0001358587 2012-09-28 2012-09-28 0001358587 oppenheimer:S000012567Member oppenheimer:AAAAMember 2012-09-28 2012-09-28 0001358587 oppenheimer:S000012567Member oppenheimer:C000034179Member oppenheimer:AAAAMember 2012-09-28 2012-09-28 0001358587 oppenheimer:S000012567Member oppenheimer:C000034180Member oppenheimer:AAAAMember 2012-09-28 2012-09-28 0001358587 oppenheimer:S000012567Member oppenheimer:C000034181Member oppenheimer:AAAAMember 2012-09-28 2012-09-28 xbrli:pure iso4217:USD xbrli:shares iso4217:USD xbrli:shares 485BPOS 2012-05-31 Oppenheimer Institutional Money Market Fund 0001358587 false 2012-09-28 2012-09-26 2012-09-28 <div style="display: none">~ http://xbrl.sec.gov/rr/role/RiskReturnDetailData column period compact * row dei_DocumentInformationDocumentAxis compact * row dei_LegalEntityAxis compact * row rr_ProspectusShareClassAxis compact * row rr_PerformanceMeasureAxis compact * row primary compact * ~</div> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Investment Objective.</b> The Fund's objective is to seek current income and stability of principal. The Fund is a money market fund.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Fees and Expenses of the Fund.</b> The table below describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Shareholder Fees.</b> The Fund does not charge any initial sales charge to buy shares or to reinvest dividends. There are no exchange fees or redemption fees and no contingent deferred sales charges.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)</b></p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Example.</b> The following Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in a class of shares of the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows: </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"><b> If shares are redeemed </b></p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"><b> If shares are not redeemed </b></p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Principal Investment Strategies.</b> The Fund is a money market fund that invests in a variety of money market instruments to seek current income. Money market instruments are short-term, high-quality, dollar-denominated debt instruments issued by the U.S. Government, domestic and foreign corporations and financial institutions, and other entities. Money market instruments include bank obligations, repurchase agreements, commercial paper, and other short-term corporate and governmental debt obligations.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">To be considered "high-quality," a debt instrument must be rated in one of the two highest credit-quality categories for short-term securities by a nationally recognized statistical rating service or, if a security is unrated, it must be determined by the Fund's investment manager, OppenheimerFunds, Inc. (the "Manager"), under the supervision of the Fund's Board, to be of comparable quality to rated securities in one of those two categories.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Principal Risks.</b> All investments carry risks to some degree. The Fund's investments are subject to changes in their value from a number of factors. However, the Fund's investments must meet strict standards set by its Board of Trustees and special rules under Federal law for money market funds. Those requirements include maintaining high credit quality, a short average maturity and diversification of the Fund's investments among issuers. Those provisions are designed to help minimize credit risks, to reduce the effects of changes in prevailing interest rates and to reduce the effect on the Fund's portfolio of a default by any one issuer. Since income on short-term securities tends to be lower than income on longer-term debt securities, the Fund's yield will likely be lower than the yield on longer-term fixed-income funds. </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> Even so, there are risks that an issuer of an obligation that the Fund holds might have its credit rating downgraded or might default on its obligations, or that interest rates might rise sharply, causing the value of the Fund's investments to fall. Also, there is the risk that the value of your investment could be eroded over time by the effects of inflation, or that poor security selection could cause the Fund to underperform other funds that have a similar objective. If there is an unexpectedly high demand for the redemption of Fund shares, the Fund might need to sell portfolio securities prior to their maturity, possibly at a loss. As a result, there is a risk that the Fund's shares could fall below $1.00 per share.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Interest Rate Risk.</b> The values of debt securities usually change when prevailing interest rates change. When interest rates fall, the values of already-issued debt securities generally rise. When interest rates rise, the values of already-issued debt securities generally fall. The values of longer-term debt securities usually change more when interest rates change than the values of shorter-term debt securities.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Credit Risk.</b> Debt securities are also subject to credit risk, which is the risk that the issuer of a security might not make principal or interest payments on the security when they are due. If the issuer fails to pay interest, the Fund's income might be reduced, and if the issuer fails to pay interest or repay principal, the value of the security might fall.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Fixed-Income Market Risks.</b> Economic and other market developments can adversely affect fixed-income securities markets in the United States, Europe and elsewhere. At times, participants in debt securities markets may develop concerns about the ability of certain issuers of debt securities to make timely principal and interest payments, or they may develop concerns about the ability of financial institutions that make markets in certain debt securities to facilitate an orderly market. Those concerns can cause increased volatility in those debt securities or debt securities markets. Under some circumstances, as was the case during the latter half of 2008 and early 2009, those concerns could cause reduced liquidity in certain debt securities markets. A lack of liquidity or other adverse credit market conditions may hamper the Fund's ability to sell the debt securities in which it invests or to find and purchase suitable debt instruments.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Who Is the Fund Designed For?</b> The Fund is designed for institutional investors who want to earn income at money market rates while preserving the value of their investment and maintaining easy access to their investment through wire redemption privileges. The Fund will invest in a variety of money market instruments to seek current income and stability of principal and to try to maintain a stable share price of $1.00. Income on short-term securities tends to be lower than income on longer-term debt securities, so the Fund's yield will likely be lower than the yield on longer-term fixed-income funds. The Fund does not invest for the purpose of seeking capital appreciation or gains and is not a complete investment program.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b> An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund. </b> </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>The Fund's Past Performance.</b> The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance (for Class E Shares) from year to year and by showing how the Fund's average annual returns for 1, 5 and 10 years compare with those of a broad measure of market performance. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund's website: <u>https://www.oppenheimerfunds.com/fund/InstitutionalMoneyMarketFund</u> </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">During the period shown, the highest return for a calendar quarter was 1.34% (3rd Qtr 07) and the lowest return was 0.04% (2nd &amp; 3rd Qtr 11). For the period from January 1, 2012 to June 30, 2012 the cumulative return before taxes was 0.11%.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Average Annual Total Returns for the periods ended December 31, 2011</b></p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">The Fund's performance reflects reinvestment of all dividends and capital gains distributions.</p> <div style="display:none">~ http://oppenheimer/role/OperatingExpensesDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000012567Member ~</div> 0.001 0 0.0001 0.0011 0 0.0011 0.001 0 0.0007 0.0017 0 0.0017 0.001 0.0025 0.0005 0.004 -0.002 0.002 <div style="display:none">~ http://oppenheimer/role/ExpenseExampleAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000012567Member ~</div> 11 17 21 36 55 108 62 96 205 141 217 487 <div style="display:none">~ http://oppenheimer/role/ExpenseExampleNoRedemptionAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000012567Member ~</div> 11 17 21 36 55 108 62 96 205 141 217 487 <div style="display:none">~ http://oppenheimer/role/BarChartDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000012567Member ~</div> 0.0536 0.0314 0.0058 0.0023 0.0018 <div style="display:none">~ http://oppenheimer/role/PerformanceTableDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000012567Member ~</div> 0.0018 0.0012 0.0008 An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. https://www.oppenheimerfunds.com/fund/InstitutionalMoneyMarketFund 2006-10-03 2006-10-03 2007-05-21 For the period from January 1, 2012 to June 30, 2012 the cumulative return before taxes was 0.11%. 0.0011 2012-06-30 highest return for a calendar quarter was 1.34% (3rd Qtr 07) 0.0134 lowest return was 0.04% (2nd & 3rd Qtr 11) 0.0004 0.0204 0.0203 0.0151 0.0188 0.0186 0.0151 The Fund's distributor has voluntarily undertaken to waive the fees payable under the Service Plan for Class P shares so that those fees are limited to 0.05% of the average annual net assets of Class P shares of the Fund. This voluntary waiver may not be amended or withdrawn until one year from the date of this prospectus.