Oppenheimer Portfolio Series

Year Ended January 31, 2018

Year Ended January 31, 2017

Year Ended January 29, 2016

Year Ended January 30, 2015

Year Ended January 31, 2014

N-CSR 1 d547649dncsr.htm OPPENHEIMER PORTFOLIO SERIES Oppenheimer Portfolio Series

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 811-21686

Oppenheimer Portfolio Series

(Exact name of registrant as specified in charter)

6803 South Tucson Way, Centennial, Colorado 80112-3924

(Address of principal executive offices) (Zip code)

Cynthia Lo Bessette

OFI Global Asset Management, Inc.

225 Liberty Street, 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: January 31

Date of reporting period: 1/31/2018

Item 1. Reports to Stockholders.

LOGO

Table of Contents



Fund Performance Discussion			3

Top Holdings and Allocations			6

Fund Expenses			9

Statement of Investments			11

Statement of Assets and Liabilities			14

Statement of Operations			16

Statements of Changes in Net Assets			18

Financial Highlights			19

Notes to Financial Statements			24

Report of Independent Registered Public Accounting Firm			35

Federal Income Tax Information			36

Board Approval of the Fund’s Investment Advisory and Sub-Advisory Agreements			37

Portfolio Proxy Voting Policies and Guidelines; Updates to Statement of Investments			40

Trustees and Officers			41

Privacy Notice			47

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 1/31/18


	Class A Shares of the Fund
	Without Sales Charge	With Sales Charge	Bloomberg Barclays U.S. Aggregate Bond Index	S&P 500 Index
1-Year	9.53%	3.23%	2.15%	26.41%

5-Year	4.51	3.28	2.01	15.91

10-Year	1.48	0.88	3.71	9.78

2 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

Fund Performance Discussion¹

MARKET OVERVIEW

Markets continued their general risk-on mode throughout 2017 and into January 2018. The U.S. economy outperformed expectations in the second half of 2017, with gross domestic product (GDP) growth exceeding the 2% trend growth rate witnessed so far during the expansion. With the economy’s continued expansion, the Federal Reserve (“Fed”) is nearing its dual mandate of full employment and price stability. While inflation has surprised to the downside for a number of months recently, the Fed believes this to be temporary and continues down its prescribed course of gradual tightening. The Fed began normalizing its balance sheet during the reporting period by discontinuing its interest reinvestment program and raised rates in December for the third time in 2017. Despite

these tightening measures, by many measures financial conditions eased in 2017.

As alluded to above, market performance was positive for most risk assets during the reporting period. Equities in the U.S. and globally performed well with the S&P 500 Index and the MSCI World Index returning 26.41% and 25.83%, respectively. Emerging market equities outperformed their developed market peers, as the MSCI Emerging Markets Index produced a return of 41.01%. U.S. Treasuries (as represented by the Bloomberg Barclays U.S. Treasury Index) generated a positive total return of 2.15%. Credit outperformed U.S. Treasuries for the year, with the Bloomberg Barclays U.S. Credit Index rising 4.84%.

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

LOGO

1. The Fund is invested in Class I shares of all underlying funds discussed in this Fund Performance Discussion.

3 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

FUND REVIEW

Against this market backdrop, the Fund’s Class A shares (without sales charge) produced a total return of 9.53%. The Fund employs a combination of sophisticated quantitative tools and qualitative analysis to seek to construct a well-diversified, globally allocated portfolio. The portfolio is allocated among OppenheimerFunds’ actively managed funds according to risk and strategically rebalanced based on market conditions. At period end, the Fund had its largest exposure to fixed-income funds. In an environment that favored equities over fixed-income, the Fund’s diversified allocation resulted in outperformance versus the Bloomberg Barclays U.S. Aggregate Bond Index’s return of 2.15% and underperformance versus the S&P 500 Index’s return of 26.41%.

Equity funds produced the strongest contribution to the Fund’s total return. All of the Fund’s domestic and foreign equity holdings provided positive returns, including its top two equity holdings: Oppenheimer Capital Appreciation Fund and Oppenheimer Value Fund. Oppenheimer Capital Appreciation Fund typically invests in large-cap U.S. growth stocks. In an environment where growth outperformed value, the underlying fund benefited. That said, value also produced positive returns this period and Oppenheimer Value Fund generated strong results. All of the underlying foreign equity funds produced positive results for the Fund this period as well, led by Oppenheimer International Growth Fund and Oppenheimer

International Equity Fund. European markets continued to outperform U.S. markets during this reporting period. This benefited both of these underlying funds, which have large allocations to Europe. Oppenheimer International Equity Fund also benefited from its exposure to Japan.

Although fixed-income underperformed equities this reporting period, the Fund did receive positive contributions from each of its fixed-income holdings, led by its exposure to Oppenheimer International Bond Fund, which typically invests in international fixed income securities in both developed and emerging market countries. This underlying fund invests in three major risk categories, or “levers” – interest rates (typically government bonds), currencies, and credit (corporate bonds and other fixed-income instruments containing credit risk). All three areas produced positive absolute results. Oppenheimer Total Return Bond Fund also performed well. This underlying fund benefited from an underweight to U.S. Treasuries relative to the Bloomberg Barclays U.S. Aggregate Bond Index, along with its exposure to both investment grade credit, high yield credit, and non-agency mortgage-backed securities (“MBS”).

In alternatives, most underlying holdings produced muted positive returns, led by Oppenheimer Global Multi Strategies Fund and Oppenheimer Fundamental Alternatives Fund. Oppenheimer Gold & Special Minerals Fund had a negative impact on performance.

4 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

In a risk-on market environment, the stocks of gold and special minerals companies underperformed.

FUND UPDATE

After the reporting period ended, Jeffrey Bennett, CFA, was named the Portfolio Manager of the Fund, effective February 27, 2018. Jeff joined OppenheimerFunds in 2016 from AllianceBernstein, where he was a Managing Director on the Alternative Investment Management team, focusing on asset allocation and portfolio construction as well as manager identification and due diligence. Previously, Jeff was director of research for Fischer & Co., a multi-family office, before which Jeff was the primary analyst at Summit Private Investments, a fund-of-hedge funds that focuses on long/ short and event-driven strategies. Jeff is a CFA^® charter holder and holds a BS in chemical engineering from the University of California, Los Angeles, as well as an MBA in analytic finance and econometrics from the University of Chicago.

5 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

Top Holdings and Allocations

ASSET CLASS ALLOCATION


Domestic Fixed Income Funds		39.6%
Domestic Equity Funds		26.5
Alternative Funds		17.5
Foreign Fixed Income Funds		11.1
Foreign Equity Funds		5.3
Money Market Funds		—*

*	Less than 0.05%.

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Total Return Bond Fund, Cl. I		24.2%
Oppenheimer Value Fund, Cl. I		11.4
Oppenheimer Capital Appreciation Fund, Cl. I		11.3
Oppenheimer International Bond Fund, Cl. I		11.1
Oppenheimer Limited-Term Government Fund, Cl. I		10.3
Oppenheimer Master Inflation Protected Securities Fund, LLC		6.6
Oppenheimer Master Loan Fund, LLC		5.0
Oppenheimer Global Multi Strategies Fund, Cl. I		4.2
Oppenheimer Real Estate Fund, Cl. I		3.0
Oppenheimer Fundamental Alternatives Fund, Cl. I		2.1

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on net assets. For more current Top 10 Fund holdings, please visit oppenheimerfunds.com.

6 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 1/31/18


	Inception Date		1-Year			5-Year			10-Year
Class A (OACIX)		4/5/05		9.53	%		4.51	%		1.48	%
Class B (OBCIX)		4/5/05		8.76			3.72			0.98
Class C (OCCIX)		4/5/05		8.69			3.74			0.72
Class R (ONCIX)		4/5/05		9.18			4.23			1.19
Class Y (OYCIX)		4/5/05		9.78			4.77			1.77

AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 1/31/18
	Inception Date		1-Year			5-Year			10-Year
Class A (OACIX)		4/5/05		3.23	%		3.28	%		0.88	%
Class B (OBCIX)		4/5/05		3.76			3.37			0.98
Class C (OCCIX)		4/5/05		7.69			3.74			0.72
Class R (ONCIX)		4/5/05		9.18			4.23			1.19
Class Y (OYCIX)		4/5/05		9.78			4.77			1.77

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 shares, the contingent deferred sales charge of 1% for the 1-year period. There is no sales charge for Class R and Class Y shares. Because Class B shares convert to Class A shares 72 months after purchase, the 10-year return for Class B shares uses Class A performance for the period after conversion. Returns for periods of less than one year are cumulative and not annualized. See Fund prospectuses and summary prospectuses for more information on share classes and sales charges.

The Fund’s performance is compared to the performance of the S&P 500 Index and the Bloomberg Barclays U.S. Aggregate Bond Index. The S&P 500 Index is a capitalization-weighted index of 500 stocks intended to be a representative sample of leading companies in leading industries within the U.S. economy. The Bloomberg Barclays U.S. Aggregate Bond Index is an index of U.S.-dollar-denominated, investment-grade U.S. corporate government and mortgage-backed securities. The indices unmanaged and cannot be purchased directly by investors. 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. Index performance includes reinvestment of income, but does not reflect transaction costs, fees, expenses or taxes. Index performance is shown for illustrative purposes only as a benchmark for the Fund’s performance, and does not predict or depict

7 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

The views in the Fund Performance Discussion represent the opinions of this Fund’s portfolio managers and are not intended as investment advice or to predict or depict the performance of any investment. These views are as of the close of business on January 31, 2018, and are subject to change based on subsequent developments. The Fund’s portfolio and strategies are subject to change.

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 PORTFOLIO SERIES CONSERVATIVE INVESTOR 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 and/or 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, 2018.

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 6 Months Ended January 31, 2018” 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 Fund’s 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). 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.

9 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Actual	Beginning Account Value August 1, 2017	Ending Account Value January 31, 2018	Expenses Paid During 6 Months Ended January 31, 2018
Class A	$ 1,000.00	$ 1,045.50	$ 2.12
Class B	1,000.00	1,042.70	6.14
Class C	1,000.00	1,042.50	5.99
Class R	1,000.00	1,044.30	3.41
Class Y	1,000.00	1,047.00	0.88
Hypothetical (5% return before expenses)
Class A	1,000.00	1,023.14	2.09
Class B	1,000.00	1,019.21	6.07
Class C	1,000.00	1,019.36	5.92
Class R	1,000.00	1,021.88	3.37
Class Y	1,000.00	1,024.35	0.87

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 funds, based on the 6-month period ended January 31, 2018 are as follows:


Class	Expense Ratios
Class A		0.41	%
Class B		1.19
Class C		1.16
Class R		0.66
Class Y		0.17

The expense ratios reflect voluntary and/or contractual 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 PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

STATEMENT OF INVESTMENTS January 31, 2018


	Shares		Value

Investment Companies—99.9%¹
Alternative Funds—17.5%
Oppenheimer Fundamental Alternatives Fund, Cl. I		485,515	$	13,604,122

Oppenheimer Global Multi Strategies Fund, Cl. I		1,155,713		26,592,946

Oppenheimer Gold & Special Minerals Fund, Cl. I		610,836		9,993,273

Oppenheimer Master Inflation Protected Securities Fund, LLC		3,517,926		42,451,488

Oppenheimer Real Estate Fund, Cl. I		793,943		19,149,912

				111,791,741

Domestic Equity Funds—26.5%
Oppenheimer Capital Appreciation Fund, Cl. I		1,068,074		72,340,644

Oppenheimer Main Street Mid Cap Fund, Cl. I		423,476		12,564,534

Oppenheimer Main Street Small Cap Fund, Cl. I		735,252		11,411,117

Oppenheimer Value Fund, Cl. I		1,833,645		73,052,415

				169,368,710

Domestic Fixed Income Funds—39.5%
Oppenheimer Limited-Term Government Fund, Cl. I		15,119,183		65,768,447

Oppenheimer Master Loan Fund, LLC		1,883,024		32,079,340

Oppenheimer Total Return Bond Fund, Cl. I		22,817,338		154,701,554

				252,549,341

Foreign Equity Funds—5.3%
Oppenheimer Developing Markets Fund, Cl. I		110,827		5,145,687

Oppenheimer International Equity Fund, Cl. I		490,134		11,478,927

Oppenheimer International Growth Fund, Cl. I		274,637		12,608,599

Oppenheimer International Small-Mid Company Fund, Cl. I		81,335		4,270,074

				33,503,287

Foreign Fixed Income Fund—11.1%
Oppenheimer International Bond Fund, Cl. I		11,588,336		70,688,848

Money Market Fund—0.0%
Oppenheimer Institutional Government Money Market Fund, Cl. E, 1.26%²		199,526		199,526

Total Investments, at Value (Cost $585,574,366)		99.9%		638,101,453

Net Other Assets (Liabilities)		0.1		594,513

Net Assets		100.0%	$	638,695,966

Footnotes to Statement of Investments

1. Is or was an affiliate, as defined in the Investment Company Act of 1940, as amended, at or during the reporting period, 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 reporting period in which the issuer was an affiliate are as follows:


	Shares January 31, 2017		Gross Additions		Gross Reductions		Shares January 31, 2018

Oppenheimer Capital Appreciation Fund, Cl. I		1,047,702		119,213		98,841		1,068,074
Oppenheimer Developing Markets Fund, Cl. I		119,978		5,306		14,457		110,827
Oppenheimer Fundamental Alternatives Fund, Cl. I		520,002		28,553		63,040		485,515
Oppenheimer Global Multi Strategies Fund, Cl. I		1,218,770		91,385		154,442		1,155,713
Oppenheimer Gold & Special Minerals Fund, Cl. I		649,773		46,330		85,267		610,836

11 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

STATEMENT OF INVESTMENTS Continued

Footnotes to Statement of Investments (Continued)


	Shares January 31, 2017		Gross Additions		Gross Reductions		Shares January 31, 2018

Oppenheimer Institutional Government Money Market Fund, Cl. E		865,415		283,794		949,683		199,526
Oppenheimer International Bond Fund, Cl. I		12,062,842		977,539		1,452,045		11,588,336
Oppenheimer International Equity Fund, Cl. I		529,090		20,180		59,136		490,134
Oppenheimer International Growth Fund, Cl. I		296,019		13,729		35,111		274,637
Oppenheimer International Small- Mid Company Fund, Cl. I		83,966		5,229		7,860		81,335
Oppenheimer Limited-Term Government Fund, Cl. I		16,199,892		960,600		2,041,309		15,119,183
Oppenheimer Main Street Mid Cap Fund, Cl. I		397,772		64,520		38,816		423,476
Oppenheimer Main Street Small Cap Fund, Cl. I		747,643		65,119		77,510		735,252
Oppenheimer Master Inflation Protected Securities Fund, LLC		3,849,228		141,470		472,772		3,517,926
Oppenheimer Master Loan Fund, LLC		2,043,568		68,754		229,298		1,883,024
Oppenheimer Real Estate Fund, Cl. I		807,449		66,361		79,867		793,943
Oppenheimer Total Return Bond Fund, Cl. I^a		24,074,319		1,583,810		2,840,791		22,817,338
Oppenheimer Value Fund, Cl. I		1,862,407		160,240		189,002		1,833,645

	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)

Oppenheimer Capital Appreciation Fund, Cl. I^b	$	72,340,644	$	247,820	$	2,444,967	$	9,309,600
Oppenheimer Developing Markets Fund, Cl. I		5,145,687		34,807		162,443		1,319,549
Oppenheimer Fundamental Alternatives Fund, Cl. I		13,604,122		266,885		35,772		290,054
Oppenheimer Global Multi Strategies Fund, Cl. I		26,592,946		1,030,883		34,286		(111,849)
Oppenheimer Gold & Special Minerals Fund, Cl. I		9,993,273		320,029		63,161		(506,268)
Oppenheimer Institutional Government Money Market Fund, Cl. E		199,526		4,398		—		—
Oppenheimer International Bond Fund, Cl. I		70,688,848		974,305		601,372		6,819,920
Oppenheimer International Equity Fund, Cl. I		11,478,927		42,187		375,614		2,584,134
Oppenheimer International Growth Fund, Cl. I		12,608,599		126,788		643,902		2,319,172
Oppenheimer International Small- Mid Company Fund, Cl. I^c		4,270,074		47,794		209,061		957,564

12 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

Footnotes to Statement of Investments (Continued)


	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)

Oppenheimer Limited-Term Government Fund, Cl. I	$	65,768,447	$	1,544,207	$	(80,726)	$	(983,166)
Oppenheimer Main Street Mid Cap Fund, Cl. I^d		12,564,534		91,813		465,581		(306,593)
Oppenheimer Main Street Small Cap Fund, Cl. I^e		11,411,117		65,651		230,880		691,700
Oppenheimer Master Inflation Protected Securities Fund, LLC		42,451,488		1,130,422^f		46,583^f		(522,874)^f
Oppenheimer Master Loan Fund, LLC		32,079,340		1,955,052^g		(121,598)^g		(112,235)^g
Oppenheimer Real Estate Fund, Cl. I^h		19,149,912		365,304		1,048,930		(1,722,296)
Oppenheimer Total Return Bond Fund, Cl. I^a		154,701,554		5,014,810		1,360,858		(792,202)
Oppenheimer Value Fund, Cl. Iⁱ		73,052,415		939,240		3,533,739		4,812,324

Total	$	638,101,453	$	14,202,395	$	11,054,825	$	24,046,534

a. Prior to June 1, 2017, this fund was named Oppenheimer Core Bond Fund.

b. This fund distributed realized gains of $5,388,012.

c. This fund distributed realized gains of $86,474.

d. This fund distributed realized gains of $1,403,900.

e. This fund distributed realized gains of $565,694.

f. Represents the amount allocated to the Fund from Oppenheimer Master Inflation Protected Securities Fund, LLC.

g. Represents the amount allocated to the Fund from Oppenheimer Master Loan Fund, LLC.

h. This fund distributed realized gains of $696,158.

i. This fund distributed realized gains of $2,936,277.

2. Rate shown is the 7-day yield at period end.

See accompanying Notes to Financial Statements.

13 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

STATEMENT OF ASSETS AND LIABILITIES January 31, 2018


Assets
Investments, at value—see accompanying statement of investments—affiliated companies (cost $585,574,366)	$	638,101,453
Cash		993,957
Receivables and other assets:
Dividends		815,138
Shares of beneficial interest sold		456,349
Investments sold		357,258
Other		32,046
Total assets		640,756,201
Liabilities
Payables and other liabilities:
Shares of beneficial interest redeemed		1,040,385
Investments purchased		814,884
Distribution and service plan fees		134,596
Trustees’ compensation		35,718
Shareholder communications		6,334
Other		28,318
Total liabilities		2,060,235
Net Assets	$	638,695,966


Composition of Net Assets
Par value of shares of beneficial interest	$	66,222
Additional paid-in capital		649,913,196
Accumulated net investment income		4,021,462
Accumulated net realized loss on investments		(67,832,001)
Net unrealized appreciation on investments		52,527,087
Net Assets	$	638,695,966

14 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Net Asset Value Per Share

Class A Shares:

Net asset value and redemption price per share (based on net assets of $445,731,721 and 46,091,101 shares of beneficial interest outstanding)		$9.67

Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)		$10.26

Class B Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $1,874,378 and 190,749 shares of beneficial interest outstanding)		$9.83

Class C Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $139,290,096 and 14,576,075 shares of beneficial interest outstanding)		$9.56

Class R Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $45,605,307 and 4,726,289 shares of beneficial interest outstanding)		$9.65

Class Y Shares:

Net asset value, redemption price and offering price per share (based on net assets of $6,194,464 and 638,007 shares of beneficial interest outstanding)		$9.71

See accompanying Notes to Financial Statements.

15 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

STATEMENT OF

OPERATIONS For the Year Ended January 31, 2018




Allocation of Income and Expenses from Master Funds¹
Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC:
Interest	$	1,127,457
Dividends		2,965
Net expenses		(208,823)

Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC		921,599


Net investment income allocated from Oppenheimer Master Loan Fund, LLC:
Interest		1,905,884
Dividends		49,168
Net expenses		(116,527)
Net investment income allocated from Oppenheimer Master Loan Fund, LLC		1,838,525

Total allocation of net investment income from master funds		2,760,124


Investment Income
Dividends from affiliated companies		11,116,921


Interest		7,992

Total investment income		11,124,913


Expenses
Distribution and service plan fees:
Class A		1,078,781
Class B		39,136
Class C		1,404,347
Class R		218,088

Transfer and shareholder servicing agent fees:
Class A		960,142
Class B		8,601
Class C		307,605
Class R		96,199
Class Y		12,672

Shareholder communications:
Class A		13,800
Class B		682
Class C		4,490
Class R		953
Class Y		155

Trustees’ compensation		8,596

Custodian fees and expenses		3,821

Other		53,602

Total expenses		4,211,670
Less waivers and reimbursements of expenses		(731,108)

Net expenses		3,480,562


Net Investment Income		10,404,475

16 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND




Realized and Unrealized Gain (Loss)
Net realized gain on:
Investment transactions in affiliated companies	$	11,129,840
Distributions received from affiliate companies		11,076,515

Net realized gain (loss) allocated from:
Oppenheimer Master Inflation Protected Securities Fund, LLC		46,583
Oppenheimer Master Loan Fund, LLC		(121,598)

Net realized gain		22,131,340

Net change in unrealized appreciation/depreciation on investment transactions		24,681,643

Net change in unrealized appreciation/depreciation allocated from:
Oppenheimer Master Inflation Protected Securities Fund, LLC		(522,874)
Oppenheimer Master Loan Fund, LLC		(112,235)

Net change in unrealized appreciation/depreciation		24,046,534


Net Increase in Net Assets Resulting from Operations	$	56,582,349

1. The Fund invests in certain affiliated mutual funds that expect to be treated as partnerships for tax purposes. See Note 4 of the accompanying Notes.

See accompanying Notes to Financial Statements.

17 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

STATEMENTS OF CHANGES IN NET ASSETS


	Year Ended January 31, 2018		Year Ended January 31, 2017
Operations
Net investment income	$	10,404,475	$	12,447,789
Net realized gain		22,131,340		4,962,814
Net change in unrealized appreciation/depreciation		24,046,534		28,019,826
Net increase in net assets resulting from operations		56,582,349		45,430,429
Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(9,351,733)		(9,034,827)
Class B		(5,347)		(66,676)
Class C		(1,929,785)		(2,025,777)
Class R		(861,904)		(800,365)
Class Y		(153,200)		(122,045)
		(12,301,969)		(12,049,690)
Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		(13,651,741)		25,104,936
Class B		(5,059,405)		(5,277,621)
Class C		(17,926,869)		(12,054,247)
Class R		(162,889)		5,319,866
Class Y		522,312		(58,536)
		(36,278,592)		13,034,398
Net Assets
Total increase		8,001,788		46,415,137
Beginning of period		630,694,178		584,279,041
End of period (including accumulated net investment income of $4,021,462 and $3,517,720, respectively)	$	638,695,966	$	630,694,178

See accompanying Notes to Financial Statements.

18 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

FINANCIAL HIGHLIGHTS


Class A	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$9.02		$8.54		$9.07		$8.74		$8.57

Income (loss) from investment operations:
Net investment income²		0.17		0.20		0.15		0.17		0.18
Net realized and unrealized gain (loss)		0.69		0.47		(0.48)		0.31		0.14

Total from investment operations		0.86		0.67		(0.33)		0.48		0.32

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.21)		(0.19)		(0.20)		(0.15)		(0.15)

Net asset value, end of period		$9.67		$9.02		$8.54		$9.07		$8.74



Total Return, at Net Asset Value³		9.53%		7.92%		(3.68)%		5.54%		3.75%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$445,732		$428,722		$381,636		$377,253		$328,792

Average net assets (in thousands)		$440,897		$413,080		$385,849		$356,752		$321,008

Ratios to average net assets:^4,5
Net investment income		1.82%		2.22%		1.70%		1.84%		2.04%
Expenses excluding specific expenses listed below		0.53%		0.54%		0.54%		0.53%		0.52%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.53%		0.54%		0.54%		0.53%		0.52%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.42%		0.44%		0.44%		0.43%		0.41%

Portfolio turnover rate		7%		9%		10%		14%		12%

1. Represents the last business day of the Fund’s reporting period.

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. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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

See accompanying Notes to Financial Statements.

19 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class B	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$9.06		$8.54		$9.05		$8.70		$8.52

Income (loss) from investment operations:
Net investment income²		0.08		0.13		0.09		0.09		0.10
Net realized and unrealized gain (loss)		0.71		0.48		(0.49)		0.33		0.15

Total from investment operations		0.79		0.61		(0.40)		0.42		0.25

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.02)		(0.09)		(0.11)		(0.07)		(0.07)

Net asset value, end of period		$9.83		$9.06		$8.54		$9.05		$8.70



Total Return, at Net Asset Value³		8.76%		7.12%		(4.45)%		4.78%		2.90%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$1,874		$6,617		$11,285		$17,607		$23,457

Average net assets (in thousands)		$3,912		$8,872		$14,222		$20,359		$26,741

Ratios to average net assets:^4,5
Net investment income		0.82%		1.43%		0.95%		1.04%		1.16%
Expenses excluding specific expenses listed below		1.30%		1.30%		1.30%		1.28%		1.31%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		1.30%		1.30%		1.30%		1.28%		1.31%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.19%		1.20%		1.20%		1.18%		1.20%

Portfolio turnover rate		7%		9%		10%		14%		12%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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

See accompanying Notes to Financial Statements.

20 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Class C	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$8.92		$8.43		$8.96		$8.63		$8.47

Income (loss) from investment operations:
Net investment income²		0.10		0.13		0.08		0.10		0.11
Net realized and unrealized gain (loss)		0.67		0.48		(0.48)		0.32		0.14

Total from investment operations		0.77		0.61		(0.40)		0.42		0.25

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.13)		(0.12)		(0.13)		(0.09)		(0.09)

Net asset value, end of period		$9.56		$8.92		$8.43		$8.96		$8.63



Total Return, at Net Asset Value³		8.69%		7.28%		(4.48)%		4.83%		2.89%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$139,290		$147,359		$150,838		$163,041		$153,973

Average net assets (in thousands)		$141,175		$153,128		$159,469		$160,307		$154,195

Ratios to average net assets:^4,5
Net investment income		1.06%		1.47%		0.95%		1.08%		1.26%
Expenses excluding specific expenses listed below		1.28%		1.29%		1.29%		1.28%		1.28%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		1.28%		1.29%		1.29%		1.28%		1.28%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.17%		1.19%		1.19%		1.18%		1.17%

Portfolio turnover rate		7%		9%		10%		14%		12%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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

See accompanying Notes to Financial Statements.

21 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class R	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$9.01		$8.53		$9.05		$8.72		$8.55

Income (loss) from investment operations:
Net investment income²		0.15		0.18		0.13		0.14		0.15
Net realized and unrealized gain (loss)		0.67		0.47		(0.48)		0.32		0.14

Total from investment operations		0.82		0.65		(0.35)		0.46		0.29

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.18)		(0.17)		(0.17)		(0.13)		(0.12)

Net asset value, end of period		$9.65		$9.01		$8.53		$9.05		$8.72



Total Return, at Net Asset Value³		9.18%		7.71%		(3.89)%		5.28%		3.40%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$45,605		$42,716		$35,442		$42,872		$43,246

Average net assets (in thousands)		$44,190		$38,675		$39,789		$43,215		$47,223

Ratios to average net assets:^4,5
Net investment income		1.59%		1.99%		1.44%		1.58%		1.69%
Expenses excluding specific expenses listed below		0.77%		0.79%		0.79%		0.78%		0.79%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.77%		0.79%		0.79%		0.78%		0.79%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.66%		0.69%		0.69%		0.68%		0.68%

Portfolio turnover rate		7%		9%		10%		14%		12%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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

See accompanying Notes to Financial Statements.

22 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Class Y	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$9.06		$8.57		$9.10		$8.77		$8.60

Income (loss) from investment operations:
Net investment income²		0.20		0.23		0.17		0.20		0.21
Net realized and unrealized gain (loss)		0.68		0.47		(0.49)		0.31		0.14

Total from investment operations		0.88		0.70		(0.32)		0.51		0.35

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.23)		(0.21)		(0.21)		(0.18)		(0.18)

Net asset value, end of period		$9.71		$9.06		$8.57		$9.10		$8.77



Total Return, at Net Asset Value³		9.78%		8.27%		(3.54)%		5.85%		4.01%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$6,195		$5,280		$5,078		$6,947		$3,546

Average net assets (in thousands)		$5,831		$5,067		$7,659		$4,601		$3,099

Ratios to average net assets:^4,5
Net investment income		2.14%		2.52%		1.93%		2.22%		2.37%
Expenses excluding specific expenses listed below		0.28%		0.29%		0.29%		0.28%		0.27%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.28%		0.29%		0.29%		0.28%		0.27%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.17%		0.19%		0.19%		0.18%		0.16%

Portfolio turnover rate		7%		9%		10%		14%		12%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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

See accompanying Notes to Financial Statements.

23 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS January 31, 2018

1. Organization

Oppenheimer Portfolio Series (the “Trust”) is registered under the Investment Company Act of 1940 (“1940 Act”), as amended, as a diversified open-end management investment company. Conservative Investor Fund (the “Fund”) is a series of the Trust whose investment objective is to seek total return. The Fund normally invests in a diversified portfolio of Oppenheimer mutual funds (individually, an “Underlying Fund” and collectively, the “Underlying Funds”). The Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”). The Manager has entered into a sub-advisory agreement with OFI.

The Fund offers Class A, Class C, Class R and Class Y shares, and previously offered Class B shares for new purchase through June 29, 2012. Subsequent to that date, no new purchases of Class B shares are permitted, however reinvestment of dividend and/or capital gain distributions and exchanges of Class B shares into and from other Oppenheimer funds are allowed. Class A shares are sold at their offering price, which is normally net asset value plus a front-end sales charge. Class C 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 R shares are sold only through retirement plans. Retirement plans that offer Class R 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 R 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 followed in the Fund’s preparation of financial statements in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”).

2. Significant Accounting Policies

Security Valuation. All investments in securities are recorded at their estimated fair value, as described in Note 3.

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.

Dividends and Distributions to Shareholders. Dividends and distributions to

24 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

2. Significant Accounting Policies (Continued)

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

Investment Income. Dividend distributions received from the Underlying Funds are recorded on the ex-dividend date. Upon receipt of notification from an Underlying Fund, and subsequent to the ex-dividend date, some of the dividend income originally recorded by the Fund may be reclassified as a tax return of capital by reducing the cost basis of the Underlying Fund and/or increasing the realized gain on sales of investments in the Underlying Fund.

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 overdraft at a rate equal to the Prime Rate plus 0.35%. The “Reduction to custodian expenses” line item, if applicable, represents earnings on cash balances maintained by the Fund during the period. Such interest expense and other custodian fees may be paid with these earnings.

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

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

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 remains open for the three preceding fiscal reporting period ends. The Fund has analyzed its tax positions for the fiscal year ended January 31, 2018, including open tax years, and does not believe there are any uncertain tax positions requiring recognition in the Fund’s financial statements.

The tax components of capital shown in the following table represent distribution requirements the Fund must satisfy under the income tax regulations, losses the Fund may be

25 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

2. Significant Accounting Policies (Continued)

able to offset against income and gains realized in future years and unrealized appreciation or depreciation of securities and other investments for federal income tax purposes.

Undistributed

Net Investment

Income

Undistributed

Long-Term

Gain

Accumulated

Loss

Carryforward^1,2,3

Net Unrealized

Appreciation

Based on cost of

Securities and

Other Investments

for Federal Income

Tax Purposes

$3,196,428

$—

$29,867,171

$15,422,092

1. At period end, the Fund had $29,867,171 of net capital loss carryforward available to offset future realized capital gains, if any, and thereby reduce future taxable gain distributions. Details of the capital loss carryforwards are included in the table below. Capital loss carryovers with no expiration, if any, must be utilized prior to those with expiration dates.


Expiring
2019	$	29,867,171

2. During the reporting period, the Fund utilized $17,263,769 of capital loss carryforward to offset capital gains realized in that fiscal year.

3. During the previous reporting period, the Fund did not utilize any capital loss carryforward.

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 are determined in accordance with federal income tax requirements, which may differ from the character of net investment income or net realized gains presented in those financial statements in accordance with U.S. GAAP. Also, due to timing of dividends and distributions, the fiscal year in which amounts are distributed may differ from the fiscal year in which the income or net realized gain was recorded by the Fund.

Accordingly, the following amounts have been reclassified for the reporting period. Net assets of the Fund were unaffected by the reclassifications.


Increase	Increase
to Accumulated	to Accumulated Net
Net Investment	Realized Loss
Income	on Investments
$2,401,236		$2,401,236

The tax character of distributions paid during the reporting periods:


	Year Ended January 31, 2018		Year Ended January 31, 2017
Distributions paid from:
Ordinary income	$	12,301,969	$	12,049,690

26 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

2. Significant Accounting Policies (Continued)

book and tax appreciation or depreciation of securities and other investments, if applicable, is attributable to the tax deferral of losses or tax realization of financial statement unrealized gain or loss.


Federal tax cost of securities	$	622,679,361

Gross unrealized appreciation	$	30,811,367
Gross unrealized depreciation		(15,389,275)

Net unrealized appreciation	$	15,422,092

Use of Estimates. The preparation of financial statements in conformity with U.S. GAAP 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.

3. Securities Valuation

The Fund calculates the net asset value of its shares based upon the net asset value of the applicable investment companies. For each investment company, the net asset value per share for a class of shares is determined as of 4:00 P.M. eastern time, on each day the New York Stock Exchange (the “Exchange”) is open for trading, except in the case of a scheduled early closing of the Exchange, in which case the Fund will calculate net asset value of the shares as of the scheduled early closing time of the Exchange. This is calculated by dividing the value of the investment company’s net assets attributable to that class by the number of outstanding shares of that class on that day.

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 least quarterly or more frequently, if necessary.

Valuations Methods and Inputs

To determine their net asset values, the Underlying Funds’ assets are valued primarily on the basis of current market quotations as generally supplied by third party portfolio pricing services or by dealers. Such market quotations are typically based on unadjusted quoted prices in active markets for identical securities or other observable market inputs.

27 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

3. Securities Valuation (Continued)

relevant facts that are reasonably available, through either public information or information available to the Manager, when determining the fair value of a security. The methodologies used for valuing securities are not necessarily an indication of the risks associated with investing in those Underlying Funds.

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 may be 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).

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

The Fund classifies each of its investments in investment companies which are publicly offered as Level 1. Investment companies that are not publicly offered, if any, are measured using net asset value and are classified as Level 2 in the fair value hierarchy. The table below categorizes amounts that are included in the Fund’s Statement of Assets and Liabilities at period end 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:
Investment Companies	$		563,570,625	$		74,530,828	$	—	$		638,101,453

Total Assets	$		563,570,625	$		74,530,828	$	—	$		638,101,453

Forward currency exchange contracts and futures contracts, if any, are reported at their unrealized appreciation/depreciation at measurement date, which represents the change in the contract’s value from trade date. All additional assets and liabilities included in the above table are reported at their market value at measurement date.

4. Investments and Risks

28 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

4. Investments and Risks (Continued)

adviser of, and the Sub-Adviser provides investment and related advisory services to, the Underlying Funds. The Fund’s Investments in Underlying Funds are included in the Statement of Investments. Shares of Underlying Funds are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of the Underlying Funds’ expenses, including their management fee.

Each of the Underlying Funds in which the Fund invests has its own investment risks, and those risks can affect the value of the Fund’s investments and therefore the value of the Fund’s shares. To the extent that the Fund invests more of its assets in one Underlying Fund than in another, the Fund will have greater exposure to the risks of that Underlying Fund.

Investment in Oppenheimer Institutional Government 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 Government Money Market Fund (“IGMMF”) to seek current income while preserving liquidity or for defensive purposes. IGMMF is a registered open-end management investment company, regulated as a money market fund under the 1940 Act, as amended. The Manager is the investment adviser of IGMMF, and the Sub-Adviser provides investment and related advisory services to IGMMF. When applicable, the Fund’s investment in IGMMF is included in the Statement of Investments. Shares of IGMMF are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of IGMMF’s Class E expenses, including its management fee.

Investment in Oppenheimer Master Funds. Certain Underlying Funds in which the Fund invests are mutual funds registered under the 1940 Act, as amended, that expect to be treated as partnerships for tax purposes, specifically Oppenheimer Master Loan Fund, LLC (“Master Loan”) and Oppenheimer Master Inflation Protected Securities Fund, LLC (“Master Inflation Protected Securities”) (the “Master Funds”). Each Master Fund has its own investment risks, and those risks can affect the value of the Fund’s investments and therefore the value of the Fund’s shares. To the extent that the Fund invests more of its assets in one Master Fund than in another, the Fund will have greater exposure to the risks of that Master Fund.

The investment objective of Master Loan is to seek income. The investment objective of Master Inflation Protected Securities is to seek total return. The Fund’s investments in the Master Funds are included in the Statement of Investments. The Fund recognizes income and gain/(loss) on its investments in each Master Fund according to its allocated pro-rata share, based on its relative proportion of total outstanding Master Fund shares held, of the total net income earned and the net gain/(loss) realized on investments sold by the Master Funds. As a shareholder, the Fund is subject to its proportional share of the Master Funds’ expenses, including their management fee. The Fund owns 2.2% of Master Loan and 28.5% of Master Inflation Protected Securities at period end.

29 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

5. Market Risk Factors

The Fund’s investments in securities and/or financial derivatives may expose the Fund to various market risk factors:

Commodity Risk. Commodity risk relates to the change in value of commodities or commodity indexes as they relate to increases or decreases in the commodities market. Commodities are physical assets that have tangible properties. Examples of these types of assets are crude oil, heating oil, metals, livestock, and agricultural products.

Credit Risk. Credit risk relates to the ability of the issuer of debt to meet interest and principal payments, or both, as they come due. In general, lower-grade, higher-yield debt securities are subject to credit risk to a greater extent than lower-yield, higher-quality securities.

Equity Risk. Equity risk relates to the change in value of equity securities as they relate to increases or decreases in the general market.

Foreign Exchange Rate Risk. Foreign exchange rate risk relates to the change in the U.S. dollar value of a security held that is denominated in a foreign currency. The U.S. dollar value of a foreign currency denominated security will decrease as the dollar appreciates against the currency, while the U.S. dollar value will increase as the dollar depreciates against the currency.

Interest Rate Risk. Interest rate risk refers to the fluctuations in value of fixed-income securities resulting from the inverse relationship between price and yield. For example, an increase in general interest rates will tend to reduce the market value of already issued fixed-income investments, and a decline in general interest rates will tend to increase their value. In addition, debt securities with longer maturities, which tend to have higher yields, are subject to potentially greater fluctuations in value from changes in interest rates than obligations with shorter maturities.

Volatility Risk. Volatility risk refers to the magnitude of the movement, but not the direction of the movement, in a financial instrument’s price over a defined time period. Large increases or decreases in a financial instrument’s price over a relative time period typically indicate greater volatility risk, while small increases or decreases in its price typically indicate lower volatility risk.

6. 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:


	Year Ended January 31, 2018				Year Ended January 31, 2017
	Shares		Amount		Shares		Amount
Class A
Sold		6,927,441	$	64,650,066		12,265,538	$	110,019,935
Dividends and/or distributions reinvested		969,633		9,182,426		998,558		8,866,800
Redeemed		(9,321,238)		(87,484,233)		(10,445,651)		(93,781,799)

Net increase (decrease)		(1,424,164)	$	(13,651,741)		2,818,445	$	25,104,936

30 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

6. Shares of Beneficial Interest (Continued)


	Year Ended January 31, 2018				Year Ended January 31, 2017
	Shares		Amount		Shares		Amount
Class B
Sold		14,790	$	139,803		72,454	$	652,263
Dividends and/or distributions reinvested		555		5,342		7,456		66,585
Redeemed		(554,543)		(5,204,550)		(671,142)		(5,996,469)

Net decrease		(539,198)	$	(5,059,405)		(591,232)	$	(5,277,621)


Class C
Sold		2,487,610	$	22,996,790		3,477,228	$	30,675,565
Dividends and/or distributions reinvested		204,382		1,913,018		227,221		1,995,245
Redeemed		(4,642,579)		(42,836,677)		(5,060,265)		(44,725,057)

Net decrease		(1,950,587)	$	17,926,869)		(1,355,816)	$	(12,054,247)


Class R
Sold		1,474,568	$	13,805,145		1,700,052	$	15,266,241
Dividends and/or distributions reinvested		87,314		825,116		85,218		755,036
Redeemed		(1,578,886)		(14,793,150)		(1,199,298)		(10,701,411)

Net increase (decrease)		(17,004)	$	(162,889)		585,972	$	5,319,866


Class Y
Sold		491,505	$	4,610,190		344,015	$	3,074,103
Dividends and/or distributions reinvested		14,320		136,038		13,168		117,323
Redeemed		(450,688)		(4,223,916)		(366,911)		(3,249,962)

Net increase (decrease)		55,137	$	522,312		(9,728)	$	(58,536)

7. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IGMMF, for the reporting period were as follows:


	Purchases		Sales
Investment securities	$	46,638,103	$	74,421,975

8. Fees and Other Transactions with Affiliates

Management Fees. Under the investment advisory agreement, the Manager does not charge a management fee, but rather collects indirect management fees from the Fund’s investments in the Underlying Funds. The weighted indirect management fees collected from the Fund’s investment in the Underlying Funds, as a percent of average daily net assets of the Fund for the reporting period was 0.46%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.

31 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

investment management fee collected by the Manager, 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. OFI Global (the “Transfer Agent”) serves as the transfer and shareholder servicing agent for the Fund. The Fund pays the Transfer Agent a fee based on annual net assets, which shall be calculated after any applicable fee waivers. Fees incurred and average net assets for each class with respect to these services are detailed in the Statement of Operations and Financial Highlights, respectively.

Sub-Transfer Agent Fees. 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.

Trustees’ Compensation. The Fund has adopted an unfunded retirement plan (the “Plan”) for the Fund’s Independent Trustees. Benefits are based on years of service and fees paid to each Trustee during their period of service. The Plan was frozen with respect to adding new participants effective December 31, 2006 (the “Freeze Date”) and existing Plan Participants as of the Freeze Date will continue to receive accrued benefits under the Plan. Active Independent Trustees as of the Freeze Date have each elected a distribution method with respect to their benefits under the Plan.

During the reporting period, the Fund’s projected benefit obligations, payments to retired Trustees and accumulated liability were as follows:


Projected Benefit Obligations Increased		$ —
Payments Made to Retired Trustees		1,019
Accumulated Liability as of January 31, 2018		8,636

The Fund’s Board of Trustees (“Board”) 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

32 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

8. Fees and Other Transactions with Affiliates (Continued)

Fund’s assets, liabilities or net investment income per share. Amounts will be deferred until distributed in accordance with the compensation deferral plan.

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

Distribution and Service Plans for Class B, Class C and Class R Shares. The Fund has adopted Distribution and Service Plans (the “Plans”) for Class B, Class C and Class R shares pursuant to Rule 12b-1 under the 1940 Act to compensate the Distributor for distributing those share classes, maintaining accounts and providing shareholder services. 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 R shares’ daily net assets. The Fund also pays a service fee under the Plans at an annual rate of 0.25% of daily net assets. The Plans continue in effect from year to year only if the Fund’s Board of Trustees votes annually to approve their continuance at an in person meeting called for that purpose. Fees incurred by the Fund under the Plans are detailed in the Statement of Operations.

Sales Charges. Front-end sales charges and 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.


Year Ended	Class A Front-End Sales Charges Retained by Distributor		Class A Contingent Deferred Sales Charges Retained by Distributor		Class B Contingent Deferred Sales Charges Retained by Distributor		Class C Contingent Deferred Sales Charges Retained by Distributor		Class R Contingent Deferred Sales Charges Retained by Distributor
January 31, 2018		$145,882		$1,397		$3,054		$10,835		$—

Waivers and Reimbursements of Expenses. Prior to June 1, 2017, the Manager

33 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

voluntarily waived fees and/or reimbursed the Fund for certain expenses in order to limit “Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses”, (the combined direct (Fund level) and indirect (Underlying Fund level) expenses), to the annual rate of 1.25%, 2.00%, 2.00%, 1.50% and 1.00%, for Class A, Class B, Class C, Class R and Class Y, respectively. Effective June 1, 2017, this expense limitation has been removed.

Effective for the period January 1, 2017 through December 31, 2017, the Transfer Agent voluntarily waived and/or reimbursed Fund expenses in an amount equal to 0.015% of average annual net assets for Classes A, B, C, R and Y.

During the reporting period, the Transfer Agent waived fees and/or reimbursed the Fund for transfer agent and shareholder servicing agent fees as follows:


Class A	$	65,903
Class B		650
Class C		21,289
Class R		6,582
Class Y		861

The Manager has also contractually agreed to waive fees and/or reimburse certain Fund expenses at an annual rate of 0.10% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable waiver and/or expense reimbursements that may apply. During the reporting period, the Manager waived fees and/or reimbursed the Fund $635,823.

34 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareholders and Board of Trustees

Oppenheimer Portfolio Series:

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of Conservative Investor Fund, a series of Oppenheimer Portfolio Series, (the “Fund”), including the statement of investments, as of January 31, 2018, the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two year period then ended, and the related notes (collectively, the “financial statements”) and the financial highlights for each of the years in the five year period then ended. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of January 31, 2018, the results of its operations for the year then ended, the changes in its net assets for each of the years in the two year period then ended, and the financial highlights for each of the years in the five year period then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements and financial highlights. Such procedures also included confirmation of securities owned as of January 31, 2018, by correspondence with the transfer agent. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements and financial highlights. We believe that our audits provide a reasonable basis for our opinion.

KPMG LLP

We have not been able to determine the specific year that we began serving as the auditor of one or more Oppenheimer Funds investment companies, however we are aware that we have served as the auditor of one or more Oppenheimer Funds investment companies since at least 1969.

Denver, Colorado

March 23, 2018

35 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

FEDERAL INCOME TAX INFORMATION Unaudited

In early 2018, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2017.

Dividends, if any, paid by the Fund during the reporting period which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 29.09% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the reporting period which are not designated as capital gain distributions are eligible for lower individual income tax rates to the extent that the Fund has received qualified dividend income as stipulated by recent tax legislation. The maximum amount allowable but not less than $2,738,421 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2018, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the reporting period, the maximum amount allowable but not less than $6,373,042 of the ordinary distributions to be paid by the Fund qualifies as an interest related dividend.

The Fund has elected the application of Section 853 of the Internal Revenue Code to permit shareholders to take a federal income tax credit or deduction, at their option, on a per share basis. The maximum amount allowable but not less than $62,456 of foreign income taxes were paid by the Fund during the reporting period. A separate notice will be mailed to each shareholder, which will reflect the proportionate share of such foreign taxes which must be treated by shareholders as gross income for federal income tax purposes.

Gross income of the maximum amount allowable but not less than $311,085 was derived from sources within foreign countries or possessions of the United States.

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

36 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY AND SUB-ADVISORY AGREEMENTS Unaudited

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

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

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

Nature, Quality and Extent of Services. The Board considered information about the nature, quality and extent of the services provided to the Fund and information regarding the Managers’ key personnel who provide such services. The Managers’ duties include providing the Fund with the services of the portfolio managers and the Sub-Adviser’s investment team, who provide research, analysis and other advisory services in regard to the Fund’s investments; and securities trading services. OFI Global is responsible for oversight of third-party service providers; monitoring compliance with applicable Fund policies and procedures and adherence to the Fund’s investment restrictions; risk management; and oversight of the Sub-Adviser. OFI Global is also responsible for providing certain administrative services to the Fund. 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 U.S. 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. OFI Global also provides the Fund with office space, facilities and equipment.

37 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY AND SUB-ADVISORY AGREEMENTS Unaudited / Continued

The Board also considered the quality of the services provided and the quality of the Managers’ resources that are available to the Fund. The Board took account of the fact that the Sub-Adviser has 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 Managers’ advisory, administrative, accounting, legal, compliance and risk management services, among other services, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of its staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Mark Hamilton and Dokyoung Lee, the portfolio managers for the Fund, and the Sub-Adviser’s investment team and analysts. The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which the Board members have become knowledgeable about through their experiences with the Managers and in connection with the review or renewal of the Fund’s service agreements or service providers. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreements.

Investment Performance of the Managers and the Fund. Throughout the year, the Managers provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Managers and by the independent consultant, comparing the Fund’s historical performance to relevant benchmarks or market indices and to the performance of other retail funds in the allocation – 30% to 50% equity category. The Board noted that the Fund’s one-year, three-year, five-year and ten-year performance was below its category median.

Fees and Expenses of the Fund. The Board reviewed the fees paid to the Adviser and the other expenses borne by the Fund. The Board also considered the comparability of the fees charged and the services provided to the Fund to the fees and services for other clients or accounts advised by the Adviser. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load allocation – 30% to 50% equity funds with comparable asset levels and distribution features. After discussions with the Board, the Adviser has agreed to contractually waive fees and/or reimburse certain Fund expenses at an annual rate of 0.10% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable fee waivers and/or expense reimbursements that apply. This fee waiver and/or expense reimbursement may not be amended or withdrawn until one year from the date of the prospectus, unless approved by the Board. The Board noted that the Fund was charged no actual management fees, exclusive of Underlying Fund management fees, while certain peer group funds did charge direct management fees. The Board also noted that the Fund’s total expenses were lower than its peer group median and category median.

Economies of Scale and Profits Realized by the Managers. The Board considered information regarding the Managers’ costs in serving as the Fund’s investment adviser, sub-

38 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund and whether those economies of scale benefit the Fund’s shareholders at the current level of Fund assets in relation to its management fee. The Fund currently does not charge a management fee.

Other Benefits to the Managers. In addition to considering the profits realized by the Managers, the Board considered information that was provided regarding the direct and indirect benefits the Managers receive as a result of their relationship with the Fund, including compensation paid to the Managers’ affiliates.

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

Based on its review of the information it received and its evaluations described above, the Board, including a majority of the independent Trustees, decided to continue the Agreements through September 30, 2018. In arriving at its decision, the Board did not identify any factor or factors as being more important than others, but considered all of the above information, and considered the terms and conditions of the Agreements, including the management fees, in light of all the surrounding circumstances.

39 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

PORTFOLIO PROXY VOTING POLICIES AND GUIDELINES;

UPDATES TO STATEMENT OF INVESTMENTS Unaudited

The Fund has adopted Portfolio Proxy Voting Policies and Guidelines 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 Guidelines 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 www.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.

40 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited


Name, Position(s) Held with the Fund, Length of Service, Year of Birth		Principal Occupation(s) During the Past 5 Years; Other Trusteeships/ Directorships Held; Number of Portfolios in the Fund Complex Currently Overseen

INDEPENDENT TRUSTEES		The address of each Trustee in the chart below is 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Trustee serves for an indefinite term, or until his or her resignation, retirement, death or removal.

Brian F. Wruble, Chairman of the Board of Trustees (since 2007) and Trustee (since 2005) Year of Birth: 1943		Governor of Community Foundation of the Florida Keys (non-profit) (since July 2012); Director of TCP Capital, Inc. (since November 2015); Chairman Emeritus of the Board of Trustees (since August 2011), Chairman of the Board of Trustees (August 2007-August 2011), Trustee of the Board of Trustees (since August 1991) of The Jackson Laboratory (non-profit); Member of Zurich Insurance Group’s Investment Management Advisory Council (insurance) (October 2004-February 2017); Treasurer (since 2007) and Trustee (since May 1992) of the Institute for Advanced Study (non-profit educational institute); Director of Special Value Opportunities Fund, LLC (registered investment company) (affiliate of the Sub- Adviser’s parent company) (September 2004-June 2015); General Partner of Odyssey Partners, L.P. (hedge fund) (September 1995-December 2007); Special Limited Partner of Odyssey Investment Partners, LLC (private equity investment) (January 1999-September 2004). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Wruble has served on the Boards of certain Oppenheimer funds since April 2001, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Beth Ann Brown, Trustee (since 2016) Year of Birth: 1968		Advisor, Board of Advisors of Caron Engineering Inc. (since December 2014); Independent Consultant (since September 2012); held the following positions at Columbia Management Investment Advisers LLC: Head of Intermediary Distribution (2008-2012), Managing Director, Strategic Relations (2005-2008), Managing Director, Head of National Accounts (2004-2005); Senior Vice President, National Account Manager (2002-2004), Senior Vice President, Key Account Manager (1999-2002) and Vice President, Key Account Manager (1996-1999) of Liberty Funds Distributor, Inc.; President and Director, of Acton Shapleigh Youth Conservation Corps (non-profit) (since 2012); and Vice President and Director of Grahamtastic Connection (non-profit) (since May 2013). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Brown has served on the Boards of certain Oppenheimer funds since January 2016, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

Edmund P. Giambastiani, Jr., Trustee (since 2013) Year of Birth: 1948		Advisory Board Member of the Maxwell School of Citizenship and Public Affairs of Syracuse University (since April 2012); Director of Mercury Defense Systems Inc. (information technology) (August 2011-February 2013); Trustee of the U.S. Naval Academy Foundation Athletic & Scholarship Program (since November 2010); Advisory Board Member of the Massachusetts Institute of Technology Lincoln Laboratory (federally-funded research development center) (since May 2010); Director of The Boeing Company (aerospace and defense) (since October 2009); Trustee of MITRE Corporation (federally-funded research development center) (since September 2008); Independent Director of QinetiQ Group Plc (defense technology and security) (February 2008-August 2011); Chairman of Monster Worldwide, Inc. (on-line career services) (March 2015-November 2016), Director of

41 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued


Edmund P. Giambastiani, Jr., (Continued)		Monster Worldwide, Inc. (on-line career services) (February 2008-June 2011); Lead Director (June 2011-March 2015); Chairman of Alenia North America, Inc. (military and defense products) (January 2008-October 2009); Director of SRA International, Inc. (information technology and services) (January 2008-July 2011); President of Giambastiani Group LLC (national security and energy consulting) (since October 2007); United States Navy, career nuclear submarine officer (June 1970-October 2007), Vice Chairman of the Joint Chiefs of Staff (2005-October 2007), Supreme Allied Commander of NATO Commander Transformation (2003-2005), Commander, U.S. Joint Forces Command (2002-2005). Since his retirement from the U.S. Navy in October 2007, Admiral Giambastiani has also served on numerous U.S. Government advisory boards, investigations and task forces for the Secretaries of Defense, State and Interior and the Central Intelligence Agency. He recently completed serving as a federal commissioner on the Military Compensation and Retirement Modernization Commission. Oversees 56 portfolios in the OppenheimerFunds complex. Admiral Giambastiani has served on the Boards of certain Oppenheimer funds since February 2013, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Elizabeth Krentzman, Trustee (since 2014) Year of Birth: 1959		Member of the University of Florida National Board Foundation (since September 2017); Member of the Cartica Funds Board of Directors (private investment funds) (since January 2017); Member of the University of Florida College of Law Association Board of Trustees and Audit Committee Member (since April 2016); Member of University of Florida Law Advisory Board, Washington, DC Alumni Group (since 2015); Advisory Board Member of the Securities and Exchange Commission Historical Society (since 2007); held the following positions at Deloitte & Touche LLP: Principal and Chief Regulatory Advisor for Asset Management Services (2007 - 2014) and U.S. Mutual Fund Leader (2011 - 2014); General Counsel of the Investment Company Institute (trade association) (June 2004 - April 2007); held the following positions at Deloitte & Touche LLP: National Director of the Investment Management Regulatory Consulting Practice (1997 - 2004), Principal (2003 - 2004), Director (1998 - 2003) and Senior Manager (1997 - 1998); Assistant Director of the Division of Investment Management - Office of Disclosure and Investment Adviser Regulation of the U.S. Securities and Exchange Commission (1996 - 1997) and various positions with the Division of Investment Management – Office of Regulatory Policy (1991 - 1996) of the U.S. Securities and Exchange Commission; Associate at Ropes & Gray LLP (1987 – 1991). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Krentzman has served on the Boards of certain Oppenheimer funds since August 2014, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Mary F. Miller, Trustee (since 2005) Year of Birth: 1942		Trustee of International House (not-for-profit) (since June 2007); Trustee of the American Symphony Orchestra (not-for-profit) (October 1998-November 2011); and Senior Vice President and General Auditor of American Express Company (financial services company) (July 1998-February 2003). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Miller has served on the Boards of certain Oppenheimer funds since August 2004, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

42 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Joel W. Motley, Trustee (since 2005) Year of Birth: 1952		Director of Office of Finance Federal Home Loan Bank (since September 2016); Director of Greenwall Foundation (since October 2013); Member of Board and Investment Committee of The Greenwall Foundation (since April 2013); Member of the Vestry of Trinity Wall Street (since April 2012); Director of Southern Africa Legal Services Foundation (since March 2012); Board Member of Pulitzer Center for Crisis Reporting (non-profit journalism) (since March 2011); Managing Director of Public Capital Advisors, LLC (privately-held financial advisor) (since January 2006); Managing Director of Carmona Motley, Inc. (privately-held financial advisor) (since January 2002); Director of Columbia Equity Financial Corp. (privately-held financial advisor) (2002-2007); Managing Director of Carmona Motley Hoffman Inc. (privately-held financial advisor) (January 1998-December 2001); Member of the Finance and Budget Committee of the Council on Foreign Relations, Member of the Investment Committee and Board of Human Rights Watch (since July 2000) and Member of the Investment Committee and Board of Historic Hudson Valley (since February 2010). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Motley has served on the Boards of certain Oppenheimer funds since October 2002, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Joanne Pace, Trustee (since 2012) Year of Birth: 1958		Advisory Board Director of Massey Quick and Company, LLC (since October 2014); Board Director of Horizon Blue Cross Blue Shield of New Jersey (since November 2012); Advisory Board Director of The Alberleen Group LLC (since March, 2012); Board Member (since January 2015), Board Member of 100 Women in Hedge Funds (non-profit) (since January 2015); Advisory Council Member of Morgan Stanley Children’s Hospital (non-profit) (since May, 2012); Senior Advisor of SECOR Asset Management, LP (2010-2011); Managing Director and Chief Operating Officer of Morgan Stanley Investment Management (2006-2010); Partner and Chief Operating Officer of FrontPoint Partners, LLC (hedge fund) (2005-2006); held the following positions at Credit Suisse: Managing Director (2003-2005); Global Head of Human Resources and member of Executive Board and Operating Committee (2004-2005), Global Head of Operations and Product Control (2003- 2004); held the following positions at Morgan Stanley: Managing Director (1997- 2003), Controller and Principal Accounting Officer (1999-2003); Chief Financial Officer (temporary assignment) for the Oversight Committee, Long Term Capital Management (1998-1999). Lead Independent Director and Chair of the Audit and Nominating Committee of The Global Chartist Fund, LLC of Oppenheimer Asset Management (2011-2012); Board Director of Managed Funds Association (2008- 2010); Board Director of Morgan Stanley Foundation (2007-2010) and Investment Committee Chair (2008-2010). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Pace has served on the Boards of certain Oppenheimer funds since November 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

43 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued


Daniel Vandivort, Trustee (since 2014) Year of Birth: 1954		Chairman and Lead Independent Director/Trustee (March 2010-September 2014), Chairman of the Audit Committee (March 2009-September 2014) and Director/ Trustee (December 2008-September 2014) of the Board of Directors/Trustees of Value Line Funds; Trustee, Board of Trustees of Huntington Disease Foundation of America (since January 2015 and June 2007-December 2013) and Treasurer, Chairman of the Audit and Finance Committee (since January 2016); Trustee, Board of Trustees, RIM Retirement Savings Plan (2005-2007); President and Chief Investment Officer, Robeco Investment Management, formerly known as Weiss Peck and Greer (January 2005-June 2007); Member, Management Committee of Robeco Investment Management (2001-2007); Chairman and Trustee of the Board of Trustees of Weiss, Peck and Greer Funds (2004-2005); Managing Director and Head of Fixed Income, Weiss, Peck and Greer (November 1994-January 2005); Managing Director and Head of Fixed Income, CS First Boston Investment Management (January 1992-November 1994); Director, Global Product Development, First Boston Asset Management (November 1989 to January 1992); Vice President, Fixed Income Sales, First Boston Corp. (May 1984-November 1989). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Vandivort has served on the Boards of certain Oppenheimer funds since 2014, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
INTERESTED TRUSTEE AND OFFICER		Mr. Steinmetz is an “Interested Trustee” because he is affiliated with the Manager and the Sub-Adviser by virtue of his positions as Chairman of the Sub-Adviser and officer and director of the Manager. Both as a Trustee and as an officer, Mr. Steinmetz serves for an indefinite term, or until his resignation, retirement, death or removal. Mr. Steinmetz’s address is 225 Liberty Street, New York, New York 10281-1008.

Arthur P. Steinmetz, Trustee (since 2015), President and Principal Executive Officer (since 2014) Year of Birth: 1958		Chairman of the Sub-Adviser (since January 2015); CEO and Chairman of the Manager (since July 2014), President of the Manager (since May 2013), a Director of the Manager (since January 2013), Director of the Sub-Adviser (since July 2014), President, Management Director and CEO of Oppenheimer Acquisition Corp. (the Sub-Adviser’s parent holding company) (since July 2014), and President and Director of OFI SteelPath, Inc. (since January 2013). Chief Investment Officer of the OppenheimerFunds advisory entities from (January 2013-December 2013); Executive Vice President of the Manager (January 2013-May 2013); Chief Investment Officer of the Sub-Adviser (October 2010-December 2012); Chief Investment Officer, Fixed-Income, of the Sub-Adviser (April 2009-October 2010); Executive Vice President of the Sub-Adviser (October 2009-December 2012); Director of Fixed Income of the Sub-Adviser (January 2009-April 2009); and a Senior Vice President of the Sub-Adviser (March 1993-September 2009). An officer of 110 portfolios in the OppenheimerFunds complex.
OTHER OFFICERS OF THE FUND		The addresses of the Officers in the chart below are as follows: for Messrs. Hamilton, Lee, Mss. Lo Bessette, Foxson and Picciotto, 225 Liberty Street, New York, New York 10281-1008, for Mr. Petersen, 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Officer serves for an indefinite term or until his or her resignation, retirement, death or removal.

Mark Hamilton¹, Vice President (since 2013) Year of Birth: 1965		Chief Investment Officer, Asset Allocation and Senior Vice President of the Sub-Adviser (since April 2013). Mr. Hamilton served at AllianceBernstein L.P. (from 1994-2013) as an Investment Director of Dynamic Asset Allocation (from 2010-2013), Head of North American Blend Team (from 2009-2010), and Senior Portfolio Manager of Blend Strategies (from 2006-2010). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

44 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Dokyoung Lee¹, Vice President (since 2014) Year of Birth: 1965		Director of Research, Global Multi-Asset Group and a Senior Vice President of the Sub-Adviser (since October 2013). Mr. Lee served at Alliance Bernstein L.P. (1994- 2013): Director of Research for Strategic Asset Allocation (2011-2013), Director of Research for Blend Strategies (2008-2011), Head of Asia Pacific Blend Strategies (2005-2008), Head of Quantitative Research and Senior Portfolio Manager for Japan Value Equities (2001-2005), Portfolio Manager for Emerging Markets Value Equities (1997-2001), and Quantitative Analyst for US Value Equities (1994-1997). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

Cynthia Lo Bessette, Secretary and Chief Legal Officer (since 2016) Year of Birth: 1969		Executive Vice President, General Counsel and Secretary of the Manager (since February 2016); Senior Vice President and Deputy General Counsel of the Manager (March 2015-February 2016); Chief Legal Officer of the Sub-Adviser and the Distributor (since February 2016); Vice President, General Counsel and Secretary of Oppenheimer Acquisition Corp. (since February 2016); General Counsel of OFI SteelPath, Inc., OFI Advisors and Index Management Solutions, LLC (since February 2016); Chief Legal Officer of OFI Global Institutional, Inc., HarbourView Asset Management Corporation, OFI Global Trust Company, Oppenheimer Real Asset Management, Inc., OFI Private Investments Inc., Shareholder Services, Inc. and Trinity Investment Management Corporation (since February 2016); Corporate Counsel (February 2012-March 2015) and Deputy Chief Legal Officer (April 2013-March 2015) of Jennison Associates LLC; Assistant General Counsel (April 2008-September 2009) and Deputy General Counsel (October 2009-February 2012) of Lord Abbett & Co. LLC. An officer of 110 portfolios in the OppenheimerFunds complex.

Jennifer Foxson, Vice President and Chief Business Officer (since 2014) Year of Birth: 1969		Senior Vice President of OppenheimerFunds Distributor, Inc. (since June 2014); Vice President of OppenheimerFunds Distributor, Inc. (April 2006-June 2014); Vice President of the Sub-Adviser (January 1998-March 2006); Assistant Vice President of the Sub-Adviser (October 1991-December 1998). An officer of 110 portfolios in the OppenheimerFunds complex.

Mary Ann Picciotto, Chief Compliance Officer and Chief Anti-Money Laundering Officer (since 2014) Year of Birth: 1973		Senior Vice President and Chief Compliance Officer of the Manager (since March 2014); Chief Compliance Officer of the Sub-Adviser, OFI SteelPath, Inc., OFI Global Trust Company, OFI Global Institutional, Inc., Oppenheimer Real Asset Management, Inc., OFI Private Investments, Inc., Harborview Asset Management Corporation, Trinity Investment Management Corporation, and Shareholder Services, Inc. (since March 2014); Managing Director of Morgan Stanley Investment Management Inc. and certain of its various affiliated entities; Chief Compliance Officer of various Morgan Stanley Funds (May 2010-January 2014); Chief Compliance Officer of Morgan Stanley Investment Management Inc. (April 2007-January 2014). An officer of 110 portfolios in the OppenheimerFunds complex.

Brian S. Petersen, Treasurer and Principal Financial & Accounting Officer (since 2016) Year of Birth: 1970		Senior Vice President of the Manager (since January 2017); Vice President of the Manager (January 2013-January 2017); Vice President of the Sub-Adviser (February 2007-December 2012); Assistant Vice President of the Sub-Adviser (August 2002- 2007). An officer of 110 portfolios in the OppenheimerFunds complex.

1. Effective February 27, 2018, Mark Hamilton and Dokyoung Lee are no longer officers of the Fund.

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

45 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND


Manager		OFI Global Asset Management, Inc.

Sub-Adviser		OppenheimerFunds, Inc.

Distributor		OppenheimerFunds Distributor, Inc.

Transfer and Shareholder Servicing Agent		OFI Global Asset Management, Inc.

Sub-Transfer Agent		Shareholder Services, Inc. DBA OppenheimerFunds Services

Independent Registered Public Accounting Firm		KPMG LLP

Legal Counsel		Kramer Levin Naftalis & Frankel LLP

46 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

PRIVACY 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 non-public personal information about our shareholders from the following sources:

● Applications or other forms.

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

● When you enroll in eDocs Direct,^SM our electronic document delivery service.

● Your transactions with us, our affiliates or others.

● Technologies on our website, including: “cookies” and web beacons, which are used to collect data on the pages you visit and the features you use.

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 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

Copies of confirmations, account statements and other documents reporting activity in your fund accounts are made available to your financial advisor (as designated by you). 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 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.

47 OPPENHEIMER PORTFOLIO SERIES CONSERVATIVE INVESTOR FUND

PRIVACY NOTICE Continued

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.

●

All transactions conducted via our websites, including redemptions, exchanges and purchases, are secured by the highest encryption standards available. SSL is used to establish a secure connection between your PC and OppenheimerFunds’ server. It transmits information in an encrypted and scrambled format.

●

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

●

You can exit the secure area by 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, safeguard that information. Strengthening your online credentials–your online security profile–typically your user name, password, and security questions and answers, can be one of your most important lines of defense on the Internet. For additional information on how you can help prevent identity theft, visit https://www. oppenheimerfunds.com/security.

Who We Are

This joint notice describes the privacy policies of the Oppenheimer funds, OppenheimerFunds, Inc., each of its investment adviser subsidiaries, OppenheimerFunds Distributor, Inc. and OFI Global Trust Co. 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 as of November 2017. 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 this privacy policy, email us by clicking on the Contact Us section of our website at oppenheimerfunds.com, write to us at P.O. Box 5270, Denver, CO 80217-5270, or call us at 800 CALL OPP (225 5677).

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		Oppenheimer Funds^® The Right Way to Invest
Visit Us oppenheimerfunds.com Call Us 800 225 5677 Follow Us		Visit us at oppenheimerfunds.com for 24-hr access to account information and transactions or call us at 800.CALL OPP (800.225.5677) for 24-hr automated information and automated transactions. Representatives also available Mon–Fri 8am-8pm ET.

		Oppenheimer funds are distributed by OppenheimerFunds Distributor, Inc. 225 Liberty Street, New York, NY 10281-1008 © 2018 OppenheimerFunds Distributor, Inc. All rights reserved. RA0540.001.0118 March 23, 2018

LOGO

Annual Report 1/31/2018 Oppenheimer Portfolio Series Moderate Investor Fund

Table of Contents



Fund Performance Discussion			3

Top Holdings and Allocations			6

Fund Expenses			9

Statement of Investments			11

Statement of Assets and Liabilities			14

Statement of Operations			16

Statements of Changes in Net Assets			18

Financial Highlights			19

Notes to Financial Statements			24

Report of Independent Registered Public Accounting Firm			35

Federal Income Tax Information			36

Board Approval of the Fund’s Investment Advisory and Sub- Advisory Agreements			37

Portfolio Proxy Voting Policies and Guidelines; Updates to Statement of Investments			40

Distribution Sources			41

Trustees and Officers			42

Privacy Notice			48

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 1/31/18


	Class A Shares of the Fund
	Without Sales Charge	With Sales Charge	Bloomberg Barclays U.S. Aggregate Bond Index	S&P 500 Index
1-Year	16.59%	9.89%	2.15%	26.41%

5-Year	7.76	6.50	2.01	15.91

10-Year	3.61	3.00	3.71	9.78

2 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Fund Performance Discussion¹

MARKET OVERVIEW

these tightening measures, by many measures financial conditions eased in 2017.

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

LOGO

1. The Fund is invested in Class I shares of all underlying funds discussed in this Fund Performance Discussion.

3 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

FUND REVIEW

Against this market backdrop, the Fund’s Class A shares (without sales charge) produced a total return of 16.59%. The Fund employs a combination of sophisticated quantitative tools and qualitative analysis to seek to construct a well-diversified, globally allocated portfolio. The portfolio is allocated among OppenheimerFunds’ actively managed funds according to risk and strategically rebalanced based on market conditions. At period end, the Fund had its largest exposure to fixed-income funds. In an environment that favored equities over fixed-income, the Fund’s diversified allocation resulted in outperformance versus the Bloomberg Barclays U.S. Aggregate Bond Index’s return of 2.15% and underperformance versus the S&P 500 Index’s return of 26.41%.

Equity funds produced the strongest contribution to the Fund’s total return. All of the Fund’s domestic and foreign equity holdings provided positive returns, including its top two holdings: Oppenheimer Capital Appreciation Fund and Oppenheimer Value Fund. Oppenheimer Capital Appreciation Fund typically invests in large-cap U.S. growth stocks. In an environment where growth outperformed value, the underlying fund benefited. That said, value also produced positive returns this period and Oppenheimer Value Fund generated strong results. All of the underlying foreign equity funds produced positive results for the Fund this period as well, led by Oppenheimer International Growth Fund and Oppenheimer International

Equity Fund. European markets continued to outperform U.S. markets during this reporting period. This benefited both of these underlying funds, which have large allocations to Europe. Oppenheimer International Equity Fund also benefited from its exposure to Japan.

4 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

In a risk-on market environment, the stocks of gold and special minerals companies underperformed.

FUND UPDATE

5 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Top Holdings and Allocations

ASSET CLASS ALLOCATION


Domestic Equity Funds		46.8%
Domestic Fixed Income Funds		21.6
Foreign Equity Funds		17.0
Alternative Funds		8.5
Foreign Fixed Income Funds		6.0
Money Market Funds		0.1

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Value Fund, Cl. I		20.1%
Oppenheimer Capital Appreciation Fund, Cl. I		20.1
Oppenheimer Total Return Bond Fund, Cl. I		13.2
Oppenheimer International Growth Fund, Cl. I		6.3
Oppenheimer International Bond Fund, Cl. I		6.0
Oppenheimer International Equity Fund, Cl. I		5.8
Oppenheimer Limited-Term Government Fund, Cl. I		5.6
Oppenheimer Master Inflation Protected Securities Fund, LLC		3.6
Oppenheimer Main Street Mid Cap Fund, Cl. I		3.4
Oppenheimer Main Street Small Cap Fund, Cl. I		3.2

6 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 1/31/18


	Inception
	Date		1-Year			5-Year			10-Year
Class A (OAMIX)		4/5/05		16.59	%		7.76	%		3.61%
Class B (OBMIX)		4/5/05		15.74			6.94			3.10
Class C (OCMIX)		4/5/05		15.69			6.95			2.82
Class R (ONMIX)		4/5/05		16.33			7.51			3.34
Class Y (OYMIX)		4/5/05		16.91			8.04			3.91
AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 1/31/18
	Inception
	Date		1-Year			5-Year			10-Year
Class A (OAMIX)		4/5/05		9.89	%		6.50	%		3.00%
Class B (OBMIX)		4/5/05		10.74			6.63			3.10
Class C (OCMIX)		4/5/05		14.69			6.95			2.82
Class R (ONMIX)		4/5/05		16.33			7.51			3.34
Class Y (OYMIX)		4/5/05		16.91			8.04			3.91

7 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

8 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Fund Expenses

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, 2018.

9 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


	Beginning		Ending		Expenses
	Account		Account		Paid During
	Value		Value		6 Months Ended
Actual	August 1, 2017		January 31, 2018		January 31, 2018

Class A	$	1,000.00	$	1,084.50	$	2.10

Class B		1,000.00		1,080.70		6.15

Class C		1,000.00		1,080.20		6.10

Class R		1,000.00		1,083.50		3.42

Class Y		1,000.00		1,086.00		0.84

Hypothetical
(5% return before expenses)

Class A		1,000.00		1,023.19		2.04

Class B		1,000.00		1,019.31		5.97

Class C		1,000.00		1,019.36		5.92

Class R		1,000.00		1,021.93		3.32

Class Y		1,000.00		1,024.40		0.82


Class	Expense Ratios

Class A	0.40	%

Class B	1.17

Class C	1.16

Class R	0.65

Class Y	0.16

10 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

STATEMENT OF INVESTMENTS January 31, 2018


	Shares		Value

Investment Companies—99.9%¹
Alternative Funds—8.5%
Oppenheimer Fundamental Alternatives Fund, Cl. I		587,747	$	16,468,662

Oppenheimer Global Multi Strategies Fund, Cl. I		1,401,676		32,252,575

Oppenheimer Gold & Special Minerals Fund, Cl. I		736,866		12,055,125

Oppenheimer Master Inflation Protected Securities Fund, LLC		5,179,639		62,503,700

Oppenheimer Real Estate Fund, Cl. I		976,792		23,560,211

				146,840,273

Domestic Equity Funds—46.8%
Oppenheimer Capital Appreciation Fund, Cl. I		5,106,160		345,840,184

Oppenheimer Main Street Mid Cap Fund, Cl. I		1,983,854		58,860,946

Oppenheimer Main Street Small Cap Fund, Cl. I		3,563,180		55,300,555

Oppenheimer Value Fund, Cl. I		8,723,891		347,559,806

				807,561,491

Domestic Fixed Income Funds—21.6%
Oppenheimer Limited-Term Government Fund, Cl. I		22,247,133		96,775,030

Oppenheimer Master Loan Fund, LLC		2,769,703		47,184,857

Oppenheimer Total Return Bond Fund, Cl. I		33,673,455		228,306,027

				372,265,914

Foreign Equity Funds—16.9%
Oppenheimer Developing Markets Fund, Cl. I		968,366		44,961,252

Oppenheimer International Equity Fund, Cl. I		4,275,433		100,130,638

Oppenheimer International Growth Fund, Cl. I		2,383,911		109,445,333

Oppenheimer International Small-Mid Company Fund, Cl. I		715,977		37,588,781

				292,126,004

Foreign Fixed Income Fund—6.0%
Oppenheimer International Bond Fund, Cl. I		17,012,232		103,774,615

Money Market Fund—0.1%
Oppenheimer Institutional Government Money Market Fund, Cl. E, 1.26%²		1,606,449		1,606,449

Total Investments, at Value (Cost $1,362,474,158)		99.9%		1,724,174,746

Net Other Assets (Liabilities)		0.1		2,165,738

Net Assets		100.0%	$	1,726,340,484

Footnotes to Statement of Investments


	Shares		Gross		Gross		Shares
	January 31, 2017		Additions		Reductions		January 31, 2018

Oppenheimer Capital Appreciation Fund, Cl. I		4,950,190		484,755		328,785		5,106,160
Oppenheimer Developing Markets Fund, Cl. I		1,034,389		23,554		89,577		968,366
Oppenheimer Fundamental Alternatives Fund, Cl. I		619,685		21,715		53,653		587,747
Oppenheimer Global Multi Strategies Fund, Cl. I		1,453,990		78,999		131,313		1,401,676
Oppenheimer Gold & Special Minerals Fund, Cl. I		770,653		38,676		72,463		736,866

11 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

STATEMENT OF INVESTMENTS Continued

Footnotes to Statement of Investments (Continued)


	Shares		Gross		Gross			Shares
	January 31, 2017		Additions		Reductions			January 31, 2018
Oppenheimer Institutional Government Money Market Fund, Cl. E		2,401,483		183,693		978,727			1,606,449
Oppenheimer International Bond Fund, Cl. I		17,448,407		1,063,669		1,499,844			17,012,232
Oppenheimer International Equity Fund, Cl. I		4,557,278		82,774		364,619			4,275,433
Oppenheimer International Growth Fund, Cl. I		2,535,010		64,765		215,864			2,383,911
Oppenheimer International Small-Mid Company Fund, Cl. I		731,208		33,328		48,559			715,977
Oppenheimer Limited-Term Government Fund, Cl. I		23,449,648		906,869		2,109,384			22,247,133
Oppenheimer Main Street Mid Cap Fund, Cl. I		1,841,968		271,296		129,410			1,983,854
Oppenheimer Main Street Small Cap Fund, Cl. I		3,572,082		249,678		258,580			3,563,180
Oppenheimer Master Inflation Protected Securities Fund, LLC		5,576,142		91,285		487,788			5,179,639
Oppenheimer Master Loan Fund, LLC		2,962,152		44,199		236,648			2,769,703
Oppenheimer Real Estate Fund, Cl. I		979,943		64,834		67,985			976,792
Oppenheimer Total Return Bond Fund, Cl. I^a		34,989,328		1,618,823		2,934,696			33,673,455
Oppenheimer Value Fund, Cl. I		8,747,923		605,396		629,428			8,723,891

	Value		Income		Realized Gain (Loss)			Change in Unrealized Gain (Loss)
Oppenheimer Capital Appreciation Fund, Cl. I^b	$	345,840,184	$	1,178,315	$	7,702,910		$	47,950,738
Oppenheimer Developing Markets Fund, Cl. I		44,961,252		302,552		974,833			11,831,650
Oppenheimer Fundamental Alternatives Fund, Cl. I		16,468,662		320,515		28,007			359,812
Oppenheimer Global Multi Strategies Fund, Cl. I		32,252,575		1,239,921		7,935			(105,889	)
Oppenheimer Gold & Special Minerals Fund, Cl. I		12,055,125		382,792		(31,133	)		(491,756	)
Oppenheimer Institutional Government Money Market Fund, Cl. E		1,606,449		16,898		—			—
Oppenheimer International Bond Fund, Cl. I		103,774,615		1,473,221		667,312			10,077,647
Oppenheimer International Equity Fund, Cl. I		100,130,638		365,487		2,428,342			23,090,431
Oppenheimer International Growth Fund, Cl. I		109,445,333		1,092,459		3,756,320			21,651,138
Oppenheimer International Small- Mid Company Fund, Cl. I^c		37,588,781		419,030		1,227,786			8,944,795

12 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Footnotes to Statement of Investments (Continued)


	Value		Income			Realized Gain (Loss)			Change in Unrealized Gain (Loss)
Oppenheimer Limited-Term Government Fund, Cl. I	$	96,775,030	$	2,235,678		$	(114,376	)	$	(1,445,666	)
Oppenheimer Main Street Mid Cap Fund, Cl. I^d		58,860,946		428,171			1,426,717			(699,033	)
Oppenheimer Main Street Small Cap Fund, Cl. I^e		55,300,555		316,533			781,299			3,635,497
Oppenheimer Master Inflation Protected Securities Fund, LLC		62,503,700		1,615,093	^h		66,403	^h		(762,020	)^h
Oppenheimer Master Loan Fund, LLC		47,184,857		2,640,371	ⁱ		(257,913	)ⁱ		109,744	ⁱ
Oppenheimer Real Estate Fund, Cl. I^f		23,560,211		444,715			943,389			(1,769,369	)
Oppenheimer Total Return Bond Fund, Cl. I^a		228,306,027		7,278,225			1,777,869			(1,010,582	)
Oppenheimer Value Fund, Cl. I^g		347,559,806		4,428,451			11,204,632			28,208,255

Total	$	1,724,174,746	$	26,178,427		$	32,590,332		$	149,575,392

a. Prior to June 1, 2017, this fund was named Oppenheimer Core Bond Fund.

b. The fund distributed realized gains of $25,618,502.

c. The fund distributed realized gains of $758,158.

d. The fund distributed realized gains of $6,547,159.

e. The fund distributed realized gains of $2,727,431.

f. The fund distributed realized gains of $851,950.

g. The fund distributed realized gains of $13,888,921.

h. Represents the amount allocated to the Fund from Oppenheimer Master Inflation Protected Securities Fund, LLC.

i. Represents the amount allocated to the Fund from Oppenheimer Master Loan Fund, LLC.

2. Rate shown is the 7-day yield at period end.

See accompanying Notes to Financial Statements.

13 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

STATEMENT OF ASSETS AND LIABILITIES January 31, 2018



Assets
Investments, at value—see accompanying statement of investments—affiliated companies (cost $1,362,474,158)	$	1,724,174,746

Cash		1,369,876

Receivables and other assets:
Dividends		1,197,580
Shares of beneficial interest sold		1,187,363
Investments sold		1,165,365
Other		77,755

Total assets		1,729,172,685


Liabilities
Payables and other liabilities:
Investments purchased		1,207,401
Shares of beneficial interest redeemed		1,127,584
Distribution and service plan fees		360,365
Trustees’ compensation		92,984
Shareholder communications		8,706
Other		35,161

Total liabilities		2,832,201

Net Assets	$	1,726,340,484



Composition of Net Assets
Par value of shares of beneficial interest	$	137,026

Additional paid-in capital		1,384,789,055

Accumulated net investment income		11,569,929

Accumulated net realized loss on investments		(31,856,114)

Net unrealized appreciation on investments		361,700,588

Net Assets	$	1,726,340,484

14 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND



Net Asset Value Per Share
Class A Shares:

Net asset value and redemption price per share (based on net assets of $1,169,055,434 and 92,318,179 shares of beneficial interest outstanding)	$	12.66

Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	13.43


Class B Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $6,365,374 and 500,395 shares of beneficial interest outstanding)	$	12.72


Class C Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $409,417,776 and 32,981,620 shares of beneficial interest outstanding)	$	12.41


Class R Shares:

Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $123,884,398 and 9,842,388 shares of beneficial interest outstanding)	$	12.59


Class Y Shares:

Net asset value, redemption price and offering price per share (based on net assets of $17,617,502 and 1,383,737 shares of beneficial interest outstanding)	$	12.73

See accompanying Notes to Financial Statements.

15 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

STATEMENT OF

OPERATIONS For the Year Ended January 31, 2018



Allocation of Income and Expenses from Master Funds¹
Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC:
Interest	$	1,611,017
Dividends		4,076
Net expenses		(277,508)

Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC		1,337,585

Net investment income allocated from Oppenheimer Master Loan Fund, LLC:
Interest		2,572,335
Dividends		68,036
Net expenses		(153,381)

Net investment income allocated from Oppenheimer Master Loan Fund, LLC		2,486,990

Total allocation of net investment income from master funds		3,824,575


Investment Income
Dividends from affiliated companies		21,922,963

Interest		16,958

Total investment income		21,939,921


Expenses
Distribution and service plan fees:
Class A		2,646,396
Class B		137,608
Class C		3,892,996
Class R		556,316

Transfer and shareholder servicing agent fees:
Class A		2,399,821
Class B		30,197
Class C		853,482
Class R		246,324
Class Y		30,303

Shareholder communications:
Class A		20,818
Class B		1,143
Class C		6,630
Class R		1,587
Class Y		154

Trustees’ compensation		22,156

Custodian fees and expenses		9,249

Other		72,010

Total expenses		10,927,190
Less waivers and reimbursements of expenses		(1,387,722)

Net expenses		9,539,468


Net Investment Income		16,225,028

16 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND



Realized and Unrealized Gain (Loss)
Net realized gain on:
Investment transactions in affiliated companies	$	32,781,842
Distributions received from affiliate companies		50,392,121
Increase from payment by affiliate		9,256

Net realized gain (loss) allocated from:
Oppenheimer Master Inflation Protected Securities Fund, LLC		66,403
Oppenheimer Master Loan Fund, LLC		(257,913)

Net realized gain		82,991,709

Net change in unrealized appreciation/depreciation on investment transactions		150,227,668

Net change in unrealized appreciation/depreciation allocated from:
Oppenheimer Master Inflation Protected Securities Fund, LLC		(762,020)
Oppenheimer Master Loan Fund, LLC		109,744

Net change in unrealized appreciation/depreciation		149,575,392


Net Increase in Net Assets Resulting from Operations	$	248,792,129

1. The Fund invests in certain affiliated mutual funds that expect to be treated as partnerships for tax purposes. See Note 4 of the accompanying Notes.

See accompanying Notes to Financial Statements.

17 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

STATEMENTS OF CHANGES IN NET ASSETS


	Year Ended		Year Ended
	January 31, 2018		January 31, 2017

Operations
Net investment income	$	16,225,028	$	21,749,327

Net realized gain		82,991,709		34,986,302

Net change in unrealized appreciation/depreciation		149,575,392		99,274,912

Net increase in net assets resulting from operations		248,792,129		156,010,541


Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(20,616,889)		(16,442,640)
Class B		—		(98,635)
Class C		(4,479,933)		(3,351,722)
Class R		(1,913,694)		(1,411,075)
Class Y		(348,945)		(157,749)

		(27,359,461)		(21,461,821)


Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		(30,489,140)		(3,929,948)
Class B		(19,057,811)		(22,375,205)
Class C		(27,410,543)		(20,465,196)
Class R		2,568,594		4,836,032
Class Y		6,410,566		(702,551)

		(67,978,334)		(42,636,868)


Net Assets
Total increase		153,454,334		91,911,852

Beginning of period		1,572,886,150		1,480,974,298

End of period (including accumulated net investment income of $11,569,929 and $11,175,858, respectively)	$	1,726,340,484	$	1,572,886,150

See accompanying Notes to Financial Statements.

18 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

FINANCIAL HIGHLIGHTS


Class A	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$11.06		$10.13		$10.66		$10.23		$9.42

Income (loss) from investment operations:
Net investment income²		0.14		0.18		0.12		0.14		0.15
Net realized and unrealized gain (loss)		1.69		0.93		(0.57)		0.54		0.80

Total from investment operations		1.83		1.11		(0.45)		0.68		0.95

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.23)		(0.18)		(0.08)		(0.25)		(0.14)

Net asset value, end of period		$12.66		$11.06		$10.13		$10.66		$10.23



Total Return, at Net Asset Value³		16.59%		10.95%		(4.24)%		6.67%		10.00%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$1,169,055		$1,050,230		$965,539		$989,811		$888,533

Average net assets (in thousands)		$1,102,710		$1,019,024		$1,016,035		$962,358		$830,952

Ratios to average net assets:^4,5
Net investment income		1.20%		1.63%		1.15%		1.34%		1.56%
Expenses excluding specific expenses listed below		0.49%		0.51%		0.50%		0.50%		0.49%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.49%		0.51%		0.50%		0.50%		0.49%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.41%		0.44%		0.43%		0.43%		0.41%

Portfolio turnover rate		6%		7%		5%		14%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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



Year Ended January 31, 2018	1.07	%
Year Ended January 31, 2017	1.10	%
Year Ended January 29, 2016	1.07	%
Year Ended January 30, 2015	1.08	%
Year Ended January 31, 2014	1.11	%

See accompanying Notes to Financial Statements.

19 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class B	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$10.99		$10.03		$10.54		$10.10		$9.30

Income (loss) from investment operations:
Net investment income (loss)²		(0.00)³		0.08		0.08		0.04		0.06
Net realized and unrealized gain (loss)		1.73		0.92		(0.59)		0.55		0.78

Total from investment operations		1.73		1.00		(0.51)		0.59		0.84

Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00		(0.04)		0.00		(0.15)		(0.04)

Net asset value, end of period		$12.72		$10.99		$10.03		$10.54		$10.10



Total Return, at Net Asset Value⁴		15.74%		10.01%		(4.93)%		5.94%		9.07%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$6,365		$23,489		$42,689		$70,936		$95,620

Average net assets (in thousands)		$13,736		$32,210		$56,585		$84,071		$102,915

Ratios to average net assets:^5,6
Net investment income (loss)		(0.02)%		0.78%		0.77%		0.37%		0.62%
Expenses excluding specific expenses listed below		1.26%		1.27%		1.26%		1.25%		1.27%
Interest and fees from borrowings		0.00%		0.00%⁷		0.00%⁷		0.00%		0.00%

Total expenses⁸		1.26%		1.27%		1.26%		1.25%		1.27%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.18%		1.20%		1.19%		1.18%		1.19%

Portfolio turnover rate		6%		7%		5%		14%		6%

1. Represents the last business day of the Fund’s reporting period.

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. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

7. Less than 0.005%.

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




Year Ended January 31, 2018	1.84	%
Year Ended January 31, 2017	1.86	%
Year Ended January 29, 2016	1.83	%
Year Ended January 30, 2015	1.83	%
Year Ended January 31, 2014	1.89	%

See accompanying Notes to Financial Statements.

20 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


Class C	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$10.85		$9.94		$10.46		$10.04		$9.26

Income (loss) from investment operations:
Net investment income²		0.05		0.09		0.04		0.06		0.08
Net realized and unrealized gain (loss)		1.65		0.91		(0.56)		0.54		0.76

Total from investment operations		1.70		1.00		(0.52)		0.60		0.84

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.14)		(0.09)		(0.00)³		(0.18)		(0.06)

Net asset value, end of period		$12.41		$10.85		$9.94		$10.46		$10.04



Total Return, at Net Asset Value⁴		15.69%		10.12%		(4.96)%		5.93%		9.11%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$409,418		$383,848		$370,818		$388,409		$359,725

Average net assets (in thousands)		$392,056		$384,610		$393,916		$383,852		$336,609

Ratios to average net assets:^5,6
Net investment income		0.43%		0.87%		0.42%		0.57%		0.79%
Expenses excluding specific expenses listed below		1.25%		1.26%		1.25%		1.25%		1.25%
Interest and fees from borrowings		0.00%		0.00%⁷		0.00%⁷		0.00%		0.00%

Total expenses⁸		1.25%		1.26%		1.25%		1.25%		1.25%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.16%		1.19%		1.18%		1.18%		1.17%

Portfolio turnover rate		6%		7%		5%		14%		6%

1. Represents the last business day of the Fund’s reporting period.

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

3. Less than $0.005 per share.

5. Annualized for periods less than one full year.

6. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

7. Less than 0.005%.

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



Year Ended January 31, 2018	1.83	%
Year Ended January 31, 2017	1.85	%
Year Ended January 29, 2016	1.82	%
Year Ended January 30, 2015	1.83	%
Year Ended January 31, 2014	1.87	%

See accompanying Notes to Financial Statements.

21 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class R	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$11.00		$10.08		$10.60		$10.17		$9.36

Income (loss) from investment operations:
Net investment income²		0.11		0.15		0.10		0.11		0.12
Net realized and unrealized gain (loss)		1.68		0.92		(0.57)		0.54		0.80

Total from investment operations		1.79		1.07		(0.47)		0.65		0.92

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.20)		(0.15)		(0.05)		(0.22)		(0.11)

Net asset value, end of period		$12.59		$11.00		$10.08		$10.60		$10.17



Total Return, at Net Asset Value³		16.33%		10.64%		(4.45)%		6.40%		9.76%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$123,884		$105,976		$92,429		$106,271		$110,232

Average net assets (in thousands)		$113,239		$100,425		$103,861		$109,830		$111,927

Ratios to average net assets:^4,5
Net investment income		0.96%		1.38%		0.97%		1.02%		1.21%
Expenses excluding specific expenses listed below		0.74%		0.76%		0.76%		0.75%		0.74%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.74%		0.76%		0.76%		0.75%		0.74%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.66%		0.69%		0.69%		0.68%		0.66%

Portfolio turnover rate		6%		7%		5%		14%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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



Year Ended January 31, 2018	1.32	%
Year Ended January 31, 2017	1.35	%
Year Ended January 29, 2016	1.33	%
Year Ended January 30, 2015	1.33	%
Year Ended January 31, 2014	1.36	%

See accompanying Notes to Financial Statements.

22 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


Class Y	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$11.12		$10.19		$10.72		$10.28		$9.47

Income (loss) from investment operations:
Net investment income²		0.20		0.21		0.17		0.15		0.19
Net realized and unrealized gain (loss)		1.67		0.92		(0.59)		0.57		0.79

Total from investment operations		1.87		1.13		(0.42)		0.72		0.98

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.26)		(0.20)		(0.11)		(0.28)		(0.17)

Net asset value, end of period		$12.73		$11.12		$10.19		$10.72		$10.28



Total Return, at Net Asset Value³		16.91%		11.16%		(3.97)%		6.95%		10.29%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$17,618		$9,343		$9,499		$9,678		$10,023

Average net assets (in thousands)		$13,977		$7,850		$9,416		$10,303		$9,064

Ratios to average net assets:^4,5
Net investment income		1.63%		1.94%		1.61%		1.41%		1.93%
Expenses excluding specific expenses listed below		0.25%		0.26%		0.26%		0.25%		0.15%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.25%		0.26%		0.26%		0.25%		0.15%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.17%		0.19%		0.19%		0.19%		0.07%

Portfolio turnover rate		6%		7%		5%		14%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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



Year Ended January 31, 2018	0.83	%
Year Ended January 31, 2017	0.85	%
Year Ended January 29, 2016	0.83	%
Year Ended January 30, 2015	0.83	%
Year Ended January 31, 2014	0.77	%

See accompanying Notes to Financial Statements.

23 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS January 31, 2018

1. Organization

Oppenheimer Portfolio Series (the “Trust”) is registered under the Investment Company Act of 1940 (“1940 Act”), as amended, as a diversified open-end management investment company. Moderate Investor Fund (the “Fund”) is a series of the Trust whose investment objective is to seek total return. The Fund normally invests in a diversified portfolio of Oppenheimer mutual funds (individually, an “Underlying Fund” and collectively, the “Underlying Funds”). The Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”). The Manager has entered into a sub-advisory agreement with OFI.

2. Significant Accounting Policies

Security Valuation. All investments in securities are recorded at their estimated fair value, as described in Note 3.

Dividends and Distributions to Shareholders. Dividends and distributions to

24 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

2. Significant Accounting Policies (Continued)

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.

The tax components of capital shown in the following table represent distribution requirements the Fund must satisfy under the income tax regulations, losses the Fund may be

25 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

2. Significant Accounting Policies (Continued)

able to offset against income and gains realized in future years and unrealized appreciation or depreciation of securities and other investments for federal income tax purposes.


Undistributed Net Investment Income	Undistributed Long-Term Gain		Accumulated Loss Carryforward^1,2		Net Unrealized Appreciation Based on cost of Securities and Other Investments for Federal Income Tax Purposes

$10,651,438		$16,613,793		$—		$314,239,748

1. During the reporting period, the Fund utilized $51,978,404 of capital loss carryforward to offset capital gains realized in that fiscal year.

2. During the previous reporting period, the Fund utilized $22,628,117 of capital loss carryforward to offset capital gains realized in that fiscal year.

Accordingly, the following amounts have been reclassified for the reporting period. Net assets of the Fund were unaffected by the reclassifications.


Increase to Paid-in Capital	Increase to Accumulated Net Investment Income		Increase to Accumulated Net Realized Loss on Investments³

$1,579,881		$11,528,504		$13,108,385

3. $1,570,625, all of which was long-term capital gain, was distributed in connection with Fund share redemptions.

The tax character of distributions paid during the reporting periods:


	Year Ended January 31, 2018		Year Ended January 31, 2017

Distributions paid from:
Ordinary income	$	27,359,461	$	21,461,821

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 at period end 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.

26 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

2. Significant Accounting Policies (Continued)


Federal tax cost of securities	$	1,409,934,998

Gross unrealized appreciation	$	340,358,090
Gross unrealized depreciation		(26,118,342)

Net unrealized appreciation	$	314,239,748

3. Securities Valuation

Valuations Methods and Inputs

Securities for which market quotations are not readily available, or when a significant event has occurred that would materially affect the value of the security, are 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. The methodologies used for valuing securities are not necessarily an indication of the risks

27 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

3. Securities Valuation (Continued)

associated with investing in those Underlying Funds.

Classifications

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)

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).

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 at period end 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:
Investment Companies	$	1,614,486,189	$	109,688,557	$	—	$	1,724,174,746

Total Assets	$	1,614,486,189	$	109,688,557	$	—	$	1,724,174,746

4. Investments and Risks

Risks of Investing in the Underlying Funds. The Fund invests in other mutual funds advised by the Manager. The Underlying Funds are registered open-end management investment companies under the 1940 Act, as amended. The Manager is the investment adviser of, and the Sub-Adviser provides investment and related advisory services to, the Underlying Funds. The Fund’s Investments in Underlying Funds are included in the Statement

28 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

4. Investments and Risks (Continued)

of Investments. Shares of Underlying Funds are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of the Underlying Funds’ expenses, including their management fee.

Investment in Oppenheimer Institutional Government Money Market Fund.

The investment objective of Master Loan is to seek income. The investment objective of Master Inflation Protected Securities is to seek total return. The Fund’s investments in the Master Funds are included in the Statement of Investments. The Fund recognizes income and gain/(loss) on its investments in each Master Fund according to its allocated pro-rata share, based on its relative proportion of total outstanding Master Fund shares held, of the total net income earned and the net gain/(loss) realized on investments sold by the Master Funds. As a shareholder, the Fund is subject to its proportional share of the Master Funds’ expenses, including their management fee. The Fund owns 3.23% of Master Loan and 41.91% of Master Inflation Protected Securities at period end.

5. Market Risk Factors

The Fund’s investments in securities and/or financial derivatives may expose the Fund to various market risk factors:

29 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

5. Market Risk Factors (Continued)

Equity Risk. Equity risk relates to the change in value of equity securities as they relate to increases or decreases in the general market.

6. 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:


	Year Ended January 31, 2018						Year Ended January 31, 2017
	Shares			Amount			Shares			Amount

Class A
Sold		11,919,071		$	140,647,926			15,595,750		$	167,224,228
Dividends and/or distributions reinvested		1,668,411			20,337,853			1,492,315			16,191,621
Redeemed		(16,207,138	)		(191,474,919	)		(17,419,127	)		(187,345,797)

Net decrease		(2,619,656	)	$	(30,489,140	)		(331,062	)	$	(3,929,948)

30 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

6. Shares of Beneficial Interest (Continued)


	Year Ended January 31, 2018						Year Ended January 31, 2017
	Shares			Amount			Shares			Amount

Class B
Sold		9,456		$	109,719			82,511		$	867,685
Dividends and/or distributions reinvested		—			—			9,085			98,026
Redeemed		(1,645,617	)		(19,167,530	)		(2,211,637	)		(23,340,916)

Net decrease		(1,636,161	)	$	(19,057,811	)		(2,120,041	)	$	(22,375,205)



Class C
Sold		4,778,797		$	55,312,088			6,311,625		$	66,016,887
Dividends and/or distributions reinvested		372,757			4,458,180			311,293			3,315,272
Redeemed		(7,548,908	)		(87,180,811	)		(8,538,147	)		(89,797,355)

Net decrease		(2,397,354	)	$	(27,410,543	)		(1,915,229	)	$	(20,465,196)



Class R
Sold		2,562,059		$	30,159,064			2,549,789		$	27,220,994
Dividends and/or distributions reinvested		150,933			1,829,302			125,071			1,349,519
Redeemed		(2,504,989	)		(29,419,772	)		(2,209,563	)		(23,734,481)

Net increase		208,003		$	2,568,594			465,297		$	4,836,032



Class Y
Sold		998,810		$	11,809,579			536,258		$	5,826,101
Dividends and/or distributions reinvested		27,637			338,547			14,064			153,438
Redeemed		(482,715	)		(5,737,560	)		(642,301	)		(6,682,090)

Net increase (decrease)		543,732		$	6,410,566			(91,979	)	$	(702,551)

7. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IGMMF, for the reporting period were as follows:


	Purchases		Sales

Investment securities	$	99,801,020	$	129,518,133

8. Fees and Other Transactions with Affiliates

Management Fees. Under the investment advisory agreement, the Manager does not charge a management fee, but rather collects indirect management fees from the Fund’s investments in the Underlying Funds. The weighted indirect management fees collected from the Fund’s investment in the Underlying Funds, as a percent of average daily net assets of the Fund for the reporting period was 0.53%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.

31 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

investment management fee collected by the Manager, 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.

During the reporting period, the Fund’s projected benefit obligations, payments to retired Trustees and accumulated liability were as follows:


Projected Benefit Obligations Increased	$	—
Payments Made to Retired Trustees		2,688
Accumulated Liability as of January 31, 2018		22,792

32 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

8. Fees and Other Transactions with Affiliates (Continued)

Fund’s assets, liabilities or net investment income per share. Amounts will be deferred until distributed in accordance with the compensation deferral plan.


Year Ended	Class A Front-End Sales Charges Retained by Distributor		Class A Contingent Deferred Sales Charges Retained by Distributor		Class B Contingent Deferred Sales Charges Retained by Distributor		Class C Contingent Deferred Sales Charges Retained by Distributor		Class R Contingent Deferred Sales Charges Retained by Distributor

January 31, 2018		$698,138		$1,758		$13,017		$35,264		$—

Waivers and Reimbursements of Expenses. Prior to June 1, 2017, the Manager

33 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

voluntarily waived fees and/or reimbursed the Fund for certain expenses in order to limit “Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses”, (the combined direct (Fund level) and indirect (Underlying Fund level) expenses), to the annual rate of 1.30%, 2.05%, 2.05%, 1.55% and 1.05%, for Class A, Class B, Class C, Class R and Class Y, respectively. Effective June 1, 2017, this expense limitation has been removed.

During the reporting period, the Transfer Agent waived fees and/or reimbursed the Fund for transfer agent and shareholder servicing agent fees as follows:


Class A	$	163,846
Class B		2,286
Class C		58,505
Class R		16,747
Class Y		1,985

The Manager has also contractually agreed to waive fees and/or reimburse certain Fund expenses at an annual rate of 0.07% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable waiver and/or expense reimbursements that may apply. During the reporting period, the Manager waived fees and/or reimbursed the Fund $1,144,353.

During the reporting period, the Manager voluntarily reimbursed the Fund $9,256 for certain transactions. The payment is reported separately in the Statement of Operations and increased the Fund’s total returns by less than 0.005%.

34 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareholders and Board of Trustees

Oppenheimer Portfolio Series:

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of Moderate Investor Fund, a series of Oppenheimer Portfolio Series, (the “Fund”), including the statement of investments, as of January 31, 2018, the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two year period then ended, and the related notes (collectively, the “financial statements”) and the financial highlights for each of the years in the five year period then ended. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of January 31, 2018, the results of its operations for the year then ended, the changes in its net assets for each of the years in the two year period then ended, and the financial highlights for each of the years in the five year period then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

KPMG LLP

Denver, Colorado

March 23, 2018

35 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

FEDERAL INCOME TAX INFORMATION Unaudited

In early 2018, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2017.

Dividends, if any, paid by the Fund during the reporting period which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 58.51% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the reporting period which are not designated as capital gain distributions are eligible for lower individual income tax rates to the extent that the Fund has received qualified dividend income as stipulated by recent tax legislation. The maximum amount allowable but not less than $11,706,413 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2018, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the reporting period, the maximum amount allowable but not less than $8,930,375 of the ordinary distributions to be paid by the Fund qualifies as an interest related dividend.

The Fund has elected the application of Section 853 of the Internal Revenue Code to permit shareholders to take a federal income tax credit or deduction, at their option, on a per share basis. The maximum amount allowable but not less than $451,180 of foreign income taxes were paid by the Fund during the reporting period. A separate notice will be mailed to each shareholder, which will reflect the proportionate share of such foreign taxes which must be treated by shareholders as gross income for federal income tax purposes.

Gross income of the maximum amount allowable but not less than $1,829,333 was derived from sources within foreign countries or possessions of the United States.

36 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited

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

37 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited / Continued

Investment Performance of the Managers and the Fund. Throughout the year, the Managers provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Managers and by the independent consultant, comparing the Fund’s historical performance to relevant benchmarks or market indices and to the performance of other retail funds in the allocation – 50% to 70% equity category. The Board noted that the Fund’s one-year, three-year, five-year and ten-year performance was below its category median.

Fees and Expenses of the Fund. The Board reviewed the fees paid to the Adviser and the other expenses borne by the Fund. The Board also considered the comparability of the fees charged and the services provided to the Fund to the fees and services for other clients or accounts advised by the Adviser. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load allocation – 50% to 70% equity funds with comparable asset levels and distribution features. After discussions with the Board, the Adviser has agreed to contractually waive fees and/or reimburse certain Fund expenses at an annual rate of 0.07% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable fee waivers and/or expense reimbursements that apply. This contractual fee waiver and/or expense reimbursement may not be amended or withdrawn until one year from the date of the prospectus, unless approved by the Board. The Board noted that the Fund was charged no actual management fees, exclusive of Underlying Fund management fees, while certain peer group funds did charge direct management fees. The Board also noted that the Fund’s total expenses were lower than its peer group median and category median.

38 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Economies of Scale and Profits Realized by the Managers. The Board considered information regarding the Managers’ costs in serving as the Fund’s investment adviser, sub-adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund and whether those economies of scale benefit the Fund’s shareholders at the current level of Fund assets in relation to its management fee. The Fund currently does not charge a management fee.

39 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

PORTFOLIO PROXY VOTING POLICIES AND GUIDELINES;

UPDATES TO STATEMENT OF INVESTMENTS Unaudited

Householding—Delivery of Shareholder Documents

40 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

DISTRIBUTION SOURCES Unaudited

For any distribution that took place over the last six months of the Fund’s reporting period, the table below details on a per-share basis the percentage of the Fund’s total distribution payment amount that was derived from the following sources: net income, net profit from the sale of securities, and other capital sources. Other capital sources represent a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the Fund is paid back to you. A return of capital distribution does not necessarily reflect the Fund’s investment performance and should not be confused with “yield” or “income.” You should not draw any conclusions about each Fund’s investment performance from the amounts of these distributions. This information is based upon income and capital gains using generally accepted accounting principles as of the date of each distribution. Because the Fund is actively managed, the relative amount of the Fund’s total distributions derived from various sources over the calendar year may change. Please note that this information should not be used for tax reporting purposes as the tax character of distributable income may differ from the amounts used for this notification. You will receive IRS tax forms in the first quarter of each calendar year detailing the actual amount of the taxable and non-taxable portion of distributions paid to you during the tax year.

For the most current information, please go to oppenheimerfunds.com. Select your Fund, and scroll down to the ‘Dividends’ table under ‘Analytics’. The Fund’s latest distribution information will be followed by the sources of any distribution, updated daily.

Fund Name

Pay
Date

Net Income

Net Profit
from Sale

Other
Capital
Sources

Oppenheimer Portfolio Series: Moderate Investor Fund

12/20/17

99.5%

0.0%

0.5%

41 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited


Name, Position(s) Held with the Fund, Length of Service, Year of Birth		Principal Occupation(s) During the Past 5 Years; Other Trusteeships/Directorships Held; Number of Portfolios in the Fund Complex Currently Overseen

INDEPENDENT TRUSTEES		The address of each Trustee in the chart below is 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Trustee serves for an indefinite term, or until his or her resignation, retirement, death or removal.

Brian F. Wruble, Chairman of the Board of Trustees (since 2007) and Trustee (since 2005) Year of Birth: 1943		Governor of Community Foundation of the Florida Keys (non-profit) (since July 2012); Director of TCP Capital, Inc. (since November 2015); Chairman Emeritus of the Board of Trustees (since August 2011), Chairman of the Board of Trustees (August 2007-August 2011), Trustee of the Board of Trustees (since August 1991) of The Jackson Laboratory (non-profit); Member of Zurich Insurance Group’s Investment Management Advisory Council (insurance) (October 2004-February 2017); Treasurer (since 2007) and Trustee (since May 1992) of the Institute for Advanced Study (non-profit educational institute); Director of Special Value Opportunities Fund, LLC (registered investment company) (affiliate of the Sub- Adviser’s parent company) (September 2004-June 2015); General Partner of Odyssey Partners, L.P. (hedge fund) (September 1995-December 2007); Special Limited Partner of Odyssey Investment Partners, LLC (private equity investment) (January 1999-September 2004). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Wruble has served on the Boards of certain Oppenheimer funds since April 2001, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Beth Ann Brown, Trustee (since 2016) Year of Birth: 1968		Advisor, Board of Advisors of Caron Engineering Inc. (since December 2014); Independent Consultant (since September 2012); held the following positions at Columbia Management Investment Advisers LLC: Head of Intermediary Distribution (2008-2012), Managing Director, Strategic Relations (2005-2008), Managing Director, Head of National Accounts (2004-2005); Senior Vice President, National Account Manager (2002-2004), Senior Vice President, Key Account Manager (1999-2002) and Vice President, Key Account Manager (1996-1999) of Liberty Funds Distributor, Inc.; President and Director, of Acton Shapleigh Youth Conservation Corps (non-profit) (since 2012); and Vice President and Director of Grahamtastic Connection (non-profit) (since May 2013). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Brown has served on the Boards of certain Oppenheimer funds since January 2016, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

Edmund P. Giambastiani, Jr., Trustee (since 2013) Year of Birth: 1948		Advisory Board Member of the Maxwell School of Citizenship and Public Affairs of Syracuse University (since April 2012); Director of Mercury Defense Systems Inc. (information technology) (August 2011-February 2013); Trustee of the U.S. Naval Academy Foundation Athletic & Scholarship Program (since November 2010); Advisory Board Member of the Massachusetts Institute of Technology Lincoln Laboratory (federally-funded research development center) (since May 2010); Director of The Boeing Company (aerospace and defense) (since October 2009); Trustee of MITRE Corporation (federally-funded research development center) (since September 2008); Independent Director of QinetiQ Group Plc (defense technology and security) (February 2008-August 2011); Chairman of Monster Worldwide, Inc. (on-line career services) (March 2015-November 2016), Director of

42 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


Edmund P. Giambastiani, Jr., (Continued)		Monster Worldwide, Inc. (on-line career services) (February 2008-June 2011); Lead Director (June 2011-March 2015); Chairman of Alenia North America, Inc. (military and defense products) (January 2008-October 2009); Director of SRA International, Inc. (information technology and services) (January 2008-July 2011); President of Giambastiani Group LLC (national security and energy consulting) (since October 2007); United States Navy, career nuclear submarine officer (June 1970-October 2007), Vice Chairman of the Joint Chiefs of Staff (2005-October 2007), Supreme Allied Commander of NATO Commander Transformation (2003-2005), Commander, U.S. Joint Forces Command (2002-2005). Since his retirement from the U.S. Navy in October 2007, Admiral Giambastiani has also served on numerous U.S. Government advisory boards, investigations and task forces for the Secretaries of Defense, State and Interior and the Central Intelligence Agency. He recently completed serving as a federal commissioner on the Military Compensation and Retirement Modernization Commission. Oversees 56 portfolios in the OppenheimerFunds complex. Admiral Giambastiani has served on the Boards of certain Oppenheimer funds since February 2013, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Elizabeth Krentzman, Trustee (since 2014) Year of Birth: 1959		Member of the University of Florida National Board Foundation (since September 2017); Member of the Cartica Funds Board of Directors (private investment funds) (since January 2017); Member of the University of Florida College of Law Association Board of Trustees and Audit Committee Member (since April 2016); Member of University of Florida Law Advisory Board, Washington, DC Alumni Group (since 2015); Advisory Board Member of the Securities and Exchange Commission Historical Society (since 2007); held the following positions at Deloitte & Touche LLP: Principal and Chief Regulatory Advisor for Asset Management Services (2007 - 2014) and U.S. Mutual Fund Leader (2011 - 2014); General Counsel of the Investment Company Institute (trade association) (June 2004 - April 2007); held the following positions at Deloitte & Touche LLP: National Director of the Investment Management Regulatory Consulting Practice (1997 - 2004), Principal (2003 - 2004), Director (1998 - 2003) and Senior Manager (1997 - 1998); Assistant Director of the Division of Investment Management - Office of Disclosure and Investment Adviser Regulation of the U.S. Securities and Exchange Commission (1996 - 1997) and various positions with the Division of Investment Management – Office of Regulatory Policy (1991 - 1996) of the U.S. Securities and Exchange Commission; Associate at Ropes & Gray LLP (1987 – 1991). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Krentzman has served on the Boards of certain Oppenheimer funds since August 2014, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Mary F. Miller, Trustee (since 2005) Year of Birth: 1942		Trustee of International House (not-for-profit) (since June 2007); Trustee of the American Symphony Orchestra (not-for-profit) (October 1998-November 2011); and Senior Vice President and General Auditor of American Express Company (financial services company) (July 1998-February 2003). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Miller has served on the Boards of certain Oppenheimer funds since August 2004, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

43 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued


Joel W. Motley, Trustee (since 2005) Year of Birth: 1952		Director of Office of Finance Federal Home Loan Bank (since September 2016); Director of Greenwall Foundation (since October 2013); Member of Board and Investment Committee of The Greenwall Foundation (since April 2013); Member of the Vestry of Trinity Wall Street (since April 2012); Director of Southern Africa Legal Services Foundation (since March 2012); Board Member of Pulitzer Center for Crisis Reporting (non-profit journalism) (since March 2011); Managing Director of Public Capital Advisors, LLC (privately-held financial advisor) (since January 2006); Managing Director of Carmona Motley, Inc. (privately-held financial advisor) (since January 2002); Director of Columbia Equity Financial Corp. (privately-held financial advisor) (2002-2007); Managing Director of Carmona Motley Hoffman Inc. (privately-held financial advisor) (January 1998-December 2001); Member of the Finance and Budget Committee of the Council on Foreign Relations, Member of the Investment Committee and Board of Human Rights Watch (since July 2000) and Member of the Investment Committee and Board of Historic Hudson Valley (since February 2010). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Motley has served on the Boards of certain Oppenheimer funds since October 2002, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Joanne Pace, Trustee (since 2012) Year of Birth: 1958		Advisory Board Director of Massey Quick and Company, LLC (since October 2014); Board Director of Horizon Blue Cross Blue Shield of New Jersey (since November 2012); Advisory Board Director of The Alberleen Group LLC (since March, 2012); Board Member (since January 2015), Board Member of 100 Women in Hedge Funds (non-profit) (since January 2015); Advisory Council Member of Morgan Stanley Children’s Hospital (non-profit) (since May, 2012); Senior Advisor of SECOR Asset Management, LP (2010-2011); Managing Director and Chief Operating Officer of Morgan Stanley Investment Management (2006-2010); Partner and Chief Operating Officer of FrontPoint Partners, LLC (hedge fund) (2005-2006); held the following positions at Credit Suisse: Managing Director (2003-2005); Global Head of Human Resources and member of Executive Board and Operating Committee (2004-2005), Global Head of Operations and Product Control (2003- 2004); held the following positions at Morgan Stanley: Managing Director (1997- 2003), Controller and Principal Accounting Officer (1999-2003); Chief Financial Officer (temporary assignment) for the Oversight Committee, Long Term Capital Management (1998-1999). Lead Independent Director and Chair of the Audit and Nominating Committee of The Global Chartist Fund, LLC of Oppenheimer Asset Management (2011-2012); Board Director of Managed Funds Association (2008- 2010); Board Director of Morgan Stanley Foundation (2007-2010) and Investment Committee Chair (2008-2010). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Pace has served on the Boards of certain Oppenheimer funds since November 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

44 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


Daniel Vandivort, Trustee (since 2014) Year of Birth: 1954		Chairman and Lead Independent Director/Trustee (March 2010-September 2014), Chairman of the Audit Committee (March 2009-September 2014) and Director/ Trustee (December 2008-September 2014) of the Board of Directors/Trustees of Value Line Funds; Trustee, Board of Trustees of Huntington Disease Foundation of America (since January 2015 and June 2007-December 2013) and Treasurer, Chairman of the Audit and Finance Committee (since January 2016); Trustee, Board of Trustees, RIM Retirement Savings Plan (2005-2007); President and Chief Investment Officer, Robeco Investment Management, formerly known as Weiss Peck and Greer (January 2005-June 2007); Member, Management Committee of Robeco Investment Management (2001-2007); Chairman and Trustee of the Board of Trustees of Weiss, Peck and Greer Funds (2004-2005); Managing Director and Head of Fixed Income, Weiss, Peck and Greer (November 1994-January 2005); Managing Director and Head of Fixed Income, CS First Boston Investment Management (January 1992-November 1994); Director, Global Product Development, First Boston Asset Management (November 1989 to January 1992); Vice President, Fixed Income Sales, First Boston Corp. (May 1984-November 1989). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Vandivort has served on the Boards of certain Oppenheimer funds since 2014, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
INTERESTED TRUSTEE AND OFFICER		Mr. Steinmetz is an “Interested Trustee” because he is affiliated with the Manager and the Sub-Adviser by virtue of his positions as Chairman of the Sub-Adviser and officer and director of the Manager. Both as a Trustee and as an officer, Mr. Steinmetz serves for an indefinite term, or until his resignation, retirement, death or removal. Mr. Steinmetz’s address is 225 Liberty Street, New York, New York 10281-1008.

Arthur P. Steinmetz, Trustee (since 2015), President and Principal Executive Officer (since 2014) Year of Birth: 1958		Chairman of the Sub-Adviser (since January 2015); CEO and Chairman of the Manager (since July 2014), President of the Manager (since May 2013), a Director of the Manager (since January 2013), Director of the Sub-Adviser (since July 2014), President, Management Director and CEO of Oppenheimer Acquisition Corp. (the Sub-Adviser’s parent holding company) (since July 2014), and President and Director of OFI SteelPath, Inc. (since January 2013). Chief Investment Officer of the OppenheimerFunds advisory entities from (January 2013-December 2013); Executive Vice President of the Manager (January 2013-May 2013); Chief Investment Officer of the Sub-Adviser (October 2010-December 2012); Chief Investment Officer, Fixed-Income, of the Sub-Adviser (April 2009-October 2010); Executive Vice President of the Sub-Adviser (October 2009-December 2012); Director of Fixed Income of the Sub-Adviser (January 2009-April 2009); and a Senior Vice President of the Sub-Adviser (March 1993-September 2009). An officer of 110 portfolios in the OppenheimerFunds complex.
OTHER OFFICERS OF THE FUND		The addresses of the Officers in the chart below are as follows: for Messrs. Hamilton, Lee, Mss. Lo Bessette, Foxson and Picciotto, 225 Liberty Street, New York, New York 10281-1008, for Mr. Petersen, 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Officer serves for an indefinite term or until his or her resignation, retirement, death or removal.

Mark Hamilton,¹ Vice President (since 2013) Year of Birth: 1965		Chief Investment Officer, Asset Allocation and Senior Vice President of the Sub-Adviser (since April 2013). Mr. Hamilton served at AllianceBernstein L.P. (from 1994-2013) as an Investment Director of Dynamic Asset Allocation (from 2010-2013), Head of North American Blend Team (from 2009-2010), and Senior Portfolio Manager of Blend Strategies (from 2006-2010). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

45 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued


Dokyoung Lee,¹ Vice President (since 2014) Year of Birth: 1965		Director of Research, Global Multi-Asset Group and a Senior Vice President of the Sub-Adviser (since October 2013). Mr. Lee served at Alliance Bernstein L.P. (1994- 2013): Director of Research for Strategic Asset Allocation (2011-2013), Director of Research for Blend Strategies (2008-2011), Head of Asia Pacific Blend Strategies (2005-2008), Head of Quantitative Research and Senior Portfolio Manager for Japan Value Equities (2001-2005), Portfolio Manager for Emerging Markets Value Equities (1997-2001), and Quantitative Analyst for US Value Equities (1994-1997). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

Cynthia Lo Bessette, Secretary and Chief Legal Officer (since 2016) Year of Birth: 1969		Executive Vice President, General Counsel and Secretary of the Manager (since February 2016); Senior Vice President and Deputy General Counsel of the Manager (March 2015-February 2016); Chief Legal Officer of the Sub-Adviser and the Distributor (since February 2016); Vice President, General Counsel and Secretary of Oppenheimer Acquisition Corp. (since February 2016); General Counsel of OFI SteelPath, Inc., OFI Advisors and Index Management Solutions, LLC (since February 2016); Chief Legal Officer of OFI Global Institutional, Inc., HarbourView Asset Management Corporation, OFI Global Trust Company, Oppenheimer Real Asset Management, Inc., OFI Private Investments Inc., Shareholder Services, Inc. and Trinity Investment Management Corporation (since February 2016); Corporate Counsel (February 2012-March 2015) and Deputy Chief Legal Officer (April 2013-March 2015) of Jennison Associates LLC; Assistant General Counsel (April 2008-September 2009) and Deputy General Counsel (October 2009-February 2012) of Lord Abbett & Co. LLC. An officer of 110 portfolios in the OppenheimerFunds complex.

Jennifer Foxson, Vice President and Chief Business Officer (since 2014) Year of Birth: 1969		Senior Vice President of OppenheimerFunds Distributor, Inc. (since June 2014); Vice President of OppenheimerFunds Distributor, Inc. (April 2006-June 2014); Vice President of the Sub-Adviser (January 1998-March 2006); Assistant Vice President of the Sub-Adviser (October 1991-December 1998). An officer of 110 portfolios in the OppenheimerFunds complex.

Mary Ann Picciotto, Chief Compliance Officer and Chief Anti-Money Laundering Officer (since 2014) Year of Birth: 1973		Senior Vice President and Chief Compliance Officer of the Manager (since March 2014); Chief Compliance Officer of the Sub-Adviser, OFI SteelPath, Inc., OFI Global Trust Company, OFI Global Institutional, Inc., Oppenheimer Real Asset Management, Inc., OFI Private Investments, Inc., Harborview Asset Management Corporation, Trinity Investment Management Corporation, and Shareholder Services, Inc. (since March 2014); Managing Director of Morgan Stanley Investment Management Inc. and certain of its various affiliated entities; Chief Compliance Officer of various Morgan Stanley Funds (May 2010-January 2014); Chief Compliance Officer of Morgan Stanley Investment Management Inc. (April 2007-January 2014). An officer of 110 portfolios in the OppenheimerFunds complex.

Brian S. Petersen, Treasurer and Principal Financial & Accounting Officer (since 2016) Year of Birth: 1970		Senior Vice President of the Manager (since January 2017); Vice President of the Manager (January 2013-January 2017); Vice President of the Sub-Adviser (February 2007-December 2012); Assistant Vice President of the Sub-Adviser (August 2002- 2007). An officer of 110 portfolios in the OppenheimerFunds complex.

1. Effective February 27, 2018 Mark Hamilton and Dokyoung Lee are no longer officers of the Fund.

46 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


Manager		OFI Global Asset Management, Inc.

Sub-Adviser		OppenheimerFunds, Inc.

Distributor		OppenheimerFunds Distributor, Inc.

Transfer and Shareholder Servicing Agent		OFI Global Asset Management, Inc.

Sub-Transfer Agent		Shareholder Services, Inc.
		DBA OppenheimerFunds Services

Independent Registered Public Accounting Firm		KPMG LLP

Legal Counsel		Kramer Levin Naftalis & Frankel LLP

47 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

PRIVACY 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 non-public personal information about our shareholders from the following sources:

● Applications or other forms.

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● Technologies on our website, including: “cookies” and web beacons, which are used to collect data on the pages you visit and the features you use.

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

Right of Refusal

48 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND

Internet Security and Encryption

●

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

Other Security Measures

How You Can Help

Who We Are

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55 OPPENHEIMER PORTFOLIO SERIES MODERATE INVESTOR FUND


		Visit us at oppenheimerfunds.com for 24-hr access to account information and transactions or call us at 800.CALL OPP (800.225.5677) for 24-hr automated information and automated transactions. Representatives also available Mon–Fri 8am-8pm ET.
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		Oppenheimer funds are distributed by OppenheimerFunds Distributor, Inc. 225 Liberty Street, New York, NY 10281-1008 © 2018 OppenheimerFunds Distributor, Inc. All rights reserved. RA0545.001.0118 March 23, 2018

LOGO

Table of Contents



Fund Performance Discussion			3

Top Holdings and Allocations			6

Fund Expenses			9

Statement of Investments			11

Statement of Assets and Liabilities			14

Statement of Operations			16

Statements of Changes in Net Assets			18

Financial Highlights			19

Notes to Financial Statements			24

Report of Independent Registered Public Accounting Firm			35

Federal Income Tax Information			36

Board Approval of the Fund’s Investment Advisory and Sub- Advisory Agreements			37

Portfolio Proxy Voting Policies and Guidelines; Updates to Statement of Investments			40

Trustees and Officers			41

Privacy Notice			48

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 1/31/18


	Class A Shares of the Fund
	Without Sales Charge	With Sales Charge	S&P 500 Index	Bloomberg Barclays U.S. Aggregate Bond Index
1-Year	21.62%	14.63%	26.41%	2.15%
5-Year	9.53	8.24	15.91	2.01
10-Year	4.82	4.20	9.78	3.71

2 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Fund Performance Discussion¹

MARKET OVERVIEW

December for the third time in 2017. Despite these tightening measures, by many measures financial conditions eased in 2017.

LOGO

1. The Fund is invested in Class I shares of all underlying funds discussed in this Fund Performance Discussion, except for Oppenheimer Master Event-Linked Bond Fund, LLC, which does not offer Class I shares.

3 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

with the Bloomberg Barclays U.S. Credit Index rising 4.84%.

FUND REVIEW

Against this market backdrop, the Fund’s Class A shares (without sales charge) produced a total return of 21.62%. In comparison, the Bloomberg Barclays U.S. Aggregate Bond Index returned of 2.15% and the S&P 500 Index returned 26.41%. The Fund employs a combination of sophisticated quantitative tools and qualitative analysis to seek to construct a well-diversified, globally allocated portfolio. The portfolio is allocated among OppenheimerFunds’ actively managed funds according to risk and strategically rebalanced based on market conditions. The Fund has roughly 20% of its assets invested in an “active component” that seeks to take advantage of short-term market conditions, and 80% invested in a “static component.” Both components performed positively during the one-year period, with the active component outperforming the static component. The active component favored equity-oriented underlying funds over interest-rate sensitive fixed-income funds, which benefited its performance during this reporting period.

UNDERLYING INVESTMENTS REVIEW

Equity funds produced the strongest contribution to the Fund’s total return for both the active and static components. All of the Fund’s domestic and foreign equity holdings provided positive returns, including its top two holdings: Oppenheimer Capital

Appreciation Fund and Oppenheimer Value Fund. Oppenheimer Capital Appreciation Fund typically invests in large-cap U.S. growth stocks. In an environment where growth outperformed value, the underlying fund benefited. That said, value also produced positive returns this period and Oppenheimer Value Fund generated strong results. All of the underlying foreign equity funds produced positive results for the Fund this period as well, led by Oppenheimer International Growth Fund and Oppenheimer International Equity Fund. European markets continued to outperform U.S. markets during this reporting period. This benefited both of these underlying funds, which have large allocations to Europe. Oppenheimer International Equity Fund also benefited from its exposure to Japan.

Although fixed income underperformed equities this reporting period, both the active and static components did receive positive contributions from each of its fixed-income holdings. The Fund’s exposure to Oppenheimer International Bond Fund, which typically invests in international fixed income securities in both developed and emerging market countries, was a top performer. This underlying fund invests in three major risk categories, or “levers” – interest rates (typically government bonds), currencies, and credit (corporate bonds and other fixed-income instruments containing credit risk). All three areas produced positive absolute results. Oppenheimer Total Return Bond Fund also performed well. This underlying fund benefited from an underweight to U.S.

4 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Treasuries relative to the Bloomberg Barclays U.S. Aggregate Bond Index, along with its exposure to both investment grade credit, high yield credit, and non-agency mortgage-backed securities (“MBS”).

In alternatives, Oppenheimer Global Multi Strategies Fund and Oppenheimer Fundamental Alternatives Fund produced muted positive returns. Oppenheimer Gold & Special Minerals Fund and Oppenheimer Master Event-Linked Bond Fund, LLC detracted from performance. Both components had allocations to Oppenheimer Gold & Special Minerals Fund, while Oppenheimer Master Event-Linked Bond Fund, LLC was held by the active component. In a risk-on market environment, the stocks of gold and special minerals companies underperformed, resulting in declines for Oppenheimer Gold & Special Minerals Fund. Event-linked bonds were impacted negatively as global insurance and reinsurance markets endured an extremely challenging environment amid an unprecedented number of large and impactful natural disaster events that occurred in late August through September. Losses from Hurricanes Harvey,

Irma, and Maria, along with a major earthquake in Mexico have contributed to what is expected to be at least the third largest level for insured losses in the market’s history.

FUND UPDATE

After the reporting period ended, effective February 27, 2018, Jeffrey Bennett, CFA, was named a co-Portfolio Manager of the Fund with Caleb Wong. Jeff joined OppenheimerFunds in 2016 from AllianceBernstein, where he was a Managing Director on the Alternative Investment Management team, focusing on asset allocation and portfolio construction as well as manager identification and due diligence. Previously, Jeff was director of research for Fischer & Co., a multi-family office, before which Jeff was the primary analyst at Summit Private Investments, a fund-of-hedge funds that focuses on long/short and event-driven strategies. Jeff is a CFA^® charter holder and holds a BS in chemical engineering from the University of California, Los Angeles, as well as an MBA in analytic finance and econometrics from the University of Chicago.

5 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Top Holdings and Allocations

ASSET CLASS ALLOCATION


Domestic Equity Funds	53.0	%
Foreign Equity Funds	29.6
Domestic Fixed Income Funds	9.9
Alternative Funds	4.4
Foreign Fixed Income Fund	2.9
Money Market Fund	0.2

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Capital Appreciation Fund, Cl. I	22.7	%
Oppenheimer Value Fund, Cl. I	22.3
Oppenheimer International Growth Fund, Cl. I	10.6
Oppenheimer International Equity Fund, Cl. I	10.1
Oppenheimer Total Return Bond Fund, Cl. I	5.8
Oppenheimer Developing Markets Fund, Cl. I	4.9
Oppenheimer Main Street Mid Cap Fund, Cl. I	4.3
Oppenheimer International Small- Mid Company Fund, Cl.I	4.0
Oppenheimer Main Street Small Cap Fund, Cl. I	3.6
Oppenheimer International Bond Fund, Cl. I	2.9

6 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 1/31/18


	Inception Date		1-Year		5-Year		10-Year
Class A (OAAAX)		4/5/05		21.62%		9.53%		4.82%
Class B (OAABX)		4/5/05		20.67		8.70		4.30
Class C (OAACX)		4/5/05		20.72		8.73		4.03
Class R (OAANX)		4/5/05		21.28		9.26		4.60
Class Y (OAAYX)		4/5/05		21.98		9.82		5.16

AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 1/31/18


	Inception Date		1-Year		5-Year		10-Year
Class A (OAAAX)		4/5/05		14.63%		8.24%		4.20%
Class B (OAABX)		4/5/05		15.67		8.41		4.30
Class C (OAACX)		4/5/05		19.72		8.73		4.03
Class R (OAANX)		4/5/05		21.28		9.26		4.60
Class Y (OAAYX)		4/5/05		21.98		9.82		5.16

The Fund’s performance is compared to the performance of the S&P 500 Index and the Bloomberg Barclays U.S. Aggregate Bond Index. The S&P 500 Index is a capitalization-weighted index of 500 stocks intended to be a representative sample of leading companies in leading industries within the U.S. economy. The Bloomberg Barclays U.S. Aggregate Bond Index is an index of U.S.-dollar-denominated, investment-grade U.S. corporate government and mortgage-backed securities. The indices are unmanaged and cannot be purchased directly by investors. 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. Index performance includes reinvestment of income, but does not reflect transaction costs, fees, expenses or taxes. Index performance is shown for illustrative purposes only as a benchmark for the Fund’s performance, and does not predict or depict

7 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

8 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Fund Expenses

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, 2018.

9 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Actual	Beginning Account Value August 1, 2017	Ending Account Value January 31, 2018	Expenses Paid During 6 Months Ended January 31, 2018
Class A	$ 1,000.00	$ 1,108.70	$ 2.87
Class B	1,000.00	1,104.80	6.97
Class C	1,000.00	1,104.00	6.86
Class R	1,000.00	1,107.50	4.15
Class Y	1,000.00	1,110.50	1.54

Hypothetical (5% return before expenses)
Class A	1,000.00	1,022.48	2.76
Class B	1,000.00	1,018.60	6.69
Class C	1,000.00	1,018.70	6.58
Class R	1,000.00	1,021.27	3.98
Class Y	1,000.00	1,023.74	1.48


Class	Expense Ratios
Class A		0.54	%
Class B		1.31
Class C		1.29
Class R		0.78
Class Y		0.29

10 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

STATEMENT OF INVESTMENTS January 31, 2018


	Shares		Value
Investment Companies—99.9%¹
Alternative Funds—4.4%
Oppenheimer Fundamental Alternatives Fund, Cl. I		363,572	$	10,187,295
Oppenheimer Global Multi Strategies Fund, Cl. I		870,291		20,025,401
Oppenheimer Gold & Special Minerals Fund, Cl. I		469,836		7,686,517
Oppenheimer Master Event-Linked Bond Fund, LLC		1,493,604		23,287,710
Oppenheimer Master Inflation Protected Securities Fund, LLC		3,653,830		44,091,474
Oppenheimer Real Estate Fund, Cl. I		547,627		13,208,757
				118,487,154
Domestic Equity Funds—52.9%
Oppenheimer Capital Appreciation Fund, Cl. I		9,005,104		609,915,675
Oppenheimer Main Street Mid Cap Fund, Cl. I		3,854,798		114,371,867
Oppenheimer Main Street Small Cap Fund, Cl. I		6,199,301		96,213,155
Oppenheimer Value Fund, Cl. I		15,013,184		598,125,242
				1,418,625,939
Domestic Fixed Income Funds—9.9%
Oppenheimer Limited-Term Government Fund, Cl. I		14,292,458		62,172,194
Oppenheimer Master Loan Fund, LLC		2,806,582		47,813,137
Oppenheimer Total Return Bond Fund, Cl. I		22,710,820		153,979,360
				263,964,691
Foreign Equity Funds—29.6%
Oppenheimer Developing Markets Fund, Cl. I		2,805,883		130,277,161
Oppenheimer International Equity Fund, Cl. I		11,557,153		270,668,529
Oppenheimer International Growth Fund, Cl. I		6,211,070		285,150,222
Oppenheimer International Small-Mid Company Fund, Cl. I		2,049,178		107,581,839
				793,677,751
Foreign Fixed Income Fund—2.9%
Oppenheimer International Bond Fund, Cl. I		12,724,854		77,621,608
Money Market Fund—0.2%
Oppenheimer Institutional Government Money Market Fund, Cl. E, 1.26%²		5,206,535		5,206,535

Total Investments, at Value (Cost $1,919,185,372)		99.9%		2,677,583,678
Net Other Assets (Liabilities)		0.1		1,686,897
Net Assets		100.0%	$	2,679,270,575

Footnotes to Statement of Investments


	Shares January 31, 2017		Gross Additions		Gross Reductions		Shares January 31, 2018
Oppenheimer Capital Appreciation Fund, Cl. I		8,365,070		1,489,321		849,287		9,005,104
Oppenheimer Developing Markets Fund, Cl. I		3,205,285		87,331		486,733		2,805,883
Oppenheimer Fundamental Alternatives Fund, Cl. I		469,210		16,023		121,661		363,572
Oppenheimer Global Multi Strategies Fund, Cl. I		902,596		82,842		115,147		870,291

11 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

STATEMENT OF INVESTMENTS Continued

Footnotes to Statement of Investments (Continued)


	Shares January 31, 2017		Gross Additions		Gross Reductions		Shares January 31, 2018
Oppenheimer Gold & Special Minerals Fund, Cl. I		516,254		28,316		74,734		469,836
Oppenheimer Institutional Government Money Market Fund, Cl. E		5,954,028		167,521		915,014		5,206,535
Oppenheimer International Bond Fund, Cl. I		14,703,828		893,551		2,872,525		12,724,854
Oppenheimer International Equity Fund, Cl. I		13,027,700		301,409		1,771,956		11,557,153
Oppenheimer International Growth Fund, Cl. I		7,535,304		210,185		1,534,419		6,211,070
Oppenheimer International Small- Mid Company Fund, Cl. I		2,337,625		107,961		396,408		2,049,178
Oppenheimer Limited-Term Government Fund, Cl. I		15,566,232		693,326		1,967,100		14,292,458
Oppenheimer Main Street Mid Cap Fund, Cl. I		3,203,148		1,027,185		375,535		3,854,798
Oppenheimer Main Street Small Cap Fund, Cl. I		7,253,252		472,790		1,526,741		6,199,301
Oppenheimer Master Event-Linked Bond Fund, LLC		1,747,468		35,393		289,257		1,493,604
Oppenheimer Master Inflation Protected Securities Fund, LLC		4,049,833		99,428		495,431		3,653,830
Oppenheimer Master Loan Fund, LLC		2,527,665		624,337		345,420		2,806,582
Oppenheimer Real Estate Fund, Cl. I		565,092		39,626		57,091		547,627
Oppenheimer Total Return Bond Fund, Cl. I^a		24,296,326		1,267,684		2,853,190		22,710,820
Oppenheimer Value Fund, Cl. I		15,149,620		1,448,703		1,585,139		15,013,184

	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)
Oppenheimer Capital Appreciation Fund, Cl. I^b	$	609,915,675	$	2,083,952	$	21,063,142	$	77,997,897
Oppenheimer Developing Markets Fund, Cl. I		130,277,161		878,796		9,678,648		28,025,711
Oppenheimer Fundamental Alternatives Fund, Cl. I		10,187,295		199,054		39,818		221,072
Oppenheimer Global Multi Strategies Fund, Cl. I		20,025,401		773,141		(7,694)		(45,925)
Oppenheimer Gold & Special Minerals Fund, Cl. I		7,686,517		245,248		100,748		(438,699)
Oppenheimer Institutional Government Money Market Fund, Cl. E		5,206,535		48,497		—		—
Oppenheimer International Bond Fund, Cl. I		77,621,608		1,035,480		263,972		7,981,636
Oppenheimer International Equity Fund, Cl. I		270,668,529		991,392		9,586,674		60,553,548

12 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Footnotes to Statement of Investments (Continued)


	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)
Oppenheimer International Growth Fund, Cl. I	$	285,150,222	$	2,856,401	$	31,357,725	$	36,052,128
Oppenheimer International Small- Mid Company Fund, Cl. I^c		107,581,839		1,203,345		8,403,628		21,236,439
Oppenheimer Limited-Term Government Fund, Cl. I		62,172,194		1,465,116		(191,870)		(813,927)
Oppenheimer Main Street Mid Cap Fund, Cl. I^d		114,371,867		834,080		3,688,312		(2,331,448)
Oppenheimer Main Street Small Cap Fund, Cl. I^e		96,213,155		552,029		3,694,858		4,362,785
Oppenheimer Master Event-Linked Bond Fund, LLC		23,287,710		1,686,910^f		(456,777)^f		(1,917,062)^f
Oppenheimer Master Inflation Protected Securities Fund, LLC		44,091,474		1,181,502^g		48,444^g		(549,824)^g
Oppenheimer Master Loan Fund, LLC		47,813,137		2,909,589^h		(181,761)^h		(169,702)^h
Oppenheimer Real Estate Fund, Cl. Iⁱ		13,208,757		252,720		852,650		(1,311,433)
Oppenheimer Total Return Bond Fund, Cl. I^a		153,979,360		5,013,289		3,162,604		(2,575,589)
Oppenheimer Value Fund, Cl. I^j		598,125,242		7,708,842		29,700,597		38,843,984
Total	$	2,677,583,678	$	31,919,383	$	120,803,718	$	265,121,591

a. Prior to June 1, 2017, this fund was named Oppenheimer Core Bond Fund.

b. This fund distributed realized gains of $45,308,565.

c. This fund distributed realized gains of $2,177,233.

d. This fund distributed realized gains of $12,753,920.

e. This fund distributed realized gains of $4,756,603.

f. Represents the amount allocated to the Fund from Oppenheimer Master Event-Linked Bond Fund, LLC.

g. Represents the amount allocated to the Fund from Oppenheimer Master Inflation Protected Securities Fund, LLC.

h. Represents the amount allocated to the Fund from Oppenheimer Master Loan Fund, LLC.

i. This fund distributed realized gains of $478,885.

j. This fund distributed realized gains of $23,975,882.

2. Rate shown is the 7-day yield at period end.

See accompanying Notes to Financial Statements.

13 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

STATEMENT OF ASSETS AND LIABILITIES January 31, 2018


Assets
Investments, at value—see accompanying statement of investments—affiliated companies (cost $1,919,185,372)	$	2,677,583,678
Cash		2,315,544
Receivables and other assets:
Investments sold		933,346
Dividends		837,559
Shares of beneficial interest sold		515,172
Other		144,802
Total assets		2,682,330,101

Liabilities
Payables and other liabilities:
Shares of beneficial interest redeemed		1,416,118
Investments purchased		840,703
Distribution and service plan fees		550,758
Trustees’ compensation		200,225
Shareholder communications		11,783
Other		39,939
Total liabilities		3,059,526

Net Assets	$	2,679,270,575


Composition of Net Assets
Par value of shares of beneficial interest	$	176,517
Additional paid-in capital		2,086,470,975
Accumulated net investment income		33,945,075
Accumulated net realized loss on investments		(199,720,298	)
Net unrealized appreciation on investments		758,398,306

Net Assets	$	2,679,270,575

14 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Net Asset Value Per Share
Class A Shares:
Net asset value and redemption price per share (based on net assets of $1,888,595,729 and 123,824,442 shares of beneficial interest outstanding)	$	15.25
Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	16.18

Class B Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $12,695,586 and 836,534 shares of beneficial interest outstanding)	$	15.18

Class C Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $579,999,334 and 38,870,934 shares of beneficial interest outstanding)	$	14.92

Class R Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge)and offering price per share (based on net assets of $134,456,781 and 8,864,631 shares of beneficial interest outstanding)	$	15.17

Class Y Shares:
Net asset value, redemption price and offering price per share (based on net assets of $63,523,145 and 4,120,666 shares of beneficial interest outstanding)	$	15.42

See accompanying Notes to Financial Statements.

15 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

STATEMENT

OF OPERATIONS For the Year Ended January 31, 2018


Allocation of Income and Expenses from Master Funds¹
Net investment income allocated from Oppenheimer Master Event-Linked Bond Fund, LLC:
Interest	$	1,680,785
Dividends		6,125
Net expenses		(114,136)

Net investment income allocated from Oppenheimer Master Event-Linked Bond Fund, LLC		1,572,774
Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC:
Interest		1,178,415
Dividends		3,087
Net expenses		(217,946)

Net investment income allocated from Oppenheimer Master Inflation Protected Securities Fund, LLC		963,556
Net investment income allocated from Oppenheimer Master Loan Fund, LLC:
Interest		2,836,552
Dividends		73,037
Net expenses		(173,408)

Net investment income allocated from Oppenheimer Master Loan Fund, LLC		2,736,181

Total allocation of net investment income from master funds		5,272,511


Investment Income
Dividends—affiliated companies		26,141,382
Interest		23,895

Total investment income		26,165,277


Expenses
Distribution and service plan fees:
Class A		4,265,198
Class B		258,190
Class C		5,498,007
Class R		607,915
Transfer and shareholder servicing agent fees:
Class A		3,806,961
Class B		56,695
Class C		1,203,479
Class R		267,904
Class Y		133,432
Shareholder communications:
Class A		27,977
Class B		1,808
Class C		7,980
Class R		1,424
Class Y		436
Asset allocation fees		2,511,310
Trustees’ compensation		34,053
Custodian fees and expenses		17,602
Other		87,663

Total expenses		18,788,034

16 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Expenses (Continued)
Less waivers and reimbursements of expenses	$	(1,377,867)

Net expenses		17,410,167

Net Investment Income		14,027,621
Realized and Unrealized Gain (Loss)
Net realized gain on:
Investment transactions in affiliated companies		121,393,812
Distributions received from affiliate companies		89,451,088
Increase from payment by affiliate		10,924
Net realized gain (loss) allocated from:
Oppenheimer Master Event-Linked Bond Fund, LLC		(456,777)
Oppenheimer Master Inflation Protected Securities Fund, LLC		48,444
Oppenheimer Master Loan Fund, LLC		(181,761)

Net realized gain		210,265,730
Net change in unrealized appreciation/depreciation on:
Investment transactions in affiliated companies		267,758,179
Net change in unrealized appreciation/depreciation allocated from:
Oppenheimer Master Event-Linked Bond Fund, LLC		(1,917,062)
Oppenheimer Master Inflation Protected Securities Fund, LLC		(549,824)
Oppenheimer Master Loan Fund, LLC		(169,702)

Net change in unrealized appreciation/depreciation		265,121,591

Net Increase in Net Assets Resulting from Operations	$	489,414,942

1. The Fund invests in certain affiliated mutual funds that expect to be treated as partnerships for tax purposes. See Note 4 of the accompanying Notes.

See accompanying Notes to Financial Statements.

17 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

STATEMENTS OF CHANGES IN NET ASSETS


	Year Ended January 31, 2018			Year Ended January 31, 2017
Operations
Net investment income	$	14,027,621		$	23,567,406
Net realized gain		210,265,730			83,039,353
Net change in unrealized appreciation/depreciation		265,121,591			165,315,369

Net increase in net assets resulting from operations		489,414,942			271,922,128

Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(20,135,054	)		(15,571,834)
Class B		—			—
Class C		(2,258,627	)		(1,236,925)
Class R		(1,116,655	)		(817,761)
Class Y		(772,087	)		(668,587)

		(24,282,423	)		(18,295,107)

Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		(80,802,213	)		(57,983,628)
Class B		(35,083,644	)		(42,745,371)
Class C		(57,650,166	)		(44,157,244)
Class R		(5,783,509	)		(3,558,847)
Class Y		(4,424,578	)		13,332,099

		(183,744,110	)		(135,112,991)

Net Assets
Total increase		281,388,409			118,514,030
Beginning of period		2,397,882,166			2,279,368,136

End of period (including accumulated net investment income of $33,945,075 and $23,221,709, respectively)	$	2,679,270,575		$	2,397,882,166

See accompanying Notes to Financial Statements.

18 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

FINANCIAL HIGHLIGHTS


Class A	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$12.68		$11.38		$12.12		$11.52		$10.27

Income (loss) from investment operations:
Net investment income²		0.10		0.15		0.09		0.11		0.13
Net realized and unrealized gain (loss)		2.63		1.27		(0.65)		0.61		1.28

Total from investment operations		2.73		1.42		(0.56)		0.72		1.41

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.16)		(0.12)		(0.18)		(0.12)		(0.16)

Net asset value, end of period		$15.25		$12.68		$11.38		$12.12		$11.52




Total Return, at Net Asset Value³		21.62%		12.50%		(4.67)%		6.26%		13.73%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$1,888,596		$1,645,373		$1,530,527		$1,599,618		$1,496,909

Average net assets (in thousands)		$1,749,924		$1,606,586		$1,646,634		$1,591,772		$1,416,982

Ratios to average net assets:^4,5
Net investment income		0.75%		1.20%		0.74%		0.93%		1.14%
Expenses excluding specific expenses listed below		0.59%		0.60%		0.59%		0.59%		0.59%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.59%		0.60%		0.59%		0.59%		0.59%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.53%		0.56%		0.55%		0.55%		0.54%

Portfolio turnover rate		9%		5%		8%		15%		9%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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


Year Ended January 31, 2018	1.22	%
Year Ended January 31, 2017	1.23	%
Year Ended January 29, 2016	1.21	%
Year Ended January 30, 2015	1.21	%
Year Ended January 31, 2014	1.26	%

See accompanying Notes to Financial Statements.

19 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

FINANCIAL HIGHLIGHTS Continued


Class B	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$12.58		$11.27		$11.96		$11.34		$10.10

Income (loss) from investment operations:
Net investment income (loss)²		(0.08)		0.04		(0.01)		0.01		0.01
Net realized and unrealized gain (loss)		2.68		1.27		(0.62)		0.61		1.29

Total from investment operations		2.60		1.31		(0.63)		0.62		1.30

Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00		0.00		(0.06)		0.00		(0.06)

Net asset value, end of period		$15.18		$12.58		$11.27		$11.96		$11.34



Total Return, at Net Asset Value³		20.67%		11.62%		(5.33)%		5.48%		12.83%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$12,696		$43,089		$79,042		$134,496		$197,214
Average net assets (in thousands)		$25,803		$58,930		$106,583		$166,076		$220,028
Ratios to average net assets:^4,5
Net investment income (loss)		(0.57)%		0.30%		(0.08)%		0.11%		0.14%
Expenses excluding specific expenses listed below		1.35%		1.35%		1.35%		1.34%		1.37%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		1.35%		1.35%		1.35%		1.34%		1.37%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.29%		1.31%		1.31%		1.30%		1.32%

Portfolio turnover rate		9%		5%		8%		15%		9%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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


Year Ended January 31, 2018	1.98	%
Year Ended January 31, 2017	1.98	%
Year Ended January 29, 2016	1.97	%
Year Ended January 30, 2015	1.96	%
Year Ended January 31, 2014	2.04	%

See accompanying Notes to Financial Statements.

20 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Class C	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$12.41		$11.14		$11.87		$11.28		$10.06

Income (loss) from investment operations:
Net investment income²		0.00³		0.05		0.00³		0.02		0.04
Net realized and unrealized gain (loss)		2.57		1.25		(0.64)		0.60		1.26

Total from investment operations		2.57		1.30		(0.64)		0.62		1.30

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.06)		(0.03)		(0.09)		(0.03)		(0.08)

Net asset value, end of period		$14.92		$12.41		$11.14		$11.87		$11.28



Total Return, at Net Asset Value⁴		20.72%		11.66%		(5.41)%		5.53%		12.93%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$579,999		$535,568		$522,227		$557,576		$535,716

Average net assets (in thousands)		$552,895		$533,800		$564,178		$562,221		$518,457

Ratios to average net assets:^5,6
Net investment income (loss)		(0.03)%		0.44%		(0.01)%		0.18%		0.35%
Expenses excluding specific expenses listed below		1.34%		1.35%		1.34%		1.34%		1.33%
Interest and fees from borrowings		0.00%		0.00%⁷		0.00%⁷		0.00%		0.00%

Total expenses⁸		1.34%		1.35%		1.34%		1.34%		1.33%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.28%		1.31%		1.30%		1.30%		1.28%

Portfolio turnover rate		9%		5%		8%		15%		9%

1. Represents the last business day of the Fund’s reporting period.

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

3. Less than $0.005 per share.

5. Annualized for periods less than one full year.

6. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

7. Less than 0.005%.

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


Year Ended January 31, 2018	1.97	%
Year Ended January 31, 2017	1.98	%
Year Ended January 29, 2016	1.96	%
Year Ended January 30, 2015	1.96	%
Year Ended January 31, 2014	2.00	%

See accompanying Notes to Financial Statements.

21 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

FINANCIAL HIGHLIGHTS Continued


Class R	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$12.62		$11.32		$12.05		$11.45		$10.21

Income (loss) from investment operations:
Net investment income²		0.07		0.11		0.06		0.08		0.09
Net realized and unrealized gain (loss)		2.61		1.28		(0.64)		0.61		1.28

Total from investment operations		2.68		1.39		(0.58)		0.69		1.37

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.13)		(0.09)		(0.15)		(0.09)		(0.13)

Net asset value, end of period		$15.17		$12.62		$11.32		$12.05		$11.45



Total Return, at Net Asset Value³		21.28%		12.29%		(4.88)%		5.99%		13.42%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$134,457		$117,356		$108,810		$119,953		$128,012

Average net assets (in thousands)		$123,173		$112,804		$120,320		$127,487		$133,527

Ratios to average net assets:^4,5
Net investment income		0.49%		0.94%		0.50%		0.66%		0.78%
Expenses excluding specific expenses listed below		0.84%		0.85%		0.84%		0.84%		0.81%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.84%		0.85%		0.84%		0.84%		0.81%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.78%		0.81%		0.80%		0.80%		0.76%

Portfolio turnover rate		9%		5%		8%		15%		9%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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


Year Ended January 31, 2018	1.47	%
Year Ended January 31, 2017	1.48	%
Year Ended January 29, 2016	1.46	%
Year Ended January 30, 2015	1.46	%
Year Ended January 31, 2014	1.48	%

See accompanying Notes to Financial Statements.

22 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Class Y	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$12.81		$11.51		$12.25		$11.65		$10.38

Income (loss) from investment operations:
Net investment income²		0.13		0.20		0.14		0.17		0.17
Net realized and unrealized gain (loss)		2.68		1.26		(0.66)		0.59		1.30

Total from investment operations		2.81		1.46		(0.52)		0.76		1.47

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.20)		(0.16)		(0.22)		(0.16)		(0.20)

Net asset value, end of period		$15.42		$12.81		$11.51		$12.25		$11.65



Total Return, at Net Asset Value³		21.98%		12.69%		(4.34)%		6.52%		14.07%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$63,523		$56,496		$38,762		$30,551		$9,416

Average net assets (in thousands)		$61,326		$41,675		$33,137		$17,424		$8,437

Ratios to average net assets:^4,5
Net investment income		0.90%		1.65%		1.14%		1.35%		1.48%
Expenses excluding specific expenses listed below		0.34%		0.35%		0.35%		0.35%		0.30%
Interest and fees from borrowings		0.00%		0.00%⁶		0.00%⁶		0.00%		0.00%

Total expenses⁷		0.34%		0.35%		0.35%		0.35%		0.30%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.28%		0.31%		0.31%		0.31%		0.25%

Portfolio turnover rate		9%		5%		8%		15%		9%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Includes the Fund’s share of the allocated expenses and/or net investment income from the master funds.

6. Less than 0.005%.

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


Year Ended January 31, 2018	0.97	%
Year Ended January 31, 2017	0.98	%
Year Ended January 29, 2016	0.97	%
Year Ended January 30, 2015	0.97	%
Year Ended January 31, 2014	0.97	%

See accompanying Notes to Financial Statements.

23 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS January 31, 2018

1. Organization

Oppenheimer Portfolio Series (the “Trust”) is registered under the Investment Company Act of 1940 (“1940 Act”), as amended, as a diversified open-end management investment company. Active Allocation Fund (the “Fund”) is a series of the Trust whose investment objective is to seek total return. The Fund normally invests in a diversified portfolio of Oppenheimer mutual funds (individually, an “Underlying Fund” and collectively, the “Underlying Funds”). The Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”). The Manager has entered into a sub-advisory agreement with OFI.

2. Significant Accounting Policies

Security Valuation. All investments in securities are recorded at their estimated fair value, as described in Note 3.

Dividends and Distributions to Shareholders. Dividends and distributions to

24 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

2. Significant Accounting Policies (Continued)

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.

The tax components of capital shown in the following table represent distribution requirements the Fund must satisfy under the income tax regulations, losses the Fund may be

25 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS Continued

2. Significant Accounting Policies (Continued)

able to offset against income and gains realized in future years and unrealized appreciation or depreciation of securities and other investments for federal income tax purposes.


Undistributed Net Investment Income	Undistributed Long-Term Gain		Accumulated Loss Carryforward^1,2,3		Net Unrealized Appreciation Based on cost of Securities and Other Investments for Federal Income Tax Purposes

$34,500,687		$—		$143,139,986		$701,458,904

1. At period end, the Fund had $143,139,986 of net capital loss carryforward available to offset future realized capital gains, if any, and thereby reduce future taxable gain distributions. Details of the capital loss carryforwards are included in the table below. Capital loss carryovers with no expiration, if any, must be utilized prior to those with expiration dates.


Expiring

2019	$	143,139,986

2. During the reporting period, the Fund utilized $190,061,560 of capital loss carryforward to offset capital gains realized in that fiscal year.

3. During the previous reporting period, the Fund utilized $75,775,769 of capital loss carryforward to offset capital gains realized in that fiscal year.

Accordingly, the following amounts have been reclassified for the reporting period. Net assets of the Fund were unaffected by the reclassifications.


Increase to Paid-in Capital	Increase to Accumulated Net Investment Income		Increase to Accumulated Net Realized Loss on Investments

$10,924		$20,978,168		$20,989,092

The tax character of distributions paid during the reporting periods:


	Year Ended January 31, 2018		Year Ended January 31, 2017

Distributions paid from:
Ordinary income	$	24,282,423	$	18,295,107

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

26 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

2. Significant Accounting Policies (Continued)

purposes at period end are noted in the following table. The primary difference between book and tax appreciation or depreciation of securities and other investments, if applicable, is attributable to the tax deferral of losses or tax realization of financial statement unrealized gain or loss.


Federal tax cost of securities	$	1,976,124,774

Gross unrealized appreciation	$	731,485,908
Gross unrealized depreciation		(30,027,004)

Net unrealized appreciation	$	701,458,904

3. Securities Valuation

Valuations Methods and Inputs

27 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS Continued

3. Securities Valuation (Continued)

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

Classifications

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)

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).

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 at period end 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:
Investment Companies	$	2,562,391,357	$	115,192,321	$	—	$	2,677,583,678

Total Assets	$	2,562,391,357	$	115,192,321	$	—	$	2,677,583,678

4. Investments and Risks

Risks of Investing in the Underlying Funds. The Fund invests in other mutual funds

28 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

4. Investments and Risks (Continued)

advised by the Manager. The Underlying Funds are registered open-end management investment companies under the 1940 Act, as amended. The Manager is the investment adviser of, and the Sub-Adviser provides investment and related advisory services to, the Underlying Funds. The Fund’s Investments in Underlying Funds are included in the Statement of Investments. Shares of Underlying Funds are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of the Underlying Funds’ expenses, including their management fee.

Investment in Oppenheimer Institutional Government Money Market Fund.

Investment in Oppenheimer Master Funds. Certain Underlying Funds in which the Fund invests are mutual funds registered under the 1940 Act, as amended, that expect to be treated as partnerships for tax purposes, specifically Oppenheimer Master Loan Fund, LLC (“Master Loan”), Oppenheimer Master Event-Linked Bond Fund, LLC (“Master Event-Linked Bond”) and Oppenheimer Master Inflation Protected Securities Fund, LLC (“Master Inflation Protected Securities”) (the “Master Funds”). Each Master Fund has its own investment risks, and those risks can affect the value of the Fund’s investments and therefore the value of the Fund’s shares. To the extent that the Fund invests more of its assets in one Master Fund than in another, the Fund will have greater exposure to the risks of that Master Fund.

The investment objective of Master Loan is to seek income. The investment objective of Master Event-Linked Bond is to seek total return. The investment objective of Master Inflation Protected Securities is to seek total return. The Fund’s investments in the Master Funds are included in the Statement of Investments. The Fund recognizes income and gain/ (loss) on its investments in each Master Fund according to its allocated pro-rata share, based on its relative proportion of total outstanding Master Fund shares held, of the total net income earned and the net gain/(loss) realized on investments sold by the Master Funds. As a shareholder, the Fund is subject to its proportional share of the Master Funds’ expenses, including their management fee. The Manager will waive fees and/or reimburse Fund expenses

29 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS Continued

4. Investments and Risks (Continued)

in an amount equal to the indirect management fees incurred through the Fund’s investment in the Master Funds. The Fund owns 3.27% of Master Loan, 8.49% of Master Event-Linked Bond and 29.55% of Master Inflation Protected Securities at period end.

5. Market Risk Factors

The Fund’s investments in securities and/or financial derivatives may expose the Fund to various market risk factors:

Equity Risk. Equity risk relates to the change in value of equity securities as they relate to increases or decreases in the general market.

6. 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:

30 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

6. Shares of Beneficial Interest (Continued)


	Year Ended January 31, 2018						Year Ended January 31, 2017
	Shares			Amount			Shares			Amount

Class A
Sold		11,520,154		$	158,595,411			15,954,799		$	192,872,344
Dividends and/or distributions reinvested		1,370,124			19,894,213			1,238,461			15,344,460
Redeemed		(18,788,195	)		(259,291,837	)		(21,910,398	)		(266,200,432)

Net decrease		(5,897,917	)	$	(80,802,213	)		(4,717,138	)	$	(57,983,628)



Class B
Sold		5,644		$	79,086			32,210		$	385,249
Dividends and/or distributions reinvested		—			—			—			—
Redeemed		(2,595,314	)		(35,162,730	)		(3,622,324	)		(43,130,620)

Net decrease		(2,589,670	)	$	(35,083,644	)		(3,590,114	)	$	(42,745,371)



Class C
Sold		4,207,402		$	56,797,604			5,564,819		$	65,687,819
Dividends and/or distributions reinvested		157,946			2,245,998			100,829			1,224,076
Redeemed		(8,639,903	)		(116,693,768	)		(9,382,498	)		(111,069,139)

Net decrease		(4,274,555	)	$	(57,650,166	)		(3,716,850	)	$	(44,157,244)



Class R
Sold		2,028,899		$	28,004,514			1,817,772		$	21,950,453
Dividends and/or distributions reinvested		75,414			1,088,982			64,142			790,866
Redeemed		(2,542,115	)		(34,877,005	)		(2,187,911	)		(26,300,166)

Net decrease		(437,802	)	$	(5,783,509	)		(305,997	)	$	(3,558,847)



Class Y
Sold		1,933,793		$	26,855,663			1,916,812		$	23,738,704
Dividends and/or distributions reinvested		51,993			762,732			52,980			663,316
Redeemed		(2,273,941	)		(32,042,973	)		(930,034	)		(11,069,921)

Net increase (decrease)		(288,155	)	$	(4,424,578	)		1,039,758		$	13,332,099

7. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IGMMF, for the reporting period were as follows:


	Purchases		Sales

Investment securities		$237,773,557		$345,678,631

8. Fees and Other Transactions with Affiliates

31 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

of the Fund for the reporting period was 0.58%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.

Asset Allocation Fees. The Fund pays the Manager an asset allocation fee equal to an annual rate of 0.10% of the first $3 billion of the daily net assets of the Fund and 0.08% of the daily net assets in excess of $3 billion.

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 indirect investment management fee collected by the Manager, 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.


Projected Benefit Obligations Increased	$	—
Payments Made to Retired Trustees		7,632
Accumulated Liability as of January 31, 2018		64,694

The Fund’s Board of Trustees (“Board”) has adopted a compensation deferral plan for Independent Trustees that enables Trustees to elect to defer receipt of all or a portion of the

32 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

8. Fees and Other Transactions with Affiliates (Continued)

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.

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

Distribution and Service Plans for Class B, Class C and Class R Shares. The Fund has adopted Distribution and Service Plans (the “Plans”) for Class B, Class C and Class R shares pursuant to Rule 12b-1 under the 1940 Act to compensate the Distributor for distributing those share classes, maintaining accounts and providing shareholder services. 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 R shares’ daily net assets. The Fund also pays a service fee under the Plans at an annual rate of 0.25% of daily net assets. The Plans continue in effect from year to year only if the Fund’s Board of Trustees votes annually to approve their continuance at an in person meeting called for that purpose. Fees incurred by the Fund under the Plans are detailed in the Statement of Operations.

33 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

Class A

Class B

Class C

Class R

Class A

Contingent

Front-End

Deferred

Sales Charges

Retained by

Year Ended

Distributor

January 31, 2018

$868,629

$—

$22,127

$41,069

$—

Waivers and Reimbursements of Expenses. Prior to June 1, 2017, the Manager voluntarily waived fees and/or reimbursed the Fund for certain expenses in order to limit “Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses”, (the combined direct (Fund level) and indirect (Underlying Fund level) expenses), to the annual rate of 1.45%, 2.20%, 2.20%, 1.70% and 1.20%, for Class A, Class B, Class C, Class R and Class Y, respectively. Effective June 1, 2017, this expense limitation has been removed.

During the reporting period, the Transfer Agent waived fees and/or reimbursed the Fund for transfer agent and shareholder servicing agent fees as follows:


Class A			$259,343
Class B			4,274
Class C			82,380
Class R			18,247
Class Y			9,099

The Manager has also contractually agreed to waive fees and/or reimburse certain Fund expenses at an annual rate of 0.04% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable waiver and/or expense reimbursements that may apply. During the reporting period, the Manager waived fees and/or reimbursed the Fund $1,004,524.

During the reporting period, the Manager voluntarily reimbursed the Fund $10,924 for certain transactions. The payment is reported separately in the Statement of Operations and increased the Fund’s total returns by less than 0.005%.

34 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareholders and Board of Trustees

Oppenheimer Portfolio Series:

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of Active Allocation Fund, a series of Oppenheimer Portfolio Series, (the “Fund”), including the statement of investments, as of January 31, 2018, the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two year period then ended, and the related notes (collectively, the “financial statements”) and the financial highlights for each of the years in the five year period then ended. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of January 31, 2018, the results of its operations for the year then ended, the changes in its net assets for each of the years in the two year period then ended, and the financial highlights for each of the years in the five year period then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements and financial highlights. Such procedures also included confirmation of securities owned as of January 31, 2018, by correspondence with the transfer agent, or by other appropriate auditing procedures. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements and financial highlights. We believe that our audits provide a reasonable basis for our opinion.

KPMG LLP

Denver, Colorado

March 23, 2018

35 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

FEDERAL INCOME TAX INFORMATION Unaudited

In early 2018, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2017.

Dividends, if any, paid by the Fund during the reporting period which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 80.31% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the reporting period which are not designated as capital gain distributions are eligible for lower individual income tax rates to the extent that the Fund has received qualified dividend income as stipulated by recent tax legislation. The maximum amount allowable but not less than $21,798,688 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2018, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the reporting period, the maximum amount allowable but not less than $6,377,408 of the ordinary distributions to be paid by the Fund qualifies as an interest related dividend.

The Fund has elected the application of Section 853 of the Internal Revenue Code to permit shareholders to take a federal income tax credit or deduction, at their option, on a per share basis. The maximum amount allowable but not less than $1,186,396 of foreign income taxes were paid by the Fund during the reporting period. A separate notice will be mailed to each shareholder, which will reflect the proportionate share of such foreign taxes which must be treated by shareholders as gross income for federal income tax purposes.

Gross income of the maximum amount allowable but not less than $4,443,549 was derived from sources within foreign countries or possessions of the United States.

36 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited

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

37 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited / Continued

The Board also considered the quality of the services provided and the quality of the Managers’ resources that are available to the Fund. The Board took account of the fact that the Sub-Adviser has 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 Managers’ advisory, administrative, accounting, legal, compliance and risk management services, among other services, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of its staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Mark Hamilton, Caleb Wong and Dokyoung Lee, the portfolio managers for the Fund, and the Sub-Adviser’s investment team and analysts. The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which the Board members have become knowledgeable about through their experiences with the Managers and in connection with the review or renewal of the Fund’s service agreements or service providers. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreements.

Investment Performance of the Managers and the Fund. Throughout the year, the Managers provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Managers and by the independent consultant, comparing the Fund’s historical performance to relevant benchmarks or market indices and to the performance of other retail funds in the allocation – 70% to 85% equity category. The Board noted that the Fund’s one-year, three-year, five-year and ten-year performance was below its category median.

Fees and Expenses of the Fund. The Board reviewed the fees paid to the Adviser and the other expenses borne by the Fund. The Board also considered the comparability of the fees charged and the services provided to the Fund to the fees and services for other clients or accounts advised by the Adviser. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load allocation – 70% to 85% equity funds with comparable asset levels and distribution features. After discussions with the Board, the Adviser has agreed to contractually waive fees and/or reimburse certain Fund expenses at an annual rate of 0.04% as calculated on the daily net assets of the Fund. This waiver and/or reimbursement is applied after (and in addition to) any other applicable fee waivers and/or expense reimbursements that apply. This fee waiver and/or expense reimbursement may not be amended or withdrawn until one year from the date of the prospectus, unless approved by the Board. The Board noted that the Fund was charged no direct traditional management fees, exclusive of Underlying Fund management fees, while certain peer group funds did charge direct traditional management fees. The Board also noted that the Fund’s total expenses, net of waivers, were higher than its peer group median and lower than its category median.

38 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Economies of Scale and Profits Realized by the Adviser and Sub-Adviser. The Board considered information regarding the Managers’ costs in serving as the Fund’s investment adviser and sub-adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund and whether those economies of scale benefit the Fund’s shareholders at the current level of Fund assets in relation to its management fee. The Board noted that the Fund currently has asset allocation fee breakpoints, which are intended to share with Fund shareholders economies of scale that may exist as the Fund’s assets grow.

39 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

PORTFOLIO PROXY VOTING POLICIES AND GUIDELINES;

UPDATES TO STATEMENT OF INVESTMENTS Unaudited

Householding—Delivery of Shareholder Documents

40 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

TRUSTEES AND OFFICERS Unaudited


Name, Position(s) Held with the Fund, Length of Service, Year of Birth		Principal Occupation(s) During the Past 5 Years; Other Trusteeships/Directorships Held; Number of Portfolios in the Fund Complex Currently Overseen

INDEPENDENT TRUSTEES		The address of each Trustee in the chart below is 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Trustee serves for an indefinite term, or until his or her resignation, retirement, death or removal.

Brian F. Wruble, Chairman of the Board of Trustees (since 2007), and Trustee (since 2005) Year of Birth: 1943		Governor of Community Foundation of the Florida Keys (non-profit) (since July 2012); Director of TCP Capital, Inc. (since November 2015); Chairman Emeritus of the Board of Trustees (since August 2011), Chairman of the Board of Trustees (August 2007-August 2011), Trustee of the Board of Trustees (since August 1991) of The Jackson Laboratory (non-profit); Member of Zurich Insurance Group’s Investment Management Advisory Council (insurance) (October 2004-February 2017); Treasurer (since 2007) and Trustee (since May 1992) of the Institute for Advanced Study (non-profit educational institute); Director of Special Value Opportunities Fund, LLC (registered investment company) (affiliate of the Sub- Adviser’s parent company) (September 2004-June 2015); General Partner of Odyssey Partners, L.P. (hedge fund) (September 1995-December 2007); Special Limited Partner of Odyssey Investment Partners, LLC (private equity investment) (January 1999-September 2004). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Wruble has served on the Boards of certain Oppenheimer funds since April 2001, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Beth Ann Brown, Trustee (since 2016) Year of Birth: 1968		Advisor, Board of Advisors of Caron Engineering Inc. (since December 2014); Independent Consultant (since September 2012); held the following positions at Columbia Management Investment Advisers LLC: Head of Intermediary Distribution (2008-2012), Managing Director, Strategic Relations (2005-2008), Managing Director, Head of National Accounts (2004-2005); Senior Vice President, National Account Manager (2002-2004), Senior Vice President, Key Account Manager (1999-2002) and Vice President, Key Account Manager (1996-1999) of Liberty Funds Distributor, Inc.; President and Director, of Acton Shapleigh Youth Conservation Corps (non-profit) (since 2012); and Vice President and Director of Grahamtastic Connection (non-profit) (since May 2013). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Brown has served on the Boards of certain Oppenheimer funds since January 2016, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

Edmund P. Giambastiani, Jr., Trustee (since 2013) Year of Birth: 1948		Advisory Board Member of the Maxwell School of Citizenship and Public Affairs of Syracuse University (since April 2012); Director of Mercury Defense Systems Inc. (information technology) (August 2011-February 2013); Trustee of the U.S. Naval Academy Foundation Athletic & Scholarship Program (since November 2010); Advisory Board Member of the Massachusetts Institute of Technology Lincoln Laboratory (federally-funded research development center) (since May 2010); Director of The Boeing Company (aerospace and defense) (since October 2009); Trustee of MITRE Corporation (federally-funded research development center) (since September 2008); Independent Director of QinetiQ Group Plc (defense technology and security) (February 2008-August 2011); Chairman of Monster Worldwide, Inc. (on-line career services) (March 2015-November 2016), Director of

41 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

TRUSTEES AND OFFICERS Unaudited / Continued


Edmund P. Giambastiani, Jr., Continued		Monster Worldwide, Inc. (on-line career services) (February 2008-June 2011); Lead Director (June 2011-March 2015); Chairman of Alenia North America, Inc. (military and defense products) (January 2008-October 2009); Director of SRA International, Inc. (information technology and services) (January 2008-July 2011); President of Giambastiani Group LLC (national security and energy consulting) (since October 2007); United States Navy, career nuclear submarine officer (June 1970-October 2007), Vice Chairman of the Joint Chiefs of Staff (2005-October 2007), Supreme Allied Commander of NATO Commander Transformation (2003-2005), Commander, U.S. Joint Forces Command (2002-2005). Since his retirement from the U.S. Navy in October 2007, Admiral Giambastiani has also served on numerous U.S. Government advisory boards, investigations and task forces for the Secretaries of Defense, State and Interior and the Central Intelligence Agency. He recently completed serving as a federal commissioner on the Military Compensation and Retirement Modernization Commission. Oversees 56 portfolios in the OppenheimerFunds complex. Admiral Giambastiani has served on the Boards of certain Oppenheimer funds since February 2013, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Elizabeth Krentzman, Trustee (since 2014) Year of Birth: 1959		Member of the University of Florida National Board Foundation (since September 2017); Member of the Cartica Funds Board of Directors (private investment funds) (since January 2017); Member of the University of Florida College of Law Association Board of Trustees and Audit Committee Member (since April 2016); Member of University of Florida Law Advisory Board, Washington, DC Alumni Group (since 2015); Advisory Board Member of the Securities and Exchange Commission Historical Society (since 2007); held the following positions at Deloitte & Touche LLP: Principal and Chief Regulatory Advisor for Asset Management Services (2007 - 2014) and U.S. Mutual Fund Leader (2011 - 2014); General Counsel of the Investment Company Institute (trade association) (June 2004 - April 2007); held the following positions at Deloitte & Touche LLP: National Director of the Investment Management Regulatory Consulting Practice (1997 - 2004), Principal (2003 - 2004), Director (1998 - 2003) and Senior Manager (1997 - 1998); Assistant Director of the Division of Investment Management - Office of Disclosure and Investment Adviser Regulation of the U.S. Securities and Exchange Commission (1996 - 1997) and various positions with the Division of Investment Management – Office of Regulatory Policy (1991 - 1996) of the U.S. Securities and Exchange Commission; Associate at Ropes & Gray LLP (1987 – 1991). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Krentzman has served on the Boards of certain Oppenheimer funds since August 2014, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Mary F. Miller, Trustee (since 2005) Year of Birth: 1942		Trustee of International House (not-for-profit) (since June 2007); Trustee of the American Symphony Orchestra (not-for-profit) (October 1998-November 2011); and Senior Vice President and General Auditor of American Express Company (financial services company) (July 1998-February 2003). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Miller has served on the Boards of certain Oppenheimer funds since August 2004, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

42 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Joel W. Motley, Trustee (since 2005) Year of Birth: 1952		Director of Office of Finance Federal Home Loan Bank (since September 2016); Director of Greenwall Foundation (since October 2013); Member of Board and Investment Committee of The Greenwall Foundation (since April 2013); Member of the Vestry of Trinity Wall Street (since April 2012); Director of Southern Africa Legal Services Foundation (since March 2012); Board Member of Pulitzer Center for Crisis Reporting (non-profit journalism) (since March 2011); Managing Director of Public Capital Advisors, LLC (privately-held financial advisor) (since January 2006); Managing Director of Carmona Motley, Inc. (privately-held financial advisor) (since January 2002); Director of Columbia Equity Financial Corp. (privately-held financial advisor) (2002-2007); Managing Director of Carmona Motley Hoffman Inc. (privately-held financial advisor) (January 1998-December 2001); Member of the Finance and Budget Committee of the Council on Foreign Relations, Member of the Investment Committee and Board of Human Rights Watch (since July 2000) and Member of the Investment Committee and Board of Historic Hudson Valley (since February 2010). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Motley has served on the Boards of certain Oppenheimer funds since October 2002, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Joanne Pace, Trustee (since 2012) Year of Birth: 1958		Advisory Board Director of Massey Quick and Company, LLC (since October 2014); Board Director of Horizon Blue Cross Blue Shield of New Jersey (since November 2012); Advisory Board Director of The Alberleen Group LLC (since March, 2012); Board Member (since January 2015), Board Member of 100 Women in Hedge Funds (non-profit) (since January 2015); Advisory Council Member of Morgan Stanley Children’s Hospital (non-profit) (since May, 2012); Senior Advisor of SECOR Asset Management, LP (2010-2011); Managing Director and Chief Operating Officer of Morgan Stanley Investment Management (2006-2010); Partner and Chief Operating Officer of FrontPoint Partners, LLC (hedge fund) (2005-2006); held the following positions at Credit Suisse: Managing Director (2003-2005); Global Head of Human Resources and member of Executive Board and Operating Committee (2004-2005), Global Head of Operations and Product Control (2003- 2004); held the following positions at Morgan Stanley: Managing Director (1997- 2003), Controller and Principal Accounting Officer (1999-2003); Chief Financial Officer (temporary assignment) for the Oversight Committee, Long Term Capital Management (1998-1999). Lead Independent Director and Chair of the Audit and Nominating Committee of The Global Chartist Fund, LLC of Oppenheimer Asset Management (2011-2012); Board Director of Managed Funds Association (2008- 2010); Board Director of Morgan Stanley Foundation (2007-2010) and Investment Committee Chair (2008-2010). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Pace has served on the Boards of certain Oppenheimer funds since November 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

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TRUSTEES AND OFFICERS Unaudited / Continued


Daniel Vandivort, Trustee (since 2014) Year of Birth: 1954		Chairman and Lead Independent Director/Trustee (March 2010-September 2014), Chairman of the Audit Committee (March 2009-September 2014) and Director/ Trustee (December 2008-September 2014) of the Board of Directors/Trustees of Value Line Funds; Trustee, Board of Trustees of Huntington Disease Foundation of America (since January 2015 and June 2007-December 2013) and Treasurer, Chairman of the Audit and Finance Committee (since January 2016); Trustee, Board of Trustees, RIM Retirement Savings Plan (2005-2007); President and Chief Investment Officer, Robeco Investment Management, formerly known as Weiss Peck and Greer (January 2005-June 2007); Member, Management Committee of Robeco Investment Management (2001-2007); Chairman and Trustee of the Board of Trustees of Weiss, Peck and Greer Funds (2004-2005); Managing Director and Head of Fixed Income, Weiss, Peck and Greer (November 1994-January 2005); Managing Director and Head of Fixed Income, CS First Boston Investment Management (January 1992-November 1994); Director, Global Product Development, First Boston Asset Management (November 1989 to January 1992); Vice President, Fixed Income Sales, First Boston Corp. (May 1984-November 1989). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Vandivort has served on the Boards of certain Oppenheimer funds since 2014, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.
INTERESTED TRUSTEE AND OFFICER		Mr. Steinmetz is an “Interested Trustee” because he is affiliated with the Manager and the Sub-Adviser by virtue of his positions as Chairman of the Sub-Adviser and officer and director of the Manager. Both as a Trustee and as an officer, Mr. Steinmetz serves for an indefinite term, or until his resignation, retirement, death or removal. Mr. Steinmetz’s address is 225 Liberty Street, New York, New York 10281-1008.

Arthur P. Steinmetz, Trustee (since 2015), President and Principal Executive Officer (since 2014) Year of Birth: 1958		Chairman of the Sub-Adviser (since January 2015); CEO and Chairman of the Manager (since July 2014), President of the Manager (since May 2013), a Director of the Manager (since January 2013), Director of the Sub-Adviser (since July 2014), President, Management Director and CEO of Oppenheimer Acquisition Corp. (the Sub-Adviser’s parent holding company) (since July 2014), and President and Director of OFI SteelPath, Inc. (since January 2013). Chief Investment Officer of the OppenheimerFunds advisory entities from (January 2013-December 2013); Executive Vice President of the Manager (January 2013-May 2013); Chief Investment Officer of the Sub-Adviser (October 2010-December 2012); Chief Investment Officer, Fixed-Income, of the Sub-Adviser (April 2009-October 2010); Executive Vice President of the Sub-Adviser (October 2009-December 2012); Director of Fixed Income of the Sub-Adviser (January 2009-April 2009); and a Senior Vice President of the Sub-Adviser (March 1993-September 2009). An officer of 110 portfolios in the OppenheimerFunds complex.
OTHER OFFICERS OF THE FUND		The addresses of the Officers in the chart below are as follows: for Messrs. Hamilton, Lee, Wong, Mss. Lo Bessette, Foxson and Picciotto, 225 Liberty Street, New York, New York 10281-1008, for Mr. Petersen, 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Officer serves for an indefinite term or until his or her resignation, retirement, death or removal.

Mark Hamilton¹, Vice President (since 2013) Year of Birth: 1965		Chief Investment Officer, Asset Allocation and Senior Vice President of the Sub-Adviser (since April 2013). Mr. Hamilton served at AllianceBernstein L.P. (from 1994-2013) as an Investment Director of Dynamic Asset Allocation (from 2010-2013), Head of North American Blend Team (from 2009-2010), and Senior Portfolio Manager of Blend Strategies (from 2006-2010). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

44 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Dokyoung Lee¹, Vice President (since 2014) Year of Birth: 1965		Director of Research, Global Multi-Asset Group and a Senior Vice President of the Sub-Adviser (since October 2013). Mr. Lee served at Alliance Bernstein L.P. (1994- 2013): Director of Research for Strategic Asset Allocation (2011-2013), Director of Research for Blend Strategies (2008-2011), Head of Asia Pacific Blend Strategies (2005-2008), Head of Quantitative Research and Senior Portfolio Manager for Japan Value Equities (2001-2005), Portfolio Manager for Emerging Markets Value Equities (1997-2001), and Quantitative Analyst for US Value Equities (1994-1997). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

Caleb Wong, Vice President (since 2005) Year of Birth: 1965		Vice President of the Sub-Adviser (since June 1999); Senior Portfolio Manager of the Sub-Adviser (since January 2005); Head of fixed income quantitative research and risk management of the Sub-Adviser (1997-1999) and worked in fixed-income quantitative research and risk management for the Sub-Adviser (since July 1996). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

Cynthia Lo Bessette, Secretary and Chief Legal Officer (since 2016) Year of Birth: 1969		Executive Vice President, General Counsel and Secretary of the Manager (since February 2016); Senior Vice President and Deputy General Counsel of the Manager (March 2015-February 2016); Chief Legal Officer of the Sub-Adviser and the Distributor (since February 2016); Vice President, General Counsel and Secretary of Oppenheimer Acquisition Corp. (since February 2016); General Counsel of OFI SteelPath, Inc., OFI Advisors and Index Management Solutions, LLC (since February 2016); Chief Legal Officer of OFI Global Institutional, Inc., HarbourView Asset Management Corporation, OFI Global Trust Company, Oppenheimer Real Asset Management, Inc., OFI Private Investments Inc., Shareholder Services, Inc. and Trinity Investment Management Corporation (since February 2016); Corporate Counsel (February 2012-March 2015) and Deputy Chief Legal Officer (April 2013-March 2015) of Jennison Associates LLC; Assistant General Counsel (April 2008-September 2009) and Deputy General Counsel (October 2009-February 2012) of Lord Abbett & Co. LLC. An officer of 110 portfolios in the OppenheimerFunds complex.

Jennifer Foxson, Vice President and Chief Business Officer (since 2014) Year of Birth: 1969		Senior Vice President of OppenheimerFunds Distributor, Inc. (since June 2014); Vice President of OppenheimerFunds Distributor, Inc. (April 2006-June 2014); Vice President of the Sub-Adviser (January 1998-March 2006); Assistant Vice President of the Sub-Adviser (October 1991-December 1998). An officer of 110 portfolios in the OppenheimerFunds complex.

Mary Ann Picciotto, Vice President and Chief Business Officer (since 2014) Year of Birth: 1969		Senior Vice President and Chief Compliance Officer of the Manager (since March 2014); Chief Compliance Officer of the Sub-Adviser, OFI SteelPath, Inc., OFI Global Trust Company, OFI Global Institutional, Inc., Oppenheimer Real Asset Management, Inc., OFI Private Investments, Inc., Harborview Asset Management Corporation, Trinity Investment Management Corporation, and Shareholder Services, Inc. (since March 2014); Managing Director of Morgan Stanley Investment Management Inc. and certain of its various affiliated entities; Chief Compliance Officer of various Morgan Stanley Funds (May 2010-January 2014); Chief Compliance Officer of Morgan Stanley Investment Management Inc. (April 2007-January 2014). An officer of 110 portfolios in the OppenheimerFunds complex.

45 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

TRUSTEES AND OFFICERS Unaudited / Continued

Brian S. Petersen,

Treasurer and Principal Financial & Accounting Officer (since 2016)

Year of Birth: 1970

Senior Vice President of the Manager (since January 2017); Vice President of the Manager (January 2013-January 2017); Vice President of the Sub-Adviser (February 2007-December 2012); Assistant Vice President of the Sub-Adviser (August 2002- 2007). An officer of 110 portfolios in the OppenheimerFunds complex.

1. Effective February 27, 2018, Mark Hamilton and Dokyoung Lee are no longer officers of the Fund.

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

46 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND


Manager		OFI Global Asset Management, Inc.

Sub-Adviser		OppenheimerFunds, Inc.

Distributor		OppenheimerFunds Distributor, Inc.

Transfer and Shareholder		OFI Global Asset Management, Inc.
Servicing Agent

Sub-Transfer Agent		Shareholder Services, Inc.
		DBA OppenheimerFunds Services

Independent Registered		KPMG LLP
Public Accounting Firm

Legal Counsel		Kramer Levin Naftalis & Frankel LLP

47 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

PRIVACY 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 non-public personal information about our shareholders from the following sources:

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Applications or other forms.

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

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When you enroll in eDocs Direct,^SM our electronic document delivery service.

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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

Right of Refusal

48 OPPENHEIMER PORTFOLIO SERIES ACTIVE ALLOCATION FUND

Internet Security and Encryption

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

Other Security Measures

How You Can Help

Who We Are

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		Visit us at oppenheimerfunds.com for 24-hr access to account information and transactions or call us at 800.CALL OPP (800.225.5677) for 24-hr automated information and automated transactions. Representatives also available Mon–Fri 8am-8pm ET.

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		Oppenheimer funds are distributed by OppenheimerFunds Distributor, Inc. 225 Liberty Street, New York, NY 10281-1008 © 2018 OppenheimerFunds Distributor, Inc. All rights reserved. RA0550.001.0118 March 23, 2018

LOGO

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			22

Report of Independent Registered Public Accounting Firm			32

Federal Income Tax Information			33

Board Approval of the Fund’s Investment Advisory and Sub- Advisory Agreements			34

Portfolio Proxy Voting Policies and Guidelines; Updates to Statement of Investments			37

Distribution Sources			38

Trustees and Officers			39

Privacy Notice			45

Class A Shares

AVERAGE ANNUAL TOTAL RETURNS AT 1/31/18


	Class A Shares of the Fund
	Without Sales Charge	With Sales Charge	S&P 500 Index	MSCI World Index
1-Year	27.83%	20.47%	26.41%	25.83%
5-Year	11.15	9.84	15.91	11.68
10-Year	7.07	6.44	9.78	6.42

2 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

Fund Performance Discussion¹

MARKET OVERVIEW

reinvestment program and raised rates in December for the third time in 2017. Despite these tightening measures, by many measures financial conditions eased in 2017.

As alluded to above, market performance was positive for most risk assets during the reporting period. Equities in the U.S. and globally performed well with the S&P 500 Index and the MSCI All Country World Index returning 26.41% and 27.48%, respectively. Emerging market equities outperformed their developed market peers, as the MSCI Emerging Markets Index produced a return of 41.01%. U.S. Treasuries (as represented by the Bloomberg Barclays U.S. Treasury Index)

LOGO

1. The Fund is invested in Class I shares of all underlying funds discussed in this Fund Performance Discussion.

3 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

generated a positive total return of 2.15%. Credit outperformed U.S. Treasuries for the year, with the Bloomberg Barclays U.S. Credit Index rising 4.84%.

FUND REVIEW

Against this market backdrop, the Fund’s Class A shares (without sales charge) produced a total return of 27.83% and outperformed its benchmarks, the S&P 500 Index and the MSCI World Index, which returned 26.41% and 25.83%, respectively.

The Fund received its strongest results from foreign equity funds this reporting period. All of the underlying foreign equity funds produced positive contributions to return for the Fund this period. Oppenheimer International Growth Fund and Oppenheimer International Equity Fund, the Fund’s largest underlying foreign equity holdings, provided the strongest contributions to return. European markets continued to outperform U.S. markets during this reporting period. This benefited both of these underlying funds, which have large allocations to Europe. Oppenheimer International Equity Fund also benefited from its exposure to Japan. Oppenheimer Developing Markets Fund and Oppenheimer International Small-Mid Company Fund also provided strong results. Oppenheimer Developing Markets Fund benefited from an environment where emerging market equities outperformed developed markets. Oppenheimer International Small-Mid Company Fund, which invests primarily in small- and mid-cap

companies domiciled outside the U.S. that offer opportunities for growth, had strong performance this period.

All of the Fund’s domestic equity holdings provided positive returns as well, including its top two holdings: Oppenheimer Capital Appreciation Fund and Oppenheimer Value Fund. Oppenheimer Capital Appreciation Fund typically invests in large-cap U.S. growth stocks. In an environment where growth outperformed value, the underlying fund benefited. That said, value also produced positive returns this period and Oppenheimer Value Fund generated strong results. The Fund’s exposure to Oppenheimer Main Street Mid Cap Fund and Oppenheimer Main Street Small Cap Fund also benefited absolute performance.

FUND UPDATE

4 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

chemical engineering from the University of California, Los Angeles, as well as an MBA in analytic finance and econometrics from the University of Chicago.

5 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

Top Holdings and Allocations

ASSET CLASS ALLOCATION


Domestic Equity Funds			50.1%
Foreign Equity Funds			49.9

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on the total market value of investments.

TOP HOLDINGS


Oppenheimer Value Fund, Cl. I			22.0%
Oppenheimer Capital Appreciation Fund, Cl. I			20.7
Oppenheimer International Growth Fund, Cl. I			19.1
Oppenheimer International Equity Fund, Cl. I			16.8
Oppenheimer International Small- Mid Company Fund, Cl. I			7.6
Oppenheimer Developing Markets Fund, Cl. I			6.4
Oppenheimer Main Street Mid Cap Fund, Cl. I			4.0
Oppenheimer Main Street Small Cap Fund, Cl. I			3.3

Portfolio holdings and allocations are subject to change. Percentages are as of January 31, 2018, and are based on net assets. For current Top Fund holdings, please visit oppenheimerfunds.com.

6 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

Share Class Performance

AVERAGE ANNUAL TOTAL RETURNS WITHOUT SALES CHARGE AS OF 1/31/18


	Inception Date	1-Year	5-Year	10-Year
Class A (OAAIX)	4/5/05	27.83%	11.15%	7.07%
Class B (OBAIX)	4/5/05	26.78	10.30	6.55
Class C (OCAIX)	4/5/05	26.83	10.33	6.26
Class R (ONAIX)	4/5/05	27.44	10.89	6.83
Class Y (OYAIX)	4/5/05	28.04	11.43	7.44

AVERAGE ANNUAL TOTAL RETURNS WITH SALES CHARGE AS OF 1/31/18
	Inception Date	1-Year	5-Year	10-Year
Class A (OAAIX)	4/5/05	20.47%	9.84%	6.44%
Class B (OBAIX)	4/5/05	21.78	10.03	6.55
Class C (OCAIX)	4/5/05	25.83	10.33	6.26
Class R (ONAIX)	4/5/05	27.44	10.89	6.83
Class Y (OYAIX)	4/5/05	28.04	11.43	7.44

The Fund’s performance is compared to the performance of the S&P 500^® Index and the MSCI^® World Index. The S&P 500^® Index is a capitalization-weighted index of 500 stocks intended to be a representative sample of leading companies in leading industries within the U.S. economy. The MSCI^® World Index is an index of issuers listed on the stock exchanges of foreign countries and the United States. It is widely recognized as a measure of global stock market performance. The indices are unmanaged and cannot be purchased directly by investors. 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. Index performance includes reinvestment of income, but does not reflect transaction costs, fees, expenses or taxes. Index performance is shown for illustrative purposes only as a benchmark for the Fund’s performance, and does not predict or depict

7 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

8 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

Fund Expenses

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, 2018.

9 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND


Actual	Beginning Account Value August 1, 2017	Ending Account Value January 31, 2018	Expenses Paid During 6 Months Ended January 31, 2018
Class A	$ 1,000.00	$ 1,132.90	$ 2.48
Class B	1,000.00	1,128.50	6.56
Class C	1,000.00	1,128.10	6.51
Class R	1,000.00	1,131.40	3.82
Class Y	1,000.00	1,134.20	1.13

Hypothetical (5% return before expenses)
Class A	1,000.00	1,022.89	2.35
Class B	1,000.00	1,019.06	6.23
Class C	1,000.00	1,019.11	6.18
Class R	1,000.00	1,021.63	3.62
Class Y	1,000.00	1,024.15	1.07


Class	Expense Ratios
Class A		0.46%
Class B		1.22
Class C		1.21
Class R		0.71
Class Y		0.21

10 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENT OF INVESTMENTS January 31, 2018


	Shares		Value
Investment Companies—99.9%¹
Domestic Equity Funds—50.0%
Oppenheimer Capital Appreciation Fund, Cl. I		2,981,202	$	201,916,796
Oppenheimer Main Street Mid Cap Fund, Cl. I		1,318,341		39,115,178
Oppenheimer Main Street Small Cap Fund, Cl. I		2,096,673		32,540,365
Oppenheimer Value Fund, Cl. I		5,409,855		215,528,606
				489,100,945
Foreign Equity Funds—49.9%
Oppenheimer Developing Markets Fund, Cl. I		1,337,978		62,122,333
Oppenheimer International Equity Fund, Cl. I		7,009,190		164,155,218
Oppenheimer International Growth Fund, Cl. I		4,059,673		186,379,576
Oppenheimer International Small-Mid Company Fund, Cl. I		1,424,623		74,792,688
				487,449,815
Total Investments, at Value (Cost $566,492,436)		99.9%		976,550,760
Net Other Assets (Liabilities)		0.1		848,473
Net Assets		100.0%	$	977,399,233

Footnotes to Statement of Investments


	Shares January 31, 2017		Gross Additions		Gross Reductions		Shares January 31, 2018
Oppenheimer Capital Appreciation Fund, Cl. I		2,848,778		323,678		191,254		2,981,202
Oppenheimer Developing Markets Fund, Cl. I		1,419,854		70,243		152,119		1,337,978
Oppenheimer International Equity Fund, Cl. I		7,355,865		272,277		618,952		7,009,190
Oppenheimer International Growth Fund, Cl. I		4,236,807		188,671		365,805		4,059,673
Oppenheimer International Small- Mid Company Fund, Cl. I		1,425,838		81,274		82,489		1,424,623
Oppenheimer Main Street Mid Cap Fund, Cl. I		1,199,448		193,957		75,064		1,318,341
Oppenheimer Main Street Small Cap Fund, Cl. I		2,068,309		178,598		150,234		2,096,673
Oppenheimer Value Fund, Cl. I		5,326,813		448,297		365,255		5,409,855

	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)
Oppenheimer Capital Appreciation Fund, Cl. I^a	$	201,916,796	$	686,053	$	34,918	$	32,096,855
Oppenheimer Developing Markets Fund, Cl. I		62,122,333		414,637		312,708		17,251,160
Oppenheimer International Equity Fund, Cl. I		164,155,218		597,178		1,221,149		40,147,625
Oppenheimer International Growth Fund, Cl. I		186,379,576		1,853,466		2,933,839		39,789,178

11 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENT OF INVESTMENTS Continued

Footnotes to Statement of Investments (Continued)


	Value		Income		Realized Gain (Loss)		Change in Unrealized Gain (Loss)

Oppenheimer International Small- Mid Company Fund, Cl. I^b	$	74,792,688	$	831,155	$	958,700	$	19,043,569
Oppenheimer Main Street Mid Cap Fund, Cl. I^c		39,115,178		283,141		(17,431)		477,596
Oppenheimer Main Street Small Cap Fund, Cl. I^d		32,540,365		185,344		216,535		2,343,383
Oppenheimer Value Fund, Cl. I^e		215,528,606		2,715,787		1,253,194		22,927,561

Total	$	976,550,760	$	7,566,761	$	6,913,612	$	174,076,927

a. This Fund distributed realized gains of $14,915,948.

b. This Fund distributed realized gains of $1,503,823.

c. This Fund distributed realized gains of $4,329,493.

d. This Fund distributed realized gains of $1,597,029.

e. This Fund distributed realized gains of $8,578,485.

See accompanying Notes to Financial Statements.

12 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENT OF ASSETS AND LIABILITIES January 31, 2018



Assets
Investments, at value—affiliated companies (cost $ 566,492,436)—see accompanying statement of investments	$	976,550,760

Cash		1,230,004

Receivables and other assets:
Shares of beneficial interest sold		381,415
Other		42,510

Total assets		978,204,689


Liabilities
Payables and other liabilities:
Shares of beneficial interest redeemed		482,198
Distribution and service plan fees		199,044
Trustees’ compensation		50,117
Investments purchased		38,370
Shareholder communications		6,384
Other		29,343

Total liabilities		805,456


Net Assets	$	977,399,233



Composition of Net Assets
Par value of shares of beneficial interest	$	50,514

Additional paid-in capital		559,809,455

Accumulated net investment loss		(48,778)

Accumulated net realized gain on investments		7,529,718

Net unrealized appreciation on investments		410,058,324

Net Assets	$	977,399,233

13 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENT OF ASSETS AND LIABILITIES Continued



Net Asset Value Per Share
Class A Shares:
Net asset value and redemption price per share (based on net assets of $674,844,525 and 34,680,558 shares of beneficial interest outstanding)	$	19.46

Maximum offering price per share (net asset value plus sales charge of 5.75% of offering price)	$	20.65


Class B Shares: Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $4,226,496 and 219,737 shares of beneficial interest outstanding)	$	19.23


Class C Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $212,996,255 and 11,231,959 shares of beneficial interest outstanding)	$	18.96


Class R Shares:
Net asset value, redemption price (excludes applicable contingent deferred sales charge) and offering price per share (based on net assets of $59,559,226 and 3,063,732 shares of beneficial interest outstanding)	$	19.44


Class Y Shares:
Net asset value, redemption price and offering price per share (based on net assets of $25,772,731 and 1,318,009 shares of beneficial interest outstanding)	$	19.55

See accompanying Notes to Financial Statements.

14 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENT OF OPERATIONS For the Year Ended January 31, 2018



Investment Income
Dividends—affiliated companies	$	7,566,761

Interest		7,279

Total investment income		7,574,040


Expenses

Distribution and service plan fees:
Class A		1,460,710
Class B		86,945
Class C		1,925,708
Class R		246,914

Transfer and shareholder servicing agent fees:
Class A		1,301,983
Class B		19,095
Class C		421,095
Class R		108,629
Class Y		49,029

Shareholder communications:
Class A		13,998
Class B		898
Class C		3,964
Class R		1,056
Class Y		144

Trustees’ compensation		11,872

Custodian fees and expenses		5,000

Other		55,736

Total expenses		5,712,776
Less waivers and reimbursements of expenses		(128,793)

Net expenses		5,583,983

Net Investment Income		1,990,057


Realized and Unrealized Gain
Net realized gain on:
Investment transactions in affiliated companies		6,913,612
Distributions received from affiliated companies		30,924,778
Increase from payment by affiliate		5,978

Net realized gain		37,844,368

Net change in unrealized appreciation/depreciation on investment transactions		174,076,927

Net Increase in Net Assets Resulting from Operations	$	213,911,352

See accompanying Notes to Financial Statements.

15 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

STATEMENTS OF CHANGES IN NET ASSETS


	Year Ended January 31, 2018		Year Ended January 31, 2017

Operations
Net investment income	$	1,990,057	$	5,672,401

Net realized gain		37,844,368		3,704,401

Net change in unrealized appreciation/depreciation		174,076,927		88,342,576

Net increase in net assets resulting from operations		213,911,352		97,719,378

Dividends and/or Distributions to Shareholders
Dividends from net investment income:
Class A		(9,188,357)		(5,575,647)
Class B		—		—
Class C		(1,569,453)		(591,489)
Class R		(685,005)		(349,363)
Class Y		(417,376)		(245,471)

		(11,860,191)		(6,761,970)


Distributions from net realized gain:
Class A		(5,750,651)		(4,099,293)
Class B		(46,784)		(119,006)
Class C		(1,877,407)		(1,418,042)
Class R		(498,952)		(339,397)
Class Y		(224,705)		(146,998)

		(8,398,499)		(6,122,736)


Beneficial Interest Transactions
Net increase (decrease) in net assets resulting from beneficial interest transactions:
Class A		4,113,274		(11,235,256)
Class B		(11,826,177)		(14,060,658)
Class C		(10,175,540)		(11,593,850)
Class R		3,238,839		(658,299)
Class Y		1,278,604		(3,119,990)

		(13,371,000)		(40,668,053)


Net Assets
Total increase		180,281,662		44,166,619
Beginning of period		797,117,571		752,950,952

End of period (including accumulated net investment income (loss) of $(48,778) and $2,059,221, respectively)	$	977,399,233	$	797,117,571

See accompanying Notes to Financial Statements.

16 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

FINANCIAL HIGHLIGHTS


Class A	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$15.59		$13.99		$14.87		$14.28		$12.30

Income (loss) from investment operations:
Net investment income²		0.07		0.14		0.07		0.11		0.12
Net realized and unrealized gain (loss)		4.24		1.74		(0.76)		0.60		1.97

Total from investment operations		4.31		1.88		(0.69)		0.71		2.09

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.27)		(0.16)		(0.19)		(0.12)		(0.11)
Distributions from net realized gain		(0.17)		(0.12)		0.00		0.00		0.00

Total dividends and/or distributions to shareholders		(0.44)		(0.28)		(0.19)		(0.12)		(0.11)

Net asset value, end of period		$19.46		$15.59		$13.99		$14.87		$14.28




Total Return, at Net Asset Value³		27.83%		13.52%		(4.78)%		4.99%		16.95%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$674,845		$537,926		$492,539		$513,521		$482,285

Average net assets (in thousands)		$598,934		$522,301		$533,833		$519,483		$442,886

Ratios to average net assets:⁴
Net investment income		0.42%		0.93%		0.45%		0.72%		0.88%
Expenses excluding specific expenses listed below		0.47%		0.48%		0.48%		0.48%		0.48%
Interest and fees from borrowings		0.00%		0.00%⁵		0.00%⁵		0.00%		0.00%

Total expenses⁶		0.47%		0.48%		0.48%		0.48%		0.48%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.46%		0.48%		0.48%		0.48%		0.47%

Portfolio turnover rate		8%		6%		8%		10%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Less than 0.005%.

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


Year Ended January 31, 2018			1.17%
Year Ended January 31, 2017			1.18%
Year Ended January 29, 2016			1.16%
Year Ended January 30, 2015			1.17%
Year Ended January 31, 2014			1.23%

See accompanying Notes to Financial Statements.

17 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class B	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$15.31		$13.69		$14.52		$13.93		$12.01

Income (loss) from investment operations:
Net investment loss²		(0.17)		(0.01)		(0.07)		(0.02)		(0.02)
Net realized and unrealized gain (loss)		4.26		1.75		(0.73)		0.61		1.94

Total from investment operations		4.09		1.74		(0.80)		0.59		1.92

Dividends and/or distributions to shareholders:
Dividends from net investment income		0.00		0.00		(0.03)		0.00		0.00
Distributions from net realized gain		(0.17)		(0.12)		0.00		0.00		0.00

Total dividends and/or distributions to shareholders		(0.17)		(0.12)		(0.03)		0.00		0.00

Net asset value, end of period		$19.23		$15.31		$13.69		$14.52		$13.93




Total Return, at Net Asset Value³		26.78%		12.73%		(5.52)%		4.24%		15.99%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$4,226		$14,088		$25,864		$44,518		$63,602

Average net assets (in thousands)		$8,692		$19,291		$35,961		$55,111		$68,259

Ratios to average net assets:⁴
Net investment loss		(1.01)%		(0.07)%		(0.44)%		(0.14)%		(0.12)%
Expenses excluding specific expenses listed below		1.24%		1.24%		1.23%		1.23%		1.25%
Interest and fees from borrowings		0.00%		0.00%⁵		0.00%⁵		0.00%		0.00%

Total expenses⁶		1.24%		1.24%		1.23%		1.23%		1.25%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.23%		1.24%		1.23%		1.23%		1.24%

Portfolio turnover rate		8%		6%		8%		10%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Less than 0.005%.

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


Year Ended January 31, 2018			1.94%
Year Ended January 31, 2017			1.94%
Year Ended January 29, 2016			1.91%
Year Ended January 30, 2015			1.92%
Year Ended January 31, 2014			2.00%

See accompanying Notes to Financial Statements.

18 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND


Class C	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$15.21		$13.65		$14.52		$13.94		$12.02

Income (loss) from investment operations:
Net investment income (loss)²		(0.06)		0.02		(0.05)		0.00		0.02
Net realized and unrealized gain (loss)		4.12		1.71		(0.75)		0.59		1.92

Total from investment operations		4.06		1.73		(0.80)		0.59		1.94

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.14)		(0.05)		(0.07)		(0.01)		(0.02)
Distributions from net realized gain		(0.17)		(0.12)		0.00		0.00		0.00

Total dividends and/or distributions to shareholders		(0.31)		(0.17)		(0.07)		(0.01)		(0.02)

Net asset value, end of period		$18.96		$15.21		$13.65		$14.52		$13.94




Total Return, at Net Asset Value³		26.83%		12.71%		(5.51)%		4.22%		16.11%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$212,996		$180,365		$172,605		$186,923		$177,813

Average net assets (in thousands)		$193,616		$179,171		$189,362		$189,422		$164,340

Ratios to average net assets:⁴
Net investment income (loss)		(0.36)%		0.16%		(0.31)%		(0.02)%		0.12%
Expenses excluding specific expenses listed below		1.22%		1.23%		1.23%		1.22%		1.23%
Interest and fees from borrowings		0.00%		0.00%⁵		0.00%⁵		0.00%		0.00%

Total expenses⁶		1.22%		1.23%		1.23%		1.22%		1.23%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		1.21%		1.23%		1.23%		1.22%		1.22%

Portfolio turnover rate		8%		6%		8%		10%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Less than 0.005%.

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


Year Ended January 31, 2018			1.92%
Year Ended January 31, 2017			1.93%
Year Ended January 29, 2016			1.91%
Year Ended January 30, 2015			1.91%
Year Ended January 31, 2014			1.98%

See accompanying Notes to Financial Statements.

19 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

FINANCIAL HIGHLIGHTS Continued


Class R	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$15.59		$13.98		$14.86		$14.25		$12.27

Income (loss) from investment operations:
Net investment income²		0.04		0.10		0.03		0.06		0.06
Net realized and unrealized gain (loss)		4.21		1.75		(0.77)		0.62		1.99

Total from investment operations		4.25		1.85		(0.74)		0.68		2.05

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.23)		(0.12)		(0.14)		(0.07)		(0.07)
Distributions from net realized gain		(0.17)		(0.12)		0.00		0.00		0.00

Total dividends and/or distributions to shareholders		(0.40)		(0.24)		(0.14)		(0.07)		(0.07)

Net asset value, end of period		$19.44		$15.59		$13.98		$14.86		$14.25




Total Return, at Net Asset Value³		27.44%		13.31%		(5.02)%		4.77%		16.68%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$59,559		$45,222		$41,159		$49,122		$52,433

Average net assets (in thousands)		$50,000		$43,838		$48,259		$52,717		$54,751

Ratios to average net assets:⁴
Net investment income		0.22%		0.68%		0.19%		0.43%		0.46%
Expenses excluding specific expenses listed below		0.72%		0.73%		0.73%		0.73%		0.71%
Interest and fees from borrowings		0.00%		0.00%⁵		0.00%⁵		0.00%		0.00%

Total expenses⁶		0.72%		0.73%		0.73%		0.73%		0.71%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.71%		0.73%		0.73%		0.73%		0.70%

Portfolio turnover rate		8%		6%		8%		10%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Less than 0.005%.

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


Year Ended January 31, 2018			1.42%
Year Ended January 31, 2017			1.43%
Year Ended January 29, 2016			1.41%
Year Ended January 30, 2015			1.42%
Year Ended January 31, 2014			1.46%

See accompanying Notes to Financial Statements.

20 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND


Class Y	Year Ended January 31, 2018		Year Ended January 31, 2017		Year Ended January 29, 2016¹		Year Ended January 30, 2015¹		Year Ended January 31, 2014

Per Share Operating Data
Net asset value, beginning of period		$15.67		$14.05		$14.94		$14.34		$12.35

Income (loss) from investment operations:
Net investment income²		0.13		0.18		0.11		0.15		0.16
Net realized and unrealized gain (loss)		4.23		1.76		(0.77)		0.60		1.98

Total from investment operations		4.36		1.94		(0.66)		0.75		2.14

Dividends and/or distributions to shareholders:
Dividends from net investment income		(0.31)		(0.20)		(0.23)		(0.15)		(0.15)
Distributions from net realized gain		(0.17)		(0.12)		0.00		0.00		0.00

Total dividends and/or distributions to shareholders		(0.48)		(0.32)		(0.23)		(0.15)		(0.15)

Net asset value, end of period		$19.55		$15.67		$14.05		$14.94		$14.34




Total Return, at Net Asset Value³		28.04%		13.88%		(4.53)%		5.24%		17.27%


Ratios/Supplemental Data
Net assets, end of period (in thousands)		$25,773		$19,517		$20,784		$20,573		$20,263

Average net assets (in thousands)		$22,559		$18,820		$22,268		$20,881		$17,842

Ratios to average net assets:⁴
Net investment income		0.72%		1.18%		0.71%		1.00%		1.21%
Expenses excluding specific expenses listed below		0.23%		0.23%		0.23%		0.23%		0.18%
Interest and fees from borrowings		0.00%		0.00%⁵		0.00%⁵		0.00%		0.00%

Total expenses⁶		0.23%		0.23%		0.23%		0.23%		0.18%
Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses		0.22%		0.23%		0.23%		0.23%		0.17%

Portfolio turnover rate		8%		6%		8%		10%		6%

1. Represents the last business day of the Fund’s reporting period.

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

4. Annualized for periods less than one full year.

5. Less than 0.005%.

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


Year Ended January 31, 2018			0.93%
Year Ended January 31, 2017			0.93%
Year Ended January 29, 2016			0.91%
Year Ended January 30, 2015			0.92%
Year Ended January 31, 2014			0.93%

See accompanying Notes to Financial Statements.

21 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS January 31, 2018

1. Organization

Oppenheimer Portfolio Series (the “Trust”) is registered under the Investment Company Act of 1940 (“1940 Act”), as amended, as a diversified open-end management investment company. Equity Investor Fund (the “Fund”) is a series of the Trust whose investment objective is to seek capital appreciation. The Fund normally invests in a diversified portfolio of Oppenheimer mutual funds (individually, an “Underlying Fund” and collectively, the “Underlying Funds”). The Fund’s investment adviser is OFI Global Asset Management, Inc. (“OFI Global” or the “Manager”), a wholly-owned subsidiary of OppenheimerFunds, Inc. (“OFI” or the “Sub-Adviser”). The Manager has entered into a sub-advisory agreement with OFI.

2. Significant Accounting Policies

Security Valuation. All investments in securities are recorded at their estimated fair value, as described in Note 3.

Dividends and Distributions to Shareholders. Dividends and distributions to

22 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

2. Significant Accounting Policies (Continued)

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.

The tax components of capital shown in the following table represent distribution requirements the Fund must satisfy under the income tax regulations, losses the Fund may be

23 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

2. Significant Accounting Policies (Continued)

able to offset against income and gains realized in future years and unrealized appreciation or depreciation of securities and other investments for federal income tax purposes.

Net Unrealized

Appreciation

Based on cost of

Securities and

Undistributed

Accumulated

Other Investments

Net Investment

Long-Term

Loss

for Federal Income

Income

Gain

Carryforward^1,2

Tax Purposes

$—

$22,624,119

$—

$394,963,926

1. During the reporting period, the Fund did not utilize any capital loss carryforward.

2. During the previous reporting period, the Fund did not utilize any capital loss carryforward.

Accordingly, the following amounts have been reclassified for the reporting period. Net assets of the Fund were unaffected by the reclassifications.


	Reduction		Reduction
	to Accumulated		to Accumulated Net
Increase	Net Investment		Realized Gain
to Paid-in Capital	Loss		on Investments³

$1,823,559		$7,762,135		$9,585,694

3. $1,817,581, all of which was long-term capital gain, was distributed in connection with Fund share redemptions.

The tax character of distributions paid during the reporting periods:


	Year Ended		Year Ended
	January 31, 2018		January 31, 2017

Distributions paid from:
Ordinary income	$	11,562,317	$	6,761,970
Long-term capital gain		8,696,373		6,122,736

Total	$	20,258,690	$	12,884,706

24 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

2. Significant Accounting Policies (Continued)


Federal tax cost of securities	$	581,586,835

Gross unrealized appreciation	$	394,963,926
Gross unrealized depreciation		—

Net unrealized appreciation	$	394,963,926

3. Securities Valuation

Valuations Methods and Inputs

Securities for which market quotations are not readily available or a significant event has occurred that would materially affect the value of the security, are 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. The methodologies used for valuing securities are not necessarily an indication of the risks associated with

25 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

3. Securities Valuation (Continued)

investing in those Underlying Funds.

Classifications

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)

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).

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 at period end based on valuation input level:


					Level 3—
	Level 1—		Level 2—		Significant
	Unadjusted		Other Significant		Unobservable
	Quoted Prices		Observable Inputs		Inputs		Value

Assets Table
Investments, at Value:
Investment Companies	$	976,550,760	$	—	$	—	$	976,550,760

Total Assets	$	976,550,760	$	—	$	—	$	976,550,760

4. Investments and Risks

26 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

4. Investments and Risks (Continued)

Underlying Funds. The Fund’s Investments in Underlying Funds are included in the Statement of Investments. Shares of Underlying Funds are valued at their net asset value per share. As a shareholder, the Fund is subject to its proportional share of the Underlying Funds’ expenses, including their management fee.

5. Market Risk Factors

The Fund’s investments in securities and/or financial derivatives may expose the Fund to various market risk factors:

Equity Risk. Equity risk relates to the change in value of equity securities as they relate to increases or decreases in the general market.

27 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

6. 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:


	Year Ended January 31, 2018						Year Ended January 31, 2017
	Shares			Amount			Shares			Amount

Class A
Sold		4,255,418		$	73,837,273			4,799,969		$	71,456,139
Dividends and/or distributions reinvested		809,186			14,824,293			631,076			9,567,117
Redeemed		(4,878,024	)		(84,548,292	)		(6,151,717	)		(92,258,512)

Net increase (decrease)		186,580		$	4,113,274			(720,672	)	$	(11,235,256)



Class B
Sold		5,494		$	88,315			10,617		$	155,045
Dividends and/or distributions reinvested		2,571			46,608			7,962			118,561
Redeemed		(708,480	)		(11,961,100	)		(987,435	)		(14,334,264)

Net decrease		(700,415	)	$	(11,826,177	)		(968,856	)	$	(14,060,658)



Class C
Sold		1,466,443		$	24,979,786			1,703,640		$	24,708,434
Dividends and/or distributions reinvested		192,073			3,432,355			134,751			1,994,308
Redeemed		(2,282,324	)		(38,587,681	)		(2,627,276	)		(38,296,592)

Net decrease		(623,808	)	$	(10,175,540	)		(788,885	)	$	(11,593,850)



Class R
Sold		925,969		$	16,305,280			713,032		$	10,693,944
Dividends and/or distributions reinvested		63,134			1,155,983			44,344			671,814
Redeemed		(826,685	)		(14,222,424	)		(800,317	)		(12,024,057)

Net increase (decrease)		162,418		$	3,238,839			(42,941	)	$	(658,299)



Class Y
Sold		485,650		$	8,400,649			159,505		$	2,397,131
Dividends and/or distributions reinvested		34,536			635,808			25,519			388,396
Redeemed		(447,862	)		(7,757,853	)		(418,614	)		(5,905,517)

Net increase (decrease)		72,324		$	1,278,604			(233,590	)	$	(3,119,990)

7. Purchases and Sales of Securities

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations, for the reporting period were as follows:


	Purchases		Sales

Investment securities	$	65,887,781	$	67,081,103

8. Fees and Other Transactions with Affiliates

Management Fees. Under the investment advisory agreement, the Manager does not charge a management fee, but rather collects indirect management fees from the Fund’s

28 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

8. Fees and Other Transactions with Affiliates (Continued)

investments in the Underlying Funds. The weighted indirect management fees collected from the Fund’s investment in the Underlying Funds, as a percent of average daily net assets of the Fund for the reporting period was 0.65%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.


Projected Benefit Obligations Increased	$	—
Payments Made to Retired Trustees		1,530
Accumulated Liability as of January 31, 2018		12,974

29 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

NOTES TO FINANCIAL STATEMENTS Continued

8. Fees and Other Transactions with Affiliates (Continued)

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.

30 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

8. Fees and Other Transactions with Affiliates (Continued)

Class A

Class B

Class C

Class R

Class A

Contingent

Front-End

Deferred

Sales Charges

Retained by

Year Ended

Distributor

January 31, 2018

$485,106

$65

$6,837

$16,396

$—

Waivers and Reimbursements of Expenses. Prior to June 1, 2017, the Manager voluntarily waived fees and/or reimbursed the Fund for certain expenses in order to limit “Expenses after payments, waivers and/or reimbursements and reduction to custodian expenses”, (the combined direct (Fund level) and indirect (Underlying Fund level) expenses), will not exceed the annual rate of 1.45%, 2.20%, 2.20%, 1.70% and 1.20%, for Class A, Class B, Class C, Class R and Class Y, respectively. Effective June 1, 2017, this expense limitation has been removed.

During the reporting period, the Transfer Agent waived fees and/or reimbursed the Fund for transfer agent and shareholder servicing agent fees as follows:


Class A	$	88,099
Class B		1,436
Class C		28,636
Class R		7,318
Class Y		3,304

During the reporting period, the Manager voluntarily reimbursed the Fund $5,978 for certain transactions. The payment is reported separately in the Statement of Operations and increased the Fund’s total returns by less than 0.005%.

31 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareholders and Board of Trustees

Oppenheimer Portfolio Series:

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of Equity Investor Fund, a series of Oppenheimer Portfolio Series, (the “Fund”), including the statement of investments, as of January 31, 2018, the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two year period then ended, and the related notes (collectively, the “financial statements”) and the financial highlights for each of the years in the five year period then ended. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of January 31, 2018, the results of its operations for the year then ended, the changes in its net assets for each of the years in the two year period then ended, and the financial highlights for each of the years in the five year period then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

KPMG _LLP

Denver, Colorado

March 23, 2018

32 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

FEDERAL INCOME TAX INFORMATION Unaudited

In early 2018, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2017.

Capital gain distributions of $0.16753 per share were paid to Class A, Class B, Class C, Class R and Class Y shareholders, respectively, on December 20, 2017. Whether received in stock or in cash, the capital gain distribution should be treated by shareholders as a gain from the sale of the capital assets held for more than one year (long-term capital gains).

Dividends, if any, paid by the Fund during the reporting period which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 94.30% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the reporting period which are not designated as capital gain distributions are eligible for lower individual income tax rates to the extent that the Fund has received qualified dividend income as stipulated by recent tax legislation. The maximum amount allowable but not less than $8,906,203 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2018, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the reporting period, the maximum amount allowable but not less than $106,395 of the ordinary distributions to be paid by the Fund qualifies as an interest related dividend and the maximum amount allowable but not less than $217,618 of the short-term capital gain distribution to be paid by the Fund qualifies as a short-term capital gain dividend.

The Fund has elected the application of Section 853 of the Internal Revenue Code to permit shareholders to take a federal income tax credit or deduction, at their option, on a per share basis. The maximum amount allowable but not less than $729,879 of foreign income taxes were paid by the Fund during the reporting period. A separate notice will be mailed to each shareholder, which will reflect the proportionate share of such foreign taxes which must be treated by shareholders as gross income for federal income tax purposes.

Gross income of the maximum amount allowable but not less than $2,515,875 was derived from sources within foreign countries or possessions of the United States.

33 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited

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

34 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

Investment Performance of the Managers and the Fund. Throughout the year, the Managers provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Managers and by the independent consultant, comparing the Fund’s historical performance to relevant benchmarks or market indices and to the performance of other retail funds in the world stock category. The Board noted that the Fund’s one-year, three-year, and ten-year performance was below its category median although its five-year performance was better than its category median.

35 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

BOARD APPROVAL OF THE FUND’S INVESTMENT ADVISORY

AND SUB-ADVISORY AGREEMENTS Unaudited / Continued

shareholders at the current level of Fund assets in relation to its management fee. The Fund currently does not charge a management fee.

36 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

PORTFOLIO PROXY VOTING POLICIES AND GUIDELINES;

UPDATES TO STATEMENT OF INVESTMENTS Unaudited

Householding—Delivery of Shareholder Documents

37 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

DISTRIBUTION SOURCES Unaudited

Other

Pay

Net Profit

Capital

Fund Name

Date

Net Income

from Sale

Sources

Oppenheimer Portfolio Series: Equity Investor Fund

12/20/17

46.1%

41.5%

12.4%

38 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited


Name, Position(s) Held with the Fund, Length of Service, Year of Birth		Principal Occupation(s) During the Past 5 Years; Other Trusteeships/ Directorships Held; Number of Portfolios in the Fund Complex Currently Overseen

INDEPENDENT TRUSTEES		The address of each Trustee in the chart below is 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Trustee serves for an indefinite term, or until his or her resignation, retirement, death or removal.

Brian F. Wruble, Chairman of the Board of Trustees (since 2007) and Trustee (since 2005) Year of Birth: 1943		Governor of Community Foundation of the Florida Keys (non-profit) (since July 2012); Director of TCP Capital, Inc. (since November 2015); Chairman Emeritus of the Board of Trustees (since August 2011), Chairman of the Board of Trustees (August 2007-August 2011), Trustee of the Board of Trustees (since August 1991) of The Jackson Laboratory (non-profit); Member of Zurich Insurance Group’s Investment Management Advisory Council (insurance) (October 2004-February 2017); Treasurer (since 2007) and Trustee (since May 1992) of the Institute for Advanced Study (non-profit educational institute); Director of Special Value Opportunities Fund, LLC (registered investment company) (affiliate of the Sub- Adviser’s parent company) (September 2004-June 2015); General Partner of Odyssey Partners, L.P. (hedge fund) (September 1995-December 2007); Special Limited Partner of Odyssey Investment Partners, LLC (private equity investment) (January 1999-September 2004). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Wruble has served on the Boards of certain Oppenheimer funds since April 2001, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Beth Ann Brown, Trustee (since 2016) Year of Birth: 1968		Advisor, Board of Advisors of Caron Engineering Inc. (since December 2014); Independent Consultant (since September 2012); held the following positions at Columbia Management Investment Advisers LLC: Head of Intermediary Distribution (2008-2012), Managing Director, Strategic Relations (2005-2008), Managing Director, Head of National Accounts (2004-2005); Senior Vice President, National Account Manager (2002-2004), Senior Vice President, Key Account Manager (1999-2002) and Vice President, Key Account Manager (1996-1999) of Liberty Funds Distributor, Inc.; President and Director, of Acton Shapleigh Youth Conservation Corps (non-profit) (since 2012); and Vice President and Director of Grahamtastic Connection (non-profit) (since May 2013). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Brown has served on the Boards of certain Oppenheimer funds since January 2016, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

Edmund P. Giambastiani, Jr., Trustee (since 2013) Year of Birth: 1948		Advisory Board Member of the Maxwell School of Citizenship and Public Affairs of Syracuse University (since April 2012); Director of Mercury Defense Systems Inc. (information technology) (August 2011-February 2013); Trustee of the U.S. Naval Academy Foundation Athletic & Scholarship Program (since November 2010); Advisory Board Member of the Massachusetts Institute of Technology Lincoln Laboratory (federally-funded research development center) (since May 2010); Director of The Boeing Company (aerospace and defense) (since October 2009); Trustee of MITRE Corporation (federally-funded research development center) (since September 2008); Independent Director of QinetiQ Group Plc (defense technology and security) (February 2008-August 2011); Chairman of Monster Worldwide, Inc. (on-line career services) (March 2015-November 2016), Director of

39 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued



Edmund P. Giambastiani, Jr., (Continued)		Monster Worldwide, Inc. (on-line career services) (February 2008-June 2011); Lead Director (June 2011-March 2015); Chairman of Alenia North America, Inc. (military and defense products) (January 2008-October 2009); Director of SRA International, Inc. (information technology and services) (January 2008-July 2011); President of Giambastiani Group LLC (national security and energy consulting) (since October 2007); United States Navy, career nuclear submarine officer (June 1970-October 2007), Vice Chairman of the Joint Chiefs of Staff (2005-October 2007), Supreme Allied Commander of NATO Commander Transformation (2003-2005), Commander, U.S. Joint Forces Command (2002-2005). Since his retirement from the U.S. Navy in October 2007, Admiral Giambastiani has also served on numerous U.S. Government advisory boards, investigations and task forces for the Secretaries of Defense, State and Interior and the Central Intelligence Agency. He recently completed serving as a federal commissioner on the Military Compensation and Retirement Modernization Commission. Oversees 56 portfolios in the OppenheimerFunds complex. Admiral Giambastiani has served on the Boards of certain Oppenheimer funds since February 2013, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Elizabeth Krentzman, Trustee (since 2014) Year of Birth: 1959		Member of the University of Florida National Board Foundation (since September 2017); Member of the Cartica Funds Board of Directors (private investment funds) (since January 2017); Member of the University of Florida College of Law Association Board of Trustees and Audit Committee Member (since April 2016); Member of University of Florida Law Advisory Board, Washington, DC Alumni Group (since 2015); Advisory Board Member of the Securities and Exchange Commission Historical Society (since 2007); held the following positions at Deloitte & Touche LLP: Principal and Chief Regulatory Advisor for Asset Management Services (2007—2014) and U.S. Mutual Fund Leader (2011—2014); General Counsel of the Investment Company Institute (trade association) (June 2004—April 2007); held the following positions at Deloitte & Touche LLP: National Director of the Investment Management Regulatory Consulting Practice (1997—2004), Principal (2003—2004), Director (1998—2003) and Senior Manager (1997 - 1998); Assistant Director of the Division of Investment Management—Office of Disclosure and Investment Adviser Regulation of the U.S. Securities and Exchange Commission (1996—1997) and various positions with the Division of Investment Management – Office of Regulatory Policy (1991—1996) of the U.S. Securities and Exchange Commission; Associate at Ropes & Gray LLP (1987 – 1991). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Krentzman has served on the Boards of certain Oppenheimer funds since August 2014, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Mary F. Miller, Trustee (since 2005) Year of Birth: 1942		Trustee of International House (not-for-profit) (since June 2007); Trustee of the American Symphony Orchestra (not-for-profit) (October 1998-November 2011); and Senior Vice President and General Auditor of American Express Company (financial services company) (July 1998-February 2003). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Miller has served on the Boards of certain Oppenheimer funds since August 2004, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

40 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND



Joel W. Motley, Trustee (since 2005) Year of Birth: 1952		Director of Office of Finance Federal Home Loan Bank (since September 2016); Director of Greenwall Foundation (since October 2013); Member of Board and Investment Committee of The Greenwall Foundation (since April 2013); Member of the Vestry of Trinity Wall Street (since April 2012); Director of Southern Africa Legal Services Foundation (since March 2012); Board Member of Pulitzer Center for Crisis Reporting (non-profit journalism) (since March 2011); Managing Director of Public Capital Advisors, LLC (privately-held financial advisor) (since January 2006); Managing Director of Carmona Motley, Inc. (privately-held financial advisor) (since January 2002); Director of Columbia Equity Financial Corp. (privately-held financial advisor) (2002-2007); Managing Director of Carmona Motley Hoffman Inc. (privately-held financial advisor) (January 1998-December 2001); Member of the Finance and Budget Committee of the Council on Foreign Relations, Member of the Investment Committee and Board of Human Rights Watch (since July 2000) and Member of the Investment Committee and Board of Historic Hudson Valley (since February 2010). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Motley has served on the Boards of certain Oppenheimer funds since October 2002, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

Joanne Pace, Trustee (since 2012) Year of Birth: 1958		Advisory Board Director of Massey Quick and Company, LLC (since October 2014); Board Director of Horizon Blue Cross Blue Shield of New Jersey (since November 2012); Advisory Board Director of The Alberleen Group LLC (since March, 2012); Board Member (since January 2015), Board Member of 100 Women in Hedge Funds (non-profit) (since January 2015); Advisory Council Member of Morgan Stanley Children’s Hospital (non-profit) (since May, 2012); Senior Advisor of SECOR Asset Management, LP (2010-2011); Managing Director and Chief Operating Officer of Morgan Stanley Investment Management (2006-2010); Partner and Chief Operating Officer of FrontPoint Partners, LLC (hedge fund) (2005-2006); held the following positions at Credit Suisse: Managing Director (2003-2005); Global Head of Human Resources and member of Executive Board and Operating Committee (2004-2005), Global Head of Operations and Product Control (2003- 2004); held the following positions at Morgan Stanley: Managing Director (1997- 2003), Controller and Principal Accounting Officer (1999-2003); Chief Financial Officer (temporary assignment) for the Oversight Committee, Long Term Capital Management (1998-1999). Lead Independent Director and Chair of the Audit and Nominating Committee of The Global Chartist Fund, LLC of Oppenheimer Asset Management (2011-2012); Board Director of Managed Funds Association (2008- 2010); Board Director of Morgan Stanley Foundation (2007-2010) and Investment Committee Chair (2008-2010). Oversees 56 portfolios in the OppenheimerFunds complex. Ms. Pace has served on the Boards of certain Oppenheimer funds since November 2012, during which time she has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Board’s deliberations.

41 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

TRUSTEES AND OFFICERS Unaudited / Continued



Daniel Vandivort, Trustee (since 2014) Year of Birth: 1954		Chairman and Lead Independent Director/Trustee (March 2010-September 2014), Chairman of the Audit Committee (March 2009-September 2014) and Director/ Trustee (December 2008-September 2014) of the Board of Directors/Trustees of Value Line Funds; Trustee, Board of Trustees of Huntington Disease Foundation of America (since January 2015 and June 2007-December 2013) and Treasurer, Chairman of the Audit and Finance Committee (since January 2016); Trustee, Board of Trustees, RIM Retirement Savings Plan (2005-2007); President and Chief Investment Officer, Robeco Investment Management, formerly known as Weiss Peck and Greer (January 2005-June 2007); Member, Management Committee of Robeco Investment Management (2001-2007); Chairman and Trustee of the Board of Trustees of Weiss, Peck and Greer Funds (2004-2005); Managing Director and Head of Fixed Income, Weiss, Peck and Greer (November 1994-January 2005); Managing Director and Head of Fixed Income, CS First Boston Investment Management (January 1992-November 1994); Director, Global Product Development, First Boston Asset Management (November 1989 to January 1992); Vice President, Fixed Income Sales, First Boston Corp. (May 1984-November 1989). Oversees 56 portfolios in the OppenheimerFunds complex. Mr. Vandivort has served on the Boards of certain Oppenheimer funds since 2014, during which time he has become familiar with the Fund’s (and other Oppenheimer funds’) financial, accounting, regulatory and investment matters and has contributed to the Boards’ deliberations.

INTERESTED TRUSTEE AND OFFICER		Mr. Steinmetz is an “Interested Trustee” because he is affiliated with the Manager and the Sub-Adviser by virtue of his positions as Chairman of the Sub-Adviser and officer and director of the Manager. Both as a Trustee and as an officer, Mr. Steinmetz serves for an indefinite term, or until his resignation, retirement, death or removal. Mr. Steinmetz’s address is 225 Liberty Street, New York, New York 10281-1008.

Arthur P. Steinmetz, Trustee (since 2015), President and Principal Executive Officer (since 2014) Year of Birth: 1958		Chairman of the Sub-Adviser (since January 2015); CEO and Chairman of the Manager (since July 2014), President of the Manager (since May 2013), a Director of the Manager (since January 2013), Director of the Sub-Adviser (since July 2014), President, Management Director and CEO of Oppenheimer Acquisition Corp. (the Sub-Adviser’s parent holding company) (since July 2014), and President and Director of OFI SteelPath, Inc. (since January 2013). Chief Investment Officer of the OppenheimerFunds advisory entities from (January 2013-December 2013); Executive Vice President of the Manager (January 2013-May 2013); Chief Investment Officer of the Sub-Adviser (October 2010-December 2012); Chief Investment Officer, Fixed-Income, of the Sub-Adviser (April 2009-October 2010); Executive Vice President of the Sub-Adviser (October 2009-December 2012); Director of Fixed Income of the Sub-Adviser (January 2009-April 2009); and a Senior Vice President of the Sub-Adviser (March 1993-September 2009). An officer of 110 portfolios in the OppenheimerFunds complex.

OTHER OFFICERS OF THE FUND		The addresses of the Officers in the chart below are as follows: for Messrs. Hamilton, Lee, Mss. Lo Bessette, Foxson and Picciotto, 225 Liberty Street, New York, New York 10281-1008, for Mr. Petersen, 6803 S. Tucson Way, Centennial, Colorado 80112-3924. Each Officer serves for an indefinite term or until his or her resignation, retirement, death or removal.

Mark Hamilton,¹ Vice President (since 2013) Year of Birth: 1965		Chief Investment Officer, Asset Allocation and Senior Vice President of the Sub-Adviser (since April 2013). Mr. Hamilton served at AllianceBernstein L.P. (from 1994-2013) as an Investment Director of Dynamic Asset Allocation (from 2010-2013), Head of North American Blend Team (from 2009-2010), and Senior Portfolio Manager of Blend Strategies (from 2006-2010). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

42 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND



Dokyoung Lee,¹ Vice President (since 2014) Year of Birth: 1965		Director of Research, Global Multi-Asset Group and a Senior Vice President of the Sub-Adviser (since October 2013). Mr. Lee served at Alliance Bernstein L.P. (1994- 2013): Director of Research for Strategic Asset Allocation (2011-2013), Director of Research for Blend Strategies (2008-2011), Head of Asia Pacific Blend Strategies (2005-2008), Head of Quantitative Research and Senior Portfolio Manager for Japan Value Equities (2001-2005), Portfolio Manager for Emerging Markets Value Equities (1997-2001), and Quantitative Analyst for US Value Equities (1994-1997). A portfolio manager and officer of other portfolios in the OppenheimerFunds complex.

Cynthia Lo Bessette, Secretary and Chief Legal Officer (since 2016) Year of Birth: 1969		Executive Vice President, General Counsel and Secretary of the Manager (since February 2016); Senior Vice President and Deputy General Counsel of the Manager (March 2015-February 2016); Chief Legal Officer of the Sub-Adviser and the Distributor (since February 2016); Vice President, General Counsel and Secretary of Oppenheimer Acquisition Corp. (since February 2016); General Counsel of OFI SteelPath, Inc., OFI Advisors and Index Management Solutions, LLC (since February 2016); Chief Legal Officer of OFI Global Institutional, Inc., HarbourView Asset Management Corporation, OFI Global Trust Company, Oppenheimer Real Asset Management, Inc., OFI Private Investments Inc., Shareholder Services, Inc. and Trinity Investment Management Corporation (since February 2016); Corporate Counsel (February 2012-March 2015) and Deputy Chief Legal Officer (April 2013-March 2015) of Jennison Associates LLC; Assistant General Counsel (April 2008-September 2009) and Deputy General Counsel (October 2009-February 2012) of Lord Abbett & Co. LLC. An officer of 110 portfolios in the OppenheimerFunds complex.

Jennifer Foxson, Vice President and Chief Business Officer (since 2014) Year of Birth: 1969		Senior Vice President of OppenheimerFunds Distributor, Inc. (since June 2014); Vice President of OppenheimerFunds Distributor, Inc. (April 2006-June 2014); Vice President of the Sub-Adviser (January 1998-March 2006); Assistant Vice President of the Sub-Adviser (October 1991-December 1998). An officer of 110 portfolios in the OppenheimerFunds complex.

Mary Ann Picciotto, Chief Compliance Officer and Chief Anti-Money Laundering Officer (since 2014) Year of Birth: 1973		Senior Vice President and Chief Compliance Officer of the Manager (since March 2014); Chief Compliance Officer of the Sub-Adviser, OFI SteelPath, Inc., OFI Global Trust Company, OFI Global Institutional, Inc., Oppenheimer Real Asset Management, Inc., OFI Private Investments, Inc., Harborview Asset Management Corporation, Trinity Investment Management Corporation, and Shareholder Services, Inc. (since March 2014); Managing Director of Morgan Stanley Investment Management Inc. and certain of its various affiliated entities; Chief Compliance Officer of various Morgan Stanley Funds (May 2010-January 2014); Chief Compliance Officer of Morgan Stanley Investment Management Inc. (April 2007-January 2014). An officer of 110 portfolios in the OppenheimerFunds complex.

Brian S. Petersen, Treasurer and Principal Financial & Accounting Officer (since 2016) Year of Birth: 1970		Senior Vice President of the Manager (since January 2017); Vice President of the Manager (January 2013-January 2017); Vice President of the Sub-Adviser (February 2007-December 2012); Assistant Vice President of the Sub-Adviser (August 2002- 2007). An officer of 110 portfolios in the OppenheimerFunds complex.

1. Effective February 27, 2018, Mark Hamilton and Dokyoung Lee are no longer officers of the Fund.

43 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND


Manager		OFI Global Asset Management, Inc.

Sub-Adviser		OppenheimerFunds, Inc.

Distributor		OppenheimerFunds Distributor, Inc.

Transfer and Shareholder		OFI Global Asset Management, Inc.
Servicing Agent

Sub-Transfer Agent		Shareholder Services, Inc.
		DBA OppenheimerFunds Services

Independent Registered		KPMG LLP
Public Accounting Firm

Legal Counsel		Kramer Levin Naftalis & Frankel LLP

44 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

PRIVACY NOTICE

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Information Sources

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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

Right of Refusal

45 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

PRIVACY NOTICE Continued

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

Other Security Measures

How You Can Help

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46 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

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47 OPPENHEIMER PORTFOLIO SERIES EQUITY INVESTOR FUND

LOGO

Visit us at oppenheimerfunds.com for 24-hr access to

account information and transactions or call us at 800.CALL

OPP (800.225.5677) for 24-hr automated information and

automated transactions. Representatives also available

Mon–Fri 8am-8pm ET.


Visit Us oppenheimerfunds.com Call Us 800 225 5677

Follow Us		Oppenheimer funds are distributed by OppenheimerFunds Distributor, Inc. 225 Liberty Street, New York, NY 10281-1008 ^© 2018 OppenheimerFunds Distributor, Inc. All rights reserved. RA0555.001.0118 March 23, 2018

Item 2. Code of Ethics.

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

Item 3. Audit Committee Financial Expert.

The Board of Trustees of the registrant has determined that Joanne Pace, the Board’s Audit Committee Chairwoman, is an audit committee financial expert and that Ms. Pace is “independent” for purposes of this Item 3.

Item 4. Principal Accountant Fees and Services.

(a)	Audit Fees

The principal accountant for the audit of the registrant’s annual financial statements billed $91,600 in fiscal 2018 and $87,000 in fiscal 2017.

(b)	Audit-Related Fees

The principal accountant for the audit of the registrant’s annual financial statements billed $24,000 in fiscal 2018 and $28,000 in fiscal 2017.

The principal accountant for the audit of the registrant’s annual financial statements billed $386,986 in fiscal 2018 and $232,185 in fiscal 2017 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

Such services include: Internal control reviews, GIPS attestation procedures, and additional audit services

(c)

Tax Fees

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2018 and no such fees in fiscal 2017.

The principal accountant for the audit of the registrant’s annual financial statements billed $591,136 in fiscal 2018 and $716,713 in fiscal 2017 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

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

(d)	All Other Fees

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2018 and no such fees in fiscal 2017.

The principal accountant for the audit of the registrant’s annual financial statements billed no such fees in fiscal 2018 and no such fees in fiscal 2017 to the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant.

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

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

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

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

(2) 0%

(f)	Not applicable as less than 50%.

(g)

The principal accountant for the audit of the registrant’s annual financial statements billed $1,002,122 in fiscal 2018 and $976,898 in fiscal 2017 to the registrant and the registrant’s investment adviser or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant related to non-audit fees. Those billings did not include any prohibited non-audit services as defined by the Securities Exchange Act of 1934.

(h)

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

Item 5. Audit Committee of Listed Registrants

Not applicable.

Item 6. Schedule of Investments.

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

b) Not applicable.

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

Not applicable.

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

Not applicable.

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

Not applicable.

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

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

None

Item 11. Controls and Procedures.

Based on their evaluation of the registrant’s disclosure controls and procedures (as defined in rule 30a-3(c) under the Investment Company Act of 1940 (17 CFR 270.30a-3(c)) as of 1/31/2018, 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. Disclosure of Securities Lending Activities for Closed-End Management Investment Companies.

Not applicable.

Item 13. Exhibits.

(a)	(1) Exhibit attached hereto.

(2) Exhibits 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 Portfolio Series


By:		/s/ Arthur P. Steinmetz
		Arthur P. Steinmetz
		Principal Executive Officer
Date:		3/16/2018

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/ Arthur P. Steinmetz
		Arthur P. Steinmetz
		Principal Executive Officer
Date:		3/16/2018


By:		/s/ Brian S. Petersen
		Brian S. Petersen
		Principal Financial Officer
Date:		3/16/2018