Oppenheimer Main Street Funds N-CSR Certified annual shareholder report (management investment company)

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 811-5360

Oppenheimer Main Street Funds, Inc.

(Exact name of registrant as specified in charter)

6803 South Tucson Way, Centennial, Colorado 80112-3924

(Address of principal executive offices) (Zip code)

Arthur S. Gabinet

OFI Global Asset Management, Inc.

Two World Financial Center, New York, New York 10281-1008

(Name and address of agent for service)

Registrant’s telephone number, including area code: (303) 768-3200

Date of fiscal year end: August 31

Date of reporting period: 8/30/2013

Item 1. Reports to Stockholders.

Table of Contents

Fund Performance Discussion	3
Top Holdings and Allocations	7
Fund Expenses	10
Statement of Investments	12
Statement of Assets and Liabilities	15
Statement of Operations	17
Statements of Changes in Net Assets	19
Financial Highlights	20
Notes to Financial Statements	26
Report of Independent Registered Public Accounting Firm	40
Federal Income Tax Information	41
Board Approval of the Fund’s Investment Advisory Agreement	42
Portfolio Proxy Voting Policies and Procedures; Updates to Statement of Investments	45
Trustees and Officers	46
Privacy Policy Notice	52

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 8/30/13*

	Class A Shares of the Fund
	Without Sales Charge	With Sales Charge	S&P 500 Index
1-Year	16.78%	10.07%	18.70%
5-Year	6.66	5.41	7.32
10-Year	6.48	5.85	7.12

Performance data quoted represents past performance, which does not guarantee future results. The investment return and principal value of an investment in the Fund will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Fund returns include changes in share price, reinvested distributions, and a 5.75% maximum applicable sales charge except where “without sales charge” is indicated. Current performance may be lower or higher than the performance quoted. Returns do not consider capital gains or income taxes on an individual’s investment. For performance data current to the most recent month-end, visit oppenheimerfunds.com or call 1.800.CALL OPP (225.5677).

*August 30, 2013, was the last business day of the Fund’s fiscal year. See Note 1 of the accompanying Notes to Financial Statements. Index returns are calculated through August 31, 2013.

2      OPPENHEIMER MAIN STREET FUND

Fund Performance Discussion

The Fund’s Class A shares (without sales charge) produced a total return of 16.78% during the reporting period, underperforming the S&P 500 Index (the “Index”), which returned 18.70%. The Fund’s underperformance relative to the Index stemmed primarily from weaker relative stock selection in the information technology, consumer staples and telecommunication services sectors. The Fund also had an overweight position in information technology, which hurt performance relative to the Index. The Fund outperformed the Index in the financials sector, where favorable stock selection and an overweight position benefited.

MARKET OVERVIEW

The reporting period began at the start of an economic rebound. Investor sentiment improved dramatically when the unemployment rate declined sharply in the fall of 2012, housing sales and prices climbed, and the European Central Bank announced credible measures to address weakness in its banking system. In addition, U.S. investors were encouraged when the Federal Reserve (the “Fed”) launched an open-ended quantitative easing program

involving monthly purchases of $85 billion of U.S. government securities. The quantitative easing program was designed to help boost the U.S. economy by keeping mortgage rates and other long-term interest rates low.

These measures generally proved effective, as evidenced by mildly accelerating economic growth, labor market gains, and higher housing prices over the first quarter of 2013. Manufacturing activity also expanded, as did

COMPARISION OF CHANGE IN VALUE OF $10,000 HYPOTHETICAL INVESTMENTS IN:

3      OPPENHEIMER MAIN STREET FUND

exploration-and-production activity surrounding domestic sources of oil and gas. In light of the nation’s improved economic prospects, several broad measures of stock market performance set new record highs in the spring.

Investor sentiment shifted dramatically in late May, when remarks by Fed chairman Ben Bernanke were widely interpreted as a signal that the central bank would begin to back away from its quantitative easing program sooner than most analysts had expected. As a result, the markets sold-off sharply and made a quick reappraisal of interest rate risk in an array of credit markets and related currencies. Equities, particularly those in emerging markets and in interest rate sensitive sectors, experienced spillover effects as a result. However, markets in the U.S. stabilized over the final months of the reporting period, as investors came to the realization that an end to the quantitative easing program did not necessarily imply an imminent increase in short-term interest rates.

FUND REVIEW

During the period, the top two performing stocks for the Fund were in the financials sector: Citigroup, Inc. and JPMorgan Chase & Co. The financials sector was the strongest performing sector for the Fund on both an absolute basis and relative to the Index. The ongoing, albeit modest, improvement in the economy – largely driven by the continued health of the housing sector – has led to lower foreclosures, increased credit quality, and rising demand for mortgages. As a

result, stocks of many banks have benefited, including JPMorgan Chase and Citigroup.

Outside of the financials sector, Ford Motor Co., Actavis, Inc. and Facebook, Inc., benefited the Fund’s performance. Ford Motor benefited from an expanding multiple as investors focused on the sustainability of improved auto sales. Ford also announced a comprehensive and credible multi-year restructuring of its European businesses, which was well received by investors. Actavis is a branded and generic drug company whose shares spiked when management announced it was combining operations with Warner Chilcott – a leading specialty pharmaceutical company based in Ireland. The merged entity is expected to benefit from revenue synergies, with complementary product lines, and cost rationalization – both of which we believe have the potential to contribute to rising profits. Social media giant Facebook rallied over the final two months of the reporting period. Facebook reported strong quarterly results and answered concerns over its ability to deliver advertising via mobile devices as its mobile business grew and made up roughly 41% of the company’s total ad revenue at period end.

The most significant detractor from performance was Apple, Inc. Despite a boost to both its share repurchase and dividend, investors reacted negatively to management’s disappointing guidance and further delays in the launch of innovative products – which the market believes are sorely needed. Apple’s recent annual Worldwide Developers

4      OPPENHEIMER MAIN STREET FUND

Conference also failed to inspire – leaving investors wondering further about the likelihood of a “game-changing” product introduction.

Also detracting from performance were America Movil SAB de CV and National Oilwell Varco, Inc. America Movil is a mobile carrier in Latin America. The Mexican government announced a reform proposal designed to create more competition, increase access to services, and reduce prices in the Mexican telecom sector. The bulk of National Oilwell Varco’s declines occurred over the first half of the period. As energy prices started to decline in the North American market in the third quarter of 2012, drilling activity weakened. This negatively impacted demand for National Oilwell Varco’s consumables and caused earnings estimates to recede. Additionally, there was some investor concern, mostly stemming from the fear of falling energy prices, that 2013 may be the peak in the company’s rig order backlog. We continue to believe that both the backlog and contribution from prior acquisitions will fuel growth of earnings and cash flow beyond 2013.

STRATEGY & OUTLOOK

We believe the Fed has acted appropriately by signaling that eventually it will lessen its monetary support of our expanding economy. While the market declined after the Fed’s comments, what seemed to be missing from the market’s response was the realization that when rates do rise, it should be a reflection of a strong economy.

Company fundamentals are better than at prior nominal highs in the market. And, as has been well documented throughout this tepid recovery, corporations have been very cautious about spending money – largely reflecting uncertainty about the economic and political outlook. This cautious behavior has resulted in a massive build-up of cash on corporate balance sheets that has greatly improved the fundamental health of many companies. As the economy improves and managements’ uncertainty lifts, these cash balances have the potential to be used in a constructive manner that may support rising equity valuations.

Domestically, housing has momentum and job creation, while not robust, at least is ongoing. We expect that company fundamentals will continue to show improvement – especially as companies tap into the large cash reserves that have been built-up. These factors have the potential to drive equity prices higher; however, rarely does the market appreciate on a straight upward trajectory. While we are not predicting a market correction, we do believe that the market may return to experiencing greater volatility.

Given this backdrop, our approach remains consistent. We aim to construct an “all weather” portfolio by targeting companies with: 1) sustainable competitive advantages; 2) skilled management with a proven track record of executing effectively; and 3) financial resources to generate improving profitability, gain market share, and/or return

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significant capital to shareholders. During volatile economic times such companies often widen their lead over weaker competitors. We seek to invest in companies, characterized by these qualities, at compelling valuations and believe this disciplined approach is essential.

  Manind Govil, CFA Portfolio Manager   Benjamin Ram Portfolio Manager

6      OPPENHEIMER MAIN STREET FUND

Top Holdings and Allocations*

TOP TEN COMMON STOCK HOLDINGS

Apple, Inc.	5.6%
JPMorgan Chase & Co.	4.3
Chevron Corp.	3.5
National Oilwell Varco, Inc.	3.4
Express Scripts Holding Co.	3.4
AutoZone, Inc.	3.1
International Business Machines Corp.	3.0
Philip Morris International, Inc.	3.0
Covidien plc	2.9
CIT Group, Inc.	2.8

Portfolio holdings and allocations are subject to change. Percentages are as of August 30, 2013, and are based on net assets. For more current Fund holdings, please visit oppenheimerfunds.com.

TOP TEN COMMON STOCK INDUSTRIES

Diversified Financial Services	10.2%
Pharmaceuticals	8.8
Computers & Peripherals	6.4
Internet Software & Services	5.9
Oil, Gas & Consumable Fuels	5.4
Health Care Providers & Services	5.3
Specialty Retail	4.8
IT Services	4.2
Insurance	4.2
Energy Equipment & Services	3.4

Portfolio holdings and allocations are subject to change. Percentages are as of August 30, 2013, and are based on net assets.

SECTOR ALLOCATION

Portfolio holdings and allocations are subject to change. Percentages are as of August 30, 2013, and are based on the total market value of common stocks.

*August 30, 2013, was the last business day of the Fund’s fiscal year. See Note 1 of the accompanying Notes to Financial Statements.

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Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 8/30/13

	Inception Date	1-Year	5-Year	10-Year
Class A (MSIGX)	2/3/88	16.78%	6.66%	6.48%
Class B (OMSBX)	10/3/94	15.71%	5.73%	5.99%
Class C (MIGCX)	12/1/93	15.92%	5.87%	5.69%
Class I (OMSIX)	12/29/11	17.28%	18.94%*	N/A
Class N (OMGNX)	3/1/01	16.47%	6.39%	6.18%
Class Y (MIGYX)	11/1/96	17.18%	7.14%	6.93%
AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 8/30/13
	Inception Date	1-Year	5-Year	10-Year
Class A (MSIGX)	2/3/88	10.07%	5.41%	5.85%
Class B (OMSBX)	10/3/94	10.71%	5.41%	5.99%
Class C (MIGCX)	12/1/93	14.92%	5.87%	5.69%
Class I (OMSIX)	12/29/11	17.28%	18.94%*	N/A
Class N (OMGNX)	3/1/01	15.47%	6.39%	6.18%
Class Y (MIGYX)	11/1/96	17.18%	7.14%	6.93%

*Shows performance since inception.

Performance data quoted represents past performance, which does not guarantee future results. The investment return and principal value of an investment in the Fund will fluctuate so that an investor’s shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance quoted. Returns do not consider capital gains or income taxes on an individual’s investment. For performance data current to the most recent month-end, visit oppenheimerfunds.com or call 1.800.CALL OPP (225.5677). Fund returns include changes in share price, reinvested distributions, and the applicable sales charge: for Class A shares, the current maximum initial sales charge of 5.75%; for Class B shares, the contingent deferred sales charge of 5% (1-year) and 2% (5-year); and for Class C and N shares, the contingent deferred sales charge of 1% for the 1-year period. There is no sales charge for Class I and Class Y shares. Because Class B shares convert to Class A shares 72 months after purchase, the 10-year return for Class B shares uses Class A performance for the period after conversion. Returns for periods of less than one year are cumulative and not annualized.

The Fund’s performance is compared to the performance of the S&P 500 Index. The S&P 500 Index is an index of large-capitalization equity securities that is a measure of the general domestic stock market. The Index is unmanaged and cannot be purchased directly by investors. Index performance includes reinvestment of income, but does not reflect transaction costs, fees, expenses or taxes. Index performance is shown for illustrative purposes only as a benchmark for the Fund’s performance, and does not predict or depict performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

The Fund’s investment strategy and focus can change over time. The mention of specific fund holdings does not constitute a recommendation by OppenheimerFunds, Inc. or its affiliates.

8      OPPENHEIMER MAIN STREET FUND

Before investing in any of the Oppenheimer funds, investors should carefully consider a fund’s investment objectives, risks, charges and expenses. Fund prospectuses and summary prospectuses contain this and other information about the funds, and may be obtained by asking your financial advisor, visiting oppenheimerfunds.com, or calling 1.800.CALL OPP (225.5677). Read prospectuses and summary prospectuses carefully before investing.

Shares of Oppenheimer funds are not deposits or obligations of any bank, are not guaranteed by any bank, are not insured by the FDIC or any other agency, and involve investment risks, including the possible loss of the principal amount invested.

9      OPPENHEIMER MAIN STREET FUND

Fund Expenses

Fund Expenses. As a shareholder of the Fund, you incur two types of costs: (1) transaction costs, which may include sales charges (loads) on purchase payments, contingent deferred sales charges on redemptions; and (2) ongoing costs, including management fees; distribution and service fees; and other Fund expenses. These examples are 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 examples are based on an investment of $1,000.00 invested at the beginning of the period and held for the entire 6-month period ended August 30, 2013.

Actual Expenses. The first section of the table provides information about actual account values and actual expenses. You may use the information in this section for the class of shares you hold, together with the amount you invested, to estimate the expense that you paid over the period. Simply divide your account value by $1,000.00 (for example, an $8,600.00 account value divided by $1,000.00 = 8.60), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes. The second section of the table provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio for each class of shares, and an assumed rate of return of 5% per year for each class before expenses, which is not the actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example for the class of shares you hold with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as front-end or contingent deferred sales charges (loads), or a $12.00 fee imposed annually on accounts valued at less than $500.00 (subject to exceptions described in the Statement of Additional Information). Therefore, the “hypothetical” section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

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Actual	Beginning Account Value March 1, 2013		Ending Account Value August 30, 2013		Expenses Paid During 6 Months Ended August 30, 2013
Class A	$	1,000.00	$	1,095.40	$	4.74
Class B		1,000.00		1,090.20		9.63
Class C		1,000.00		1,091.10		8.68
Class I		1,000.00		1,097.50		2.68
Class N		1,000.00		1,093.80		6.16
Class Y		1,000.00		1,097.00		3.26
Hypothetical (5% return before expenses)
Class A		1,000.00		1,020.56		4.57
Class B		1,000.00		1,015.89		9.29
Class C		1,000.00		1,016.80		8.38
Class I		1,000.00		1,022.51		2.59
Class N		1,000.00		1,019.20		5.94
Class Y		1,000.00		1,021.96		3.15

Expenses are equal to the Fund’s annualized expense ratio for that class, multiplied by the average account value over the period, multiplied by 183/365 (to reflect the one-half year period). Those annualized expense ratios, excluding indirect expenses from affiliated funds, based on the 6-month period ended August 30, 2013 are as follows:

Class	Expense Ratios
Class A		0.90	%
Class B		1.83
Class C		1.65
Class I		0.51
Class N		1.17
Class Y		0.62

The expense ratios reflect voluntary waivers and/or reimbursements of expenses by the Fund’s Manager and Transfer Agent. Some of these undertakings may be modified or terminated at any time, as indicated in the Fund’s prospectus. The “Financial Highlights” tables in the Fund’s financial statements, included in this report, also show the gross expense ratios, without such waivers or reimbursements and reduction to custodian expenses, if applicable.

11      OPPENHEIMER MAIN STREET FUND

STATEMENT OFINVESTMENTSAugust 30, 2013*

	Shares		Value
Common Stocks—98.6%
Consumer Discretionary—9.2%
Auto Components—0.6%
Delphi Automotive plc	693,790	$	38,172,326
Automobiles—1.2%
Ford Motor Co.	4,485,250		72,616,197
Media—1.8%
Time Warner, Inc.	1,852,720		112,145,142
Specialty Retail—4.8%
AutoZone, Inc.1	455,857		191,432,589
TJX Cos., Inc. (The)	1,987,680		104,790,490
			296,223,079
Textiles, Apparel & Luxury Goods—0.8%
PVH Corp.	402,030		51,761,362
Consumer Staples—8.4%
Beverages—0.5%
Dr Pepper Snapple Group, Inc.	690,980		30,928,265
Food Products—3.3%
J.M. Smucker Co. (The)	288,210		30,590,609
Kraft Foods Group, Inc.	1,594,523		82,548,456
Mondelez International, Inc., Cl. A	3,028,990		92,899,123
			206,038,188
Household Products—1.6%
Henkel AG & Co. KGaA	630,449		51,244,058
Henkel AG & Co. KGaA, Preference	533,751		51,717,525
			102,961,583
Tobacco—3.0%
Philip Morris International, Inc.	2,249,678		187,713,132
Energy—8.8%
Energy Equipment & Services—3.4%
National Oilwell Varco, Inc.	2,877,470		213,796,021
Oil, Gas & Consumable Fuels—5.4%
Chevron Corp.	1,790,219		215,596,074
Noble Energy, Inc.	1,915,260		117,654,422
			333,250,496
Financials—19.6%
Commercial Banks—3.2%
CIT Group, Inc.1	3,645,866		174,527,605
M&T Bank Corp.	245,590		27,835,171
			202,362,776
Consumer Finance—2.0%
Discover Financial Services	2,641,880		124,828,830

	Shares		Value
Diversified Financial Services—10.2%
Citigroup, Inc.	2,558,390	$	123,646,989
CME Group, Inc.	784,040		55,753,084
JPMorgan Chase & Co.	5,314,280		268,530,568
McGraw Hill Financial, Inc.	2,493,998		145,574,663
Moody’s Corp.	401,070		25,492,009
MSCI, Inc., Cl. A1	414,570		15,550,521
			634,547,834
Insurance—4.2%
American International Group, Inc.1	2,440,270		113,374,944
Lincoln National Corp.	1,115,870		46,911,175
Marsh & McLennan Cos., Inc.	2,361,570		97,367,531
			257,653,650
Health Care—17.3%
Biotechnology—0.3%
Gilead Sciences, Inc.1	339,280		20,448,406
Health Care Equipment & Supplies—2.9%
Covidien plc	3,082,120		183,077,928
Health Care Providers & Services—5.3%
Express Scripts Holding Co.1	3,285,472		209,875,951
UnitedHealth Group, Inc.	1,606,930		115,281,158
			325,157,109
Pharmaceuticals—8.8%
AbbVie, Inc.	1,415,180		60,300,820
Actavis, Inc.1	734,710		99,318,098
Allergan, Inc.	1,332,500		117,766,350
Pfizer, Inc.	3,241,223		91,434,901
Sanofi	642,070		61,684,138
Zoetis, Inc.	3,833,412		111,743,960
			542,248,267
Industrials—9.9%
Aerospace & Defense—0.6%
L-3 Communications Holdings, Inc.	382,490		34,550,322
Air Freight & Couriers—1.4%
United Parcel Service, Inc., Cl. B	1,023,736		87,611,327
Commercial Services & Supplies—3.1%
ADT Corp. (The)	1,043,764		41,573,120
Tyco International Ltd.	4,484,488		148,167,483
			189,740,603
Professional Services—1.6%
Towers Watson & Co., Cl. A	1,221,400		100,460,150

12      OPPENHEIMER MAIN STREET FUND

	Shares		Value
Road & Rail—3.2%
Canadian National Railway Co.	1,524,680	$	142,908,256
CSX Corp.	2,306,510		56,763,211
			199,671,467
Information Technology—21.3%
Communications Equipment—1.5%
QUALCOMM, Inc.	1,420,988		94,183,085
Computers & Peripherals—6.4%
Apple, Inc.	710,955		346,270,633
Western Digital Corp.	837,610		51,931,820
			398,202,453
Electronic Equipment, Instruments, & Components—0.9%
Corning, Inc.	4,201,960		58,995,518
Internet Software & Services—5.9%
eBay, Inc.1	3,374,750		168,703,752
Facebook, Inc., Cl. A1	2,306,570		95,215,210
Google, Inc., Cl. A1	123,446		104,546,417
			368,465,379
IT Services—4.2%
Amdocs Ltd.	1,214,410		44,763,153
International Business Machines Corp.	1,039,280		189,429,566
Mastercard, Inc., Cl. A	54,670		33,134,394
			267,327,113
Software—2.4%
Microsoft Corp.	4,459,410		148,944,294

	Shares		Value
Materials—2.9%
Chemicals—0.8%
Air Products & Chemicals, Inc.	385,200	$	39,344,328
PPG Industries, Inc.	80,080		12,509,297
			51,853,625
Construction Materials—2.1%
Vulcan Materials Co.	2,744,953		131,208,753
Telecommunication Services—0.6%
Wireless Telecommunication Services—0.6%
America Movil SAB de CV, Series L, ADR	2,087,790		40,294,347
Utilities—0.6%
Electric Utilities—0.6%
Exelon Corp.	1,290,110		39,335,454
Total Common Stocks
(Cost $4,409,409,480)			6,146,774,481
Investment Company—1.7%
Oppenheimer Institutional Money Market Fund, Cl. E, 0.10%2,3 (Cost $104,613,190)	104,613,190		104,613,190
Total Investments, at Value (Cost $4,514,022,670)	100.3%		6,251,387,671
Liabilities in Excess of Other Assets	(0.3)		(20,392,116	)
Net Assets	100.0%	$	6,230,995,555

Footnotes to Statement of Investments

*August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.

1. Non-income producing security.

2. Is or was an affiliate, as defined in the Investment Company Act of 1940, at or during the period ended August 30, 2013, by virtue of the Fund owning at least 5% of the voting securities of the issuer or as a result of the Fund and the issuer having the same investment adviser. Transactions during the period in which the issuer was an affiliate are as follows:

13      OPPENHEIMER MAIN STREET FUND

STATEMENT OFINVESTMENTSContinued

Footnotes to Statement of Investments (Continued)

	Shares August 31, 2012		Gross Additions		Gross Reductions		Shares August 30, 2013
Oppenheimer Institutional Money Market Fund, Cl. E		215,909,645		1,575,636,484		1,686,932,939		104,613,190
					Value		Income
Oppenheimer Institutional Money Market Fund, Cl. E					$	104,613,190	$	122,242

3. Rate shown is the 7-day yield as of August 30, 2013.

See accompanying Notes to Financial Statements.

14      OPPENHEIMER MAIN STREET FUND

STATEMENT OFASSETS AND LIABILITIESAugust 30, 2013¹

Assets
Investments, at value—see accompanying statement of investments:
Unaffiliated companies (cost $4,409,409,480)	$	6,146,774,481
Affiliated companies (cost $104,613,190)		104,613,190
		6,251,387,671
Receivables and other assets:
Investments sold		24,500,902
Dividends		9,636,349
Shares of beneficial interest sold		1,171,188
Other		361,379
Total assets		6,287,057,489
Liabilities
Payables and other liabilities:
Investments purchased		45,954,890
Shares of beneficial interest redeemed		7,066,874
Distribution and service plan fees		1,268,651
Transfer and shareholder servicing agent fees		984,989
Shareholder communications		322,792
Trustees’ compensation		302,337
Other		161,401
Total liabilities		56,061,934
Net Assets	$	6,230,995,555
Composition of Net Assets
Par value of shares of beneficial interest	$	1,477,945
Additional paid-in capital		4,835,137,351
Accumulated net investment income		31,465,233
Accumulated net realized loss on investments and foreign currency transactions		(374,449,975)
Net unrealized appreciation on investments and translation of assets and liabilities denominated in foreign currencies		1,737,365,001
Net Assets	$	6,230,995,555

1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.

15      OPPENHEIMER MAIN STREET FUND

STATEMENT OFASSETS AND LIABILITIESContinued

Net Asset Value Per Share
Class A Shares:
Net asset value and redemption price per share (based on net assets of $4,588,619,173 and 108,246,452 shares of beneficial interest outstanding)	$	42.39
Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	44.98
Class B Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $205,385,708 and 5,023,713 shares of beneficial interest outstanding)	$	40.88
Class C Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $582,360,296 and 14,293,560 shares of beneficial interest outstanding)	$	40.74
Class I Shares:
Net asset value, redemption price and offering price per share (based on net assets of $25,203,233 and 595,351 shares of beneficial interest outstanding)	$	42.33
Class N Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $105,629,739 and 2,524,129 shares of beneficial interest outstanding)	$	41.85
Class Y Shares:
Net asset value, redemption price and offering price per share (based on net assets of $723,797,406 and 17,111,250 shares of beneficial interest outstanding)	$	42.30

See accompanying Notes to Financial Statements

16      OPPENHEIMER MAIN STREET FUND

STATEMENT OFOPERATIONSFor the Year Ended August 30, 2013¹

Investment Income
Dividends:
Unaffiliated companies (net of foreign withholding taxes of $707,620)	$	109,836,520
Affiliated companies		122,242
Interest		4,214
Other income		187,959
Total investment income		110,150,935
Expenses
Management fees		27,365,656
Distribution and service plan fees:
Class A		10,852,110
Class B		2,242,442
Class C		5,671,140
Class N		519,099
Transfer and shareholder servicing agent fees:
Class A		8,732,554
Class B		899,084
Class C		1,079,783
Class I		4,576
Class N		225,993
Class Y		576,622
Shareholder communications:
Class A		798,176
Class B		94,103
Class C		94,672
Class I		35
Class N		9,688
Class Y		57,039
Trustees’ compensation		272,736
Custodian fees and expenses		45,864
Other		514,189
Total expenses		60,055,561
Less waivers and reimbursements of expenses		(213,392	)
Net expenses		59,842,169
Net Investment Income		50,308,766

1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.

17      OPPENHEIMER MAIN STREET FUND

STATEMENT OF OPERATIONS Continued

Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investments from unaffiliated companies	$	452,726,594
Foreign currency transactions		(7,338	)
Total net realized gain		452,719,256
Net change in unrealized appreciation/depreciation on:
Investments		395,107,600
Translation of assets and liabilities denominated in foreign currencies		1,876,601
Total net change in unrealized appreciation/depreciation		396,984,201
Net Increase in Net Assets Resulting from Operations	$	900,012,223
See accompanying Notes to Financial Statements.

18      OPPENHEIMER MAIN STREET FUND

STATEMENTS OFCHANGES IN NET ASSETS

	Year Ended August 30, 20131			Year Ended August 31, 2012
Operations
Net investment income	$	50,308,766		$	32,966,842
Net realized gain		452,719,256			459,771,971
Net change in unrealized appreciation/depreciation		396,984,201			422,832,670
Net increase in net assets resulting from operations		900,012,223			915,571,483
Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(45,859,228	)		(19,858,694	)
Class B		—			—
Class C		(1,160,384	)		—
Class I		(118,640	)		—
Class N		(657,051	)		(224,882	)
Class Y		(5,745,955	)		(1,128,895	)
		(53,541,258	)		(21,212,471	)
Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		(377,598,983	)		(396,931,045	)
Class B		(72,598,234	)		(65,686,763	)
Class C		(50,416,841	)		(60,685,629	)
Class I		22,664,904			10,000
Class N		(11,382,513	)		(13,442,864	)
Class Y		415,824,203			90,283,757
		(73,507,464	)		(446,452,544	)
Net Assets
Total increase		772,963,501			447,906,468
Beginning of period		5,458,032,054			5,010,125,586
End of period (including accumulated net investment income of $31,465,233 and $34,240,620, respectively)	$	6,230,995,555		$	5,458,032,054
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.
See accompanying Notes to Financial Statements.

19      OPPENHEIMER MAIN STREET FUND

FINANCIAL HIGHLIGHTS

Class A	Year Ended August 30, 20131		Year Ended August 31, 2012		Year Ended August 31, 2011		Year Ended August 31, 2010		Year Ended August 31, 2009
Per Share Operating Data
Net asset value, beginning of period	$	36.69	$	30.93	$	27.17	$	26.17	$	32.25
Income (loss) from investment operations:
Net investment income2		0.37		0.25		0.20		0.21		0.29
Net realized and unrealized gain (loss)		5.73		5.67		3.73		1.04		(6.00)
Total from investment operations		6.10		5.92		3.93		1.25		(5.71)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.40)		(0.16)		(0.17)		(0.25)		(0.37)
Net asset value, end of period	$	42.39	$	36.69	$	30.93	$	27.17	$	26.17
Total Return, at Net Asset Value3		16.78%		19.21%		14.46%		4.75%		(17.29)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	4,588,619	$	4,318,726	$	4,005,609	$	3,959,992	$	4,237,059
Average net assets (in thousands)	$	4,494,340	$	4,164,196	$	4,453,926	$	4,309,071	$	3,967,782
Ratios to average net assets:4
Net investment income		0.95%		0.74%		0 .62%		0.76%		1.26%
Total expenses5		0.93%		0.97%		0 .99%		1.03%		1.06%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.93%		0.97%		0 .99%		1.03%		1.05%
Portfolio turnover rate		46%		37%		35%		53%		120%
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.
2. Per share amounts calculated based on the average shares outstanding during the period.
3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
4. Annualized for periods less than one full year.
5. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	0.93	%
	Year Ended August 31, 2012	0.97	%
	Year Ended August 31, 2011	0.99	%
	Year Ended August 31, 2010	1.03	%
	Year Ended August 31, 2009	1.06	%
See accompanying Notes to Financial Statements.

20      OPPENHEIMER MAIN STREET FUND

Class B	Year Ended August 30, 20131		Year Ended August 31, 2012		Year Ended August 31, 2011		Year Ended August 31, 2010		Year Ended August 31, 2009
Per Share Operating Data
Net asset value, beginning of period	$	35.33	$	29.90	$	26.37	$	25.42	$	31.13
Income (loss) from investment operations:
Net investment income (loss)2		0.01		(0.05)		(0.09)		(0.02)		0.11
Net realized and unrealized gain (loss)		5.54		5.48		3.62		1.01		(5.73)
Total from investment operations		5.55		5.43		3.53		0.99		(5.62)
Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00		0.00		0.00		(0.04)		(0.09)
Net asset value, end of period	$	40.88	$	35.33	$	29.90	$	26.37	$	25.42
Total Return, at Net Asset Value3		15.71%		18.16%		13.39%		3.88%		(17.94)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	205,386	$	245,172	$	267,723	$	355,717	$	429,906
Average net assets (in thousands)	$	224,582	$	257,205	$	332,239	$	390,057	$	441,757
Ratios to average net assets:4
Net investment income (loss)		0.02%		(0.15)%		(0.28)%		(0.08)%		0.50%
Total expenses5		1.92%		1.97%		2.00%		2.05%		1.99%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.86%		1.85%		1.89%		1.88%		1.83%
Portfolio turnover rate		46%		37%		35%		53%		120%
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.
2. Per share amounts calculated based on the average shares outstanding during the period.
3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.
4. Annualized for periods less than one full year.
5. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	1.92	%
	Year Ended August 31, 2012	1.97	%
	Year Ended August 31, 2011	2.00	%
	Year Ended August 31, 2010	2.05	%
	Year Ended August 31, 2009	1.99	%
See accompanying Notes to Financial Statements.

21      OPPENHEIMER MAIN STREET FUND

FINANCIALHIGHLIGHTSContinued

Class C	Year Ended August 30, 20131		Year Ended August 31, 2012		Year Ended August 31, 2011		Year Ended August 31, 2010		Year Ended August 31, 2009
Per Share Operating Data
Net asset value, beginning of period	$	35.22	$	29.77	$	26.20	$	25.27	$	30.99
Income (loss) from investment operations:
Net investment income (loss)2		0.07		0.003		(0.04)		0.01		0.12
Net realized and unrealized gain (loss)		5.53		5.45		3.61		0.99		(5.71)
Total from investment operations		5.60		5.45		3.57		1.00		(5.59)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.08)		0.00		0.00		(0.07)		(0.13)
Net asset value, end of period	$	40.74	$	35.22	$	29.77	$	26.20	$	25.27
Total Return, at Net Asset Value4		15.92%		18.31%		13.63%		3.96%		(17.89)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	582,360	$	550,341	$	520,988	$	522,449	$	563,551
Average net assets (in thousands)	$	568,419	$	535,180	$	577,960	$	565,220	$	533,614
Ratios to average net assets:5
Net investment income (loss)		0.20%		0.00%6		(0.12)%		0.03%		0.52%
Total expenses7		1.68%		1.71%		1.73%		1.76%		1.80%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.68%		1.71%		1.73%		1.76%		1.79%
Portfolio turnover rate		46%		37%		35%		53%		120%
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes. 2. Per share amounts calculated based on the average shares outstanding during the period. 3. Less than $0.005 per share. 4. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. 5. Annualized for periods less than one full year. 6. Less than 0.005%. 7. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	1.68%
	Year Ended August 31, 2012	1.71%
	Year Ended August 31, 2011	1.73%
	Year Ended August 31, 2010	1.76%
	Year Ended August 31, 2009	1.80%
See accompanying Notes to Financial Statements.

22      OPPENHEIMER MAIN STREET FUND

Class I	Year Ended August 30, 20131		Period Ended August 31, 20122
Per Share Operating Data
Net asset value, beginning of period	$	36.82	$	32.31
Income (loss) from investment operations:
Net investment income3		0.50		0.29
Net realized and unrealized gain		5.75		4.22
Total from investment operations		6.25		4.51
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.74)		0.00
Net asset value, end of period	$	42.33	$	36.82
Total Return, at Net Asset Value4		17.28%		13.96%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	25,203	$	11
Average net assets (in thousands)	$	15,305	$	11
Ratios to average net assets:5
Net investment income		1 .26%		1.22%
Total expenses6		0 .51%		0.50%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0 .51%		0.50%
Portfolio turnover rate		46%		37%

1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes.

2. For the period from December 29, 2011 (inception of offering) to August 31, 2012.

3. Per share amounts calculated based on the average shares outstanding during the period.

4. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.

5. Annualized for periods less than one full year.

6. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	0.51%
	Period Ended August 31, 2012	0.50%
See accompanying Notes to Financial Statements.

23      OPPENHEIMER MAIN STREET FUND

FINANCIALHIGHLIGHTSContinued

Class N	Year Ended August 30, 20131		Year Ended August 31, 2012		Year Ended August 31, 2011		Year Ended August 31, 2010		Year Ended August 31, 2009
Per Share Operating Data
Net asset value, beginning of period	$	36.17	$	30.49	$	26.77	$	25.80	$	31.73
Income (loss) from investment operations:
Net investment income2		0.26		0.16		0.12		0.14		0.23
Net realized and unrealized gain (loss)		5.66		5.59		3.68		1.02		(5.88)
Total from investment operations		5.92		5.75		3.80		1.16		(5.65)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.24)		(0.07)		(0.08)		(0.19)		(0.28)
Net asset value, end of period	$	41.85	$	36.17	$	30.49	$	26 .77	$	25 .80
Total Return, at Net Asset Value3		16 .47%		18 .91%		14 .18%		4.48%		(17.51)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	105,630	$	101,596	$	98,147	$	106,628	$	117,889
Average net assets (in thousands)	$	104,731	$	99,620	$	111,540	$	119,175	$	111,693
Ratios to average net assets:4
Net investment income		0.68%		0.48%		0.37%		0.50%		1.01%
Total expenses5		1.20%		1.22%		1.23%		1.28%		1.33%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.20%		1.22%		1.23%		1.28%		1.30%
Portfolio turnover rate		46%		37%		35%		53%		120%
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes. 2. Per share amounts calculated based on the average shares outstanding during the period. 3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. 4. Annualized for periods less than one full year. 5. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	1.20%
	Year Ended August 31, 2012	1.22%
	Year Ended August 31, 2011	1.23%
	Year Ended August 31, 2010	1.28%
	Year Ended August 31, 2009	1.33%
See accompanying Notes to Financial Statements.

24      OPPENHEIMER MAIN STREET FUND

Class Y	Year Ended August 30, 20131		Year Ended August 31, 2012		Year Ended August 31, 2011		Year Ended August 31, 2010		Year Ended August 31, 2009
Per Share Operating Data
Net asset value, beginning of period	$	36.81	$	31.04	$	27.27	$	26.27	$	32.44
Income (loss) from investment operations:
Net investment income2		0.49		0.40		0.33		0.37		0.42
Net realized and unrealized gain (loss)		5.72		5.67		3.75		1.03		(6.07)
Total from investment operations		6.21		6.07		4.08		1.40		(5.65)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.72)		(0.30)		(0.31)		(0.40)		(0.52)
Net asset value, end of period	$	42.30	$	36.81	$	31.04	$	27.27	$	26.27
Total Return, at Net Asset Value3		17.18%		19.70%		14.94%		5.27%		(16.82)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	723,798	$	242,186	$	117,659	$	98,434	$	474,142
Average net assets (in thousands)	$	469,824	$	192,143	$	117,050	$	436,261	$	417,293
Ratios to average net assets:4
Net investment income		1.21%		1.16%		1.03%		1.30%		1.79%
Total expenses5		0.61%		0.54%		0.57%		0.49%		0.49%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.61%		0.54%		0.57%		0.49%		0.49%
Portfolio turnover rate		46%		37%		35%		53%		120%
1. August 30, 2013 represents the last business day of the Fund’s 2013 fiscal year. See Note 1 of the accompanying Notes. 2. Per share amounts calculated based on the average shares outstanding during the period. 3. Assumes an initial investment on the business day before the first day of the fiscal period, with all dividends and distributions reinvested in additional shares on the reinvestment date, and redemption at the net asset value calculated on the last business day of the fiscal period. Sales charges are not reflected in the total returns. Total returns are not annualized for periods less than one full year. Returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. 4. Annualized for periods less than one full year. 5. Total expenses including indirect expenses from affiliated fund were as follows:

	Year Ended August 30, 2013	0.61%
	Year Ended August 31, 2012	0.54%
	Year Ended August 31, 2011	0.57%
	Year Ended August 31, 2010	0.49%
	Year Ended August 31, 2009	0.49%
See accompanying Notes to Financial Statements.

25      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTS

1. Significant Accounting Policies

Oppenheimer Main Street Fund (the “Fund”) is a diversified open-end management investment company registered under the Investment Company Act of 1940, as amended. The Fund’s investment objective is to seek capital appreciation. The Fund’s investment adviser was OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”) through December 31, 2012. Effective January 1, 2013, the Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OFI. The Manager has entered into a sub-advisory agreement with OFI, as of the same effective date.

The Fund offers Class A, Class C, Class I, Class N and Class Y shares, and previously offered Class B shares for new purchase through June 29, 2012. Subsequent to that date, no new purchases of Class B shares are permitted, however reinvestment of dividend and/or capital gain distributions and exchanges of Class B shares into and from other Oppenheimer funds will be allowed. Class A shares are sold at their offering price, which is normally net asset value plus a front-end sales charge. Class C and Class N shares are sold, and Class B shares were sold, without a front-end sales charge but may be subject to a contingent deferred sales charge (“CDSC”). Class N shares are sold only through retirement plans. Retirement plans that offer Class N shares may impose charges on those accounts. Class I and Class Y shares are sold to certain institutional investors or intermediaries without either a front-end sales charge or a CDSC, however, the intermediaries may impose charges on their accountholders who beneficially own Class I and Class Y shares. All classes of shares have identical rights and voting privileges with respect to the Fund in general and exclusive voting rights on matters that affect that class alone. Earnings, net assets and net asset value per share may differ due to each class having its own expenses, such as transfer and shareholder servicing agent fees and shareholder communications, directly attributable to that class. Class A, B, C and N shares have separate distribution and/or service plans under which they pay fees. Class I and Class Y shares do not pay such fees. Class B shares will automatically convert to Class A shares 72 months after the date of purchase.

The following is a summary of significant accounting policies consistently followed by the Fund.

Fiscal Year End. The last day of the Fund’s fiscal year was the last day the New York Stock Exchange was open for trading. The Fund’s financial statements have been presented through that date to maintain consistency with the Fund’s net asset value calculations used for shareholder transactions.

Investment in Oppenheimer Institutional Money Market Fund. The Fund is permitted to invest daily available cash balances in an affiliated money market fund. The Fund may invest the available cash in Class E shares of Oppenheimer Institutional Money Market Fund (“IMMF”) to seek current income while preserving liquidity. IMMF is a registered open-end management investment company, regulated as a money market fund under the Investment Company Act of 1940, as amended. The Manager is the investment adviser of IMMF, and the Sub-Adviser provides investment and related advisory services to IMMF. When applicable, the Fund’s investment in IMMF is included in the Statement of Investments. Shares of IMMF are valued at their net asset value per share. As a shareholder, the Fund is subject to its

26      OPPENHEIMER MAIN STREET FUND

1. Significant Accounting Policies (Continued)

proportional share of IMMF’s Class E expenses, including its management fee. The Manager will waive fees and/or reimburse Fund expenses in an amount equal to the indirect management fees incurred through the Fund’s investment in IMMF.

Foreign Currency Translation. The Fund’s accounting records are maintained in U.S. dollars. The values of securities denominated in foreign currencies and amounts related to the purchase and sale of foreign securities and foreign investment income are translated into U.S. dollars as of the close of the New York Stock Exchange (the “Exchange”), normally 4:00 P.M. Eastern time, on each day the Exchange is open for trading. Foreign exchange rates may be valued primarily using a reliable bank, dealer or service authorized by the Board of Trustees.

Reported net realized gains and losses from foreign currency transactions arise from sales of portfolio securities, sales and maturities of short-term securities, sales of foreign currencies, exchange rate fluctuations between the trade and settlement dates on securities transactions, and the difference between the amounts of dividends, interest, and foreign withholding taxes recorded on the Fund’s books and the U.S. dollar equivalent of the amounts actually received or paid. Net unrealized appreciation and depreciation on the translation of assets and liabilities denominated in foreign currencies arise from changes in the values of assets and liabilities, including investments in securities at fiscal period end, resulting from changes in exchange rates.

The effect of changes in foreign currency exchange rates on investments is separately identified from the fluctuations arising from changes in market values of securities held and reported with all other foreign currency gains and losses in the Fund’s Statement of Operations.

Allocation of Income, Expenses, Gains and Losses. Income, expenses (other than those attributable to a specific class), gains and losses are allocated on a daily basis to each class of shares based upon the relative proportion of net assets represented by such class. Operating expenses directly attributable to a specific class are charged against the operations of that class.

Federal Taxes. The Fund intends to comply with provisions of the Internal Revenue Code applicable to regulated investment companies and to distribute substantially all of its investment company taxable income, including any net realized gain on investments not offset by capital loss carryforwards, if any, to shareholders. Therefore, no federal income or excise tax provision is required. The Fund files income tax returns in U.S. federal and applicable state jurisdictions. The statute of limitations on the Fund’s tax return filings generally remain open for the three preceding fiscal reporting period ends.

The tax components of capital shown in the following table represent distribution requirements the Fund must satisfy under the income tax regulations, losses the Fund may be able to offset against income and gains realized in future years and unrealized appreciation or depreciation of securities and other investments for federal income tax purposes.

27      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTS   Continued

1. Significant Accounting Policies (Continued)

Undistributed Net Investment Income	Undistributed Long-Term Gain		Accumulated Loss Carryforward1,2,3		Net Unrealized Appreciation Based on cost of Securities and Other Investments for Federal Income Tax Purposes
$32,096,608		$—		$370,280,058		$1,733,195,082

1. As of August 30, 2013, the Fund had $370,280,058 of net capital loss carryforwards available to offset future realized capital gains, if any, and thereby reduce future taxable gain distributions. Details of the capital loss carryforwards are included in the table below. Capital loss carryovers with no expiration, if any, must be utilized prior to those with expiration dates.

Expiring
2016	$	1,217,331
2017		2,625,602
2018		366,437,125
Total	$	370,280,058

Of these losses, $3,842,933 are subject to loss limitation rules resulting from merger activity. These limitations generally reduce the utilization of these losses to a maximum of $2,594,283 per year.

2. During the fiscal year ended August 30, 2013, the Fund utilized $452,146,453 of capital loss carryforward to offset capital gains realized in that fiscal year.

3. During the fiscal year ended August 31, 2012, the Fund utilized $463,161,049 of capital loss carryforward to offset capital gains realized in that fiscal year.

Net investment income (loss) and net realized gain (loss) may differ for financial statement and tax purposes. The character of dividends and distributions made during the fiscal year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. Also, due to timing of dividends and distributions, the fiscal year in which amounts are distributed may differ from the fiscal year in which the income or net realized gain was recorded by the Fund.

Accordingly, the following amounts have been reclassified for August 31, 2013. Net assets of the Fund were unaffected by the reclassifications.

Reduction to Paid-in Capital	Increase to Accumulated Net Investment Income		Increase to Accumulated Net Realized Loss on Investments
$34,775		$457,105		$422,330

The tax character of distributions paid during the years ended August 31, 2013 and August 31, 2012 was as follows:

	Year Ended August 31, 2013		Year Ended August 31, 2012
Distributions paid from:
Ordinary income	$	53,541,258	$	21,212,471

28      OPPENHEIMER MAIN STREET FUND

1. Significant Accounting Policies (Continued)

The aggregate cost of securities and other investments and the composition of unrealized appreciation and depreciation of securities and other investments for federal income tax purposes as of August 30, 2013 are noted in the following table. The primary difference between book and tax appreciation or depreciation of securities and other investments, if applicable, is attributable to the tax deferral of losses or tax realization of financial statement unrealized gain or loss.

Federal tax cost of securities	$	4,518,192,589
Gross unrealized appreciation	$	1,758,949,826
Gross unrealized depreciation		(25,754,744)
Net unrealized appreciation	$	1,733,195,082

Trustees’ Compensation. The Board of Trustees has adopted a compensation deferral plan for independent trustees that enables trustees to elect to defer receipt of all or a portion of the annual compensation they are entitled to receive from the Fund. For purposes of determining the amount owed to the Trustee under the plan, deferred amounts are treated as though equal dollar amounts had been invested in shares of the Fund or in other Oppenheimer funds selected by the Trustee. The Fund purchases shares of the funds selected for deferral by the Trustee in amounts equal to his or her deemed investment, resulting in a Fund asset equal to the deferred compensation liability. Such assets are included as a component of “Other” within the asset section of the Statement of Assets and Liabilities. Deferral of trustees’ fees under the plan will not affect the net assets of the Fund, and will not materially affect the Fund’s assets, liabilities or net investment income per share. Amounts will be deferred until distributed in accordance with the compensation deferral plan.

Dividends and Distributions to Shareholders. Dividends and distributions to shareholders, which are determined in accordance with income tax regulations and may differ from U.S. generally accepted accounting principles, are recorded on the ex-dividend date. Income and capital gain distributions, if any, are declared and paid annually or at other times as deemed necessary by the Manager.

Investment Income. Dividend income is recorded on the ex-dividend date or upon ex-dividend notification in the case of certain foreign dividends where the ex-dividend date may have passed. Non-cash dividends included in dividend income, if any, are recorded at the fair market value of the securities received. Interest income is recognized on an accrual basis. Discount and premium, which are included in interest income on the Statement of Operations, are amortized or accreted daily.

Custodian Fees. “Custodian fees and expenses” in the Statement of Operations may include interest expense incurred by the Fund on any cash overdrafts of its custodian account during the period. Such cash overdrafts may result from the effects of failed trades in portfolio securities and from cash outflows resulting from unanticipated shareholder redemption activity. The Fund pays interest to its custodian on such cash overdrafts, to the extent they are

29      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTSContinued

1. Significant Accounting Policies (Continued)

not offset by positive cash balances maintained by the Fund, at a rate equal to the Federal Funds Rate plus 0.50%. The “Reduction to custodian expenses” line item, if applicable, represents earnings on cash balances maintained by the Fund during the period. Such interest expense and other custodian fees may be paid with these earnings.

Security Transactions. Security transactions are recorded on the trade date. Realized gains and losses on securities sold are determined on the basis of identified cost.

Indemnifications. The Fund’s organizational documents provide current and former trustees and officers with a limited indemnification against liabilities arising in connection with the performance of their duties to the Fund. In the normal course of business, the Fund may also enter into contracts that provide general indemnifications. The Fund’s maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against the Fund. The risk of material loss from such claims is considered remote.

Other. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates.

2. Securities Valuation

The Fund calculates the net asset value of its shares as of the close of the New York Stock Exchange (the “Exchange”), normally 4:00 P.M. Eastern time, on each day the Exchange is open for trading.

The Fund’s Board has adopted procedures for the valuation of the Fund’s securities and has delegated the day-to-day responsibility for valuation determinations under those procedures to the Manager. The Manager has established a Valuation Committee which is responsible for determining a “fair valuation” for any security for which market quotations are not “readily available.” The Valuation Committee’s fair valuation determinations are subject to review, approval and ratification by the Fund’s Board at its next regularly scheduled meeting covering the calendar quarter in which the fair valuation was determined.

Valuation Methods and Inputs

Securities are valued using unadjusted quoted market prices, when available, as supplied primarily by third party pricing services or dealers.

The following methodologies are used to determine the market value or the fair value of the types of securities described below:

Securities traded on a registered U.S. securities exchange (including exchange-traded derivatives other than futures and futures options) are valued based on the last sale price of the security reported on the principal exchange on which it is traded, prior to the time when the Fund’s assets are valued. In the absence of a sale, the security is valued at the last sale

30      OPPENHEIMER MAIN STREET FUND

2. Securities Valuation (Continued)

price on the prior trading day, if it is within the spread of the current day’s closing “bid” and “asked” prices, and if not, at the current day’s closing bid price. A security of a foreign issuer traded on a foreign exchange but not listed on a registered U.S. securities exchange is valued based on the last sale price on the principal exchange on which the security is traded, as identified by the third party pricing service used by the Manager, prior to the time when the Fund’s assets are valued. If the last sale price is unavailable, the security is valued at the most recent official closing price on the principal exchange on which it is traded. If the last sales price or official closing price for a foreign security is not available, the security is valued at the mean between the bid and asked price per the exchange or, if not available from the exchange, obtained from two dealers. If bid and asked prices are not available from either the exchange or two dealers, the security is valued by using one of the following methodologies (listed in order of priority); (1) using a bid from the exchange, (2) the mean between the bid and asked price as provided by a single dealer, or (3) a bid from a single dealer.

Shares of a registered investment company that are not traded on an exchange are valued at that investment company’s net asset value per share.

Corporate and government debt securities (of U.S. or foreign issuers) and municipal debt securities, event-linked bonds, loans, mortgage-backed securities, collateralized mortgage obligations, and asset-backed securities are valued at the mean between the “bid” and “asked” prices utilizing evaluated prices obtained from third party pricing services or broker-dealers who may use matrix pricing methods to determine the evaluated prices.

Short-term money market type debt securities with a remaining maturity of sixty days or less are valued at cost adjusted by the amortization of discount or premium to maturity (amortized cost), which approximates market value. Short-term debt securities with a remaining maturity in excess of sixty days are valued at the mean between the “bid” and “asked” prices utilizing evaluated prices obtained from third party pricing services or broker-dealers.

A description of the standard inputs that may generally be considered by the third party pricing vendors in determining their evaluated prices is provided below.

Security Type	Standard inputs generally considered by third- party pricing vendors
Corporate debt, government debt, municipal, mortgage-backed and asset-backed securities	Reported trade data, broker-dealer price quotations, benchmark yields, issuer spreads on comparable securities, the credit quality, yield, maturity, and other appropriate factors.
Loans	Information obtained from market participants regarding reported trade data and broker-dealer price quotations.
Event-linked bonds	Information obtained from market participants regarding reported trade data and broker-dealer price quotations.

If a market value or price cannot be determined for a security using the methodologies described above, or if, in the “good faith” opinion of the Manager, the market value or price obtained does not constitute a “readily available market quotation,” or a significant event

31      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTSContinued

2. Securities Valuation (Continued)

has occurred that would materially affect the value of the security the security is fair valued either (i) by a standardized fair valuation methodology applicable to the security type or the significant event as previously approved by the Valuation Committee and the Fund’s Board or (ii) as determined in good faith by the Manager’s Valuation Committee. The Valuation Committee considers all relevant facts that are reasonably available, through either public information or information available to the Manager, when determining the fair value of a security. Fair value determinations by the Manager are subject to review, approval and ratification by the Fund’s Board at its next regularly scheduled meeting covering the calendar quarter in which the fair valuation was determined. Those fair valuation standardized methodologies include, but are not limited to, valuing securities at the last sale price or initially at cost and subsequently adjusting the value based on: changes in company specific fundamentals, changes in an appropriate securities index, or changes in the value of similar securities which may be further adjusted for any discounts related to security-specific resale restrictions. When possible, such methodologies use observable market inputs such as unadjusted quoted prices of similar securities, observable interest rates, currency rates and yield curves. The methodologies used for valuing securities are not necessarily an indication of the risks associated with investing in those securities nor can it be assured that the Fund can obtain the fair value assigned to a security if it were to sell the security.

To assess the continuing appropriateness of security valuations, the Manager, or its third party service provider who is subject to oversight by the Manager, regularly compares prior day prices, prices on comparable securities, and sale prices to the current day prices and challenges those prices exceeding certain tolerance levels with the third party pricing service or broker source. For those securities valued by fair valuations, whether through a standardized fair valuation methodology or a fair valuation determination, the Valuation Committee reviews and affirms the reasonableness of the valuations based on such methodologies and fair valuation determinations on a regular basis after considering all relevant information that is reasonably available.

Classifications

Each investment asset or liability of the Fund is assigned a level at measurement date based on the significance and source of the inputs to its valuation. Various data inputs are used in determining the value of each of the Fund’s investments as of the reporting period end. These data inputs are categorized in the following hierarchy under applicable financial accounting standards:

1) Level 1-unadjusted quoted prices in active markets for identical assets or liabilities (including securities actively traded on a securities exchange)

2) Level 2-inputs other than unadjusted quoted prices that are observable for the asset or liability (such as unadjusted quoted prices for similar assets and market corroborated inputs such as interest rates, prepayment speeds, credit risks, etc.)

3) Level 3-significant unobservable inputs (including the Manager’s own judgments about assumptions that market participants would use in pricing the asset or liability).

32      OPPENHEIMER MAIN STREET FUND

2. Securities Valuation (Continued)

The inputs used for valuing securities are not necessarily an indication of the risks associated with investing in those securities.

The table below categorizes amounts that are included in the Fund’s Statement of Assets and Liabilities as of August 30, 2013 based on valuation input level:

	Level 1— Unadjusted Quoted Prices		Level 2— Other Significant Observable Inputs		Level 3— Significant Unobservable Inputs		Value
Assets Table
Investments, at Value:
Common Stocks
Consumer Discretionary	$	570,918,106	$	—	$	—	$	570,918,106
Consumer Staples		424,679,585		102,961,583		—		527,641,168
Energy		547,046,517		—		—		547,046,517
Financials		1,219,393,090		—		—		1,219,393,090
Health Care		1,009,247,572		61,684,138		—		1,070,931,710
Industrials		612,033,869		—		—		612,033,869
Information Technology		1,336,117,842		—		—		1,336,117,842
Materials		183,062,378		—		—		183,062,378
Telecommunication Services		40,294,347		—		—		40,294,347
Utilities		39,335,454		—		—		39,335,454
Investment Company		104,613,190		—	��	—		104,613,190
Total Assets	$	6,086,741,950	$	164,645,721	$	—	$	6,251,387,671

Currency contracts and forwards, if any, are reported at their unrealized appreciation/ depreciation at measurement date, which represents the change in the contract’s value from trade date. Futures, if any, are reported at their variation margin at measurement date, which represents the amount due to/from the Fund at that date. All additional assets and liabilities included in the above table are reported at their market value at measurement date.

The table below shows the transfers between Level 1 and Level 2. The Fund’s policy is to recognize transfers in and transfers out as of the beginning of the reporting period.

	Transfers out of Level 1*		Transfers into Level 2*
Assets Table
Investments, at Value:
Common Stocks
Consumer Staples	$	(13,922,493)	$	13,922,493
Total Assets	$	(13,922,493)	$	13,922,493

* Transferred from Level 1 to Level 2 because of the absence of a readily available unadjusted quoted market price due to a significant event occurring before the Fund’s assets were valued but after the close of the securities’ respective exchanges.

33      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTSContinued

3. Shares of Beneficial Interest

The Fund has authorized an unlimited number of $0.01 par value shares of beneficial interest of each class. Transactions in shares of beneficial interest were as follows:

	Year Ended August 30, 2013						Year Ended August 31, 20121
	Shares			Amount			Shares			Amount
Class A
Sold		7,304,054		$	285,427,397			8,273,928		$	281,340,845
Dividends and/or distributions reinvested		1,199,774			43,961,194			592,239			18,975,326
Acquisition—Note 6		—			—			162,319			5,442,544
Redeemed		(17,965,663	)		(706,987,574	)		(20,829,158	)		(702,689,760	)
Net decrease		(9,461,835	)	$	(377,598,983	)		(11,800,672	)	$	(396,931,045	)
Class B
Sold		163,618		$	6,117,747			809,371		$	26,145,846
Dividends and/or distributions reinvested		—			—			—			—
Acquisition—Note 6		—			—			109,319			3,549,586
Redeemed		(2,078,787	)		(78,715,981	)		(2,932,816	)		(95,382,195	)
Net decrease		(1,915,169	)	$	(72,598,234	)		(2,014,126	)	$	(65,686,763	)
Class C
Sold		1,076,878		$	40,966,629			940,760		$	30,598,371
Dividends and/or distributions reinvested		30,200			1,066,655			—			—
Acquisition—Note 6		—			—			68,853			2,226,713
Redeemed		(2,437,303	)		(92,450,125	)		(2,887,640	)		(93,510,713	)
Net decrease		(1,330,225	)	$	(50,416,841	)		(1,878,027	)	$	(60,685,629	)
Class I
Sold		627,883		$	24,005,900			310		$	10,000
Dividends and/or distributions reinvested		3,229			118,412			—			—
Redeemed		(36,071	)		(1,459,408	)		—			—
Net increase		595,041		$	22,664,904			310		$	10,000
Class N
Sold		552,113		$	21,072,973			615,299		$	20,615,557
Dividends and/or distributions reinvested		17,652			638,131			6,876			217,566
Acquisition—Note 6		—			—			9,645			319,350
Redeemed		(854,727	)		(33,093,617	)		(1,042,062	)		(34,595,337	)
Net decrease		(284,962	)	$	(11,382,513	)		(410,242	)	$	(13,442,864	)

34      OPPENHEIMER MAIN STREET FUND

3. Shares of Beneficial Interest (Continued)

	Year Ended August 30, 2013						Year Ended August 31, 20121
	Shares			Amount			Shares			Amount
Class Y
Sold		13,990,629		$	553,841,334			4,612,885		$	152,585,720
Dividends and/or distributions reinvested		153,123			5,609,777			32,832			1,051,944
Redeemed		(3,611,943	)		(143,626,908	)		(1,857,359	)		(63,353,907	)
Net increase		10,531,809		$	415,824,203			2,788,358		$	90,283,757

1. For the year ended August 31, 2012, for Class A, Class B, Class C, Class N and Class Y shares, and for the period from December 29, 2011 (inception of offering) to August 31, 2012, for Class I shares.

4. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IMMF, for the year ended August 30, 2013 were as follows:

	Purchases		Sales
Investment securities	$	2,687,188,700	$	2,622,379,835

5. Fees and Other Transactions with Affiliates

Management Fees. Under the investment advisory agreement, the Fund pays the Manager a management fee based on the daily net assets of the Fund at an annual rate as shown in the following table:

Fee Schedule
Up to $200 million	0.65	%
Next $150 million	0.60
Next $150 million	0.55
Over $500 million	0.45

Sub-Adviser Fees. The Manager has retained the Sub-Adviser to provide the day-to-day portfolio management of the Fund. Under the Sub-Advisory Agreement, the Manager pays the Sub-Adviser an annual fee in monthly installments, equal to a percentage of the investment management fee collected by the Manager from the Fund, which shall be calculated after any investment management fee waivers. The fee paid to the Sub-Adviser is paid by the Manager, not by the Fund.

Transfer Agent Fees. OppenheimerFunds Services (“OFS”), a division of OFI, acted as the transfer and shareholder servicing agent for the Fund through December 31, 2012. Effective January 1, 2013, OFI Global (the “Transfer Agent”) serves as the transfer and shareholder servicing agent for the Fund. Fees incurred by the Fund with respect to these services are detailed in the Statement of Operations.

Sub-Transfer Agent Fees. Effective January 1, 2013, the Transfer Agent has retained Shareholder Services, Inc., a wholly-owned subsidiary of OFI (the “Sub-Transfer Agent”), to

35      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTSContinued

5. Fees and Other Transactions with Affiliates (Continued)

provide the day-to-day transfer agent and shareholder servicing of the Fund. Under the Sub-Transfer Agency Agreement, the Transfer Agent pays the Sub-Transfer Agent an annual fee in monthly installments, equal to a percentage of the transfer agent fee collected by the Transfer Agent from the Fund, which shall be calculated after any applicable fee waivers. The fee paid to the Sub-Transfer Agent is paid by the Transfer Agent, not by the Fund.

Distribution and Service Plan (12b-1) Fees. Under its General Distributor’s Agreement with the Fund, OppenheimerFunds Distributor, Inc. (the “Distributor”) acts as the Fund’s principal underwriter in the continuous public offering of the Fund’s classes of shares.

Service Plan for Class A Shares. The Fund has adopted a Service Plan (the “Plan”) for Class A shares under Rule 12b-1 of the Investment Company Act of 1940. Under the Plan, the Fund reimburses the Distributor for a portion of its costs incurred for services provided to accounts that hold Class A shares. Reimbursement is made periodically at an annual rate of up to 0.25% of the daily net assets of Class A shares of the Fund. The Distributor currently uses all of those fees to pay dealers, brokers, banks and other financial institutions periodically for providing personal service and maintenance of accounts of their customers that hold Class A shares. Any unreimbursed expenses the Distributor incurs with respect to Class A shares in any fiscal year cannot be recovered in subsequent periods. Fees incurred by the Fund under the Plan are detailed in the Statement of Operations.

Distribution and Service Plans for Class B, Class C and Class N Shares. The Fund has adopted Distribution and Service Plans (the “Plans”) for Class B, Class C and Class N shares under Rule 12b-1 of the Investment Company Act of 1940 to compensate the Distributor for its services in connection with the distribution of those shares and servicing accounts. Under the Plans, the Fund pays the Distributor an annual asset-based sales charge of 0.75% on Class B and Class C shares daily net assets and 0.25% on Class N shares daily net assets. The Distributor also receives a service fee of 0.25% per year under each plan. If either the Class B, Class C or Class N plan is terminated by the Fund or by the shareholders of a class, the Board of Trustees and its independent trustees must determine whether the Distributor shall be entitled to payment from the Fund of all or a portion of the service fee and/or asset-based sales charge in respect to shares sold prior to the effective date of such termination. Fees incurred by the Fund under the Plans are detailed in the Statement of Operations. The Distributor determines its uncompensated expenses under the Plans at calendar quarter ends. The Distributor’s aggregate uncompensated expenses under the Plans at June 30, 2013 were as follows:

Class B	$	9,587,386
Class C		51,857,882
Class N		5,249,567

Sales Charges. Front-end sales charges and contingent deferred sales charges (“CDSC”) do not represent expenses of the Fund. They are deducted from the proceeds of sales of Fund shares prior to investment or from redemption proceeds prior to remittance, as applicable.

36      OPPENHEIMER MAIN STREET FUND

5. Fees and Other Transactions with Affiliates (Continued)

The sales charges retained by the Distributor from the sale of shares and the CDSC retained by the Distributor on the redemption of shares is shown in the following table for the period indicated.

Year Ended	Class A Front-End Sales Charges Retained by Distributor		Class A Contingent Deferred Sales Charges Retained by Distributor		Class B Contingent Deferred Sales Charges Retained by Distributor		Class C Contingent Deferred Sales Charges Retained by Distributor		Class N Contingent Deferred Sales Charges Retained by Distributor
August 30, 2013		$954,202		$311		$296,473		$19,081		$1,248

Waivers and Reimbursements of Expenses. The Manager will waive fees and/or reimburse Fund expenses in an amount equal to the indirect management fees incurred through the Fund’s investment in IMMF. During the year ended August 30, 2013, the Manager waived fees and/or reimbursed the Fund $89,341 for IMMF management fees.

The Transfer Agent has voluntarily agreed to limit transfer and shareholder servicing agent fees for Classes B, C, N and Y shares to 0.35% of average annual net assets per class and for Class A shares to 0.30% of average annual net assets of the class.

During the year ended August 30, 2013, the Transfer Agent waived transfer and shareholder servicing agent fees as follows:

Class B $ 124,051

6. Acquisition of Oppenheimer Principal Protected Main Street Fund III

On January 19, 2012, the Fund acquired all of the net assets of Oppenheimer Principal Protected Main Street Fund III, pursuant to an Agreement and Plan of Reorganization approved by the Oppenheimer Principal Protected Main Street Fund III shareholders on January 13, 2012. The exchange qualified as a tax-free reorganization for federal income tax purposes.

Details of the merger are shown in the following table:

	Exchange Ratio to One Share of the Oppenheimer Principal Protected Main Street Fund III		Shares of Capital Stock Issued by the Fund		Value of Issued Shares of Capital Stock		Combined Net Assets on January 19, 20121
Class A		0.843830		162,319		$5,442,544		$4,173,101,749
Class B		0.874893		109,319		$3,549,586		$   269,090,064
Class C		0.880821		68,853		$2,226,713		$   541,041,221
Class N		0.854530		9,645		$   319,350		$   100,475,517

1. The net assets acquired included an unused capital loss carryforward of $3,249,188, potential utilization subject to tax limitations.

37      OPPENHEIMER MAIN STREET FUND

NOTES TOFINANCIAL STATEMENTS Continued

7. Pending Litigation

Since 2009, seven class action lawsuits have been pending in the U.S. District Court for the District of Colorado against OppenheimerFunds, Inc. (“OFI”), OppenheimerFunds Distributor, Inc., the Fund’s principal underwriter and distributor (the “Distributor”), and certain funds (but not including the Fund) advised by OFI Global Asset Management, Inc. and distributed by the Distributor (the “Defendant Funds”). The lawsuits also name as defendants certain officers and current and former trustees of the respective Defendant Funds. The lawsuits raise claims under federal securities law and allege, among other things, that the disclosure documents of the respective Defendant Funds contained misrepresentations and omissions and that the respective Defendant Funds’ investment policies were not followed. The plaintiffs in these actions seek unspecified damages, equitable relief and awards of attorneys’ fees and litigation expenses. The Defendant Funds’ Boards of Trustees have also engaged counsel to represent the Funds and the present and former Independent Trustees named in those suits. On August 26, 2013, the parties in six of these lawsuits executed a memorandum of understanding setting forth the terms of proposed settlements of those actions. The proposed settlements are subject to a variety of contingencies, including the execution of settlement agreements, which will require preliminary and final approval by the court. The proposed settlements do not resolve a seventh outstanding lawsuit relating to Oppenheimer California Municipal Fund.

Other class action and individual lawsuits have been filed since 2008 in various state and federal courts against OFI and certain of its affiliates by investors seeking to recover investments they allegedly lost as a result of the “Ponzi” scheme run by Bernard L. Madoff and his firm, Bernard L. Madoff Investment Securities, LLC (“BLMIS”). Plaintiffs in these suits allege that they suffered losses as a result of their investments in several funds managed by an affiliate of OFI and assert a variety of claims, including breach of fiduciary duty, fraud, negligent misrepresentation, unjust enrichment, and violation of federal and state securities laws and regulations, among others. They seek unspecified damages, equitable relief and awards of attorneys’ fees and litigation expenses. Neither the Distributor, nor any of the Oppenheimer mutual funds, their independent trustees or directors are named as defendants in these lawsuits. None of the Oppenheimer mutual funds invested in any funds or accounts managed by Madoff or BLMIS. On February 28, 2011, a stipulation of partial settlement of three groups of consolidated putative class action lawsuits relating to these matters was filed in the U.S. District Court for the Southern District of New York. On August 19, 2011, the court entered an order and final judgment approving the settlement as fair, reasonable and adequate. In September 2011, certain parties filed notices of appeal from the court’s order approving the settlement. The settlement does not resolve other outstanding lawsuits against OFI and its affiliates relating to BLMIS.

On April 16, 2010, a lawsuit was filed in New York state court against (i) OFI, (ii) an affiliate of OFI and (iii) AAArdvark IV Funding Limited (“AAArdvark IV”), an entity advised by OFI’s affiliate, in connection with investments made by the plaintiffs in AAArdvark IV. Plaintiffs allege breach of contract and common law fraud claims against the defendants and seek compensatory damages, costs and disbursements, including attorney fees. On April 11, 2013, the court granted defendants’ motion for summary judgment, dismissing plaintiffs’ fraud claim with prejudice and dismissing their contract claim without prejudice, and granted

38      OPPENHEIMER MAIN STREET FUND

7. Pending Litigation (Continued)

plaintiffs leave to replead their contract claim to assert a cause of action for specific performance within 30 days. On May 9, 2013, plaintiffs filed a notice of appeal from the court’s dismissal order. On July 15, 2011, a lawsuit was filed in New York state court against OFI, an affiliate of OFI and AAArdvark Funding Limited (“AAArdvark I”), an entity advised by OFI’s affiliate, in connection with investments made by the plaintiffs in AAArdvark I. The complaint alleges breach of contract and common law fraud claims against the defendants and seeks compensatory damages, costs and disbursements, including attorney fees. On November 9, 2011, a lawsuit was filed in New York state court against OFI, an affiliate of OFI and AAArdvark XS Funding Limited (“AAArdvark XS”), an entity advised by OFI’s affiliate, in connection with investments made by the plaintiffs in AAArdvark XS. The complaint alleges breach of contract against the defendants and seeks compensatory damages, costs and disbursements, including attorney fees.

OFI believes the lawsuits and appeals described above are without legal merit and, with the exception of actions it has settled, is defending against them vigorously. While it is premature to render any opinion as to the outcome in these lawsuits, or whether any costs that the Defendant Funds may bear in defending the suits might not be reimbursed by insurance, OFI believes that these suits should not impair the ability of OFI or the Distributor to perform their respective duties to the Fund, and that the outcome of all of the suits together should not have any material effect on the operations of any of the Oppenheimer mutual funds.

39      OPPENHEIMER MAIN STREET FUND

REPORTOFINDEPENDENT REGISTERED PUBLIC

ACCOUNTING FIRM

The Board of Trustees and Shareholders of Oppenheimer Main Street Funds:

We have audited the accompanying statement of assets and liabilities of Oppenheimer Main Street Fund, a series of Oppenheimer Main Street Funds, including the statement of investments, as of August 30, 2013, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two-year period then ended, and the financial highlights for each of the years or periods in the five-year period then ended. These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits 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 and financial highlights are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. Our procedures included confirmation of securities owned as of August 30, 2013, by correspondence with the custodian, transfer agent and brokers, or by other appropriate auditing procedures where replies from brokers were not received. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Oppenheimer Main Street Fund as of August 30, 2013, the results of its operations for the year then ended, the changes in its net assets for each of the years in the two-year period then ended, and the financial highlights for each of the years or periods in the five-year period then ended, in conformity with U.S. generally accepted accounting principles.

KPMGLLP

Denver, Colorado

October 17, 2013

40      OPPENHEIMER MAIN STREET FUND

FEDERALINCOME TAX INFORMATION   Unaudited

In early 2013, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2012.

Dividends, if any, paid by the Fund during the fiscal year ended August 30, 2013 which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 100% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the fiscal year ended August 30, 2013 which are not designated as capital gain distributions are eligible for lower individual income tax rates to the extent that the Fund has received qualified dividend income as stipulated by recent tax legislation. The maximum amount allowable but not less than $109,602,752 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2013, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the fiscal year ended August 30, 2013, the maximum amount allowable but not less than $57,848 of the ordinary distributions to be paid by the Fund qualifies as an interest related dividend.

The foregoing information is presented to assist shareholders in reporting distributions received from the Fund to the Internal Revenue Service. Because of the complexity of the federal regulations which may affect your individual tax return and the many variations in state and local tax regulations, we recommend that you consult your tax advisor for specific guidance.

41      OPPENHEIMER MAIN STREET FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT

ADVISORY AGREEMENTUnaudited

The Fund has entered into an investment advisory agreement with OFI Global Asset Management, Inc. (“OFI Global” or the “Adviser”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”) (“OFI Global” and “OFI” together the “Managers”) and OFI Global has entered into a sub-advisory agreement with OFI whereby OFI provides investment sub-advisory services to the Fund (collectively, the “Agreements”). Each year, the Board of Trustees (the “Board”), including a majority of the independent Trustees, is required to determine whether to renew the Agreements. The Investment Company Act of 1940, as amended, requires that the Board request and evaluate, and that the Managers provide, such information as may be reasonably necessary to evaluate the terms of the Agreements. The Board employs an independent consultant to prepare a report that provides information, including comparative information that the Board requests for that purpose. In addition to in-person meetings focused on this evaluation, the Board receives information throughout the year regarding Fund services, fees, expenses and performance.

The Adviser, Sub-Adviser and the independent consultant provided information to the Board on the following factors: (i) the nature, quality and extent of the Managers’ services, (ii) the investment performance of the Fund and the Managers, (iii) the fees and expenses of the Fund, including comparative expense information, (iv) the profitability of the Managers and their affiliates, including an analysis of the cost of providing services, (v) whether economies of scale are realized as the Fund grows and whether fee levels reflect these economies of scale for Fund investors and (vi) other benefits to the Managers from their relationship with the Fund. The Board was aware that there are alternatives to retaining the Managers.

Outlined below is a summary of the principal information considered by the Board as well as the Board’s conclusions.

Nature, Quality and Extent of Services. The Board considered information about the nature, quality and extent of the services provided to the Fund and information regarding the Managers’ key personnel who provide such services. The Sub-Adviser’s duties include providing the Fund with the services of the portfolio managers and the Sub-Adviser’s investment team, who provide research, analysis and other advisory services in regard to the Fund’s investments; securities trading services; oversight of third-party service providers; monitoring compliance with applicable Fund policies and procedures and adherence to the Fund’s investment restrictions; and risk management. The Managers are responsible for providing certain administrative services to the Fund as well. Those services include providing and supervising all administrative and clerical personnel who are necessary in order to provide effective corporate administration for the Fund; compiling and maintaining records with respect to the Fund’s operations; preparing and filing reports required by the Securities and Exchange Commission; preparing periodic reports regarding the operations of the Fund for its shareholders; preparing proxy materials for shareholder meetings; and preparing the registration statements required by Federal and state securities laws for the sale of the Fund’s shares. The Managers also provide the Fund with office space, facilities and equipment.

The Board also considered the quality of the services provided and the quality of the Managers’ resources that are available to the Fund. The Board took account of the fact that the Sub-Adviser has had over fifty years of experience as an investment adviser and that its assets under management rank it among the top mutual fund managers in the United States. The Board evaluated the Sub-Adviser’s advisory, administrative, accounting, legal, compliance

42      OPPENHEIMER MAIN STREET FUND

services and risk management, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of its staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Manind Govil and Benjamin Ram, the portfolio managers for the Fund, and the Sub-Adviser’s investment team and analysts. The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which its members have become knowledgeable about in connection with the renewal of the Fund’s service agreements. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreement.

Investment Performance of the Fund, the Adviser and the Sub-Adviser. Throughout the year, the Adviser and the Sub-Adviser provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Adviser, the Sub-Adviser and the independent consultant, comparing the Fund’s historical performance to its benchmark and to the performance of other retail large blend funds. The Board considered that the Fund outperformed its category median for the one-year, three-year and five-year periods, although it underperformed its category median for the ten-year period. The Board also considered that the Fund’s performance for the one- and three-year periods was in the second quintile of its category. The Board also noted that the Fund had changed portfolio managers effective May 19, 2009 and that the Fund’s one- and three-year rankings are evidence of the strong performance the portfolio managers have delivered for the Fund.

Costs of Services by the Adviser. The Board reviewed the fees paid to the Adviser and the other expenses borne by the Fund. The Board also considered the comparability of the fees charged and the services provided to the Fund to the fees and services for other clients or accounts advised by the Adviser. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load large blend funds with comparable asset levels and distribution features. The Fund’s contractual management fees and total expenses were lower than its peer group median and category median. Within the total asset range of $5 billion to $10 billion, the Fund’s effective rate was lower than its peer group median and category median.

Economies of Scale and Profits Realized by the Adviser and Sub-Adviser. The Board considered information regarding the Managers’ costs in serving as the Fund’s investment adviser and sub-adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund. The Board noted that the Fund currently has management fee breakpoints, which are intended to share with Fund shareholders economies of scale that may exist as the Fund’s assets grow. Based on the Board’s evaluation, the Managers agreed to a revised breakpoint schedule as negotiated by the Board that, effective December 2013, an additional fee breakpoint of 0.43% will be added for assets in excess of $10 billion.

43      OPPENHEIMER MAIN STREET FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT

ADVISORY AGREEMENTUnaudited / Continued

Other Benefits to the Managers. In addition to considering the profits realized by the Managers, the Board considered information that was provided regarding the direct and indirect benefits the Managers receive as a result of their relationship with the Fund, including compensation paid to the Managers’ affiliates and research provided to the Adviser in connection with permissible brokerage arrangements (soft dollar arrangements). The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund.

Conclusions. These factors were also considered by the independent Trustees meeting separately from the full Board, assisted by experienced counsel to the Fund and to the independent Trustees. Fund counsel and the independent Trustees’ counsel are independent of the Managers within the meaning and intent of the Securities and Exchange Commission Rules.

Based on its review of the information it received and its evaluations described above, the Board, including a majority of the independent Trustees, decided to continue the Agreements through September 30, 2014. In arriving at its decision, the Board did not identify any factor or factors as being more important than others, but considered all of the above information, and considered the terms and conditions of the Agreements, including the management fees, in light of all the surrounding circumstances.

44      OPPENHEIMER MAIN STREET FUND

PORTFOLIO PROXY VOTING POLICIES AND PROCEDURES;

UPDATES TO STATEMENTS OF INVESTMENTS  Unaudited

The Fund has adopted Portfolio Proxy Voting Policies and Procedures under which the Fund votes proxies relating to securities (“portfolio proxies”) held by the Fund. A description of the Fund’s Portfolio Proxy Voting Policies and Procedures is available (i) without charge, upon request, by calling the Fund toll-free at 1.800.CALL OPP (225.5677), (ii) on the Fund’s website at oppenheimerfunds.com, and (iii) on the SEC’s website at www.sec.gov. In addition, the Fund is required to file Form N-PX, with its complete proxy voting record for the 12 months ended June 30th, no later than August 31st of each year. The Fund’s voting record is available (i) without charge, upon request, by calling the Fund toll-free at 1.800.CALL OPP (225.5677), and (ii) in the Form N-PX filing on the SEC’s website at www.sec.gov.

The Fund files its complete schedule of portfolio holdings with the SEC for the first quarter and the third quarter of each fiscal year on Form N-Q. The Fund’s Form N-Q filings are available on the SEC’s website at www.sec.gov. Those forms may be reviewed and copied at the SEC’s Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330.

Householding—Delivery of Shareholder Documents

This is to inform you about OppenheimerFunds’ “householding” policy. If more than one member of your household maintains an account in a particular fund, OppenheimerFunds will mail only one copy of the fund’s prospectus (or, if available, the fund’s summary prospectus), annual and semiannual report and privacy policy. The consolidation of these mailings, called householding, benefits your fund through reduced mailing expense, and benefits you by reducing the volume of mail you receive from OppenheimerFunds. Householding does not affect the delivery of your account statements.

Please note that we will continue to household these mailings for as long as you remain an OppenheimerFunds shareholder, unless you request otherwise. If you prefer to receive multiple copies of these materials, please call us at 1.800.CALL-OPP (225-5677). You may also notify us in writing or via email. We will begin sending you individual copies of the prospectus (or, if available, the summary prospectus), reports and privacy policy within 30 days of receiving your request to stop householding.

45      OPPENHEIMER MAIN STREET FUND

TRUSTEES AND OFFICERSUnaudited

Name, Position(s) Held with the Fund, Length of Service, Age	Principal Occupation(s) During the Past 5 Years; Other Trusteeships/Directorships Held; Number of Portfolios in the Fund Complex Currently Overseen
INDEPENDENT TRUSTEES	The address of each Trustee in the chart below is 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Trustee serves for an indefinite term, or until his or her resignation, retirement, death or removal.
Sam Freedman, Chairman of the Board of Trustees (since 2012) and Trustee (since 1996) Year of Birth: 1940	Director of Colorado UpLIFT (charitable organization) (since September 1984). Mr. Freedman held several positions with the Sub-Adviser and with subsidiary or affiliated companies of the Sub-Adviser (until October 1994). Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Freedman has served on the Boards of certain Oppenheimer funds since 1996, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Edward L. Cameron, Trustee (since 2001) Year of Birth: 1938	Member of The Life Guard of Mount Vernon (George Washington historical site) (June 2000-June 2006); Partner of PricewaterhouseCoopers LLP (accounting firm) (July 1974-June 1999); Chairman of Price Waterhouse LLP Global Investment Management Industry Services Group (accounting firm) (July 1994-June 1998). Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Cameron has served on the Boards of certain Oppenheimer funds since 1999, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Jon S. Fossel, Trustee (since 1990) Year of Birth: 1942	Chairman of the Board (2006-December 2011) and Director (June 2002-December 2011) of UNUMProvident (insurance company); Director of Northwestern Energy Corp. (public utility corporation) (November 2004-December 2009); Director of P.R. Pharmaceuticals (October 1999-October 2003); Director of Rocky Mountain Elk Foundation (non-profit organization) (February 1998-February 2003 and February 2005-February 2007); Chairman and Director (until October 1996) and President and Chief Executive Officer (until October 1995) of the Sub-Adviser; President, Chief Executive Officer and Director of the following: Oppenheimer Acquisition Corp. (“OAC”) (parent holding company of the Sub-Adviser), Shareholders Services, Inc. and Shareholder Financial Services, Inc. (until October 1995). Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Fossel has served on the Boards of certain Oppenheimer funds since 1990, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Richard F. Grabish, Trustee (since 2012) Year of Birth: 1948	Formerly Senior Vice President and Assistant Director of Sales and Marketing (March 1997-December 2007), Director (March 1987-December 2007) and Manager of Private Client Services (June 1985-June 2005) of A.G. Edwards & Sons, Inc. (broker/dealer and investment firm); Chairman and Chief Executive Officer of A.G. Edwards Trust Company, FSB (March 2001-December 2007); President and Vice Chairman of A.G. Edwards Trust Company, FSB (investment adviser) (April 1987-March 2001); President of A.G. Edwards Trust Company, FSB (investment adviser) (June 2005-December 2007). Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Grabish has served on the Boards of certain Oppenheimer funds since 2001, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

46      OPPENHEIMER MAIN STREET FUND

Beverly L. Hamilton, Trustee (since 2002) Year of Birth: 1946	Trustee of Monterey Institute for International Studies (educational organization) (since February 2000); Board Member of Middlebury College (educational organization) (December 2005-June 2011); Chairman (since 2010) of American Funds’ Emerging Markets Growth Fund, Inc. (mutual fund); Director of The California Endowment (philanthropic organization) (April 2002-April 2008); Director (February 2002-2005) and Chairman of Trustees (2006-2007) of the Community Hospital of Monterey Peninsula; Director (October 1991-2005); Vice Chairman (2006-2009) of American Funds’ Emerging Markets Growth Fund, Inc. (mutual fund); President of ARCO Investment Management Company (February 1991-April 2000); Member of the investment committees of The Rockefeller Foundation (2001-2006) and The University of Michigan (since 2000); Advisor at Credit Suisse First Boston’s Sprout venture capital unit (venture capital fund) (1994-January 2005); Trustee of MassMutual Institutional Funds (investment company) (1996-June 2004); Trustee of MML Series Investment Fund (investment company) (April 1989-June 2004); Member of the investment committee of Hartford Hospital (2000-2003); and Advisor to Unilever (Holland) pension fund (2000-2003). Oversees 38 portfolios in the OppenheimerFunds complex. Ms. Hamilton has served on the Boards of certain Oppenheimer funds since 2002, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Victoria J. Herget, Trustee (since 2012) Year of Birth:1951	Independent Director of the First American Funds (mutual fund family) (2003-2011); former Managing Director (1993-2001), Principal (1985-1993), Vice President (1978-1985) and Assistant Vice President (1973-1978) of Zurich Scudder Investments (and its predecessor firms); Board Chair (2008-Present) and Director (2004-Present), United Educators (insurance company); Trustee (1992-2007), Chair of the Board of Trustees (1999-2007), Investment Committee Chair (1994-1999) and Investment Committee member (2007-2010) of Wellesley College; Trustee (since 2000) and Chair (since 2010), Newberry Library; Trustee, Mather LifeWays (since 2001); Trustee, BoardSource (2006-2009) and Chicago City Day School (1994-2005). Oversees 38 portfolios in the OppenheimerFunds complex. Ms. Herget has served on the Boards of certain Oppenheimer funds since 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Robert J. Malone, Trustee (since 2002) Year of Birth: 1944	Chairman of the Board (since 2012) and Director (since August 2005) of Jones International University (educational organization) (since August 2005); Chairman, Chief Executive Officer and Director of Steele Street Bank Trust (commercial banking) (since August 2003); Trustee of the Gallagher Family Foundation (non-profit organization) (since 2000); Board of Directors of Opera Colorado Foundation (non-profit organization) (2008-2012); Director of Colorado UpLIFT (charitable organization) (1986-2010); Director of Jones Knowledge, Inc. (2006-2010); Former Chairman of U.S. Bank-Colorado (subsidiary of U.S. Bancorp and formerly Colorado National Bank) (July 1996-April 1999); Director of Commercial Assets, Inc. (real estate investment trust) (1993-2000); Director of U.S. Exploration, Inc. (oil and gas exploration) (1997-February 2004); Chairman of the Board (1991-1994) and Trustee (1985-1994) of Regis University; and Chairman of the Board (1990-1991 and Trustee (1984-1999) of Young Presidents Organization. Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Malone has served on the Boards of certain Oppenheimer funds since 2002, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

47      OPPENHEIMER MAIN STREET FUND

TRUSTEES AND OFFICERSUnaudited / Continued

F. William Marshall, Jr., Trustee (since 2001) Year of Birth: 1942	Trustee Emeritus of Worcester Polytech Institute (WPI) (private university) (since 2009); Trustee of MassMutual Select Funds (formerly MassMutual Institutional Funds) (investment company) (since 1996), MML Series Investment Fund (investment company) (since 1996) and Mass Mutual Premier Funds (investment company) (since January 2012); President and Treasurer of the SIS Fund (private charitable fund) (January 1999 – March 2011); Former Trustee of WPI (1985-2008); Former Chairman of the Board (2004-2006) and Former Chairman of the Investment Committee of WPI (1994-2008); Chairman of SIS & Family Bank, F.S.B. (formerly SIS Bank) (commercial bank) (January 1999-July 1999); Executive Vice President of Peoples Heritage Financial Group, Inc. (commercial bank) (January 1999-July 1999); and Former President and Chief Executive Officer of SIS Bancorp. (1993-1999). Oversees 42 portfolios in the OppenheimerFunds complex. Mr. Marshall has served on the Boards of certain Oppenheimer funds since 2000, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
Karen L. Stuckey, Trustee (since 2012) Year of Birth: 1953	Partner (1990-2012) of PricewaterhouseCoopers LLP (held various positions 1975-1990); Emeritus Trustee (since 2006), Trustee (1992-2006) and member of Executive, Nominating and Audit Committees and Chair of Finance Committee of Lehigh University; and member, Women’s Investment Management Forum since inception. Oversees 38 portfolios in the OppenheimerFunds complex. Ms. Stuckey has served on the Boards of certain Oppenheimer funds since 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
James D. Vaughn, Trustee (since 2012) Year of Birth:1945	Retired; former managing partner (1994-2001) of Denver office of Deloitte & Touche LLP, (held various positions 1969-1993); Trustee and Chairman of the Audit Committee of Schroder Funds (2003-2012); Board member and Chairman of Audit Committee of AMG National Trust Bank (since 2005); Trustee and Investment Committee member, University of South Dakota Foundation (since 1996); Board member, Audit Committee Member and past Board Chair, Junior Achievement (since 1993); former Board member, Mile High United Way, Boys and Girls Clubs, Boy Scouts, Colorado Business Committee for the Arts, Economic Club of Colorado and Metro Denver Network. Oversees 38 portfolios in the OppenheimerFunds complex. Mr. Vaughn has served on the Boards of certain Oppenheimer funds since 2012, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
INTERESTED TRUSTEE AND OFFICER	Mr. Glavin is an “Interested Trustee” because he is affiliated with the Manager and the Sub-Adviser by virtue of his positions as an officer and director of the Manager and a director of the Sub-Adviser, and as a shareholder of the Sub-Adviser’s parent company. Both as a Trustee and as an officer, he serves for an indefinite term, or until his resignation, retirement, death or removal. Mr. Glavin’s address is Two World Financial Center, 225 Liberty Street, 11th Floor, New York, New York 10281-1008.
William F. Glavin, Jr., Trustee, President and Principal Executive Officer (since 2009) Year of Birth: 1958	Director, Chairman and Chief Executive Officer of the Manager (since January 2013); President of the Manager (January 2013-May 2013); Chairman of the Sub-Adviser (December 2009-December 2012); Chief Executive Officer (January 2009-December 2012) and Director of the Sub-Adviser (since January 2009); President of the Sub-Adviser (May 2009-December 2012); Management Director (since June 2009), President (since December 2009) and Chief Executive Officer (since January 2011) of Oppenheimer Acquisition Corp. (“OAC”) (the Sub-Adviser’s parent holding company); Director of Oppenheimer Real Asset Management, Inc. (since March

48      OPPENHEIMER MAIN STREET FUND

William F. Glavin, Jr., Continued	2010); Executive Vice President (March 2006-February 2009) and Chief Operating Officer (July 2007-February 2009) of Massachusetts Mutual Life Insurance Company (OAC’s parent company); Director (May 2004-March 2006) and Chief Operating Officer and Chief Compliance Officer (May 2004-January 2005), President (January 2005-March 2006) and Chief Executive Officer (June 2005-March 2006) of Babson Capital Management LLC; Director (March 2005-March 2006), President (May 2003-March 2006) and Chief Compliance Officer (July 2005-March 2006) of Babson Capital Securities, Inc. (a broker-dealer); President (May 2003-March 2006) of Babson Investment Company, Inc.; Director (May 2004-August 2006) of Babson Capital Europe Limited; Director (May 2004-October 2006) of Babson Capital Guernsey Limited; Director (May 2004-March 2006) of Babson Capital Management LLC; Non-Executive Director (March 2005-March 2007) of Baring Asset Management Limited; Director (February 2005-June 2006) Baring Pension Trustees Limited; Director and Treasurer (December 2003-November 2006) of Charter Oak Capital Management, Inc.; Director (May 2006-September 2006) of C.M. Benefit Insurance Company; Director (May 2008-June 2009) and Executive Vice President (June 2007-July 2009) of C.M. Life Insurance Company; President (March 2006-May 2007) of MassMutual Assignment Company; Director (January 2005-December 2006), Deputy Chairman (March 2005-December 2006) and President (February 2005-March 2005) of MassMutual Holdings (Bermuda) Limited; Director (May 2008-June 2009) and Executive Vice President (June 2007-July 2009) of MML Bay State Life Insurance Company; Chief Executive Officer and President (April 2007-January 2009) of MML Distributors, LLC; and Chairman (March 2006-December 2008) and Chief Executive Officer (May 2007-December 2008) of MML Investors Services, Inc. An officer of 89 portfolios in the OppenheimerFunds complex.
OTHER OFFICERS OF THE FUND	The addresses of the Officers in the chart below are as follows: for Messrs. Govil, Ram, Gabinet and Ms. Nasta, Two World Financial Center, 225 Liberty Street, New York, New York 10281-1008, for Messrs. Vandehey and Wixted, 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Officer serves for an indefinite term or until his or her resignation, retirement, death or removal.
Manind Govil, Vice President (since 2009) Year of Birth: 1969	Senior Vice President, the Main Street Team Leader and a portfolio manager of the Sub-Adviser (since May 2009). Portfolio manager with RS Investment Management Co. LLC (October 2006-March 2009). Head of equity investments at The Guardian Life Insurance Company of America (August 2005-October 2006) when Guardian Life Insurance acquired an interest in RS Investment Management Co. LLC. Lead portfolio manager - large cap blend/core equity, co-head of equities and head of equity research (2001-July 2005), and was lead portfolio manager - core equity (April 1996-July 2005), at Mercantile Capital Advisers, Inc. A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.
Benjamin Ram, Vice President (since 2009) Year of Birth: 1972	Vice President of the Sub-Adviser (since May 2009); Senior Portfolio Manager of the Sub-Adviser (since January 2011) and Portfolio Manager of the Sub-Adviser (May 2009-December 2010). Sector manager for financial investments and a co portfolio manager for mid-cap portfolios with the RS Core Equity Team of RS Investment Management Co. LLC (October 2006-May 2009). Portfolio Manager of Mid Cap Strategies, Sector Manager Financials at The Guardian Life Insurance Company of America (January 2006-October 2006) when Guardian Life Insurance acquired an interest in RS Investment Management Co. LLC. Financial analyst (2003-2005), and co-portfolio manager (2005-2006) at Mercantile Capital Advisers, Inc.; bank analyst at Legg Mason Securities (2000-2003) and a senior financial analyst at the CitiFinancial division of Citigroup, Inc. (1997-2000). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

49      OPPENHEIMER MAIN STREET FUND

TRUSTEES AND OFFICERSUnaudited / Continued

Arthur S. Gabinet, Secretary and Chief Legal Officer (since 2011) Year of Birth: 1958	Executive Vice President, Secretary and General Counsel of the Manager (since January 2013); General Counsel OFI SteelPath, Inc. (since January 2013); Executive Vice President (May 2010-December 2012) and General Counsel (since January 2011) of the Sub-Adviser; General Counsel of the Distributor (since January 2011); General Counsel of Centennial Asset Management Corporation (January 2011-December 2012); Executive Vice President (January 2011-December 2012) and General Counsel of HarbourView Asset Management Corporation (since January 2011); Assistant Secretary (since January 2011) and Director (since January 2011) of OppenheimerFunds International Ltd. and OppenheimerFunds plc; Director of Oppenheimer Real Asset Management, Inc. (January 2011-December 2012) and General Counsel (since January 2011); Executive Vice President (January 2011-December 2011) and General Counsel of Shareholder Financial Services, Inc. and Shareholder Services, Inc. (since January 2011); Executive Vice President (January 2011-December 2012) and General Counsel of OFI Private Investments Inc. (since January 2011); Vice President of OppenheimerFunds Legacy Program (January 2011-December 2011); Executive Vice President (January 2011-December 2012) and General Counsel of OFI Global Institutional, Inc. (since January 2011); General Counsel, Asset Management of the Sub-Adviser (May 2010-December 2010); Principal, The Vanguard Group (November 2005-April 2010); District Administrator, U.S. Securities and Exchange Commission (January 2003-October 2005). An officer of 89 portfolios in the OppenheimerFunds complex.
Christina M. Nasta, Vice President and Chief Business Officer (since 2011) Year of Birth: 1973	Senior Vice President of OppenheimerFunds Distributor, Inc. (since January 2013); Senior Vice President of the Sub-Adviser (July 2010-December 2012); Vice President of the Sub-Adviser (January 2003-July 2010); Vice President of OppenheimerFunds Distributor, Inc. (January 2003-July 2010). An officer of 89 portfolios in the OppenheimerFunds complex.
Mark S. Vandehey, Vice President and Chief Compliance Officer (since 2004) Year of Birth: 1950	Senior Vice President and Chief Compliance Officer of the Manager (since January 2013); Chief Compliance Officer of OFI SteelPath, Inc. (since January 2013); Senior Vice President of the Sub-Adviser (March 2004-December 2012); Chief Compliance Officer of the Sub-Adviser, OppenheimerFunds Distributor, Inc., OFI Global Trust Company, OFI Global Institutional, Inc., Oppenheimer Real Asset Management, Inc., OFI Private Investments, Inc., Harborview Asset Management Corporation, Trinity Investment Management Corporation, and Shareholder Services, Inc. (since March 2004); Vice President of OppenheimerFunds Distributor, Inc., Centennial Asset Management Corporation and Shareholder Services, Inc. (June 1983-December 2012). An officer of 89 portfolios in the OppenheimerFunds complex.
Brian W. Wixted, Treasurer and Principal Financial & Accounting Officer (since 1999) Year of Birth: 1959	Senior Vice President of the Manager (since January 2013); Treasurer of the Sub-Adviser, HarbourView Asset Management Corporation, Shareholder Financial Services, Inc., Shareholder Services, Inc., and Oppenheimer Real Asset Management, Inc. (March 1999-June 2008), OFI Private Investments, Inc. (March 2000-June 2008), OppenheimerFunds International Ltd. and OppenheimerFunds plc (since May 2000), OFI Global Institutional, Inc. (November 2000-June 2008), and OppenheimerFunds Legacy Program (charitable trust program established by the Sub-Adviser) (June 2003-December 2011); Treasurer and Chief Financial Officer of OFI Global Trust Company (since May 2000); Assistant Treasurer of Oppenheimer Acquisition Corporation (March 1999-June 2008). An officer of 89 portfolios in the OppenheimerFunds complex.

The Fund’s Statement of Additional Information contains additional information about the Fund’s Trustees and Officers and is available without charge upon request, by calling 1.800.CALL OPP (225.5677).

50      OPPENHEIMER MAIN STREET FUND

OPPENHEIMERMAIN STREET FUND

Manager	OFI Global Asset Management, Inc.
Sub-Adviser	OppenheimerFunds, Inc.
Distributor	OppenheimerFunds Distributor, Inc.
Transfer and Shareholder Servicing Agent	OFI Global Asset Management, Inc.
Sub-Transfer Agent	Shareholder Services, Inc. DBA OppenheimerFunds Services
Independent Registered Public Accounting Firm	KPMGLLP
Legal Counsel	K&L Gates LLP

© 2013 OppenheimerFunds, Inc. All rights reserved.

51      OPPENHEIMER MAIN STREET FUND

PRIVACY POLICY NOTICE

As an Oppenheimer fund shareholder, you are entitled to know how we protect your personal information and how we limit its disclosure.

Information Sources

We obtain nonpublic personal information about our shareholders from the following sources:

• Applications or other forms

• When you create a user ID and password for online account access

• When you enroll in eDocs Direct, our electronic document delivery service

• Your transactions with us, our affiliates or others

• A software program on our website, often referred to as a “cookie,” which indicates which parts of our site you’ve visited

• When you set up challenge questions to reset your password online

If you visit oppenheimerfunds.com and do not log on to the secure account information areas, we do not obtain any personal information about you. When you do log on to a secure area, we do obtain your user ID and password to identify you. We also use this information to provide you with products and services you have requested, to inform you about products and services that you may be interested in and assist you in other ways.

We do not collect personal information through our website unless you willingly provide it to us, either directly by email or in those areas of the website that request information. In order to update your personal information (including your mailing address, email address and phone number) you must first log on and visit your user profile.

If you have set your browser to warn you before accepting cookies, you will receive the warning message with each cookie. You can refuse cookies by turning them off in your browser. However, doing so may limit your access to certain sections of our website.

We use cookies to help us improve and manage our website. For example, cookies help us recognize new versus repeat visitors to the site, track the pages visited, and enable some special features on the website. This data helps us provide a better service for our website visitors.

Protection of Information

We do not disclose any non-public personal information (such as names on a customer list) about current or former customers to anyone, except as permitted by law.

Disclosure of Information

We send your financial advisor (as designated by you) copies of confirmations, account statements and other documents reporting activity in your fund accounts. We may also use details about you and your investments to help us, our financial service affiliates, or firms that jointly market their financial products and services with ours, to better serve your investment needs or suggest financial services or educational material that may be of interest to you. If this requires us to provide you with an opportunity to “opt in” or “opt out” of such information sharing with a firm not affiliated with us, you will receive notification on how to do so, before any such sharing takes place.

Right of Refusal

We will not disclose your personal information to unaffiliated third parties (except as permitted by law), unless we first offer you a reasonable opportunity to refuse or “opt out” of such disclosure.

52      OPPENHEIMER MAIN STREET FUND

Internet Security and Encryption

In general, the email services provided by our website are encrypted and provide a secure and private means of communication with us. To protect your own privacy, confidential and/or personal information should only be communicated via email when you are advised that you are using a secure website. As a security measure, we do not include personal or account information in non-secure emails, and we advise you not to send such information to us in non-secure emails. Instead, you may take advantage of the secure features of our website to encrypt your email correspondence. To do this, you will need to use a browser that supports Secure Sockets Layer (SSL) protocol.

We do not guarantee or warrant that any part of our website, including files available for download, are free of viruses or other harmful code. It is your responsibility to take appropriate precautions, such as use of an anti-virus software package, to protect your computer hardware and software.

• All transactions, including redemptions, exchanges and purchases, are secured by SSL and 128-bit encryption. SSL is used to establish a secure connection between your PC and OppenheimerFunds’ server. It transmits information in an encrypted and scrambled format.

• Encryption is achieved through an electronic scrambling technology that uses a “key” to code and then decode the data. Encryption acts like the cable converter box you may have on your television set. It scrambles data with a secret code so that no one can make sense of it while it is being transmitted. When the data reaches its destination, the same software unscrambles the data.

• You can exit the secure area by either closing your browser, or for added security, you can use the Log Out button before you close your browser.

Other Security Measures

We maintain physical, electronic and procedural safeguards to protect your personal account information. Our employees and agents have access to that information only so that they may offer you products or provide services, for example, when responding to your account questions.

How You Can Help

You can also do your part to keep your account information private and to prevent unauthorized transactions. If you obtain a user ID and password for your account, do not allow it to be used by anyone else. Also, take special precautions when accessing your account on a computer used by others.

Who We Are

This joint notice describes the privacy policies of the Oppenheimer funds, OppenheimerFunds, Inc., and each of its financial institution subsidiaries, the trustee of OppenheimerFunds Individual Retirement Accounts (IRAs) and the custodian of the OppenheimerFunds 403(b)(7) tax sheltered custodial accounts. It applies to all Oppenheimer fund accounts you presently have, or may open in the future, using your Social Security number—whether or not you remain a shareholder of our funds. This notice was last updated November 2012. In the event it is updated or changed, we will post an updated notice on our website at oppenheimerfunds.com. If you have any questions about these privacy policies, write to us at P.O. Box 5270, Denver, CO 80217-5270, email us by clicking on the Contact Us section of our website at oppenheimerfunds.com or call us at 1.800.CALL OPP (225.5677).

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55      OPPENHEIMER MAIN STREET FUND

Item 2. Code of Ethics.

The registrant has adopted a code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller or persons performing similar functions.

Item 3. Audit Committee Financial Expert.

The Board of Trustees of the registrant has determined that F. William Marshall, Jr., the Chairman of the Board’s Audit Committee, is the audit committee financial expert and that Mr. Marshall is “independent” for purposes of this Item 3.

Item 4. Principal Accountant Fees and Services.

(a) Audit Fees

The principal accountant for the audit of the registrant’s annual financial statements billed $31,500 in fiscal 2013 and $30,900 in fiscal 2012.

(b) Audit-Related Fees

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2013 and no such fees in fiscal 2012.

The principal accountant for the audit of the registrant’s annual financial statements billed $477,830 in fiscal 2013 and $583,556 in fiscal 2012 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

Such services include: Internal control reviews, compliance procedures, GIPS attestation procedures, internal audit training, surprise exams, system conversion testing, corporate restructuring.

(c) Tax Fees

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2013 and $3,600 in fiscal 2012.

The principal accountant for the audit of the registrant’s annual financial statements billed $492,036 in fiscal 2013 and $317,764 in fiscal 2012 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

Such services include: tax compliance, tax planning and tax advice. Tax compliance generally involves preparation of original and amended tax returns, claims for a refund and tax payment-planning services. Tax planning and tax advice includes assistance with tax audits and appeals, tax advice related to mergers and acquisitions and requests for rulings or technical advice from taxing authorities.

(d) All Other Fees

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2013 and no such fees in fiscal 2012.

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2013 and no such fees in fiscal 2012 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

Such fees would include the cost to the principal accountant of attending audit committee meetings and consultations regarding the registrant’s retirement plan with respect to its Trustees.

(e) (1) During its regularly scheduled periodic meetings, the registrant’s audit committee will pre-approve all audit, audit-related, tax and other services to be provided by the principal accountants of the registrant.

The audit committee has delegated pre-approval authority to its Chairman for any subsequent new engagements that arise between regularly scheduled meeting dates provided that any fees such pre-approved are presented to the audit committee at its next regularly scheduled meeting.

Under applicable laws, pre-approval of non-audit services may be waived provided that: 1) the aggregate amount of all such services provided constitutes no more than five percent of the total amount of fees paid by the registrant to its principal accountant during the fiscal year in which services are provided 2) such services were not recognized by the registrant at the time of engagement as non-audit services and 3) such services are promptly brought to the attention of the audit committee of the registrant and approved prior to the completion of the audit.

(2) 0%

(f) Not applicable as less than 50%.

(g) The principal accountant for the audit of the registrant’s annual financial statements billed $969,866 in fiscal 2013 and $904,920 in fiscal 2012 to the registrant and the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant related to non-audit fees. Those billings did not include any prohibited non-audit services as defined by the Securities Exchange Act of 1934.

(h) The registrant’s audit committee of the board of Trustees has considered whether the provision of non-audit services that were rendered to the registrant’s investment adviser, and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant’s independence. No such services were rendered.

Item 5. Audit Committee of Listed Registrants

Not applicable.

Item 6. Schedule of Investments.

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

b) Not applicable.

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

Not applicable.

Item 8. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable.

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

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

The Fund’s Governance Committee Provisions with Respect to Nominations of Directors/Trustees to the Respective Boards

None

Item 11. Controls and Procedures.

Based on their evaluation of the registrant’s disclosure controls and procedures (as defined in rule 30a-3(c) under the Investment Company Act of 1940 (17 CFR 270.30a-3(c)) as of 8/30/2013, the registrant’s principal executive officer and principal financial officer found the registrant’s disclosure controls and procedures to provide reasonable assurances that information required to be disclosed by the registrant in the reports that it files under the Securities Exchange Act of 1934 (a) is accumulated and communicated to registrant’s management, including its principal executive officer and principal financial officer, to allow timely decisions regarding required disclosure, and (b) is recorded, processed, summarized and reported, within the time periods specified in the rules and forms adopted by the U.S. Securities and Exchange Commission.

There have been no changes in the registrant’s internal controls over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits.

(a) (1) Exhibit attached hereto.

(2) Exhibits attached hereto.

(3) Not applicable.

(b) Exhibit attached hereto.

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.

Oppenheimer Main Street Funds, Inc.
By:	/s/ William F. Glavin, Jr.
	William F. Glavin, Jr.
	Principal Executive Officer
Date:	10/14/2013

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/ William F. Glavin, Jr.
	William F. Glavin, Jr.
	Principal Executive Officer
Date:	10/14/2013

By:	/s/ Brian W. Wixted
	Brian W. Wixted
	Principal Financial Officer
Date:	10/14/2013