Mutual Fund Summary Prospectus (497k)

OPPENHEIMER MAIN STREET SMALL- & MID-CAP FUND ^®

Supplement dated November 15 , 2012 to the

Summary Prospectus

This supplement amends the Oppenheimer Main Street Small- & Mid-Cap Fund ^® (the "Fund") summary prospectus (the "Summary Prospectus") dated October 26, 2012.

Effective immediately:

The section titled "Portfolio Managers," on page 3, is deleted in its entirety and replaced by the following:

Portfolio Managers. Raymond Anello, CFA, has been lead portfolio manager of the Fund since November 2012, co-portfolio manager of the Fund since April 2011 and Vice President of the Fund since May 2011. Matthew P. Ziehl, CFA, has been co-portfolio manager and Vice President of the Fund since May 2009. Raman Vardharaj, CFA, has been co-portfolio manager and Vice President of the Fund since May 2009. Joy Budzinski, Kristin Ketner Pak, Magnus Krantz and Adam Weiner have been co-portfolio managers and Vice Presidents of the Fund since November 2012.

Effective January 14 , 2013 :

The first paragraph of the section titled "Principal Investment Strategies," on page 2, is deleted in its entirety and replaced by the following:

Principal Investment Strategies. Under normal market conditions, the Fund will invest at least 80% of its net assets, including any borrowings for investment purposes, in securities of “small-cap” and “mid-cap” companies. A company’s “market capitalization” is the value of its outstanding common stock. The Fund considers small-cap and mid-cap companies to be those having a market capitalization in the range of the Russell 2500™ Index and the Russell Midcap® Index, measures of small- to mid-cap issuers. The capitalization ranges of those indices are subject to change at any time due to market activity or changes in the composition of the indices. The ranges of the Russell 2500™ Index and the Russell Midcap® Index generally widen over time and are reconstituted annually to preserve their small- and mid-cap characteristics. The Fund measures a company’s capitalization at the time the Fund buys a security and is not required to sell a security if the company’s capitalization moves outside of the Fund’s capitalization definition.

November 15, 2012 PS0847.033

OPPENHEIMER

Main Street Small- & Mid-Cap Fund ^®

Summary Prospectus October 26, 2012

NYSE Ticker Symbols
Class A	OPMSX
Class B	OPMBX
Class C	OPMCX
Class N	OPMNX
Class Y	OPMYX
Class I	OPMIX

Before you invest, you may want to review the Fund's prospectus, which contains more information about the Fund and its risks. You can find the Fund's prospectus, Statement of Additional Information, Annual Report and other information about the Fund online at https://www.oppenheimerfunds.com/fund/MainStreetSmallMidCapFund. You can also get this information at no cost by calling 1.800.225.5677 or by sending an email request to: info@oppenheimerfunds.com.

The Fund's prospectus and Statement of Additional Information ("SAI"), both dated October 26, 2012, as supplemented, and pages 6 through 64 of its most recent Annual Report, dated June 30, 2012, are incorporated by reference into this Summary Prospectus. You can access the Fund's prospectus and SAI at https://www.oppenheimerfunds.com/fund/MainStreetSmallMidCapFund . The Fund's prospectus is also available from financial intermediaries who are authorized to sell Fund shares.

Investment Objective. The Fund seeks capital appreciation.

Fees and Expenses of the Fund. 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 10 of the prospectus and in the sections "How to Buy Shares" beginning on page 51 and "Appendix A" in the Fund's Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class B	Class C	Class N	Class Y	Class I
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	5.75%	None	None	None	None	None
Maximum Deferred Sales Charge (Load) (as % of the lower of original offering price or redemption proceeds)	None	5%	1%	1%	None	None

Annual Fund Operating Expenses (deducted from Fund assets): (% of average daily net assets)
	Class A	Class B	Class C	Class N	Class Y	Class I ¹
Management Fees	0.63%	0.63%	0.63%	0.63%	0.63%	0.63%
Distribution and/or Service (12b-1) Fees	0.25%	1.00%	1.00%	0.50%	None	None
Other Expenses	0.36%	0.70%	0.37%	0.44%	0.22%	0.05%
Total Annual Fund Operating Expenses	1.24%	2.33%	2.00%	1.57%	0.85%	0.68%
Fee Waiver and/or Expense Reimbursement ²	(0.03%)	(0.27%)	0.00%	(0.06%)	0.00%	0.00%
Total Annual Operating Expenses after Fee Waiver and/or Expense Reimbursement	1.21%	2.06%	2.00%	1.51%	0.85%	0.68%

1. Estimated expenses for the first fiscal year that Class I shares are offered. Class I shares will first be offered on the date of this prospectus.
2. 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 voluntary expense limitation may not be amended or withdrawn until one year from the date of this prospectus.

Example. 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:

If shares are redeemed									If shares are not redeemed
	1 Year		3 Years		5 Years		10 Years		1 Year		3 Years		5 Years		10 Years
Class A	$	692	$	945	$	1,218	$	1,995	$	692	$	945	$	1,218	$	1,995
Class B	$	711	$	1,009	$	1,435	$	2,139	$	211	$	709	$	1,235	$	2,139
Class C	$	305	$	634	$	1,088	$	2,350	$	205	$	634	$	1,088	$	2,350
Class N	$	255	$	494	$	856	$	1,877	$	155	$	494	$	856	$	1,877
Class Y	$	87	$	272	$	473	$	1,053	$	87	$	272	$	473	$	1,053
Class I*	$	70	$	218	$	380	$	849	$	70	$	218	$	380	$	849

* Based on estimated expenses for Class I shares for the first fiscal year.

Portfolio Turnover. 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 81% of the average value of its portfolio.

Principal Investment Strategies. The Fund mainly invests in common stocks of "small-cap" and "mid-cap" companies. A company's "market capitalization" is the value of its outstanding common stock. Under normal market conditions, the Fund will invest at least 80% of its net assets, including any borrowings for investment purposes, in securities of companies having a market capitalization in the range of the Russell 2500™ Index, a measure of small- to mid-cap issuers. The capitalization range of that index is subject to change due to market activity or changes in the composition of the index. The range of the Russell 2500™ Index generally widens over time and it is reconstituted annually to preserve its small- and mid-cap character. The Fund measures a company's capitalization at the time the Fund buys a security and is not required to sell a security if the company's capitalization moves outside of the Fund's capitalization definition.
The portfolio managers use both fundamental research and quantitative models to identify investment opportunities. While the process may change over time or vary in particular cases, in general the selection process currently:

aims to maintain broad diversification across all major economic sectors;
uses quantitative models, including sector-specific factors, to rank securities within each economic sector;
uses a fundamental approach to analyze issuers based on factors such as a company's financial performance, competitive strength, industry position, business practices and management; and
considers market trends, current industry outlooks and general economic conditions.

     In constructing the portfolio, the Fund seeks to limit exposure to so-called "top-down" or "macro" risks, such as overall stock market movements, economic cycles, and interest rate or currency fluctuations. Instead, the portfolio managers seek to add value by selecting individual securities with superior company-specific fundamental attributes or relative valuations that they expect to outperform their industry and sector peers. This is commonly referred to as a "bottom-up" approach to portfolio construction.
     The portfolio managers consider stock rankings, benchmark weightings and capitalization outlooks in determining security weightings for individual issuers. Although the Fund mainly invests in U.S. companies, it can invest in securities issued by companies or governments in any country. The Fund primarily invests in common stock but may also invest in other types of securities, such as units of master limited partnerships or other securities that are consistent with its investment objective.
     The portfolio managers might sell a security if the price is approaching their price target, if the company's competitive position has deteriorated or the company's management has performed poorly, or if they have identified more attractive investment prospects.

Principal Risks. 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.

Main Risks of Investing in Stock. 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.

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.

Main Risks of Small- and Mid-Sized Companies. 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.

Investing in Small Unseasoned Companies. The Fund can invest in the securities of small unseasoned companies. These are companies that have been in operation for less than three years, including the operations of any predecessors. In addition to the other risks of smaller issuers, these securities may have a very limited trading market, making it harder for the Fund to sell them at an acceptable price. The price of these securities may be very volatile, especially in the short term.

Main Risks of Foreign Investing. Foreign securities are subject to special risks. Foreign issuers are usually not subject to the same accounting and disclosure requirements that U.S. companies are subject to, which may make it difficult for the Fund to evaluate a foreign company's operations or financial condition. A change in the value of a foreign currency against the U.S. dollar will result in a change in the U.S. dollar value of securities denominated in that foreign currency and in the value of any income or distributions the Fund may receive on those securities. The value of foreign investments may be affected by exchange control regulations, foreign taxes, higher transaction and other costs, delays in the settlement of transactions, changes in economic or monetary policy in the United States or abroad, expropriation or nationalization of a company's assets, or other political and economic factors. These risks may be greater for investments in developing or emerging market countries.

Who Is the Fund Designed For? The Fund is designed primarily for investors seeking capital appreciation over the long term. Those investors should be willing to assume the greater risks of short-term share price fluctuations that are typical for a fund focusing on stocks of smaller companies. Because of its focus on long-term growth, the Fund may be more appropriate for investors with longer term investment goals. The Fund is not designed for investors needing an assured level of current income. The Fund is not a complete investment program and may not be appropriate for all investors. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.

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 Performance. 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:
https://www.oppenheimerfunds.com/fund/MainStreetSmallMidCapFund

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 31.48% (2nd Qtr 09) and the lowest return was -27.43% (4th Qtr 08). For the period from January 1, 2012 to September 30, 2012 the cumulative return before sales charges and taxes was 13.66%

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.

Performance information for Class I shares will be provided after those shares have one full calendar year of performance.

Average Annual Total Returns for the periods ended December 31, 2011
	1 Year	5 Years	10 Years
Class A Shares (inception 8/2/99)
Return Before Taxes	(8.25%)	(1.23%)	5.69%
Return After Taxes on Distributions	(8.33%)	(1.59%)	5.07%
Return After Taxes on Distributions and Sale of Fund Shares	(5.36%)	(1.10%)	4.85%
Class B Shares (inception 8/2/99)	(8.25%)	(1.18%)	5.83%
Class C Shares (inception 8/2/99)	(4.37%)	(0.78%)	5.54%
Class N Shares (inception 3/1/01)	(3.90%)	(0.31%)	6.02%
Class Y Shares (inception 8/2/99)	(2.31%)	0.35%	6.80%
Russell 2500™ Index	(2.51%)	1.24%	6.57%
(reflects no deduction for fees, expenses or taxes)

Investment Adviser. OppenheimerFunds, Inc. is the Fund's investment adviser (the "Manager").

Portfolio Managers. Matthew P. Ziehl, CFA, has been lead portfolio manager and Vice President of the Fund since May 2009, Raymond Anello, CFA, has been co-lead portfolio manager of the Fund since April 2011 and Vice President of the Fund since May 2011, and Raman Vardharaj, CFA, has been co-portfolio manager and Vice President of the Fund since May 2009.

Purchase and Sale of Fund Shares. You can buy most classes of Fund shares with a minimum initial investment of $1,000 and make additional investments with as little as $50. For certain investment plans and retirement accounts, the minimum initial investment is $500 and, for some, the minimum additional investment is $25. For certain fee based programs the minimum initial investment is $250. For Class I shares, the minimum initial investment is $5 million per account. The Class I share minimum initial investment will be waived for retirement plan service provider platforms.

Shares may be purchased through a financial intermediary or the Distributor and redeemed through a financial intermediary or the Transfer Agent on days the New York Stock Exchange is open for trading. Shareholders may purchase or redeem shares by mail, through the website at www.oppenheimerfunds.com or by calling 1.800.225.5677.

Share transactions may be paid by check, by Federal Funds wire or directly from or into your bank account.

Class B shares are no longer offered for new purchases. Any investments for existing Class B share accounts will be made in Class A shares of Oppenheimer Money Market Fund.

Taxes. If your shares are not held in a tax-deferred account, Fund distributions are subject to Federal income tax as ordinary income or as capital gains and they may also be subject to state or local taxes.

Payments to Broker-Dealers and Other Financial Intermediaries. If you purchase Fund shares through a broker-dealer or other financial intermediary (such as a bank), the Fund, the Manager, or their related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

For More Information About Oppenheimer Main Street Small- & Mid-Cap Fund

You can access the Fund's prospectus and SAI at https://www.oppenheimerfunds.com/fund/MainStreetSmallMidCapFund. You can also request additional information about the Fund or your account:

By Telephone:	Call OppenheimerFunds Services toll-free: 1.800.CALL OPP (225.5677)
By Mail:	For requests by mail: OppenheimerFunds Services P.O. Box 5270 Denver, Colorado 80217-5270	For courier or express mail requests: OppenheimerFunds Services 12100 East Iliff Avenue, Suite 300 Aurora, Colorado 80014
On the Internet:	You can read or download information on the OppenheimerFunds website at: www.oppenheimerfunds.com