UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Investment Company Act File Number: 811-02603

T. Rowe Price Prime Reserve Fund, Inc.

(Exact name of registrant as specified in charter)

100 East Pratt Street, Baltimore, MD 21202

(Address of principal executive offices)

David Oestreicher

100 East Pratt Street, Baltimore, MD 21202

(Name and address of agent for service)

Registrant’s telephone number, including area code: (410) 345-2000

Date of fiscal year end: May 31

Date of reporting period: May 31, 2012

The views and opinions in this report were current as of May 31, 2012. They are not guarantees of performance or investment results and should not be taken as investment advice. Investment decisions reflect a variety of factors, and the managers reserve the right to change their views about individual stocks, sectors, and the markets at any time. As a result, the views expressed should not be relied upon as a forecast of the fund’s future investment intent. The report is certified under the Sarbanes-Oxley Act, which requires mutual funds and other public companies to affirm that, to the best of their knowledge, the information in their financial reports is fairly and accurately stated in all material respects.

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The Federal Reserve kept short-term interest rates extremely low throughout the year ended May 31, 2012, and central bank officials have extended the time frame of their commitment to keep them low—from mid-2013 to late 2014—to support a subpar U.S. economic recovery. Like many other money market funds, the T. Rowe Price Prime Reserve Fund continued to offer investors principal stability and liquidity, albeit with yields and total returns barely above 0%.

The U.S. economy expanded over the last year, albeit at a modest pace compared with what is typically seen in the years following a deep recession. The manufacturing sector is healthy, and job growth accelerated in the early months of 2012 before moderating in the spring. The housing market remains in the doldrums, however, and national unemployment remains somewhat elevated. Still, the economy has shown resilience in the face of a nascent recession and ongoing sovereign debt crisis in Europe, a slowdown in Chinese growth, and bouts of global market volatility. We believe growth will continue at a modest to moderate pace in the months ahead, but there is the possibility that disruptive events overseas or a U.S. government failure to prevent or moderate tax increases and spending cuts scheduled to take place at the end of 2012 could jeopardize the expansion.

To support the economy, the Federal Reserve maintained highly accommodative monetary policies over the last year, keeping the fed funds target rate in its 0.00% to 0.25% range established at the end of 2008. Although the Fed’s second round of purchasing massive quantities of Treasuries ended in June 2011, central bank officials indicated that they would likely keep short-term interest rates very low until late 2014. The Fed also implemented a plan to shift the average maturity of its holdings by purchasing intermediate- and long-term Treasury securities through June 2012 and selling Treasuries maturing in three years or less.

Your fund returned 0.01% in the 6- and in the 12-month periods ended May 31, 2012. As shown in the Performance Comparison table, the fund fared about the same as its peer group average in both periods. Like many of its peers, T. Rowe Price has voluntarily waived all or a portion of the management fee it is entitled to receive from the fund in an effort to maintain a 0% or positive net yield for the fund.

While short-term performance comparisons in this near-0% interest rate environment are difficult, the fund’s 10-year return has been competitive and has placed it in the top quartile of all taxable money funds. Based on cumulative total return, Lipper ranked the Prime Reserve Fund 65 of 256, 129 of 244, 59 of 231, and 47 of 187 money market instrument funds for the 1-, 3-, 5-, and 10-year periods ended May 31, 2012, respectively. (Results will vary for other time periods. Past performance cannot guarantee future results.)

Financial markets continue to be unsettled by a series of worries emanating from multiple directions. The slowly spreading sovereign debt and banking crisis in Europe, the disappointing U.S. employment trends, and the possibility that our economy could be undercut by a significant tightening of fiscal policy—a so-called fiscal cliff—around year-end have combined to create a mood of uncertainty for investors. Such uncertainty defers economic recovery and leaves the Federal Reserve few options other than to continue its massively stimulative monetary policy. Although we are more than three and a half years into the era of 0% interest rates, it seems this extraordinary policy will be with us for quite some time to come.

Money market funds have to contend not only with ultra-low interest rates, but also with a significantly changing credit situation. The European crisis has caused most investors to rethink their views toward many European bank borrowers; indeed, our fund now has no unsecured exposure to European banks. The pull-back in European bank funding by money funds has been compounded by a systematic series of ratings agency downgrades by Moody’s, which, when complete, will render many money-center banks unable to tap money funds for the short-term unsecured funding to which they had grown accustomed. The money fund industry, as a whole, appears well prepared for such changes. Most funds have become quite discerning as to whom they are willing to lend to, and for how long. Still, the number of high-quality borrowers continues to shrink, and the opportunities for yield enhancement have been virtually eliminated from our market.

Rates in the money market space showed little change over the past six months. The U.S. Treasury bill market remains subject to limited supply and episodic flights to quality. Yields are up somewhat from our last report. At the end of May, three-month bills yielded about 0.07%, six-month bills 0.12%, and the one-year bill around 0.18%. Ninety-day LIBOR, the basis for pricing in most of the commercial paper and certificate of deposit (CD) markets, was at 0.47%, also somewhat higher versus the prior six months. However, most of the high-quality names in which we invest have much lower yields. Yields of municipal variable rate securities, which have come to represent a sizable portion of the portfolio, have recently risen to around 0.20% versus 0.12% at the end of November 2011.

Portfolio holdings continue to represent our bias toward quality. Treasury debt, Treasury-guaranteed debt, Canadian debt, as well as banks in Canada and Australia represent our largest positions in an otherwise highly diversified portfolio. Municipal variable rate demand notes continue to represent more than 30% of the portfolio, as their yields and liquidity attributes make them attractive investments for now. We’ve also opportunistically added some very high-quality asset-backed debt when we felt their structures presented value. Recently, we have begun adding very high-quality industrial and pharmaceutical names to the portfolio.

While we remain very defensive in our posture toward credit risk, we are also quite aggressive in our posture toward interest rates. Barring a credit-negative headline event or a significant shift in Fed policy, most money market rates should continue to crowd around 0% for some time to come. Thus, we are quite comfortable keeping the portfolio’s weighted average maturity near the permissible maximum of 60 days.

With the potential for the economy to stall, Europe still simmering, and the inability of Washington to address significant policy matters, our view is that the Fed has no choice but to leave its 0% interest rate policy in place at least until late 2014. This, unfortunately, means that money fund returns are likely to remain very low for some time. Nevertheless, our focus remains on principal stability, quality, and liquidity—even as the interest rate environment currently results in little return for money market investors.

The committee chairman has day-to-day responsibility for managing the portfolio and works with committee members in developing and executing the fund’s investment program.

Since money market funds are managed to maintain a constant $1.00 share price, there should be little risk of principal loss. However, there is no assurance the fund will avoid principal losses if fund holdings default or are downgraded or if interest rates rise sharply in an unusually short period. In addition, the fund’s yield will vary; it is not fixed for a specific period like the yield on a bank certificate of deposit. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. Although a money market fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in it.

Fed funds target rate: The interest rate charged on overnight loans of reserves by one financial institution to another in the United States. The Federal Reserve sets a target federal funds rate to affect the direction of interest rates.

LIBOR: The London Interbank Offered Rate, which is a benchmark for short-term taxable rates.

Lipper average: The averages of available mutual fund performance returns for specified time periods in categories defined by Lipper Inc.

SEC yield (7-day unsubsidized simple): A method of calculating a money fund’s yield by annualizing the fund’s net investment income for the last seven days of each period divided by the fund’s net asset value at the end of the period. Yield will vary and is not guaranteed.

Weighted average life: A measure of a fund’s credit-quality risk. In general, the longer the average life, the greater the fund’s credit-quality risk. The average life is the dollar-weighted average maturity of a portfolio’s individual securities without taking into account interest rate readjustment dates. Money funds must maintain a weighted average life of less than 120 days.

Weighted average maturity: A measure of a fund’s interest rate sensitivity. In general, the longer the average maturity, the greater the fund’s sensitivity to interest rate changes. The weighted average maturity may take into account the interest rate readjustment dates for certain securities. Money funds must maintain a weighted average maturity of less than 60 days.

This chart shows the value of a hypothetical $10,000 investment in the fund over the past 10 fiscal year periods or since inception (for funds lacking 10-year records). The result is compared with benchmarks, which may include a broad-based market index and a peer group average or index. Market indexes do not include expenses, which are deducted from fund returns as well as mutual fund averages and indexes.

As a mutual fund shareholder, you may incur two types of costs: (1) transaction costs, such as redemption fees or sales loads, and (2) ongoing costs, including management fees, distribution and service (12b-1) fees, and other fund expenses. The following example is intended to help you understand your ongoing costs (in dollars) of investing in the fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an investment of $1,000 invested at the beginning of the most recent six-month period and held for the entire period.

Actual Expenses
The first line of the following table (Actual) provides information about actual account values and expenses based on the fund’s actual returns. You may use the information on this line, together with your account balance, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number on the first line under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes
The information on the second line of the table (Hypothetical) is based on hypothetical account values and expenses derived from the fund’s actual expense ratio and an assumed 5% per year rate of return before expenses (not the fund’s actual return). You may compare the ongoing costs of investing in the fund with other funds by contrasting this 5% hypothetical example and the 5% hypothetical examples that appear in the shareholder reports of the other funds. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period.

Note: T. Rowe Price charges an annual account service fee of $20, generally for accounts with less than $10,000. The fee is waived for any investor whose T. Rowe Price mutual fund accounts total $50,000 or more; accounts electing to receive electronic delivery of account statements, transaction confirmations, prospectuses, and shareholder reports; or accounts of an investor who is a T. Rowe Price Preferred Services, Personal Services, or Enhanced Personal Services client (enrollment in these programs generally requires T. Rowe Price assets of at least $100,000). This fee is not included in the accompanying table. If you are subject to the fee, keep it in mind when you are estimating the ongoing expenses of investing in the fund and when comparing the expenses of this fund with other funds.

You should also be aware that the expenses shown in the table highlight only your ongoing costs and do not reflect any transaction costs, such as redemption fees or sales loads. Therefore, the second line of the table is useful in comparing ongoing costs only and will not help you determine the relative total costs of owning different funds. To the extent a fund charges transaction costs, however, the total cost of owning that fund is higher.

T. Rowe Price Prime Reserve Fund, Inc. (the fund), is registered under the Investment Company Act of 1940 (the 1940 Act) as a diversified, open-end management investment company. The fund commenced operations on January 26, 1976. The fund seeks preservation of capital, liquidity, and, consistent with these, the highest possible current income.

Basis of Preparation The accompanying financial statements were prepared in accordance with accounting principles generally accepted in the United States of America, which require the use of estimates made by management. Management believes that estimates and valuations are appropriate; however, actual results may differ from those estimates, and the valuations reflected in the accompanying financial statements may differ from the value ultimately realized upon sale or maturity.

Investment Transactions, Investment Income, and Distributions Income and expenses are recorded on the accrual basis. Premiums and discounts on debt securities are amortized for financial reporting purposes. Paydown gains and losses are recorded as an adjustment to interest income. Income tax-related interest and penalties, if incurred, would be recorded as income tax expense. Investment transactions are accounted for on the trade date. Realized gains and losses are reported on the identified cost basis. Distributions to shareholders are recorded on the ex-dividend date. Income distributions are declared daily and paid monthly.

Credits The fund earns credits on temporarily uninvested cash balances held at the custodian, which reduce the fund’s custody charges. Custody expense in the accompanying financial statements is presented before reduction for credits, which are reflected as expenses paid indirectly.

New Accounting Pronouncements In May 2011, the Financial Accounting Standards Board (FASB) issued amended guidance to align fair value measurement and disclosure requirements in U.S. GAAP with International Financial Reporting Standards. The guidance is effective for fiscal years and interim periods beginning on or after December 15, 2011. Adoption will have no effect on net assets or results of operations.

In December 2011, the FASB issued amended guidance to enhance disclosure for offsetting assets and liabilities. The guidance is effective for fiscal years and interim periods beginning on or after January 1, 2013; adoption will have no effect on the fund’s net assets or results of operations.

The fund values its investments and computes its net asset value per share each day that the New York Stock Exchange is open for business. In accordance with Rule 2a-7 under the 1940 Act, securities are valued at amortized cost, which approximates fair value. Securities for which amortized cost is deemed not to reflect fair value are stated at fair value as determined in good faith by the T. Rowe Price Valuation Committee, established by the fund’s Board of Directors.

Various inputs are used to determine the value of the fund’s financial instruments. These inputs are summarized in the three broad levels listed below:

Level 2 – observable inputs other than Level 1 quoted prices (including, but not limited to, quoted prices for similar financial instruments, interest rates, prepayment speeds, and credit risk)

Observable inputs are those based on market data obtained from sources independent of the fund, and unobservable inputs reflect the fund’s own assumptions based on the best information available. The input levels are not necessarily an indication of the risk or liquidity associated with financial instruments at that level. For example, securities held by a money market fund are generally high quality and liquid; however, they are reflected as Level 2 because the inputs used to determine fair value are not quoted prices in an active market. On May 31, 2012, all of the fund’s financial instruments were classified as Level 2, based on the inputs used to determine their values.

Consistent with its investment objective, the fund engages in the following practices to manage exposure to certain risks and/or to enhance performance. The investment objective, policies, program, and risk factors of the fund are described more fully in the fund’s prospectus and Statement of Additional Information.

Restricted Securities The fund may invest in securities that are subject to legal or contractual restrictions on resale. Prompt sale of such securities at an acceptable price may be difficult and may involve substantial delays and additional costs.

Repurchase Agreements All repurchase agreements are fully collateralized by U.S. government securities. Collateral is in the possession of the fund’s custodian or, for tri-party agreements, the custodian designated by the agreement. Collateral is evaluated daily to ensure that its market value exceeds the delivery value of the repurchase agreements at maturity. Although risk is mitigated by the collateral, the fund could experience a delay in recovering its value and a possible loss of income or value if the counterparty fails to perform in accordance with the terms of the agreement.

No provision for federal income taxes is required since the fund intends to continue to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code and distribute to shareholders all of its taxable income and gains. Distributions determined in accordance with federal income tax regulations may differ in amount or character from net investment income and realized gains for financial reporting purposes. Financial reporting records are adjusted for permanent book/tax differences to reflect tax character but are not adjusted for temporary differences.

The fund files U.S. federal, state, and local tax returns as required. The fund’s tax returns are subject to examination by the relevant tax authorities until expiration of the applicable statute of limitations, which is generally three years after the filing of the tax return but which can be extended to six years in certain circumstances. Tax returns for open years have incorporated no uncertain tax positions that require a provision for income taxes.

Reclassifications to paid-in capital relate primarily to a tax practice that treats a portion of the proceeds from each redemption of capital shares as a distribution of taxable net investment income and/or realized capital gain. For the year ended May 31, 2012, the following reclassifications were recorded to reflect tax character (there was no impact on results of operations or net assets):

Distributions during the years ended May 31, 2012 and May 31, 2011, totaled $572,000 and $702,000, respectively, and were characterized as ordinary income for tax purposes. At May 31, 2012, the tax-basis cost of investments and components of net assets were as follows:

The fund is managed by T. Rowe Price Associates, Inc. (Price Associates), a wholly owned subsidiary of T. Rowe Price Group, Inc. (Price Group). The investment management agreement between the fund and Price Associates provides for an annual investment management fee, which is computed daily and paid monthly. The fee consists of an individual fund fee, equal to 0.05% of the fund’s average daily net assets, and a group fee. The group fee rate is calculated based on the combined net assets of certain mutual funds sponsored by Price Associates (the group) applied to a graduated fee schedule, with rates ranging from 0.48% for the first $1 billion of assets to 0.28% for assets in excess of $300 billion. The fund’s group fee is determined by applying the group fee rate to the fund’s average daily net assets. At May 31, 2012, the effective annual group fee rate was 0.30%.

Price Associates may voluntarily waive all or a portion of its management fee to the extent necessary for the fund to maintain a zero or positive net yield (voluntary waiver). Any amounts waived under this voluntary agreement are not subject to repayment by the fund. Price Associates may amend or terminate this voluntary waiver at any time without prior notice. For the year ended May 31, 2012, management fees waived totaled $16,603,000.

In addition, the fund has entered into service agreements with Price Associates and two wholly owned subsidiaries of Price Associates (collectively, Price). Price Associates computes the daily share price and provides certain other administrative services to the fund. T. Rowe Price Services, Inc., provides shareholder and administrative services in its capacity as the fund’s transfer and dividend disbursing agent. T. Rowe Price Retirement Plan Services, Inc., provides subaccounting and recordkeeping services for certain retirement accounts invested in the fund. For the year ended May 31, 2012, expenses incurred pursuant to these service agreements were $123,000 for Price Associates; $5,637,000 for T. Rowe Price Services, Inc.; and $1,937,000 for T. Rowe Price Retirement Plan Services, Inc. The total amount payable at period-end pursuant to these service agreements is reflected as Due to Affiliates in the accompanying financial statements.

As of May 31, 2012, T. Rowe Price Group, Inc., and/or its wholly owned subsidiaries owned 184,857 shares of the fund, representing less than 1% of the fund’s net assets.

Price Associates has developed and manages an interfund lending program that provides temporary liquidity to the T. Rowe Price-sponsored mutual funds. The program permits the borrowing and lending of cash between the fund and other T. Rowe Price-sponsored mutual funds at rates beneficial to both the borrowing and lending funds. Pursuant to program guidelines, the fund may lend up to 15% of its net assets, and no more than 5% of its net assets may be lent to any one borrower. Loans totaling 10% or more of a borrowing fund’s total assets require collateralization at 102% of the value of the loan; loans of less than 10% are unsecured. During the year ended May 31, 2012, the fund earned $3,000 in interest income related to loans made to other funds on 10 days in the average amount of $8,850,000 and at an average annual rate of 1.12%. At May 31, 2012, there were no loans outstanding.

To the Board of Directors and Shareholders of
T. Rowe Price Prime Reserve Fund, Inc.

In our opinion, the accompanying statement of assets and liabilities, including the portfolio of investments, and the related statements of operations and of changes in net assets and the financial highlights present fairly, in all material respects, the financial position of T. Rowe Price Prime Reserve Fund, Inc. (the “Fund”) at May 31, 2012, and the results of its operations, the changes in its net assets and the financial highlights for each of the periods indicated therein, in conformity with accounting principles generally accepted in the United States of America. These financial statements and financial highlights (hereafter referred to as “financial statements”) are the responsibility of the Fund’s management; our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits of these financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits, which included confirmation of securities at May 31, 2012 by correspondence with the custodian and brokers, provide a reasonable basis for our opinion.

We are providing this information as required by the Internal Revenue Code. The amounts shown may differ from those elsewhere in this report because of differences between tax and financial reporting requirements.

A description of the policies and procedures used by T. Rowe Price funds and portfolios to determine how to vote proxies relating to portfolio securities is available in each fund’s Statement of Additional Information, which you may request by calling 1-800-225-5132 or by accessing the SEC’s website, sec.gov. The description of our proxy voting policies and procedures is also available on our website, troweprice.com. To access it, click on the words “Our Company” at the top of our corporate homepage. Then, when the next page appears, click on the words “Proxy Voting Policies” on the left side of the page.

Each fund’s most recent annual proxy voting record is available on our website and through the SEC’s website. To access it through our website, follow the directions above, then click on the words “Proxy Voting Records” on the right side of the Proxy Voting Policies page.

The fund files a complete schedule of portfolio holdings with the Securities and Exchange Commission for the first and third quarters of each fiscal year on Form N-Q. The fund’s Form N-Q is available electronically on the SEC’s website (sec.gov); hard copies may be reviewed and copied at the SEC’s Public Reference Room, 100 F St. N.E., Washington, DC 20549. For more information on the Public Reference Room, call 1-800-SEC-0330.

On March 6, 2012, the fund’s Board of Directors (Board), including a majority of the fund’s independent directors, approved the continuation of the investment management agreement (Advisory Contract) between the fund and its investment advisor, T. Rowe Price Associates, Inc. (Advisor). In connection with their deliberations, the Board requested, and the Advisor provided, such information as the Board (with advice from independent legal counsel) deemed reasonably necessary. The Board considered a variety of factors in connection with its review of the Advisory Contract, also taking into account information provided by the Advisor during the course of the year, as discussed below:

Services Provided by the Advisor
The Board considered the nature, quality, and extent of the services provided to the fund by the Advisor. These services included, but were not limited to, directing the fund’s investments in accordance with its investment program and the overall management of the fund’s portfolio, as well as a variety of related activities, such as financial, investment operations, and administrative services; compliance; maintaining the fund’s records and registrations; and shareholder communications. The Board also reviewed the background and experience of the Advisor’s senior management team and investment personnel involved in the management of the fund, as well as the Advisor’s compliance record. The Board concluded that it was satisfied with the nature, quality, and extent of the services provided by the Advisor.

Investment Performance of the Fund
The Board reviewed the fund’s average annual total returns over the three-month and 1-, 3-, 5-, and 10-year periods, as well as the fund’s year-by-year returns, and compared these returns with a wide variety of previously agreed upon comparable performance measures and market data, including those supplied by Lipper and Morningstar, which are independent providers of mutual fund data.

On the basis of this evaluation and the Board’s ongoing review of investment results, and factoring in the relative market conditions during certain of the performance periods, the Board concluded that the fund’s performance was satisfactory.

Costs, Benefits, Profits, and Economies of Scale
The Board reviewed detailed information regarding the revenues received by the Advisor under the Advisory Contract and other benefits that the Advisor (and its affiliates) may have realized from its relationship with the fund, including any research received under “soft dollar” agreements and commission-sharing arrangements with broker-dealers. The Board considered that the Advisor may receive some benefit from soft-dollar arrangements pursuant to which research is received from broker-dealers that execute the applicable fund’s portfolio transactions. The Board received information on the estimated costs incurred and profits realized by the Advisor from managing T. Rowe Price mutual funds. The Board also reviewed estimates of the profits realized from managing the fund in particular, and the Board concluded that the Advisor’s profits were reasonable in light of the services provided to the fund.

The Board also considered whether the fund benefits under the fee levels set forth in the Advisory Contract from any economies of scale realized by the Advisor. Under the Advisory Contract, the fund pays a fee to the Advisor for investment management services composed of two components—a group fee rate based on the combined average net assets of most of the T. Rowe Price mutual funds (including the fund) that declines at certain asset levels and an individual fund fee rate based on the fund’s average daily net assets—and the fund pays its own expenses of operations. However, the Board noted that an arrangement is in place whereby the Advisor may voluntarily waive all or a portion of the management fee it is entitled to receive from the fund or pay all or a portion of the fund’s operating expenses in order to maintain a zero or positive net yield for the fund. The Board concluded that the advisory fee structure for the fund continued to provide for a reasonable sharing of benefits from any economies of scale with the fund’s investors.

Fees
The Board was provided with information regarding industry trends in management fees and expenses, and the Board reviewed the fund’s management fee rate, operating expenses, and total expense ratio in comparison with fees and expenses of other comparable funds based on information and data supplied by Lipper. The information provided to the Board indicated that the fund’s management fee rate and total expense ratio (after including voluntary management fee waivers and expenses paid by the Advisor) were at or below the median for comparable funds.

The Board also reviewed the fee schedules for institutional accounts and private accounts with similar mandates that are advised or subadvised by the Advisor and its affiliates. Management provided the Board with information about the Advisor’s responsibilities and services provided to institutional account clients, including information about how the requirements and economics of the institutional business are fundamentally different from those of the mutual fund business. The Board considered information showing that the mutual fund business is generally more complex from a business and compliance perspective than the institutional business and that the Advisor generally performs significant additional services and assumes greater risk in managing the fund and other T. Rowe Price mutual funds than it does for institutional account clients.

On the basis of the information provided and the factors considered, the Board concluded that the fees paid by the fund under the Advisory Contract are reasonable.

Approval of the Advisory Contract
As noted, the Board approved the continuation of the Advisory Contract. No single factor was considered in isolation or to be determinative to the decision. Rather, the Board concluded, in light of a weighting and balancing of all factors considered, that it was in the best interests of the fund and its shareholders for the Board to approve the continuation of the Advisory Contract (including the fees to be charged for services thereunder). The independent directors were advised throughout the process by independent legal counsel.

Your fund is overseen by a Board of Directors (Board) that meets regularly to review a wide variety of matters affecting the fund, including performance, investment programs, compliance matters, advisory fees and expenses, service providers, and other business affairs. The Board elects the fund’s officers, who are listed in the final table. At least 75% of the Board’s members are independent of T. Rowe Price Associates, Inc. (T. Rowe Price), and its affiliates; “inside” or “interested” directors are employees or officers of T. Rowe Price. The business address of each director and officer is 100 East Pratt Street, Baltimore, Maryland 21202. The Statement of Additional Information includes additional information about the fund directors and is available without charge by calling a T. Rowe Price representative at 1-800-638-5660.

The registrant has adopted a code of ethics, as defined in Item 2 of Form N-CSR, applicable to its principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. A copy of this code of ethics is filed as an exhibit to this Form N-CSR. No substantive amendments were approved or waivers were granted to this code of ethics during the period covered by this report.

The registrant’s Board of Directors/Trustees has determined that Mr. Anthony W. Deering qualifies as an audit committee financial expert, as defined in Item 3 of Form N-CSR. Mr. Deering is considered independent for purposes of Item 3 of Form N-CSR.

(a) – (d) Aggregate fees billed to the registrant for the last two fiscal years for professional services rendered by the registrant’s principal accountant were as follows:

Audit fees include amounts related to the audit of the registrant’s annual financial statements and services normally provided by the accountant in connection with statutory and regulatory filings. Audit-related fees include amounts reasonably related to the performance of the audit of the registrant’s financial statements and specifically include the issuance of a report on internal controls and, if applicable, agreed-upon procedures related to fund acquisitions. Tax fees include amounts related to services for tax compliance, tax planning, and tax advice. The nature of these services specifically includes the review of distribution calculations and the preparation of Federal, state, and excise tax returns. All other fees include the registrant’s pro-rata share of amounts for agreed-upon procedures in conjunction with service contract approvals by the registrant’s Board of Directors/Trustees.

(e)(1) The registrant’s audit committee has adopted a policy whereby audit and non-audit services performed by the registrant’s principal accountant for the registrant, its investment adviser, and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant require pre-approval in advance at regularly scheduled audit committee meetings. If such a service is required between regularly scheduled audit committee meetings, pre-approval may be authorized by one audit committee member with ratification at the next scheduled audit committee meeting. Waiver of pre-approval for audit or non-audit services requiring fees of a de minimis amount is not permitted.

(2) No services included in (b) – (d) above were approved pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.

(f) Less than 50 percent of the hours expended on the principal accountant’s engagement to audit the registrant’s financial statements for the most recent fiscal year were attributed to work performed by persons other than the principal accountant’s full-time, permanent employees.

(g) The aggregate fees billed for the most recent fiscal year and the preceding fiscal year by the registrant’s principal accountant for non-audit services rendered to the registrant, its investment adviser, and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant were $1,375,000 and $1,539,000 respectively.

(h) All non-audit services rendered in (g) above were pre-approved by the registrant’s audit committee. Accordingly, these services were considered by the registrant’s audit committee in maintaining the principal accountant’s independence.

(a) Not applicable. The complete schedule of investments is included in Item 1 of this Form N-CSR.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

(a) The registrant’s principal executive officer and principal financial officer have evaluated the registrant’s disclosure controls and procedures within 90 days of this filing and have concluded that the registrant’s disclosure controls and procedures were effective, as of that date, in ensuring that information required to be disclosed by the registrant in this Form N-CSR was recorded, processed, summarized, and reported timely.

(b) The registrant’s principal executive officer and principal financial officer are aware of no change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

(a)(1) The registrant’s code of ethics pursuant to Item 2 of Form N-CSR is attached.

(2) Separate certifications by the registrant's principal executive officer and principal financial officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 and required by Rule 30a-2(a) under the Investment Company Act of 1940, are attached.

(b) A certification by the registrant's principal executive officer and principal financial officer, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and required by Rule 30a-2(b) under the Investment Company Act of 1940, is attached.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

T. Rowe Price Prime Reserve Fund, Inc.

	By	/s/ Edward C. Bernard
		Edward C. Bernard
		Principal Executive Officer

Date July 13, 2012

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

	By	/s/ Edward C. Bernard
		Edward C. Bernard
		Principal Executive Officer

Date July 13, 2012


	By	/s/ Gregory K. Hinkle
		Gregory K. Hinkle
		Principal Financial Officer

Date July 13, 2012

Independent Directors

Name
(Year of Birth)		Principal Occupation(s) and Directorships of Public Companies and
Year Elected*		Other Investment Companies During the Past Five Years

William R. Brody		President and Trustee, Salk Institute for Biological Studies (2009
(1944)		to present); Director, Novartis, Inc. (2009 to present); Director, IBM
2009		(2007 to present); President and Trustee, Johns Hopkins University
		(1996 to 2009); Chairman of Executive Committee and Trustee,
		Johns Hopkins Health System (1996 to 2009)

Jeremiah E. Casey		Retired
(1940)
2006

Anthony W. Deering		Chairman, Exeter Capital, LLC, a private investment firm (2004
(1945)		to present); Director, Under Armour (2008 to present); Director,
1979		Vornado Real Estate Investment Trust (2004 to present); Director
		and Member of the Advisory Board, Deutsche Bank North America
		(2004 to present); Director, Mercantile Bankshares (2002 to 2007)

Donald W. Dick, Jr.		Principal, EuroCapital Partners, LLC, an acquisition and management
(1943)		advisory firm (1995 to present)
2001

Robert J. Gerrard, Jr.		Director and Chairman of Compensation Committee, Syniverse
(1952)		Holdings, Inc. (2008 to 2011); Executive Vice President and General
2012		Counsel, Scripps Networks, LLC (1997 to 2009); Advisory Board
		Member, Pipeline Crisis/Winning Strategies (1997 to present)

Karen N. Horn		Senior Managing Director, Brock Capital Group, an advisory and
(1943)		investment banking firm (2004 to present); Director, Eli Lilly and
2003		Company (1987 to present); Director, Simon Property Group (2004
		to present); Director, Norfolk Southern (2008 to present)

Theo C. Rodgers		President, A&R Development Corporation (1977 to present)
(1941)
2005

Cecelia E. Rouse, Ph.D.		Professor and Researcher, Princeton University (1992 to present);
(1963)		Director, MDRC (2011 to present); Member, National Academy of
2012		Education (2010 to present); Research Associate, National Bureau
		of Economic Research’s Labor Studies Program (1998 to 2009
		and 2011 to present); Member, President’s Council of Economic
		Advisors (2009 to 2011); Member, The MacArthur Foundation
		Network on the Transition to Adulthood and Public Policy (2000 to
		2008); Member, National Advisory Committee for the Robert Wood
		Johnson Foundation’s Scholars in Health Policy Research Program
		(2008); Director and Member, National Economic Association
		(2006 to 2008); Member, Association of Public Policy Analysis and
		Management Policy Council (2006 to 2008); Member, Hamilton
		Project’s Advisory Board at The Brookings Institute (2006 to 2008);
		Chair of Committee on the Status of Minority Groups in the Economic
		Profession, American Economic Association (2006 to 2008)

John G. Schreiber		Owner/President, Centaur Capital Partners, Inc., a real estate
(1946)		investment company (1991 to present); Cofounder and Partner,
1992		Blackstone Real Estate Advisors, L.P. (1992 to present); Director,
		General Growth Properties, Inc. (2010 to present)

Mark R. Tercek		President and Chief Executive Officer, The Nature Conservancy (2008
(1957)		to present); Managing Director, The Goldman Sachs Group, Inc.
2009		(1984 to 2008)

*Each independent director oversees 136 T. Rowe Price portfolios and serves until retirement, resignation, or election of a successor.

Inside Directors

Name
(Year of Birth)
Year Elected*
[Number of T. Rowe Price		Principal Occupation(s) and Directorships of Public Companies and
Portfolios Overseen]		Other Investment Companies During the Past Five Years

Edward C. Bernard		Director and Vice President, T. Rowe Price; Vice Chairman of the
(1956)		Board, Director, and Vice President, T. Rowe Price Group, Inc.;
2006		Chairman of the Board, Director, and President, T. Rowe Price
[136]		Investment Services, Inc.; Chairman of the Board and Director,
		T. Rowe Price Retirement Plan Services, Inc., T. Rowe Price Savings
		Bank, and T. Rowe Price Services, Inc.; Chairman of the Board, Chief
		Executive Officer, and Director, T. Rowe Price International; Chief
		Executive Officer, Chairman of the Board, Director, and President,
		T. Rowe Price Trust Company; Chairman of the Board, all funds

Michael C. Gitlin		Director of Fixed Income, T. Rowe Price (2009 to present); Global
(1970)		Head of Trading, T. Rowe Price (2007 to 2009); Vice President, Price
2010		Hong Kong, Price Singapore, T. Rowe Price, T. Rowe Price Group, Inc.,
[46]		and T. Rowe Price International

*Each inside director serves until retirement, resignation, or election of a successor.

Officers

Name (Year of Birth)
Position Held With Prime Reserve Fund		Principal Occupation(s)

Steven G. Brooks, CFA (1954)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Group, Inc.

M. Helena Condez (1962)		Vice President, T. Rowe Price
Vice President

G. Richard Dent (1960)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Group, Inc.

Roger L. Fiery III, CPA (1959)		Vice President, Price Hong Kong, Price
Vice President		Singapore, T. Rowe Price, T. Rowe Price Group,
		Inc., T. Rowe Price International, and T. Rowe
		Price Trust Company

Kathryn A. Floyd, CFA (1982)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Group, Inc.

Jared S. Franz (1977)		Assistant Vice President, T. Rowe Price;
Vice President		formerly student, University of Illinois at
		Chicago (to 2008)

John R. Gilner (1961)		Chief Compliance Officer and Vice President,
Chief Compliance Officer		T. Rowe Price; Vice President, T. Rowe Price
		Group, Inc., and T. Rowe Price Investment
		Services, Inc.

Gregory S. Golczewski (1966)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Trust Company

Gregory K. Hinkle, CPA (1958)		Vice President, T. Rowe Price, T. Rowe Price
Treasurer		Group, Inc., and T. Rowe Price Trust Company

Alan D. Levenson, Ph.D. (1958)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Group, Inc.

Patricia B. Lippert (1953)		Assistant Vice President, T. Rowe Price and
Secretary		T. Rowe Price Investment Services, Inc.

Joseph K. Lynagh, CFA (1958)		Vice President, T. Rowe Price, T. Rowe Price
President		Group, Inc., and T. Rowe Price Trust Company

Samy B. Muaddi, CFA (1984)		Vice President, T. Rowe Price and T. Rowe Price
Vice President		Group, Inc.

David Oestreicher (1967)		Director and Vice President, T. Rowe Price
Vice President		Investment Services, Inc., T. Rowe Price
		Retirement Plan Services, Inc., T. Rowe
		Price Services, Inc., and T. Rowe Price Trust
		Company; Vice President, Price Hong Kong,
		Price Singapore, T. Rowe Price, T. Rowe Price
		Group, Inc., and T. Rowe Price International

Deborah D. Seidel (1962)		Vice President, T. Rowe Price, T. Rowe Price
Vice President		Group, Inc., T. Rowe Price Investment Services,
		Inc., and T. Rowe Price Services, Inc.

Chen Shao (1980)		Assistant Vice President, T. Rowe Price
Assistant Vice President

Douglas D. Spratley, CFA (1969)		Vice President, T. Rowe Price
Vice President

Julie L. Waples (1970)		Vice President, T. Rowe Price
Vice President

Edward A. Wiese, CFA (1959)		Director and Vice President, T. Rowe Price Trust
Vice President		Company; Vice President, T. Rowe Price and
		T. Rowe Price Group, Inc.; Chief Investment
		Officer, Director, and Vice President, T. Rowe
		Price Savings Bank

Unless otherwise noted, officers have been employees of T. Rowe Price or T. Rowe Price International for at least 5 years.