0000823483 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024044Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024045Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024046Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024047Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024048Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000109444Member oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024044Member rr:AfterTaxesOnDistributionsMember oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:C000024044Member rr:AfterTaxesOnDistributionsAndSalesMember oppenheimer:AAAAMember 2012-12-28 2012-12-28 0000823483 oppenheimer:S000008827Member oppenheimer:SandP500IndexAAAAMember oppenheimer:AAAAMember 2012-12-28 2012-12-28 xbrli:pure iso4217:USD xbrli:shares iso4217:USD xbrli:shares 485BPOS 2008-08-31 OPPENHEIMER MAIN STREET FUND 0000823483 false 2012-12-28 2012-12-27 2012-12-28 <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 seeks capital appreciation.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Fees and Expenses of the Fund.</b> This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts is available from your financial professional and in the section "About Your Account" beginning on page 11 of the prospectus and in the sections "How to Buy Shares" beginning on page 54 and "Appendix A" in the Fund's Statement of Additional Information.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Shareholder Fees (fees paid directly from your investment) </b></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> Portfolio Turnover.</b> The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the annual fund operating expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 37% of the average value of its portfolio.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Principal Investment Strategies.</b> The Fund mainly invests in common stocks of U.S. companies of different capitalization ranges. The Fund currently focuses on "larger capitalization" issuers, which are considered to be companies with market capitalizations equal to the companies in the Russell 1000. The portfolio managers use fundamental research and quantitative models to select securities for the Fund's portfolio, which is comprised of both growth and value stocks. While the process may change over time or vary in particular cases, in general the selection process currently uses:</p> <ul><li> <p style="font-size:12;padding-top:0;padding-bottom:0;padding-left:0;">a fundamental approach in analyzing issuers on factors such as a company's financial performance and prospects, industry position, and business model and management strength. Industry outlook, market trends and general economic conditions may also be considered.</p> </li><li> <p style="font-size:12;padding-top:0;padding-bottom:0;padding-left:0;">quantitative models to rank securities within each sector to identify potential buy and sell candidates for further fundamental analysis. A number of company-specific factors are analyzed in constructing the models, including valuation, fundamentals and momentum.</p> </li></ul> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> The portfolio is constructed and regularly monitored based upon several analytical tools, including quantitative investment models. The Fund aims to maintain a broadly diversified portfolio across major economic sectors by applying investment parameters for both sector and position size. The portfolio managers use the following sell criteria: the stock price is approaching its target, deterioration in the company's competitive position, poor execution by the company's management, or identification of more attractive alternative investment ideas.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Principal Risks.</b> The price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. <i>These risks mean that you can lose money by investing in the Fund.</i> </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Main Risks of Investing in Stock.</b> The value of the Fund's portfolio may be affected by changes in the stock markets. Stock markets may experience significant short-term volatility and may fall sharply at times. Different stock markets may behave differently from each other and U.S. stock markets may move in the opposite direction from one or more foreign stock markets.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">The prices of individual stocks generally do not all move in the same direction at the same time and a variety of factors can affect the price of a particular company's stock. These factors may include, but are not limited to: poor earnings reports, a loss of customers, litigation against the company, general unfavorable performance of the company's sector or industry, or changes in government regulations affecting the company or its industry.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> At times, the Fund may emphasize investments in a particular industry or economic or market sector. To the extent that the Fund increases its emphasis on investments in a particular industry or sector, the value of its investments may fluctuate more in response to events affecting that industry or sector, such as changes in economic conditions, government regulations, availability of basic resources or supplies, or other events that affect that industry or sector more than others. </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> <b>Main Risks of Small- and Mid-Sized Companies.</b> The stock prices of small- and mid-sized companies may be more volatile and their securities may be more difficult to sell than those of larger companies. They may not have established markets, may have fewer customers and product lines, may have unseasoned management or less management depth and may have more limited access to financial resources. Smaller companies may not pay dividends or provide capital gains for some time, if at all.</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 primarily for investors seeking capital appreciation. Those investors should be willing to assume the risks of short-term share price fluctuations that are typical for a fund that focuses on stock. The Fund is not designed for investors needing current income. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.</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. </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 A 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/MainStreetFund </u> </p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 18.65% (2nd Qtr 09) and the lowest return was -22.27% (4th Qtr 08). For the period from January 1, 2012 through September 30, 2012 the cumulative return before sales charges and taxes was 17.10%.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;">The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.</p> <p style="font-size:12;padding-top:2;padding-bottom:0;padding-left:0;"> Performance information for Class I shares will be provided after those shares have one full calendar year of performance. </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> <div style="display:none">~http://oppenheimer/role/ShareholderFeesDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> 0.0575 0 0 0.05 0 0.01 0 0.01 0 0 0 0 <div style="display:none">~ http://oppenheimer/role/OperatingExpensesDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> 0.0047 0.0024 0.0026 0.0097 0 0.0097 0.0047 0.0099 0.0051 0.0197 -0.0012 0.0185 0.0047 0.0099 0.0025 0.0171 0 0.0171 0.0047 0.0049 0.0026 0.0122 0 0.0122 0.0047 0 0.0007 0.0054 0 0.0054 0.0047 0 0.0003 0.005 0 0.005 <div style="display:none">~ http://oppenheimer/role/ExpenseExampleAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> 669 690 275 225 55 51 868 913 543 390 174 161 1083 1261 936 674 303 280 1702 1802 2036 1486 679 630 <div style="display:none">~ http://oppenheimer/role/ExpenseExampleNoRedemptionAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> 669 190 175 125 55 51 868 613 543 390 174 161 1083 1061 936 674 303 280 1702 1802 2036 1486 679 630 <div style="display:none">~ http://oppenheimer/role/BarChartDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> -0.1942 0.2695 0.0939 0.0574 0.1491 0.042 -0.3874 0.2877 0.1578 -0.0022 <div style="display:none">~ http://oppenheimer/role/PerformanceTableDataAAAA column period compact * column rr_ProspectusShareClassAxis compact * row primary compact * row dei_LegalEntityAxis compact oppenheimer_S000008827Member ~</div> -0.0596 -0.0603 -0.0378 -0.0606 -0.0195 -0.0148 0.0019 0.0211 -0.022 -0.0292 -0.0205 -0.0217 -0.0176 -0.0129 -0.0057 -0.0025 0.0198 0.0148 0.016 0.0213 0.0182 0.023 0.0298 0.0292 You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds. 25000 0.37 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 price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. These risks mean that you can lose money by investing in the Fund. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For the period from January 1, 2012 through September 30, 2012 the cumulative return before sales charges and taxes was 17.10%. 0.1710 2012-09-30 highest return for a calendar quarter was 18.65% (2nd Qtr 09) 0.1865 lowest return was -22.27% (4th Qtr 08) -0.2227 https://www.oppenheimerfunds.com/fund/MainStreetFund After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary. 1988-02-03 1994-10-03 1993-12-01 2001-03-01 1996-11-01 The Fund's transfer agent has voluntarily agreed to limit its fees for Classes B, C, N and Y to 0.35% of average annual net assets per class per fiscal year, and to 0.30% of average annual net assets per fiscal year for Class A. This fee waiver and/or expense limitation may not be amended or withdrawn until one year from the date of this prospectus.