N-CSRS

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 811-10001

Oppenheimer Main Street Select Fund

(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: July 31

Date of reporting period: 1/31/2013

Item 1. Reports to Stockholders.

Table of Contents

Fund Performance Discussion	3
Top Holdings and Allocations	6
Fund Expenses	9
Statement of Investments	11
Statement of Assets and Liabilities	13
Statement of Operations	15
Statements of Changes in Net Assets	16
Financial Highlights	17
Notes to Financial Statements	27
Board Approval of the Fund’s Investment Advisory Agreement	39
Portfolio Proxy Voting Policies and Procedures; Updates to Statement of Investments	42
Trustee and Officers	43
Privacy Policy Notice	44

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 1/31/13

	Class A Shares of the Fund		S&P 500 Index	Russell 1000 Index
	Without Sales Charge	With Sales Charge
6-Month	9.18%	2.90%	9.91%	10.89%
1-Year	15.32	8.69	16.78	17.03
5-Year	3.49	2.27	3.97	4.28
10-Year	8.57	7.93	7.93	8.36

The 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. Returns for periods of less than one year are cumulative and not annualized. For performance data current to the most recent month-end, visit oppenheimerfunds.com or call 1.800.CALL OPP (225.5677).

2 OPPENHEIMER MAIN STREET SELECT FUND

Fund Performance Discussion

The Fund’s Class A shares (without sales charge) produced a cumulative total return of 9.18% during the reporting period. On a relative basis, the Fund underperformed the S&P 500 Index (the “Index”), which returned 9.91%. The Fund’s underperformance stemmed primarily from weaker relative stock selection in the health care and industrials sectors. The strongest performing sector for the Fund relative to the Index was financials, where favorable stock selection benefited.

MARKET OVERVIEW

While domestic and international macroeconomic concerns remained throughout the period, U.S. equities generally performed positively as Central Bank actions and other events helped to calm market jitters. In the U.S., the Fed introduced a third round of quantitative easing, under which it announced plans to purchase mortgage-backed bonds on a monthly basis until the labor market shows signs of substantial improvement. Equities in the U.S. were also bolstered by the continued improvement of the housing market. However, the market did experience volatility due to uncertainty over the outcome of the Presidential election. In addition, the lack of visibility about resolution of the “fiscal cliff” weighed further on both business and consumer spending. These concerns were not enough to offset the gains, and although an ongoing, contentious debate regarding government spending and fiscal policy remained, the U.S. Congress enacted a last minute temporary resolution to the fiscal cliff in the final month of the period.

Outside of the U.S., the results of elections in Greece and continued efforts by European

policymakers to stabilize the situation in the region made far less likely the imminent fracturing of the Eurozone and the serious consequences that might have for the euro. The European Central Bank also increased its efforts to stimulate economic growth, as it committed to potentially unlimited bond purchases to ease financing pressure on countries like Spain and Italy. Under the plan, these and other members of the European Union (excluding Greece) would be able to maintain access to funding at sustainable interest rates, on the condition that they continue with strict reform programs.

FUND REVIEW

During the period, the top two performing stocks for the Fund were Citigroup, Inc. and JPMorgan Chase & Co. Citigroup’s stock performed positively as both a newly appointed CEO and announced cost restructurings, including headcount reductions, resulted in a boost to earnings expectations. Additionally, the market viewed an improving housing market as favorable to Citigroup’s book of existing home mortgages, potentially resulting in future profit growth

OPPENHEIMER MAIN STREET SELECT FUND 3

for the company and creating demand for new mortgage loans. JPMorgan also performed positively due to the general rise in home prices and increases in both existing home sales and new housing, which could benefit the company’s profitability. Also, management reinstated its aggressive share repurchase program after it was suspended in response to the trading debacle earlier in the year. As a consequence, earnings revisions have been on an upward trajectory, helping to buoy the stock price higher.

Outside of financials, consumer discretionary stock Ford Motor Co. and information technology stock eBay, Inc. benefited the Fund’s performance. Ford Motor benefited from an expanding multiple as investors focused on the sustainability of improved automobile sales. During the fourth quarter of 2012, North American sales were strong. Ford, too, had strong sales without relying on incentives, thus demonstrating pricing discipline. Additionally, Ford announced a comprehensive and credible multi-year restructuring of its European businesses which was well-received by investors. During the period, eBay’s earnings beat expectations and management raised guidance for both 2012 revenues and profits. The company also benefited from a turnaround in its Marketplace segment with improvements to the user experience leading to increased loyalty and greater volumes of transactions. PayPal, eBay’s online payment service, continued to be a significant contributor to eBay’s growth with results that exceeded expectations.

The most significant detractor from Fund performance this period was information technology stock Apple, Inc. Having realized strong investment returns earlier in 2012, Apple gave back some of its relative outperformance during the period as investors sought to lock in gains. And, despite successful launches of the iPhone 5 and iPad mini, the company endured a couple of missteps which called into question management’s ability to execute flawlessly. This, in combination with the success of competing products – particularly in smartphones from Samsung – helped to bring down earnings expectations. In our opinion, Apple will continue to benefit from a sustainable competitive advantage due largely to product innovation.

Also detracting slightly from performance were health care holding Express Scripts Holding Co. and telecommunication services stock America Movil SAB de CV. Express Scripts administers the prescription drug benefits of millions of health plan members in the U.S. and Canada. Reported earnings were strong for this pharmacy benefit manager; however, management guidance for the upcoming year was disappointing, relative to market expectations, resulting in selling pressure on the stock. The effects of a continuation in sluggish economic activity and poor employment gains may weigh on Express’ volume growth. Additionally, increased uncertainty about the timing and impact of synergy realizations from the recently completed acquisition of Medco has put further stress on earnings estimates. We

4 OPPENHEIMER MAIN STREET SELECT FUND

continue to believe the company’s profitability will benefit both from the integration of Medco and as higher margin generics become a larger portion of sales. America Movil is a top mobile carrier in Latin America. The company faced stronger competition in the region and also was faced with increased regulation in Mexico, where regulators have reduced the fees it charges rivals to connect to its network.

STRATEGY & OUTLOOK

Despite macroeconomic headwinds, we believe that many U.S. corporations have continued to build balance sheet strength and have generally made effective capital allocation decisions. While profit growth may remain slow, we believe balance sheets are likely to remain healthy and returns on capital should remain stable. While we expect market volatility to continue through 2013, we believe that even in an uncertain

macroeconomic environment, there exist solid investment opportunities.

Our long-term investment process remains the same. We seek companies that we believe have sustainable competitive advantages, the management skill and financial resources to generate stronger profit margins, take market share from weaker players, and/or return significant capital to shareholders. We focus on leading firms in structurally attractive industries with committed management teams that have proven records of performance. We seek to invest in such companies when their valuations are attractive, and believe that this disciplined approach is the key to generating positive long-term returns. We believe our investment strategy has the potential to provide both upside participation and a degree of downside protection.

OPPENHEIMER MAIN STREET SELECT FUND 5

Top Holdings and Allocations

TOP TEN COMMON STOCK HOLDINGS
JPMorgan Chase & Co.	6.4	%
Apple, Inc.	6.0
eBay, Inc.	5.4
International Business Machines Corp.	5.0
Chevron Corp.	4.1
Ford Motor Co.	4.1
Citigroup, Inc.	4.0
Philip Morris International, Inc.	3.8
CIT Group, Inc.	3.7
United Parcel Service, Inc., Cl. B	3.7

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2013, and are based on net assets. For more current Fund holdings, please visit oppenheimerfunds.com.

TOP TEN COMMON STOCK INDUSTRIES
Diversified Financial Services	12.3	%
Internet Software & Services	7.0
Pharmaceuticals	6.5
Oil, Gas & Consumable Fuels	6.0
Computers & Peripherals	6.0
Food Products	5.1
IT Services	5.0
Automobiles	4.1
Tobacco	3.8
Commercial Banks	3.7

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2013, and are based on net assets.

SECTOR ALLOCATION

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2013, and are based on the total market value of common stocks.

6 OPPENHEIMER MAIN STREET SELECT FUND

Share Class Performance

AVERAGE ANNUAL RETURNS WITHOUT SALES CHARGE AS OF 1/31/13

	Inception Date		6-Month		1-Year		5-Year		10-Year
Class A (OMSOX)		9/25/00		9.18%		15.32%		3.49%		8.57%
Class B (OMOBX)		9/25/00		8.64%		14.33%		2.64%		8.04%
Class C (OMSCX)		9/25/00		8.80%		14.55%		2.73%		7.78%
Class N (OMSNX)		3/1/01		9.01%		14.93%		3.19%		8.22%
Class Y (OMSYX)		9/25/00		9.30%		15.68%		3.87%		8.99%
AVERAGE ANNUAL RETURNS WITH SALES CHARGE AS OF 1/31/13
	Inception Date		6-Month		1-Year		5-Year		10-Year
Class A (OMSOX)		9/25/00		2.90%		8.69%		2.27%		7.93%
Class B (OMOBX)		9/25/00		3.64%		9.33%		2.27%		8.04%
Class C (OMSCX)		9/25/00		7.80%		13.55%		2.73%		7.78%
Class N (OMSNX)		3/1/01		8.01%		13.93%		3.19%		8.22%
Class Y (OMSYX)		9/25/00		9.30%		15.68%		3.87%		8.99%

The 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 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 and the Russell 1000 Index. The S&P 500 Index is an unmanaged index of large-capitalization equity securities that is a measure of the general domestic stock market. The Russell 1000 Index is an index that is a widely used measure of domestic, large-cap stock performance, and is made up of the top 1,000 stocks in the Russell 3000 Index. The indices are unmanaged and cannot be purchased directly by investors. Index performance is shown for illustrative purposes only and does not predict or depict

OPPENHEIMER MAIN STREET SELECT FUND 7

the performance of the Fund. While index comparisons may be useful to provide a benchmark for the Fund’s performance, it must be noted that the Fund’s investments are not limited to the investments comprising the indices.

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.

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.

8 OPPENHEIMER MAIN STREET SELECT 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 January 31, 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.

OPPENHEIMER MAIN STREET SELECT FUND 9

Actual	Beginning Account Value August 1, 2012		Ending Account Value January 31, 2013		Expenses Paid During 6 Months Ended January 31, 2013
Class A	$	1,000.00	$	1,091.80	$	6.40
Class B		1,000.00		1,086.40		11.31
Class C		1,000.00		1,088.00		10.31
Class N		1,000.00		1,090.10		7.88
Class Y		1,000.00		1,093.00		4.55
Hypothetical (5% return before expenses)
Class A		1,000.00		1,019.11		6.18
Class B		1,000.00		1,014.42		10.92
Class C		1,000.00		1,015.38		9.95
Class N		1,000.00		1,017.69		7.61
Class Y		1,000.00		1,020.87		4.39

Expenses are equal to the Fund’s annualized expense ratio for that class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period). Those annualized expense ratios, excluding indirect expenses from affiliated fund, based on the 6-month period ended January 31, 2013 are as follows:

Class	Expense Ratios
Class A		1.21	%
Class B		2.14
Class C		1.95
Class N		1.49
Class Y		0.86

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.

10 OPPENHEIMER MAIN STREET SELECT FUND

STATEMENT OF INVESTMENTS    January 31, 2013 / Unaudited

	Shares		Value
Common Stocks—95.9%
Consumer Discretionary—10.6%
Automobiles—4.1%
Ford Motor Co.		4,729,990	$	61,253,370
Hotels, Restaurants & Leisure—0.5%
Yum! Brands, Inc.		108,470		7,044,042
Media—2.5%
McGraw-Hill Cos., Inc. (The)		640,304		36,830,286
Specialty Retail—3.5%
AutoZone, Inc.1		77,970		28,825,509
CarMax, Inc.1		140,550		5,540,481
TJX Cos., Inc. (The)		393,200		17,764,776
				52,130,766
Consumer Staples—11.9%
Beverages—3.0%
Dr Pepper Snapple Group, Inc.		1,000,530		45,093,887
Food Products—5.1%
J.M. Smucker Co. (The)		380,090		33,687,377
Kraft Foods Group, Inc.		938,176		43,362,495
				77,049,872
Tobacco—3.8%
Philip Morris International, Inc.		642,944		56,681,943
Energy—9.2%
Energy Equipment & Services—3.2%
National Oilwell Varco, Inc.		651,980		48,337,797
Oil, Gas & Consumable Fuels—6.0%
Chevron Corp.		536,391		61,765,424
Enbridge Energy Management LLC1		1		19
Noble Energy, Inc.		271,100		29,221,869
				90,987,312
Financials—19.3%
Commercial Banks—3.7%
CIT Group, Inc.1		1,324,854		56,107,567
Diversified Financial Services—12.3%
Citigroup, Inc.		1,421,748		59,940,896
CME Group, Inc., Cl. A		485,400		28,075,536
JPMorgan Chase & Co.		2,051,520		96,524,016
				184,540,448

	Shares		Value
Insurance—3.3%
Marsh & McLennan Cos., Inc.		1,384,220	$	49,112,125
Health Care—12.3%
Health Care Equipment & Supplies—2.8%
Covidien plc		675,140		42,088,228
Health Care Providers & Services—3.0%
Express Scripts Holding Co.1		851,570		45,490,869
Pharmaceuticals—6.5%
Actavis, Inc.1		530,390		45,820,392
Bristol-Myers Squibb Co.		962,990		34,802,458
Pfizer, Inc.		578,570		15,783,390
				96,406,240
Industrials—9.9%
Air Freight & Couriers—3.7%
United Parcel Service, Inc., Cl. B		696,830		55,251,651
Commercial Services & Supplies—3.5%
Tyco International Ltd.		1,744,230		52,728,073
Professional Services—1.5%
Towers Watson & Co., Cl. A		361,350		22,071,258
Road & Rail—1.2%
CSX Corp.		831,610		18,320,368
Information Technology—18.0%
Computers & Peripherals—6.0%
Apple, Inc.		195,986		89,234,386
Internet Software & Services—7.0%
eBay, Inc.1		1,438,460		80,453,068
Google, Inc., Cl. A1		31,363		23,700,705
				104,153,773
IT Services—5.0%
International Business Machines Corp.		371,810		75,503,457
Materials—1.9%
Construction Materials—1.9%
Vulcan Materials Co.		499,950		28,277,172
Telecommunication Services—2.8%
Wireless Telecommunication Services—2.8%
America Movil SAB de CV, Series L, ADR		1,652,832		41,585,253
Total Common Stocks (Cost $1,068,901,775)				1,436,280,143

OPPENHEIMER MAIN STREET SELECT FUND 11

STATEMENT OF INVESTMENTS    January 31, 2013 / Unaudited

	Shares			Value
Investment Companies—3.7%
iShares S&P 500 Value Index Fund		518,000		$	36,632,960
Oppenheimer Institutional Money Market Fund, Cl. E, 0.15%2,3		18,310,527			18,310,527
Total Investment Companies (Cost $51,784,894)					54,943,487
Total Investments, at Value (Cost $1,120,686,669)		99.6	%		1,491,223,630
Assets in Excess of Other Liabilities		0.4			6,681,897
Net Assets		100.0%		$	1,497,905,527

Footnotes to Statement of Investments

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 January 31, 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:

	Shares July 31, 2012	Gross Additions	Gross Reductions	Shares January 31, 2013
Oppenheimer Institutional Money Market Fund, Cl. E	15,206,579	212,384,774	209,280,826	18,310,527
			Value	Income
Oppenheimer Institutional Money Market Fund, Cl. E			$18,310,527	$14,993

3. Rate shown is the 7-day yield as of January 31, 2013.

See accompanying Notes to Financial Statements.

12 OPPENHEIMER MAIN STREET SELECT FUND

STATEMENT OF ASSETS AND LIABILITIES    
      January 31, 2013 / Unaudited

Assets
Investments, at value—see accompanying statement of investments:
Unaffiliated companies (cost $1,102,376,142)	$	1,472,913,103
Affiliated companies (cost $18,310,527)		18,310,527
		1,491,223,630
Cash		256,456
Receivables and other assets:
Investments sold		7,895,639
Dividends		1,600,506
Other		88,873
Total assets		1,501,065,104
Liabilities
Payables and other liabilities:
Shares of beneficial interest redeemed		2,318,241
Transfer and shareholder servicing agent fees		325,688
Distribution and service plan fees		281,564
Shareholder communications		130,495
Trustees’ compensation		67,525
Other		36,064
Total liabilities		3,159,577
Net Assets	$	1,497,905,527
Composition of Net Assets
Par value of shares of beneficial interest	$	102,106
Additional paid-in capital		1,624,169,052
Accumulated net investment income		577,282
Accumulated net realized loss on investments		(497,479,874	)
Net unrealized appreciation on investments		370,536,961
Net Assets	$	1,497,905,527

OPPENHEIMER MAIN STREET SELECT FUND 13

STATEMENT OF ASSETS AND LIABILITIES    
      Unaudited / (Continued)

Net Asset Value Per Share
Class A Shares:
Net asset value and redemption price per share (based on net assets of $1,000,018,180 and 67,265,854 shares of beneficial interest outstanding)	$	14.87
Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	15.78
Class B Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $83,520,013 and 5,983,315 shares of beneficial interest outstanding)	$	13.96
Class C Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $249,265,764 and 17,697,211 shares of beneficial interest outstanding)	$	14.09
Class N Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $89,002,559 and 6,120,558 shares of beneficial interest outstanding)	$	14.54
Class Y Shares:
Net asset value, redemption price and offering price per share (based on net assets of $76,099,011 and 5,039,140 shares of beneficial interest outstanding)	$	15.10

See accompanying Notes to Financial Statements.

14 OPPENHEIMER MAIN STREET SELECT FUND

STATEMENT OF OPERATIONS    

 For the Six Months Ended January 31, 2013 / Unaudited

Investment Income
Dividends:
Unaffiliated companies	$	16,318,385
Affiliated companies		14,993
Interest		543
Other income		32,403
Total investment income		16,366,324
Expenses
Management fees		4,887,716
Distribution and service plan fees:
Class A		1,200,470
Class B		439,597
Class C		1,226,608
Class N		228,135
Transfer and shareholder servicing agent fees:
Class A		1,296,825
Class B		218,371
Class C		314,104
Class N		142,334
Class Y		55,001
Shareholder communications:
Class A		98,365
Class B		22,508
Class C		21,170
Class N		4,332
Class Y		6,063
Trustees’ compensation		42,162
Custodian fees and expenses		4,880
Other		163,794
Total expenses		10,372,435
Less waivers and reimbursements of expenses		(43,178	)
Net expenses		10,329,257
Net Investment Income		6,037,067
Realized and Unrealized Gain
Net realized gain on unaffiliated companies		76,003,215
Net change in unrealized appreciation/depreciation on investments		45,449,124
Net Increase in Net Assets Resulting from Operations	$	127,489,406

See accompanying Notes to Financial Statements.

OPPENHEIMER MAIN STREET SELECT FUND 15

STATEMENTS OF CHANGES IN NET ASSETS    

	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012
Operations
Net investment income	$	6,037,067		$	2,933,947
Net realized gain		76,003,215			49,804,113
Net change in unrealized appreciation/depreciation		45,449,124			72,591,557
Net increase in net assets resulting from operations		127,489,406			125,329,617
Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(6,332,333	)		(1,809,690	)
Class B		—			—
Class C		—			—
Class N		(350,564	)		—
Class Y		(643,786	)		(281,769	)
		(7,326,683	)		(2,091,459	)
Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		(41,389,626	)		(108,466,754	)
Class B		(17,134,287	)		(35,301,046	)
Class C		(12,960,829	)		(43,680,530	)
Class N		(9,090,485	)		(12,197,349	)
Class Y		6,405,919			1,811,660
		(74,169,308	)		(197,834,019	)
Net Assets
Total increase (decrease)		45,993,415			(74,595,861	)
Beginning of period		1,451,912,112			1,526,507,973
End of period (including accumulated net investment income of $577,282 and $1,866,898, respectively)	$	1,497,905,527		$	1,451,912,112

See accompanying Notes to Financial Statements.

16 OPPENHEIMER MAIN STREET SELECT FUND

FINANCIAL HIGHLIGHTS    

Class A	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012			Year Ended July 29, 20111			Year Ended July 30, 20101			Year Ended July 31, 2009			Year Ended July 31, 2008
Per Share Operating Data
Net asset value, beginning of period	$	13.71		$	12.52		$	11.11		$	9.81		$	11.90		$	15.35
Income (loss) from investment operations:
Net investment income2		0.07			0.05			0.02			0.05			0.09			0.10
Net realized and unrealized gain (loss)		1.18			1.16			1.39			1.29			(2.08	)		(1.98	)
Total from investment operations		1.25			1.21			1.41			1.34			(1.99	)		(1.88	)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.09	)		(0.02	)		0.00			(0.03	)		(0.07	)		(0.12	)
Distributions from net realized gain		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Tax return of capital distribution		0.00			0.00			0.00			(0.01	)		0.00			0.00
Total dividends and/or distributions to shareholders		(0.09	)		(0.02	)		0.00			(0.04	)		(0.10	)		(1.57	)
Net asset value, end of period	$	14.87		$	13.71		$	12.52		$	11.11		$	9.81		$	11.90
Total Return, at Net Asset Value3		9.18	%		9.73	%		12.69	%		13.69	%		(16.56	)%		(13.62	)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	1,000,018		$	962,017		$	988,188		$	1,025,633		$	1,024,470		$	1,853,930
Average net assets (in thousands)	$	982,539		$	940,509		$	1,063,673		$	1,065,511		$	1,088,256		$	2,282,800
Ratios to average net assets:4
Net investment income		0.99	%		0.40	%		0.13	%		0.44	%		0.95	%		0.69	%
Total expenses5		1.21	%		1.24	%		1.22	%		1.25	%		1.30	%		1.12	%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.21	%		1.24	%		1.22	%		1.25	%		1.24	%		1.12	%
Portfolio turnover rate		19	%		37	%		58	%		66	%		124	%		146	%

OPPENHEIMER MAIN STREET SELECT FUND 17

FINANCIAL HIGHLIGHTS    (Continued)

1. July 29, 2011 and July 30, 2010 represent the last business days of the Fund’s respective reporting periods.

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:

Six Months Ended January 31, 2013	1.21	%
Year Ended July 31, 2012	1.24	%
Year Ended July 29, 2011	1.22	%
Year Ended July 30, 2010	1.25	%
Year Ended July 31, 2009	1.30	%
Year Ended July 31, 2008	1.12	%

See accompanying Notes to Financial Statements.

18 OPPENHEIMER MAIN STREET SELECT FUND

Class B	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012			Year Ended July 29, 20111			Year Ended July 30, 20101			Year Ended July 31, 2009			Year Ended July 31, 2008
Per Share Operating Data
Net asset value, beginning of period	$	12.85		$	11.81		$	10.56		$	9.36		$	11.36		$	14.71
Income (loss) from investment operations:
Net investment income (loss)2		0.00	3		(0.05	)		(0.08	)		(0.04	)		0.01			(0.01	)
Net realized and unrealized gain (loss)		1.11			1.09			1.33			1.24			(1.98	)		(1.89	)
Total from investment operations		1.11			1.04			1.25			1.20			(1.97	)		(1.90	)
Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00			0.00			0.00			0.00			0.00			0.00
Distributions from net realized gain		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Tax return of capital distribution		0.00			0.00			0.00			0.00			0.00			0.00
Total dividends and/or distributions to shareholders		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Net asset value, end of period	$	13.96		$	12.85		$	11.81		$	10.56		$	9.36		$	11.36
Total Return, at Net Asset Value4		8.64	%		8.81	%		11.84	%		12.82	%		(17.32	)%		(14.29	)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	83,520		$	93,397		$	120,245		$	150,292		$	185,921		$	307,836
Average net assets (in thousands)	$	87,769		$	103,801		$	141,973		$	172,970		$	196,338		$	418,258
Ratios to average net assets:5
Net investment income (loss)		0.06	%		(0.44	)%		(0.69	)%		(0.35	)%		0.16	%		(0.07	)%
Total expenses6		2.22	%		2.23	%		2.20	%		2.23	%		2.18	%		1.90	%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		2.14	%		2.08	%		2.05	%		2.06	%		2.04	%		1.90	%
Portfolio turnover rate		19	%		37	%		58	%		66	%		124	%		146	%

OPPENHEIMER MAIN STREET SELECT FUND 19

FINANCIAL HIGHLIGHTS    (Continued)

1. July 29, 2011 and July 30, 2010 represent the last business days of the Fund’s respective reporting periods.

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

Six Months Ended January 31, 2013	2.22	%
Year Ended July 31, 2012	2.23	%
Year Ended July 29, 2011	2.20	%
Year Ended July 30, 2010	2.23	%
Year Ended July 31, 2009	2.18	%
Year Ended July 31, 2008	1.90	%

See accompanying Notes to Financial Statements.

20 OPPENHEIMER MAIN STREET SELECT FUND

Class C	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012			Year Ended July 29, 20111			Year Ended July 30, 20101			Year Ended July 31, 2009			Year Ended July 31, 2008
Per Share Operating Data
Net asset value, beginning of period	$	12.95		$	11.90		$	10.63		$	9.42		$	11.41		$	14.78
Income (loss) from investment operations:
Net investment income (loss)2		0.02			(0.04	)		(0.07	)		(0.03	)		0.02			0.00	3
Net realized and unrealized gain (loss)		1.12			1.09			1.34			1.24			(1.98	)		(1.90	)
Total from investment operations		1.14			1.05			1.27			1.21			(1.96	)		(1.90	)
Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00			0.00			0.00			0.00			0.00			(0.02	)
Distributions from net realized gain		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Tax return of capital distribution		0.00			0.00			0.00			0.00			0.00			0.00
Total dividends and/or distributions to shareholders		0.00			0.00			0.00			0.00			(0.03	)		(1.47	)
Net asset value, end of period	$	14.09		$	12.95		$	11.90		$	10.63		$	9.42		$	11.41
Total Return, at Net Asset Value4		8.80	%		8.82	%		11.95	%		12.85	%		(17.16	)%		(14.24	)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	249,266		$	241,730		$	266,186		$	282,261		$	297,329		$	479,789
Average net assets (in thousands)	$	245,074		$	241,841		$	290,329		$	299,670		$	307,891		$	604,615
Ratios to average net assets:5
Net investment income (loss)		0.25	%		(0.34	)%		(0.60	)%		(0.30	)%		0.21	%		(0.01	)%
Total expenses6		1.95	%		1.98	%		1.95	%		2.00	%		2.02	%		1.83	%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.95	%		1.98	%		1.95	%		2.00	%		1.99	%		1.83	%
Portfolio turnover rate		19	%		37	%		58	%		66	%		124	%		146	%

OPPENHEIMER MAIN STREET SELECT FUND 21

FINANCIAL HIGHLIGHTS    (Continued)

1. July 29, 2011 and July 30, 2010 represent the last business days of the Fund’s respective reporting periods.

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

Six Months Ended January 31, 2013	1.95	%
Year Ended July 31, 2012	1.98	%
Year Ended July 29, 2011	1.95	%
Year Ended July 30, 2010	2.00	%
Year Ended July 31, 2009	2.02	%
Year Ended July 31, 2008	1.83	%

See accompanying Notes to Financial Statements.

22 OPPENHEIMER MAIN STREET SELECT FUND

Class N	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012			Year Ended July 29, 20111			Year Ended July 30, 20101			Year Ended July 31, 2009			Year Ended July 31, 2008
Per Share Operating Data
Net asset value, beginning of period	$	13.39		$	12.25		$	10.89		$	9.62		$	11.69		$	15.12
Income (loss) from investment operations:
Net investment income (loss)2		0.05			0.01			(0.02	)		0.02			0.06			0.05
Net realized and unrealized gain (loss)		1.15			1.13			1.38			1.27			(2.04	)		(1.94	)
Total from investment operations		1.20			1.14			1.36			1.29			(1.98	)		(1.89	)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.05	)		0.00			0.00			(0.01	)		(0.06	)		(0.09	)
Distributions from net realized gain		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Tax return of capital distribution		0.00			0.00			0.00			(0.01	)		0.00			0.00
Total dividends and/or distributions to shareholders		(0.05	)		0.00			0.00			(0.02	)		(0.09	)		(1.54	)
Net asset value, end of period	$	14.54		$	13.39		$	12.25		$	10.89		$	9.62		$	11.69
Total Return, at Net Asset Value3		9.01	%		9.31	%		12.49	%		13.42	%		(16.83	)%		(13.91	)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	89,003		$	90,631		$	94,814		$	96,516		$	95,203		$	129,855
Average net assets (in thousands)	$	92,214		$	90,581		$	101,524		$	99,801		$	92,119		$	141,529
Ratios to average net assets:4
Net investment income (loss)		0.70	%		0.10	%		(0.16	)%		0.18	%		0.68	%		0.38	%
Total expenses5		1.49	%		1.54	%		1.51	%		1.56	%		1.61	%		1.43	%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.49	%		1.54	%		1.50	%		1.52	%		1.51	%		1.43	%
Portfolio turnover rate		19	%		37	%		58	%		66	%		124	%		146	%

OPPENHEIMER MAIN STREET SELECT FUND 23

FINANCIAL HIGHLIGHTS    (Continued)

1. July 29, 2011 and July 30, 2010 represent the last business days of the Fund’s respective reporting periods.

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:

Six Months Ended January 31, 2013	1.49	%
Year Ended July 31, 2012	1.54	%
Year Ended July 29, 2011	1.51	%
Year Ended July 30, 2010	1.56	%
Year Ended July 31, 2009	1.61	%
Year Ended July 31, 2008	1.43	%

See accompanying Notes to Financial Statements.

24 OPPENHEIMER MAIN STREET SELECT FUND

Class Y	Six Months Ended January 31, 2013 (Unaudited)			Year Ended July 31, 2012			Year Ended July 29, 20111			Year Ended July 30, 20101			Year Ended July 31, 2009			Year Ended July 31, 2008
Per Share Operating Data
Net asset value, beginning of period	$	13.95		$	12.75		$	11.27		$	9.94		$	12.11		$	15.60
Income (loss) from investment operations:
Net investment income2		0.10			0.09			0.06			0.10			0.13			0.15
Net realized and unrealized gain (loss)		1.19			1.17			1.42			1.31			(2.13	)		(2.00	)
Total from investment operations		1.29			1.26			1.48			1.41			(2.00	)		(1.85	)
Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.14	)		(0.06	)		0.00			(0.06	)		(0.14	)		(0.19	)
Distributions from net realized gain		0.00			0.00			0.00			0.00			(0.03	)		(1.45	)
Tax return of capital distribution		0.00			0.00			0.00			(0.02	)		0.00			0.00
Total dividends and/or distributions to shareholders		(0.14	)		(0.06	)		0.00			(0.08	)		(0.17	)		(1.64	)
Net asset value, end of period	$	15.10		$	13.95		$	12.75		$	11.27		$	9.94		$	12.11
Total Return, at Net Asset Value3		9.30	%		10.00	%		13.13	%		14.25	%		(16.22	)%		(13.26	)%
Ratios/Supplemental Data
Net assets, end of period (in thousands)	$	76,099		$	64,137		$	57,075		$	47,548		$	161,707		$	357,648
Average net assets (in thousands)	$	69,260		$	57,816		$	55,754		$	125,884		$	187,451		$	368,893
Ratios to average net assets:4
Net investment income		1.33	%		0.66	%		0.45	%		0.90	%		1.40	%		1.11	%
Total expenses5		0.86	%		0.97	%		0.87	%		0.80	%		0.78	%		0.69	%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.86	%		0.97	%		0.87	%		0.80	%		0.78	%		0.69	%
Portfolio turnover rate		19	%		37	%		58	%		66	%		124	%		146	%

OPPENHEIMER MAIN STREET SELECT FUND 25

FINANCIAL HIGHLIGHTS    (Continued)

1. July 29, 2011 and July 30, 2010 represent the last business days of the Fund’s respective reporting periods.

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:

Six Months Ended January 31, 2013	0.86	%
Year Ended July 31, 2012	0.97	%
Year Ended July 29, 2011	0.87	%
Year Ended July 30, 2010	0.80	%
Year Ended July 31, 2009	0.78	%
Year Ended July 31, 2008	0.69	%

See accompanying Notes to Financial Statements.

26 OPPENHEIMER MAIN STREET SELECT FUND

NOTES TO FINANCIAL STATEMENTS    

1. Significant Accounting Policies

Oppenheimer Main Street Select Fund (the “Fund”) is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. 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 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 will be 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 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 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 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.

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 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.

OPPENHEIMER MAIN STREET SELECT FUND 27

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

1. Significant Accounting Policies (Continued)

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.

During the fiscal year ended July 31, 2012, the Fund utilized $49,789,800 of capital loss carryforward to offset capital gains realized in that fiscal year. Details of the fiscal year ended July 31, 2012 capital loss carryforwards are included in the table below. Capital loss carryforwards with no expiration, if any, must be utilized prior to those with expiration dates. Capital losses with no expiration will be carried forward to future years if not offset by gains.

Expiring
2017	$	179,039,334
2018		394,360,923
Total	$	573,400,257

As of January 31, 2013, it is estimated that the capital loss carryforwards would be $497,397,042 expiring by 2018. The estimated capital loss carryforward represents the carryforward as of the end of the last fiscal year, increased or decreased by capital losses or gains realized in the first six months of the current fiscal year. During the six months ended January 31, 2013, it is estimated that the Fund will utilize $76,003,215 of capital loss carryforward to offset realized capital gains.

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.

28 OPPENHEIMER MAIN STREET SELECT FUND

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 January 31, 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.

1. Significant Accounting Policies (Continued)

Federal tax cost of securities	$	1,120,769,502
Gross unrealized appreciation	$	372,614,920
Gross unrealized depreciation		(2,160,792	)
Net unrealized appreciation	$	370,454,128

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. The tax character of distributions is determined as of the Fund’s fiscal year end. Therefore, a portion of the Fund’s distributions made to shareholders prior to the Fund’s fiscal year end may ultimately be categorized as a tax return of capital.

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 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,

OPPENHEIMER MAIN STREET SELECT FUND 29

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

1. Significant Accounting Policies (Continued)

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 price on the prior trading day, if it is within the spread of the current day’s closing “bid” and

30 OPPENHEIMER MAIN STREET SELECT FUND

2. Securities Valuation (Continued)

“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

OPPENHEIMER MAIN STREET SELECT FUND 31

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

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 SELECT 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 January 31, 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	$	157,258,464	$	—	$	—	$	157,258,464
Consumer Staples		178,825,702		—		—		178,825,702
Energy		139,325,109		—		—		139,325,109
Financials		289,760,140		—		—		289,760,140
Health Care		183,985,337		—		—		183,985,337
Industrials		148,371,350		—		—		148,371,350
Information Technology		268,891,616		—		—		268,891,616
Materials		28,277,172		—		—		28,277,172
Telecommunication Services		41,585,253		—		—		41,585,253
Investment Companies		54,943,487		—		—		54,943,487
Total Assets	$	1,491,223,630	$	—	$	—	$	1,491,223,630

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.

There have been no significant changes to the fair valuation methodologies of the Fund during the period.

3. Shares of Beneficial Interest

The Fund has authorized an unlimited number of $0.001 par value shares of beneficial interest of each class. Transactions in shares of beneficial interest were as follows:

	Six Months Ended January 31, 2013						Year Ended July 31, 2012
	Shares			Amount			Shares			Amount
Class A
Sold		4,243,884		$	60,518,515			8,522,552		$	110,338,425
Dividends and/or distributions reinvested		436,370			6,144,081			146,848			1,748,956
Redeemed		(7,574,032	)		(108,052,222	)		(17,407,450	)		(220,554,135	)
Net decrease		(2,893,778	)	$	(41,389,626	)		(8,738,050	)	$	(108,466,754	)

OPPENHEIMER MAIN STREET SELECT FUND 33

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

3. Shares of Beneficial Interest (Continued)

	Six Months Ended January 31, 2013						Year Ended July 31, 2012
	Shares			Amount			Shares			Amount
Class B
Sold		47,653		$	638,723			818,078		$	9,887,618
Dividends and/or distributions reinvested		—			—			—			—
Redeemed		(1,333,026	)		(17,773,010	)		(3,729,931	)		(45,188,664	)
Net decrease		(1,285,373	)	$	(17,134,287	)		(2,911,853	)	$	(35,301,046	)
Class C
Sold		877,574		$	11,880,825			1,786,282		$	21,851,094
Dividends and/or distributions reinvested		—			—			—			—
Redeemed		(1,841,774	)		(24,841,654	)		(5,501,974	)		(65,531,624	)
Net decrease		(964,200	)	$	(12,960,829	)		(3,715,692	)	$	(43,680,530	)
Class N
Sold		669,264		$	9,281,992			1,497,364		$	18,803,912
Dividends and/or distributions reinvested		24,246			333,867			—			—
Redeemed		(1,339,278	)		(18,706,344	)		(2,473,093	)		(31,001,261	)
Net decrease		(645,768	)	$	(9,090,485	)		(975,729	)	$	(12,197,349	)
Class Y
Sold		1,003,301		$	14,608,816			1,377,212		$	18,032,752
Dividends and/or distributions reinvested		44,392			634,368			22,842			276,391
Redeemed		(607,251	)		(8,837,265	)		(1,278,746	)		(16,497,483	)
Net increase		440,442		$	6,405,919			121,308		$	1,811,660

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 six months ended January 31, 2013, were as follows:

	Purchases		Sales
Investment securities		$278,433,844		$337,624,903

34 OPPENHEIMER MAIN STREET SELECT FUND

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:

5. Fees and Other Transactions with Affiliates (Continued)

Fee Schedule
Up to $200 million	0.75	%
Next $200 million	0.72
Next $200 million	0.69
Next $200 million	0.66
Next $4.2 billion	0.60
Over $5 billion	0.58

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”) will serve as the transfer and shareholder servicing agent for the Fund. The Fund pays the Transfer Agent a per account fee.

Additionally, Class Y shares are subject to minimum fees of $10,000 annually for assets of $10 million or more. The Class Y shares are subject to the minimum fees in the event that the per account fee does not equal or exceed the applicable minimum fees. The Transfer Agent may voluntarily waive the minimum fees.

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 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

OPPENHEIMER MAIN STREET SELECT FUND 35

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

5. Fees and Other Transactions with Affiliates (Continued)

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 December 31, 2012 were as follows:

Class C	$	8,352,571
Class N		2,736,058

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. 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.

Six Months 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
January 31, 2013		$137,868		$78		$55,753		$4,712		$36

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 six months ended January 31, 2013, the Manager waived fees and/or reimbursed the Fund $8,429 for IMMF management fees.

36 OPPENHEIMER MAIN STREET SELECT FUND

5. Fees and Other Transactions with Affiliates (Continued)

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; this limit also applied to Class A shares prior to October 1, 2012. Effective October 1, 2012, OFS has voluntarily agreed to limit its fees for Class A shares to 0.30% of average annual net assets of the class.

During the six months ended January 31, 2013, OFS waived transfer and shareholder servicing agent fees as follows:

Class B $34,749

Some of these undertakings may be modified or terminated at any time; some may not be modified or terminated until after one year from the date of the current prospectus, as indicated therein.

6. Pending Litigation

Since 2009, a number of class action lawsuits have been pending in federal courts against OFI, OppenheimerFunds Distributor, Inc., the Fund’s principal underwriter and distributor (the “Distributor”), and certain funds (but not including the Fund) advised by the Manager and distributed by the Distributor (the “Defendant Funds”). Several of these 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.

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

OPPENHEIMER MAIN STREET SELECT FUND 37

NOTES TO FINANCIAL STATEMENTS    Unaudited / (Continued)

6. Pending Litigation (Continued)

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 OFI, an affiliate of OFI and 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 against the defendants and seek compensatory damages, costs and disbursements, including attorney fees. 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 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.

38 OPPENHEIMER MAIN STREET SELECT FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT

ADVISORY AGREEMENTUnaudited

Each year, the Board of Trustees (the “Board”), including a majority of the independent Trustees, is required to determine whether to renew the Fund’s investment advisory agreement (the “Agreement”). The Investment Company Act of 1940, as amended, requires that the Board request and evaluate, and that the Manager provide, such information as may be reasonably necessary to evaluate the terms of the Agreement. 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 Manager and the independent consultant provided information to the Board on the following factors: (i) the nature, quality and extent of the Manager’s services, (ii) the investment performance of the Fund and the Manager, (iii) the fees and expenses of the Fund, including comparative expense information, (iv) the profitability of the Manager and its 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 Manager from its relationship with the Fund. The Board was aware that there are alternatives to retaining the Manager.

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 Manager’s key personnel who provide such services. The Manager’s duties include providing the Fund with the services of the portfolio managers and the Manager’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 Manager is 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 Manager also provides the Fund with office space, facilities and equipment.

The Board also considered the quality of the services provided and the quality of the Manager’s resources that are available to the Fund. The Board took account of the fact that the Manager 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 Manager’s advisory, administrative, accounting, legal, compliance services and risk management, and information the Board has received regarding the experience and professional qualifications of the Manager’s 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 Anthony Gennaro, the

OPPENHEIMER MAIN STREET SELECT FUND 39

BOARD APPROVAL OF THE FUND’S INVESTMENT

ADVISORY AGREEMENTUnaudited / (Continued)

portfolio managers for the Fund, and the Manager’s investment team and analysts. The Board members also considered the totality of their experiences with the Manager as directors or trustees of the Fund and other funds advised by the Manager. The Board considered information regarding the quality of services provided by affiliates of the Manager, 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 Manager’s experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreement.

Investment Performance of the Manager and the Fund. Throughout the year, the Manager provided information on the investment performance of the Fund, including comparative performance information. The Board also reviewed information, prepared by the Manager and by the independent consultant, comparing the Fund’s historical performance to relevant market indices and to the performance of other retail front-end load and no-load large-cap core funds. The Board concluded that the Fund outperformed its performance universe median for the three- and ten-year periods, but underperformed its performance universe median for the one- and five-year periods. The Board noted a change to the Fund’s portfolio management team on May 19, 2009 and a change to the Fund’s name on November 1, 2010. The Board also considered that the Fund’s performance had improved in 2012, with year-to-date performance as of April 30, 2012 ranking in the first quintile.

Costs of Services by the Manager. The Board reviewed the fees paid to the Manager 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 Manager. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load large-cap core funds with comparable asset levels and distribution features. The Board noted that the Fund’s actual and contractual management fees, as well as its total expenses were higher than that of the respective expense group median and average. The Board considered that actual management fees are less than two basis points higher than the expense group median.

Economies of Scale and Profits Realized by the Manager. The Board considered information regarding the Manager’s costs in serving as the Fund’s investment adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Manager’s profitability from its relationship with the Fund. The Board reviewed whether the Manager may realize economies of scale in managing and supporting the Fund. The Board concluded 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.

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

40 OPPENHEIMER MAIN STREET SELECT 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 Manager 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 Agreement. In addition, the Board, including a majority of the Independent Trustees, approved the restructuring of the Fund’s investment advisory arrangement so that effective January 1, 2013, (i) OFI Global Asset Management, Inc. (“OFI Global”), a wholly owned subsidiary of the Manager, will serve as the investment adviser to the Fund in place of the Manager under a Restated Advisory Agreement (“Restated Advisory Agreement”), and (ii) OFI Global will enter into a Sub-Advisory Agreement (“Sub-Advisory Agreement”) with the Manager to provide investment sub-advisory services to the Fund. OFI Global will pay the Manager a percentage of the net investment advisory fee (after all applicable waivers have been deducted) that it receives from the Fund. The Agreement will continue until the earlier of August 31, 2013 or the effective date of the Restated Advisory Agreement between the Fund and OFI Global. The Restated Advisory Agreement and Sub-Advisory Agreement will continue until August 31, 2013.

The Board concluded, as to each of the factors set forth above, that renewing the Agreement, Restated Advisory Agreement and Sub-Advisory Agreement was in the best interests of the Fund and its shareholders. In arriving at its decisions, the Board did not single out 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 Agreement, Restated Advisory Agreement and Sub-Advisory Agreement, including the management fees, in light of all the surrounding circumstances.

OPPENHEIMER MAIN STREET SELECT FUND 41

PORTFOLIO PROXY VOTING POLICIES AND PROCEDURES;

UPDATES TO STATEMENTS OF INVESTMENTSUnaudited

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.

42 OPPENHEIMER MAIN STREET SELECT FUND

 OPPENHEIMER MAIN STREET SELECT FUND

Trustees and Officers	Sam Freedman, Chairman of the Board of Trustees and Trustee
	Edward L. Cameron, Trustee
	Jon S. Fossel, Trustee
	Richard F. Grabish, Trustee
	Beverly L. Hamilton, Trustee
	Victoria J. Herget, Trustee
	Robert J. Malone, Trustee
	F. William Marshall, Jr., Trustee
	Karen L. Stuckey, Trustee
	James D. Vaughn, Trustee
	William F. Glavin, Jr., Trustee, President and Principal Executive Officer
	Manind Govil, Vice President
	Anthony W. Gennaro, Jr., Vice President
	Arthur S. Gabinet, Secretary and Chief Legal Officer
	Christina M. Nasta, Vice President and Chief Business Officer
	Mark S. Vandehey, Vice President and Chief Compliance Officer
	Brian W. Wixted, Treasurer and Principal Financial & Accounting Officer
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	KPMG LLP
Counsel	K&L Gates LLP
	The financial statements included herein have been taken from the records of the Fund without examination of those records by the independent registered public accounting firm.
© 2013 OppenheimerFunds, Inc. All rights reserved.

OPPENHEIMER MAIN STREET SELECT FUND 43

 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:

l Applications or other forms

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

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

l Your transactions with us, our affiliates or others

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

l 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.

44 OPPENHEIMER MAIN STREET SELECT 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.

l 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.

l 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.

l 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).

OPPENHEIMER MAIN STREET SELECT FUND 45

Item 2. Code of Ethics.

Not applicable to semiannual reports.

Item 3. Audit Committee Financial Expert.

Not applicable to semiannual reports.

Item 4. Principal Accountant Fees and Services.

Not applicable to semiannual reports.

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 1/31/2013, 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)    Not applicable to semiannual reports.

(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 Select Fund
By:	/s/ William F. Glavin, Jr.
	William F. Glavin, Jr.
	Principal Executive Officer

Date: 3/14/2013

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: 3/14/2013

By:	/s/ Brian W. Wixted
	Brian W. Wixted
	Principal Financial Officer

Date: 3/14/2013

EX-99.CERT

Exhibit 99.CERT

Section 302 Certifications

CERTIFICATIONS

I, William F. Glavin, Jr., certify that:

1. I have reviewed this report on Form N-CSR of Oppenheimer Main Street Select Fund;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of Trustees (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: 3/14/2013

/s/ William F. Glavin, Jr.

William F. Glavin, Jr.

Principal Executive Officer

Exhibit 99.CERT

Section 302 Certifications

CERTIFICATIONS

I, Brian W. Wixted, certify that:

1. I have reviewed this report on Form N-CSR of Oppenheimer Main Street Select Fund;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of Trustees (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: 3/14/2013

/s/ Brian W. Wixted

Brian W. Wixted

Principal Financial Officer

EX-99.906CERT

EX-99.906CERT

Section 906 Certifications

CERTIFICATION PURSUANT TO 18 U.S.C SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

William F. Glavin, Jr., Principal Executive Officer, and Brian W. Wixted, Principal Financial Officer, of Oppenheimer Main Street Select Fund (the “Registrant”), each certify to the best of his knowledge that:

1. The Registrant’s periodic report on Form N-CSR for the period ended 1/31/2013 (the “Form N-CSR”) fully complies with the requirements of Section 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Form N-CSR fairly presents, in all material respects, the financial condition and results of operations of the Registrant. This certification is being furnished to the Commission solely pursuant to 18 U.S.C. § 1350 and is not being filed as part of the Form N-CSR filed with the Commission.

Principal Executive Officer	Principal Financial Officer
Oppenheimer Main Street Select Fund	Oppenheimer Main Street Select Fund
/s/ William F. Glavin, Jr.	/s/ Brian W. Wixted
William F. Glavin, Jr.	Brian W. Wixted
Date: 3/14/2013	Date: 3/14/2013