12/31/09) Ageny shares Sine Ineption 1 Year (7/12/06) 0.42% 3.07% Institutions may all toll-free for the urrent yield of the fund s Ageny shares. Individuals or entities for whom institutions may purhase or redeem shares should all the institution diretly. PORTFOLIO MANAGEMENT The fund's investment adviser is The Dreyfus Corporation. PURCHASE AND SALE OF FUND SHARES In general, the fund s minimum initial investment is $275,000,000 and there is no minimum subsequent investment. You may sell your shares on any business day by alling or by visiting TAX INFORMATION The fund antiipates that dividends and other distributions paid by the fund are subjet to federal inome tax, and may be subjet to state and loal taxes, exept when your investment is through an IRA 401(k) plan or other taxadvantaged investment plan. PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES If you purhase shares through a broker-dealer or other finanial intermediary (suh as a bank), the fund and its related ompanies may pay the intermediary for the sale of fund shares and related servies. These payments may reate a onflit of interest by influening the broker-dealer or other intermediary and your salesperson to reommend the fund over another investment. Ask your salesperson or visit your finanial intermediary s website for more information. 3

8 Dreyfus Institutional Reserves Treasury Fund INVESTMENT OBJECTIVE Fund Summary The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. FEES AND EXPENSES This table desribes the fees and expenses that you may pay if you buy and hold shares of the fund. Dreyfus has agreed to pay all of the fund expenses, exept management fees, Rule 12b-1 fees, and ertain other expenses, inluding the fees and expenses of the non-interested Board members and their ounsel. Annual fund operating expenses (expenses that you pay eah year as perentage of the value of your investment) Management fees 0.14 Rule 12b-1 fee 0.15 Other expenses * 0.00 Total annual fund operating expenses * 0.29 * Amounts do not reflet the fee paid by the fund to the U.S. Treasury Department in onnetion with the fund s partiipation under the Treasury Department s Temporary Guarantee Program for Money Market Funds (the Program). If the Program fee had been refleted, Other expenses would have been 0.03% and Total annual fund operating expenses would have been 0.32%. These fees would have refleted the fund s partiipation in the Program for the period from Deember 19, 2008 through April 30, 2009 (the termination date of the fund s partiipation in the Program). EXAMPLE The Example is intended to help you ompare the ost of investing in the fund with the ost of investing in other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indiated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return eah year and that the fund s operating expenses remain the same. Although your atual osts may be higher or lower, based on these assumptions your osts would be: 1 Year 3 Years 5 Years 10 Years $30 $93 $163 $368 PRINCIPAL INVESTMENT STRATEGY As a money market fund, the fund is subjet to maturity, quality and diversifiation requirements designed to help it maintain a stable share prie. To pursue its goal, the fund normally invests only in U.S. Treasury seurities baked by the full faith and redit of the U.S. government and in repurhase agreements, inluding tri-party repurhase agreements, ollateralized by U.S. Treasury seurities and other seurities issued or guaranteed as to prinipal and interest by the U.S. government. PRINCIPAL RISKS An investment in the fund is not insured or guaranteed by the Federal Deposit Insurane Corporation (FDIC) or any other government ageny. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. 4

9 The fund s yield will flutuate as the short-term seurities in its portfolio mature and the proeeds are reinvested in seurities with different interest rates. Additionally, while the fund has maintained a onstant share prie sine ineption, and will ontinue to try to do so, neither Dreyfus nor its affiliates are required to make a apital infusion, enter into a apital support agreement or take other ations to prevent the fund s share prie from falling below $1.00. The following are the prinipal risks that ould redue the fund s inome level and/or share prie: Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. Liquidity risk. When there is little or no ative trading market for speifi types of seurities, it an beome more diffiult to sell the seurities at or near their pereived value. In suh a market, the value of suh seurities may fall dramatially, potentially lowering the fund s share prie, even during periods of delining interest rates. Also, during suh periods, redemptions by a few large investors in the fund may have a signifiant adverse effet on the fund s net asset value and remaining fund shareholders. U.S. Treasury seurities risk. A seurity baked by the U.S. Treasury or the full faith and redit of the United States is guaranteed only as to the timely payment of interest and prinipal when held to maturity, but the market pries for suh seurities are not guaranteed and will flutuate. Counterparty risk. The risk that a ounterparty in a repurhase agreement ould fail to honor the terms of its agreement. PERFORMANCE The bar hart and table shown illustrate the risks of investing in the fund. The bar hart shows hanges in the performane of the fund s Ageny shares from year to year. The table shows the average annual total returns of the fund s Ageny shares over time. The fund s past performane (before and after taxes) is no guarantee of future results. More reent performane information may be available at The performane figures for the fund s Ageny shares prior to September 13, 2008 represent the performane of the predeessor fund s Ageny shares. Year-by-year total returns as of 12/31 eah year (%) Ageny shares Best Quarter (Q1, 2007): 1.23%. Worst Quarter (Q4, 2009): 0.00%. Average annual total returns (as of 12/31/09) Ageny shares 1 Year Sine Ineption (11/09/06) 0.00% 2.16% 5

10 Institutions may all toll-free for the urrent yield of the fund s Ageny shares. Individuals or entities for whom institutions may purhase or redeem shares should all the institution diretly. PORTFOLIO MANAGEMENT The fund s investment adviser is The Dreyfus Corporation. PURCHASE AND SALE OF FUND SHARES In general, the fund s minimum initial investment is $275,000,000 and there is no minimum subsequent investment. You may sell your shares on any business day by alling or by visiting TAX INFORMATION The fund antiipates that dividends and other distributions paid by the fund are subjet to federal inome tax, and may be subjet to state and loal taxes, exept when your investment is through an IRA 401(k) plan or other taxadvantaged investment plan. PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES If you purhase shares through a broker-dealer or other finanial intermediary (suh as a bank), the fund and its related ompanies may pay the intermediary for the sale of fund shares and related servies. These payments may reate a onflit of interest by influening the broker-dealer or other intermediary and your salesperson to reommend the fund over another investment. Ask your salesperson or visit your finanial intermediary s website for more information. 6

11 Dreyfus Institutional Reserves Treasury Prime Fund INVESTMENT OBJECTIVE Fund Summary The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. FEES AND EXPENSES This table desribes the fees and expenses that you may pay if you buy and hold shares of the fund. Dreyfus has agreed to pay all of the fund expenses, exept management fees, Rule 12b-1 fees, and ertain other expenses, inluding the fees and expenses of the non-interested Board members and their ounsel. Annual fund operating expenses (expenses that you pay eah year as perentage of the value of your investment) Management fees 0.16 Rule 12b-1 fee 0.14 Other expenses * 0.00 Total annual fund operating expenses * 0.30 * Amounts do not reflet the fee paid by the fund to the U.S. Treasury Department in onnetion with the fund s partiipation under the Treasury Department s Temporary Guarantee Program for Money Market Funds (the Program). If the Program fee had been refleted, Other expenses would have been 0.01% and Total annual fund operating expenses would have been 0.31%. These fees would have refleted the fund s partiipation in the Program for the period from Deember 19, 2008 through April 30, 2009 (the termination date of the fund s partiipation in the Program). EXAMPLE The Example is intended to help you ompare the ost of investing in the fund with the ost of investing in other mutual funds. The Example assumes that you invest $10,000 in the fund for the time periods indiated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return eah year and that the fund s operating expenses remain the same. Although your atual osts may be higher or lower, based on these assumptions your osts would be: 1 Year 3 Years 5 Years 10 Years $31 $97 $169 $381 PRINCIPAL INVESTMENT STRATEGY As a money market fund, the fund is subjet to maturity, quality and diversifiation requirements designed to help it maintain a stable share prie. To pursue its goal, the fund normally invests only in U.S. Treasury seurities baked by the full faith and redit of the U.S. government. PRINCIPAL RISKS An investment in the fund is not insured or guaranteed by the Federal Deposit Insurane Corporation (FDIC) or any other government ageny. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. 7

12 The fund s yield will flutuate as the short-term seurities in its portfolio mature and the proeeds are reinvested in seurities with different interest rates. Additionally, while the fund has maintained a onstant share prie sine ineption, and will ontinue to try to do so, neither Dreyfus nor its affiliates are required to make a apital infusion, enter into a apital support agreement or take other ations to prevent the fund s share prie from falling below $1.00. The following are the prinipal risks that ould redue the fund s inome level and/or share prie: Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. U.S. Treasury seurities risk. A seurity baked by the U.S. Treasury or the full faith and redit of the United States is guaranteed only as to the timely payment of interest and prinipal when held to maturity, but the market pries for suh seurities are not guaranteed and will flutuate. PERFORMANCE The bar hart and table shown illustrate the risks of investing in the fund. The bar hart shows hanges in the performane of the fund s Ageny shares from year to year. The table shows the average annual total returns of the fund s Ageny shares over time. The fund s past performane (before and after taxes) is no guarantee of future results. More reent performane information may be available at The performane figures for the fund s Ageny shares prior to September 13, 2008 represent the performane of the predeessor fund s Ageny shares. Year-by-year total returns as of 12/31 eah year (%) Ageny shares Best Quarter (Q1, 2009): 0.00%. Worst Quarter (Q4,2009): 0.00%. Average annual total returns (as of 12/31/09) Ageny shares Sine Ineption 1 Year ( 09/13/08 ) 0.00% 0.12% Institutions may all toll-free for the urrent yield of the fund s Ageny shares. Individuals or entities for whom institutions may purhase or redeem shares should all the institution diretly. PORTFOLIO MANAGEMENT The fund s investment adviser is The Dreyfus Corporation. 8

13 PURCHASE AND SALE OF FUND SHARES In general, the fund s minimum initial investment is $275,000,000 and there is no minimum subsequent investment. You may sell your shares on any business day by alling or by visiting TAX INFORMATION The fund antiipates that dividends and other distributions paid by the fund are subjet to federal inome tax, and may be subjet to state and loal taxes, exept when your investment is through an IRA 401(k) plan or other taxadvantaged investment plan. PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES If you purhase shares through a broker-dealer or other finanial intermediary (suh as a bank), the fund and its related ompanies may pay the intermediary for the sale of fund shares and related servies. These payments may reate a onflit of interest by influening the broker-dealer or other intermediary and your salesperson to reommend the fund over another investment. Ask your salesperson or visit your finanial intermediary s website for more information. 9

14 Fund Details GOAL AND APPROACH Eah fund is a money market mutual fund with a separate investment portfolio. The operations and results of one fund are unrelated to those of eah other fund. This ombined prospetus has been prepared for the onveniene of investors so that investors an onsider three investment hoies in one doument. Eah fund seeks to maintain a stable share prie of $1.00 (although it annot guarantee that it will always do so) and is designed to offer urrent investment inome and high liquidity. The main differene among the funds are the seurities in whih they invest. Dreyfus Institutional Reserves Money Fund invests in a range of high quality money market instruments. Dreyfus Institutional Reserves Treasury Fund invests only in U.S. Treasury seurities and repurhase agreements ollateralized by U.S. Treasury seurities and other seurities issued or guaranteed as to prinipal and interest by the U.S. government. Dreyfus Institutional Reserves Treasury Prime Fund invests only in U.S. Treasury seurities. Eah fund is required to maintain an average dollar-weighted portfolio maturity of 90 days or less and buy individual seurities that have remaining maturities of 13 months or less. Dreyfus Institutional Reserves Money Fund The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. To pursue its goal, the fund invests in a diversified portfolio of high-quality, dollardenominated short-term debt seurities, inluding: seurities issued or guaranteed as to prinipal and interest by the U.S. government or its agenies or instrumentalities ertifiates of deposit, time deposits, bankers aeptanes and other short-term seurities issued by domesti or foreign banks or thrifts or their subsidiaries or branhes repurhase agreements, inluding tri-party repurhase agreements asset-baked seurities muniipal seurities domesti and foreign ommerial paper, and other short-term orporate obligations, inluding those with floating or variable rates of interest obligations issued or guaranteed by one or more foreign governments or any of their politial subdivisions or agenies Generally, the fund is required to invest at least 95% of its assets in the seurities of issuers with the highest redit rating or the unrated equivalent as determined by Dreyfus, with the remainder invested in seurities with the seond-highest redit rating. The fund may invest more than 25% of its net assets in domesti or dollardenominated foreign bank obligations. Dreyfus Institutional Reserves Treasury Fund The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. To pursue its goal, the fund invests only in U.S. Treasury seurities baked by the full faith and redit of the U.S. government and in repurhase agreements, inluding tri-party repurhase agreements, 10

15 ollateralized by U.S. Treasury seurities and other seurities issued or guaranteed as to prinipal and interest by the U.S. government. Dreyfus Institutional Reserves Treasury Prime Fund The fund seeks as high a level of urrent inome as is onsistent with the preservation of apital and the maintenane of liquidity. To pursue its goal, the fund invests only in U.S. Treasury seurities baked by the full faith and redit of the U.S. government. 11

16 INVESTMENT RISKS An investment in the fund is not insured or guaranteed by the Federal Deposit Insurane Corporation (FDIC) or any other government ageny. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund. The fund s yield will flutuate as the short-term seurities in its portfolio mature and the proeeds are reinvested in seurities with different interest rates. Additionally, while the fund has maintained a onstant share prie sine ineption, and will ontinue to try to do so, neither Dreyfus nor its affiliates are required to make a apital infusion, enter into a apital support agreement or take other ations to prevent the fund s share prie from falling below $1.00. The following are the prinipal risks that ould redue the fund s inome level and/or share prie: Dreyfus Institutional Reserves Money Fund Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. The fund s yield will vary; it is not fixed for a speifi period like the yield on a bank ertifiate of deposit. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. However, the extremely short maturities of the seurities held in money market portfolios - a means of ahieving an overall fund objetive of prinipal safety - redues their potential for prie flutuation. A low interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of fund assets and ould impair the fund s ability to maintain a stable net asset value. Credit risk. Failure of an issuer to make timely interest or prinipal payments, or a deline or pereption of a deline in the redit quality of a seurity, an ause the seurity s prie to fall, potentially lowering the fund s share prie. Although the fund invests only in high-quality debt seurities, any of the fund s holdings ould have its redit rating downgraded or ould default. The redit quality of the seurities held by the fund an hange rapidly in ertain market environments, and the default of a single holding ould have the potential to ause signifiant deterioration of the fund s net asset value. Liquidity risk. When there is little or no ative trading market for speifi types of seurities, it an beome more diffiult to sell the seurities at or near their pereived value. In suh a market, the value of suh seurities may fall dramatially, potentially lowering the fund s share prie, even during periods of delining interest rates. Also, during suh periods, redemptions by a few large investors in the fund may have a signifiant adverse effet on the fund s net asset value and remaining fund shareholders. Banking industry risk. The risks generally assoiated with onentrating investments in the banking industry, suh as interest rate risk, redit risk, and regulatory developments relating to the banking industry. Foreign investment risk. The risks generally assoiated with dollar-denominated foreign investments, suh as eonomi and politial developments, seizure or nationalization of deposits, imposition of taxes or other restritions on payment of prinipal and interest. Government seurities risk. Not all obligations of the U.S. government, its agenies and instrumentalities are baked by the full faith and redit of the U.S. Treasury. Some obligations are baked only by the redit of the issuing ageny or instrumentality, and in some ases there may be some risk of default by the issuer. Any guarantee by the U.S. government or its agenies or instrumentalities of a seurity held by the fund does not apply to the market value of suh seurity or to shares of the fund itself. A seurity baked by the U.S. Treasury or the full faith and redit of the United States is guaranteed only as to the timely payment of interest and prinipal when held to maturity. In addition, beause many types of U.S. government seurities trade 12

17 atively outside the United States, their pries may rise and fall as hanges in global eonomi onditions affet the demand for these seurities. Counterparty risk. The risk that a ounterparty in a repurhase agreement ould fail to honor the terms of its agreement. In addition to the prinipal risks desribed above, the fund is subjet to the following additional risk. Muniipal seurities risk. Investments in muniipal seurities may be affeted by a variety of fators in the ities, states and regions in whih the fund invests, as well as the muniipal market as a whole. Speial fators, suh as legislative hanges and loal and business developments, may adversely affet the yield and/or market value of the fund s investments in muniipal seurities. Other fators inlude the general onditions of the muniipal seurities market, the size of a partiular offering, the maturity of the obligation and the rating of the issue. Dreyfus Institutional Reserves Treasury Fund Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. The fund s yield will vary; it is not fixed for a speifi period like the yield on a bank ertifiate of deposit. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. However, the extremely short maturities of the seurities held in money market portfolios - a means of ahieving an overall fund objetive of prinipal safety - redues their potential for prie flutuation. A low interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of fund assets and ould impair the fund s ability to maintain a stable net asset value. Liquidity risk. When there is little or no ative trading market for speifi types of seurities, it an beome more diffiult to sell the seurities at or near their pereived value. In suh a market, the value of suh seurities may fall dramatially, potentially lowering the fund s share prie, even during periods of delining interest rates. Also, during suh periods, redemptions by a few large investors in the fund may have a signifiant adverse effet on the fund s net asset value and remaining fund shareholders. U.S. Treasury seurities risk. A seurity baked by the U.S. Treasury or the full faith and redit of the United States is guaranteed only as to the timely payment of interest and prinipal when held to maturity, but the market pries for suh seurities are not guaranteed and will flutuate. Beause U.S. Treasury seurities trade atively outside the United States, their pries may rise and fall as hanges in global eonomi onditions affet the demand for these seurities. Counterparty risk. The risk that a ounterparty in a repurhase agreement ould fail to honor the terms of its agreement. Dreyfus Institutional Reserves Treasury Prime Fund Interest rate risk. This risk refers to the deline in the pries of fixed-inome seurities that may aompany a rise in the overall level of interest rates. The fund s yield will vary; it is not fixed for a speifi period like the yield on a bank ertifiate of deposit. A sharp and unexpeted rise in interest rates ould ause a money market fund s share prie to drop below a dollar. However, the extremely short maturities of the seurities held in money market portfolios - a means of ahieving an overall fund objetive of prinipal safety - redues their potential for prie flutuation. A low interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of fund assets and ould impair the fund s ability to maintain a stable net asset value. U.S. Treasury seurities risk. A seurity baked by the U.S. Treasury or the full faith and redit of the United States is guaranteed only as to the timely payment of interest and prinipal when held to maturity, but the market pries for suh seurities are not guaranteed and will flutuate. Beause U.S. Treasury seurities trade 13

18 atively outside the United States, their pries may rise and fall as hanges in global eonomi onditions affet the demand for these seurities. 14

19 MANAGEMENT The investment adviser for the fund is The Dreyfus Corporation (Dreyfus), 200 Park Avenue, New York, New York Founded in 1947, Dreyfus manages approximately $290 billion in 190 mutual fund portfolios. For the past fisal year, Dreyfus Institutional Reserves Money Fund, Dreyfus Institutional Reserves Treasury Fund and Dreyfus Institutional Reserves Treasury Prime Fund eah paid Dreyfus a management fee at an annual rate of 0.14%, 0.14% and 0.16%, respetively, of the value of suh fund s average daily net assets. A disussion regarding the basis for the board s approving the funds management agreement with Dreyfus is available in the funds annual report for the fisal period ended Deember 31, Dreyfus is the primary mutual fund business of The Bank of New York Mellon Corporation (BNY Mellon), a global finanial servies ompany foused on helping lients move and manage their finanial assets, operating in 34 ountries and serving more than 100 markets. BNY Mellon is a leading provider of finanial servies for institutions, orporations and high-net-worth individuals, providing asset and wealth management, asset serviing, issuer servies, and treasury servies through a worldwide lient-foused team. BNY Mellon has more than $22.3 trillion in assets under ustody and administration and $1.1 trillion in assets under management, and it servies more than $12.0 trillion in outstanding debt. Additional information is available at The Dreyfus asset management philosophy is based on the belief that disipline and onsisteny are important to investment suess. For eah fund, Dreyfus seeks to establish lear guidelines for portfolio management and to be systemati in making deisions. This approah is designed to provide eah fund with a distint, stable identity. MBSC Seurities Corporation (MBSC), a wholly owned subsidiary of Dreyfus, serves as distributor of the fund and for the other funds in the Dreyfus Family of Funds. Rule 12b-1 fees and shareholder servies fees, as appliable, are paid to MBSC for finaning the sale and distribution of fund shares and for providing shareholder aount servie and maintenane, respetively. Dreyfus or MBSC may provide ash payments out of its own resoures to finanial intermediaries that sell shares of funds in the Dreyfus Family of Funds or provide other servies. Suh payments are separate from any sales harges, 12b-1 fees and/or shareholder servies fees or other expenses that may be paid by a fund to those intermediaries. Beause those payments are not made by fund shareholders or the fund, the fund s total expense ratio will not be affeted by any suh payments. These payments may be made to intermediaries, inluding affiliates, that provide shareholder serviing, subadministration, reordkeeping and/or sub-transfer ageny servies, marketing support and/or aess to sales meetings, sales representatives and management representatives of the finanial intermediary. Cash ompensation also may be paid from Dreyfus or MBSC s own resoures to intermediaries for inlusion of a fund on a sales list, inluding a preferred or selet sales list or in other sales programs. These payments sometimes are referred to as revenue sharing. From time to time, Dreyfus or MBSC also may provide ash or non-ash ompensation to finanial intermediaries or their representatives in the form of oasional gifts; oasional meals, tikets or other entertainment; support for due diligene trips; eduational onferene sponsorships; support for reognition programs; and other forms of ash or non-ash ompensation permissible under broker-dealer regulations. In some ases, these payments or ompensation may reate an inentive for a finanial intermediary or its employees to reommend or sell shares of the fund to you. Please ontat your finanial representative for details about any payments they or their firm may reeive in onnetion with the sale of fund shares or the provision of servies to the fund. The fund, Dreyfus and MBSC have eah adopted a ode of ethis that permits its personnel, subjet to suh ode, to invest in seurities, inluding seurities that may be purhased or held by the fund. Eah ode of ethis restrits the personal seurities transations of employees, and requires portfolio managers and other investment personnel to omply with the ode s prelearane and dislosure proedures. The primary purpose of the respetive odes is to ensure that personal trading by employees does not disadvantage any fund managed by Dreyfus or its affiliates. 15

20 Shareholder Guide BUYING AND SELLING SHARES Eah fund is designed for institutional investors, partiularly banks, ating for themselves or in a fiduiary, advisory, ageny, ustodial or similar apaity. Generally, eah investor will be required to open a single master aount with a fund for all purposes. In ertain ases, a fund may request investors to maintain separate master aounts for shares held by the investor (i) for its own aount, for the aount of other institutions and for aounts for whih the institution ats as a fiduiary, and (ii) for aounts for whih the investor ats in some other apaity. An institution may arrange with a fund s transfer agent for sub-aounting servies and will be harged diretly for the ost of suh servies. Institutions purhasing Ageny shares for the benefit of their lients may impose poliies, limitations and fees whih are different from those desribed in this prospetus. The funds offer other lasses of shares, whih are desribed in separate prospetuses. Institutions purhasing fund shares on behalf of their lients determine whih lass of shares is suitable for their lients. Valuing Shares You pay no sales harges to invest in shares of a fund. Your prie for shares is the net asset value per share (NAV), whih is generally alulated as of 12:00 noon, 5:00 p.m. and 8:00 p.m., on days the New York Stok Exhange, or the transfer agent (as on Good Friday) as to Dreyfus Institutional Reserves Money Fund only, is open for regular business. Your order will be pried at the next NAV alulated after your order is reeived in proper form by the fund s transfer agent or other authorized entity. Eah fund s portfolio seurities are valued at amortized ost, whih does not take into aount unrealized gains or losses. As a result, portfolio seurities are valued at their aquisition ost, adjusted over time based on the disounts or premiums refleted in their purhase prie. Eah fund uses the amortized ost method of valuation pursuant to Rule 2a-7 under the Investment Company At of 1940 in order to be able to prie its shares at $1.00 per share. In aordane with Rule 2a-7, eah fund is subjet to ertain maturity, quality and diversifiation requirements to help it maintain the $1.00 per share prie. When alulating its NAV, eah fund ompares the NAV using amortized ost to its NAV using available market quotations or market equivalents, whih generally are provided by an independent priing servie approved by the fund s board. The priing servie s proedures are reviewed under the general supervision of the board. As to Dreyfus Institutional Reserves Money Fund and Dreyfus Institutional Reserves Treasury Fund, orders in proper form plaed prior to 12:00 noon or 5:00 p.m., and payments for whih are reeived in or onverted into Federal Funds by the fund s ustodian by 6:00 p.m., will beome effetive at the prie determined at 12:00 noon or 5:00 p.m., respetively, on that day. In either ase, shares purhased will reeive the dividend delared on that day. As to Dreyfus Institutional Reserves Treasury Prime Fund only, orders in proper form plaed prior to 12:00 noon or 3:00 p.m., and payments for whih are reeived in or onverted into Federal Funds by the fund s ustodian by 6:00 p.m., will beome effetive at the prie determined at 12:00 noon or 5:00 p.m., respetively, on that day. In either ase, shares purhased will reeive the dividend delared on that day. Orders for shares plaed between 3:00 p.m. and 5:00 p.m. will not be aepted and exeuted, and notie of the purhase order being rejeted will be given to the institution plaing the order, and any funds reeived will be returned promptly to the sending institution. Orders effeted through ompatible omputer failities after 5:00 p.m., but by 8:00 p.m., will beome effetive at the prie determined at 8:00 p.m. on that day, if Federal Funds are reeived by the fund s ustodian by 11:00 a.m. on the following business day. In this ase, shares purhased will start earning dividends on the business day 16

21 following the date the order beame effetive. Orders effeted between 5:00 p.m. and 8:00 p.m., by a means other than a ompatible omputer faility (and otherwise in proper form), will beome effetive on the following business day. For all funds, all times are Eastern time. How to Buy Shares By Wire. To open an aount by wire, or purhase additional shares, please ontat a Dreyfus Investments Division representative by alling ( in New York) for more information. By Computer. You may input new aount data and retrieve an aount number for your reords by aessing The Dreyfus Lion Remote System. Be sure to print a report of transations for your reords. Please ontat the Dreyfus Investments Division by alling ( in New York) for more information about The Dreyfus Lion Remote System or any other ompatible omputerized trading system. The minimum initial investment is $275,000,000, with no minimum subsequent investment, unless: (a) the investor has invested at least $275,000,000 in the aggregate among any fund: or (b) the investor has, in the opinion of Dreyfus Investments Division, adequate intent and availability of assets to reah a future level of investment of $275,000,000 among the funds. How to Sell Shares Investors may sell (redeem) shares at any time. Shares will be sold at the next NAV alulated after your order is reeived in proper form by the fund s transfer agent or other authorized entity. If a redemption request is reeived in proper form by the fund s transfer agent or other authorized entity by 5:00 p.m. the proeeds for the redemption, if transfer by wire is requested, ordinarily will be transmitted in Federal Funds on the same day, and the shares will not reeive the dividend delared on that day. If a request for redemption is reeived in proper form by the fund s transfer agent or other authorized entity after 5:00 p.m., but by 8:00 p.m., the proeeds of the redemption ordinarily will be transmitted in Federal Funds on the next business day, and the shares will reeive the dividend delared on that day. All times are Eastern time. Any ertifiates representing fund shares being sold must be returned with your redemption request. The proessing of redemption and the delivery of the proeeds may be delayed beyond the same or next business day, depending on the irumstane, for any period (i) during whih the New York Stok Exhange is losed (other than on holidays or weekends), or during whih trading on the New York Stok Exhange is restrited; (ii) when an emergeny exists that makes diffiult the disposal of seurities owned by the fund or the determination of the fair value of the fund s net assets; or (iii) as permitted by order of the Seurities and Exhange Commission for the protetion of fund shareholders. If, for one of these reasons, the proessing of redemptions and the delivery of redemption proeeds is delayed beyond the same or next business day, the delay may be for up to seven days.for these purposes, the Seurities and Exhange Commission determines the onditions under whih trading shall be deemed to be restrited and an emergeny shall be deemed to exist. Before selling reently purhased shares, please note that if a fund has not yet olleted payment for the shares being sold, the fund may delay selling the shares for up to eight business days or until it has olleted payment. By Wire. To redeem shares, please ontat a Dreyfus Investments Division representative by alling ( in New York) with information about your transation. Be sure the fund has your bank aount information on file. Proeeds will be wired to your bank. By Computer. You may redeem shares by aessing The Dreyfus Lion Remote System to onfirm bank aount information or selet from multiple wire instrutions. Be sure to print a report of transations for your reords. 17

22 General poliies Unless the investor delines teleservie privileges on the appliation, the investor may be responsible for any fraudulent telephone order as long as Dreyfus takes reasonable measures to verify the order. Money market funds generally are used by investors for short-term investments, often in plae of bank heking or savings aounts, or for ash management purposes. Investors value the ability to add and withdraw their funds quikly, without restrition. For this reason, although Dreyfus disourages exessive trading and other abusive trading praties, the funds have not adopted poliies and proedures, or imposed redemption fees or other restritions suh as minimum holding periods, to deter frequent purhases and redemptions of fund shares. Dreyfus also believes that money market funds, suh as the funds, are not targets of abusive trading praties, beause money market funds seek to maintain a $1.00 per share prie and typially do not flutuate in value based on market pries. However, frequent purhases and redemptions of the fund s shares ould inrease the fund s transation osts, suh as market spreads and ustodial fees, and may interfere with the effiient management of the fund s portfolio, whih ould detrat from the fund s performane. Aordingly, eah fund reserves the right to refuse any purhase or exhange request. Eah fund also reserves the right to: refuse any purhase or exhange request hange or disontinue its exhange privilege, or temporarily suspend the privilege during unusual market onditions hange its minimum investment amounts Eah fund also reserves the right to make a redemption in kind payment in portfolio seurities rather than ash if the amount being redeemed is deemed by the manager to be large enough to affet fund operations. Investors are urged to all Dreyfus Investments Division before effeting any large transation. Eah fund may also proess purhase and sale orders and alulate its NAV on days that the fund s primary trading markets are open and the fund s management determines to do so. 18

23 DISTRIBUTIONS AND TAXES Eah fund earns dividends, interest and other inome from its investments, and distributes this inome (less expenses) to shareholders as dividends. Eah fund also realizes apital gains from its investments, and distributes these gains (less any losses) to shareholders as apital gain distributions. Eah fund normally pays dividends one a month and apital gain distributions, if any, annually. Fund dividends and apital gain distributions will be reinvested in the fund unless the investor instruts the fund otherwise. There are no fees or sales harges on reinvestments. Distributions paid by the funds are subjet to federal inome tax, and may also be subjet to state or loal taxes (unless the investor is investing through a tax-advantaged retirement aount). For federal tax purposes, in general, ertain fund distributions, inluding distributions of short-term apital gains, are taxable to investors as ordinary inome. The tax status of any distribution generally is the same regardless of how long the investor has been in the fund and whether distributions are reinvested or taken in ash. An investor s sale of shares, inluding exhanges into other funds, may result in a apital gain or loss for tax purposes. A apital gain or loss on an investment in the fund generally is the differene between the ost of the investor s shares and the amount reeived when the investor sells them. The tax status of an investor s distributions will be detailed in the investor s annual tax statement from the fund. Beause everyone s tax situation is unique, please onsult your tax adviser before investing. 19