Oppenheimer Portfolio Series

*January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements. Index returns are calculated through January 31, 2015.

During the reporting period, the Fund’s Class A shares (without sales charge) produced a total return of 5.54%. On a relative basis, the Fund underperformed the Barclays U.S. Aggregate Bond Index and the S&P 500 Index, which returned 6.61% and 14.22%, respectively.

In 2014, the U.S. Federal Reserve (the “Fed”) began reducing its monthly purchases of U.S. government Treasuries and mortgage-backed securities (“MBS”) in steady $10 billion increments, and completed the process at the end of October, thereby ending the quantitative easing (“QE”) program’s purchases. Tapering the QE program in increments helped reduce market volatility and enabled investors to prepare for a post-QE market environment. Although growth in the U.S. softened for the first quarter, partially attributed to cold weather effects across much of the country, it was positive in the second and third quarters of 2014, with Gross Domestic Product (“GDP”) growing at

4.6% and 5.0%, respectively. According to estimates as of the reporting period’s end, GDP in the fourth quarter slowed with an increase of 2.2%.

While economic growth in the U.S. remained largely on track, it slowed in other areas, including Europe, and parts of both Latin America and Asia Pacific. Interest rates in core Europe dropped significantly, and turned negative in many cases. The U.S. dollar rallied strongly against most currencies, but especially the Russian ruble, Brazilian real, the euro, and Japanese yen. In many cases, the large move in currencies represented buying of the U.S. dollar due to a positive

1. The Fund is invested in Class I shares of all underlying funds discussed in this Fund Performance Discussion, except for Oppenheimer Master Inflation Protected Securities Fund, LLC and Oppenheimer Master Loan Fund, LLC, which do not offer Class I shares.

U.S. economic outlook compared to weakening growth prospects elsewhere, in addition to anticipated higher rates in the U.S. The euro was challenged by persistent weakness in Europe and elevated concerns about deflation. Other nations faced headwinds as well. Japan’s economy remained moribund and falling commodity prices pressured natural resource exporters such as Brazil, Russia and Australia. Russia was also under pressure due to sanctions related to hostilities in eastern Ukraine and Crimea, and the precipitous drop in oil prices. Even countries with positive economic fundamentals saw their currencies drop versus the dollar.

FUND REVIEW

Against this backdrop, our allocation to domestic equity underlying funds produced the strongest contribution to the Fund’s return. The largest underlying domestic equity holdings of the Fund were Oppenheimer Value Fund and Oppenheimer Capital Appreciation Fund. The Fund also had allocations to Oppenheimer Main Street Mid Cap Fund and Oppenheimer Main Street Small Cap Fund. All of these underlying funds produced positive absolute performance, but Oppenheimer Capital Appreciation Fund was the top performer as large-cap U.S. growth stocks generally outperformed large-cap U.S. value stocks, as well as mid-cap and small-cap stocks. Oppenheimer Capital Appreciation Fund received its best results

from holdings in the information technology and health care sectors. Relative to its benchmarks, this underlying fund outperformed the S&P 500 Index and the Russell 1000 Growth Index. Oppenheimer Value Fund also experienced its strongest contribution to performance from the information technology and health care sectors. This underlying fund underperformed the S&P 500 Index and the Russell 1000 Value Index, due largely to weaker relative stock selection in the financials sector. Oppenheimer Main Street Mid Cap Fund underperformed its benchmark, the Russell Midcap Index. Its performance was driven by holdings in the information technology and health care sectors, with relative underperformance in the financials sector. Oppenheimer Main Street Small Cap Fund outperformed its benchmark, the Russell 2000 Index. This underlying fund’s performance was driven by holdings in the industrials and financials sectors.

The Fund had a smaller investment in foreign equity funds, which was the largest detractor from absolute performance this period, as equities outside of the U.S. experienced volatility. The Fund’s largest foreign equity underlying funds at period end were Oppenheimer International Growth Fund and Oppenheimer International Value Fund. Both underlying funds produced negative returns this reporting period, and underperformed their benchmark, the MSCI All Country World

ex-U.S. Index. The performance of these underlying funds was negatively impacted by their exposure to certain European stocks. The Fund also had smaller allocations to Oppenheimer Developing Markets Fund and Oppenheimer International Small Company Fund. Oppenheimer Developing Markets Fund produced a positive total return but underperformed its benchmark, the MSCI Emerging Markets Index. This underlying fund received strong contributions to return from the financials and information technology sectors, but investments in the United Kingdom and Russia drove its underperformance. Oppenheimer International Small Company Fund produced a positive return and outperformed the negative return of its benchmark, the MSCI All Country World Ex U.S. Small Cap Net Index. Investments in the health care, information technology and materials sectors drove this underlying fund’s performance.

The Fund’s fixed-income underlying funds produced a positive contribution to return this reporting period. The Fund’s largest underlying fixed-income holding, Oppenheimer Core Bond Fund, was the strongest performer. This underlying fund continued to favor corporate bonds, mortgages and other securitized products over government bonds this reporting period, which benefited performance as these investments outperformed U.S. Treasuries. Relative to its benchmarks, this underlying

fund outperformed the Barclays U.S. Aggregate Bond Index and the Citigroup Broad Investment Grade Bond Index, but underperformed the Barclays Credit Index.

The Fund’s next largest underlying fixed-income funds were Oppenheimer Limited-Term Government Fund, Oppenheimer International Bond Fund and Oppenheimer Master Loan Fund, LLC. Oppenheimer Limited-Term Government Fund produced a muted return during the reporting period, as U.S. Government bonds lagged higher-yielding fixed-income sectors and equities. An allocation to mortgage-backed securities benefited this underlying fund during the reporting period. Relative to its benchmarks, this underlying fund outperformed the Barclays U.S. 1-3 Year Government Bond Index, but underperformed the Barclays U.S. Government Bond Index.

Oppenheimer International Bond Fund produced a positive return this reporting period. This underlying fund outperformed its Reference Index, which is a customized weighted index comprised of 50% of the Citigroup Non-U.S. Dollar World Government Bond Index, 30% of the J.P. Morgan Government Bond Index and 20% of the J.P. Morgan Emerging Markets Bond Index. This underlying fund’s lower than typical foreign currency exposure helped performance as the U.S. dollar strengthened against most other currencies. In addition, this underlying fund’s

underweights in the Japanese yen and the euro were beneficial, as was its overweight to international credit exposure, especially in high grade emerging market sovereign and high yield European credit. The underlying fund’s overall short duration exposure detracted from performance as rates declined in most developed countries. Its underweight duration positions in Europe detracted the most.

Oppenheimer Master Loan Fund, LLC, which invests primarily in senior loans, produced a modest positive return and underperformed its benchmark, the J.P. Morgan Leveraged Loan Index. This underlying fund’s relative underperformance stemmed from the energy sector, as a result of the sudden and precipitous drop in oil prices.

The Fund’s allocation to underlying alternative funds had a positive effect on performance this period. The Fund’s largest positions within alternatives were Oppenheimer Master Inflation Protected Securities Fund, LLC and Oppenheimer Global Multi Strategies Fund. Oppenheimer Master Inflation Protected Securities Fund, LLC, invests primarily in Treasury Inflation Protected Securities (TIPS), whose performance is closely correlated to U.S. inflation rates. This underlying fund produced positive performance, but underperformed its benchmark, the Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index.

Oppenheimer Global Multi Strategies Fund seeks to offer the benefit of four major alternative strategy categories: Global Macro, Equity Market Neutral, Fixed-Income Alternatives and Volatility. It produced a positive return, with contributions from three of its four major alternative strategy categories, Equity Market Neutral, Global Macro and Fixed Income Alternatives. Relative to its benchmark, this underlying fund outperformed the BofA Merrill Lynch 3-Month U.S. Treasury Bill Index as absolute return strategies generally outpaced short-term U.S. Government securities. The Fund also had exposure to Oppenheimer Real Estate Fund, Oppenheimer Gold & Special Minerals Fund and Oppenheimer Commodity Strategy Total Return Fund. Oppenheimer Real Estate Fund produced positive performance in an environment of solid real estate fundamentals that were supported both by macroeconomic factors and the capital markets. Relative to its benchmark, the Fund outperformed the FTSE/NAREIT Equity REIT Index. Oppenheimer Gold & Special Minerals Fund produced negative returns as the stocks of most gold producers fell sharply in response to plummeting commodity prices in an environment of sluggish global economic growth and intensifying geopolitical tensions. Oppenheimer Commodity Strategy Total Return Fund experienced declines for the same reason, with energy in particular falling over the second half of 2014. Oppenheimer

Gold & Special Minerals Fund underperformed its benchmark, the MSCI World Index, but performed more in line with other gold and special minerals stocks within the Philadelphia Gold & Silver Index. Oppenheimer Commodity Strategy Total Return Fund underperformed the Bloomberg Commodity Index for the reporting period.

ASSET CLASS ALLOCATION


Domestic Fixed Income Funds		43.0%
Domestic Equity Funds		21.7
Alternative Funds		18.8
Foreign Fixed income Funds		11.0
Foreign Equity Funds		4.3
Money Market Fund		1.2

Portfolio holdings and allocations are subject to change. Percentages are as of January 30, 2015, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Core Bond Fund, Cl. I		26.4%
Oppenheimer Limited-Term Government Fund, Cl. I		11.7
Oppenheimer International Bond Fund, Cl. I		10.9
Oppenheimer Value Fund, Cl. I		9.3
Oppenheimer Capital Appreciation Fund, Cl. I		9.2
Oppenheimer Master Inflation Protected Securities Fund, LLC		7.6
Oppenheimer Master Loan Fund, LLC		4.9
Oppenheimer Global Multi Strategies Fund, Cl. I		4.8
Oppenheimer Real Estate Fund, Cl. I		3.3
Oppenheimer Main Street Mid Cap Fund, Cl. I		1.7

Portfolio holdings and allocations are subject to change. Percentages are as of January 30, 2015, and are based on net assets. For more current Top 10 Fund holdings, please visit oppenheimerfunds.com.

* January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements.

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 (“CDSC”) of 1% for the 1-year period. Prior to 7/1/14, Class R shares were named Class N shares. Beginning 7/1/14, new purchases of Class R shares will no longer be subject to a CDSC upon redemption (any CDSC will remain in effect for purchases prior to 7/1/14). There is no sales charge for Class Y shares. Because Class B shares convert to Class A shares 72 months after purchase, the 10-year return for Class B shares uses Class A performance for the period after conversion.

The Fund’s performance is compared to the performance of the S&P 500 Index and the Barclays U.S. Aggregate Bond Index. The S&P 500 Index is a broad-based measure of domestic stock performance. The Barclays U.S. Aggregate Bond Index is an index of U.S. Government and corporate bonds. 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 performance of the Fund. The Fund’s performance reflects the effects of the Fund’s business and operating expenses.

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

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.

Fund Expenses. As a shareholder of the Fund, you incur two types of costs: (1) transaction costs, which may include sales charges (loads) on purchase payments, contingent deferred sales charges on redemptions; and (2) ongoing costs, including management fees; distribution and service fees; and other Fund expenses. These examples are intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The examples are based on an investment of $1,000.00 invested at the beginning of the period and held for the entire 6-month period ended January 30, 2015.

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 30, 2015” 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.

Expenses are equal to the Fund’s annualized expense ratio for that class, multiplied by the average account value over the period, multiplied by 183/365 (to reflect the one-half year period). Those annualized expense ratios, excluding indirect expenses from affiliated funds, based on the 6-month period ended January 30, 2015 are as follows:

The expense ratios reflect voluntary and/or contractual waivers and/or reimbursements of expenses by the Fund’s Manager. 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.

*January 30, 2015, represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

1. Is or was an affiliate, as defined in the Investment Company Act of 1940, as amended, at or during the period ended January 30, 2015, by virtue of the Fund owning at least 5% of the voting securities of the issuer or as a result of the Fund and the issuer having the same investment adviser. Transactions during the period in which the issuer was an affiliate are as follows:

b. Prior to June 30, 2014, this Fund was named Oppenheimer Main Street Small- & Mid-Cap Fund.

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

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

1. January 30, 2015, represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

3. Effective July 1, 2014, Class N shares were renamed Class R. See Note 1 of the accompanying Notes.

1. January 30, 2015, represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

2. Effective July 1, 2014, Class N shares were renamed Class R. See Note 1 of the accompanying Notes.

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

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

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

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


Year Ended January 30, 2015	1.06	%
Year Ended January 31, 2014	1.08	%
Year Ended January 31, 2013	1.08	%
Year Ended January 31, 2012	1.10	%
Year Ended January 31, 2011	1.10	%

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

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

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

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


Year Ended January 30, 2015	1.81	%
Year Ended January 31, 2014	1.87	%
Year Ended January 31, 2013	1.90	%
Year Ended January 31, 2012	1.96	%
Year Ended January 31, 2011	1.98	%

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

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

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


Year Ended January 30, 2015	1.81	%
Year Ended January 31, 2014	1.84	%
Year Ended January 31, 2013	1.82	%
Year Ended January 31, 2012	1.86	%
Year Ended January 31, 2011	1.88	%

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

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

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


Year Ended January 30, 2015	1.31	%
Year Ended January 31, 2014	1.35	%
Year Ended January 31, 2013	1.39	%
Year Ended January 31, 2012	1.39	%
Year Ended January 31, 2011	1.42	%

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

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

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

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


Year Ended January 30, 2015	0.81	%
Year Ended January 31, 2014	0.83	%
Year Ended January 31, 2013	0.80	%
Year Ended January 31, 2012	0.79	%
Year Ended January 31, 2011	0.75	%

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 will be allowed. As of July 1, 2014, Class N shares were renamed Class R shares. Class N shares subject to a CDSC on July 1, 2014, will continue to be subject to a CDSC after the shares are renamed. Purchases of Class R shares occurring on or after July 1, 2014, will not be subject to a CDSC upon redemption. Class A shares are sold at their offering price, which is normally net asset value plus a front-end sales charge. Class C and Class R 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 consistently followed by the Fund.

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

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

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

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

Custodian Fees. “Custodian fees and expenses” in the Statement of Operations may include interest expense incurred by the Fund on any cash overdrafts of its custodian account during the period. Such cash overdrafts may result from the effects of failed trades in portfolio securities and from cash outflows resulting from unanticipated shareholder redemption activity. The Fund pays interest to its custodian on such cash overdraft at a rate equal to the 1 Month LIBOR Rate plus 2.00%. 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.

excise tax provision is required. The Fund files income tax returns in U.S. federal and applicable state jurisdictions. The statute of limitations on the Fund’s tax return filings generally remain open for the three preceding fiscal reporting period ends.

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

1. As of January 30, 2015, the Fund had $57,205,236 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.

2. During the fiscal year ended January 30, 2015, the Fund utilized $19,984,914 of capital loss carryforward to offset capital gains realized in that fiscal year.

3. During the fiscal year ended January 31, 2014, the Fund utilized $5,655,071 of capital loss carryforward to offset capital gains realized in that fiscal year.

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

Accordingly, the following amounts have been reclassified for January 30, 2015. Net assets of the Fund were unaffected by the reclassifications.

The tax character of distributions paid during the years ended January 31, 2015 and January 31, 2014 was as follows:

The aggregate cost of securities and other investments and the composition of unrealized appreciation and depreciation of securities and other investments for federal income tax purposes as of January 30, 2015 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.

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

The Fund calculates the net asset value of its shares based upon the net asset value of the applicable Underlying Fund. For each Underlying Fund, the net asset value per share for a class of shares is determined as of the close of the New York Stock Exchange (the “Exchange”), normally 4:00 P.M. Eastern time, on each day the Exchange is open for trading by dividing the value of the Underlying Fund’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 its next regularly scheduled meeting covering the calendar quarter in which the fair valuation was determined.

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.

If a market value or price cannot be determined for a security using the methodologies described above, or if, in the “good faith” opinion of the Manager, the market value or price obtained does not constitute a “readily available market quotation,” or a significant event has occurred that would materially affect the value of the security the security is fair valued either (i) by a standardized fair valuation methodology applicable to the security type or the significant event as previously approved by the Valuation Committee and the Fund’s Board or (ii) as determined in good faith by the Manager’s Valuation Committee. The Valuation Committee considers all relevant facts that are reasonably available, through either public information or information available to the Manager, when determining the fair value of a security. Fair value determinations by the Manager are subject to review, approval and ratification by the Fund’s Board at its next regularly scheduled meeting covering the calendar quarter in which the fair valuation was determined. The methodologies used for valuing securities are not necessarily an indication of the risks associated with investing in those Underlying Funds.

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

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

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

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

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

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 those Underlying Funds which are publicly offered and reported on an exchange as Level 1, and those Underlying Funds which are not publicly offered as Level 2, without consideration as to the classification level of the specific investments held by the Underlying Funds.

The table below categorizes amounts that are included in the Fund’s Statement of Assets and Liabilities as of January 30, 2015 based on valuation input level:

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.

Risks of Investing in the Underlying Funds. 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.

Significant Holdings. As of year-end, the Fund’s investment in Oppenheimer Core Bond Fund, accounted for 26.4% of the Fund’s net assets. Additional information on Oppenheimer Core Bond Fund, including the audited financials, can be found on the SEC website.

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

Investment in Oppenheimer Master Funds. The Fund is permitted to invest in entities sponsored and/or advised by the Manager or an affiliate. Certain of these entities in which

the Fund invests are mutual funds registered under the Investment Company Act of 1940 that expect to be treated as partnerships for tax purposes, specifically Oppenheimer Master Loan Fund, LLC and Oppenheimer Master Inflation Protected Securities Fund, LLC (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 Oppenheimer Master Loan Fund, LLC is to seek income. The investment objective of Oppenheimer Master Inflation Protected Securities Fund, LLC 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 in an amount equal to the indirect management fees incurred through the Fund’s investment in the Master Funds.

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:

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IMMF, for the year ended January 30, 2015 were as follows:

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 year ended January 30, 2015 was 0.49%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.

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

Transfer Agent Fees. 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. 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 year ended January 30, 2015, the Fund’s projected benefit obligations, payments to retired Trustees and accumulated liability were as follows:

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 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.

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 vote annually to approve its 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.

Waivers and Reimbursements of Expenses. The Manager has contractually agreed to waive fees and/or reimburse 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 1.25%, 2.00%, 2.00%, 1.50% and 1.00%, for Class A, Class B, Class C, Class R and Class Y, respectively. The expense limitations do not include extraordinary expenses and other expenses not incurred in the ordinary course of the Fund’s business. Notwithstanding the foregoing limits, the Manager is not required to waive or reimburse Fund expenses in excess of the amount of indirect management fees earned from investments in the Underlying Funds.

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 year ended January 30, 2015, the manager waived fees and/or reimbursed the Fund $583,557.

These undertakings may be modified or terminated as set forth according to the terms in the prospectus.

In 2009, seven class action lawsuits were filed in the U.S. District Court for the District of Colorado against OppenheimerFunds, Inc. (“OFI”), OppenheimerFunds Distributor, Inc., the Fund’s principal underwriter and distributor (the “Distributor”), and certain funds (but not including the Fund) advised by OFI Global Asset Management, Inc. and distributed by the Distributor (the “Defendant Funds”). The lawsuits also named as defendants certain officers and current and former trustees of the respective Defendant Funds. The lawsuits raised claims under federal securities laws and alleged, among other things, that the disclosure documents of the respective Defendant Funds contained misrepresentations and omissions and that the respective Defendant Funds’ investment policies were not followed. The plaintiffs in these actions sought unspecified damages, equitable relief and awards of attorneys’ fees and litigation expenses. The Defendant Funds’ Boards of Trustees also engaged counsel to represent the Funds and the present and former Independent Trustees named in those suits. In March 2014, the parties in six of these lawsuits executed stipulations and agreements of settlement resolving those actions. In July 2014, the court entered an order and final judgment approving the settlements as fair, reasonable and adequate. The settlements do not resolve a seventh outstanding lawsuit relating to Oppenheimer Rochester California Municipal Fund (the “California Fund Suit”). OFI believes the California Fund Suit is without legal merit and is defending the suit vigorously. While it is premature to render any opinion as to the outcome in the California Fund Suit, or whether any costs that OFI may bear in defending the California Fund Suit might not be reimbursed by insurance, OFI believes the California Fund Suit should not impair the ability of OFI or the Distributor to perform their respective duties to the Fund, and that the outcome of the California Fund Suit should not have any material effect on the operations of any of the Oppenheimer funds.

We have audited the accompanying statement of assets and liabilities of Conservative Investor Fund (a series of Oppenheimer Portfolio Series), including the statement of investments, as of January 30, 2015, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two-year period then ended, and the financial highlights for each of the years in the five-year period then ended. These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. Our procedures included confirmation of securities owned as of January 30, 2015, by correspondence with the custodian, transfer agent and brokers, or by other appropriate auditing procedures where replies from brokers were not received. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Conservative Investor Fund as of January 30, 2015, 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.

In early 2015, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2014.

Dividends, if any, paid by the Fund during the fiscal year ended January 30, 2015 which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 14.58% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the fiscal year ended January 30, 2015 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 $2,141,233 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2015, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the fiscal year ended January 30, 2015, the maximum amount allowable but not less than $6,443,873 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 $59,473 of foreign income taxes were paid by the Fund during the fiscal year ended January 30, 2015. 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 $423,794 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.

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 renew the Agreements. The Investment Company Act of 1940, as amended, requires that the Board request and evaluate, and that the Managers provide, such information as may be reasonably necessary to evaluate the terms of the Agreements. The Board employs an independent consultant to prepare a report that provides information, including comparative information that the Board requests for that purpose. In addition to in-person meetings focused on this evaluation, the Board receives information throughout the year regarding Fund services, fees, expenses and performance.

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

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

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

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

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

The Board evaluated the Sub-Adviser’s advisory, administrative, accounting, legal, compliance services and risk management, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of its staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Mark Hamilton and Dokyoung Lee, the portfolio managers for the Fund, and the experience of the portfolio managers and the investment performance of the investment companies in which the Fund invests (the “Underlying Funds”). The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which its members have become knowledgeable about in connection with the renewal of the Fund’s service agreements. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreement.

Investment Performance of the Fund, the Adviser and the Sub-Adviser. Throughout the year, the Adviser and the Sub-Adviser provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Adviser, the Sub-Adviser and the independent consultant, comparing the Fund’s historical performance to its benchmark and to the performance of other retail funds in the conservative allocation category. The Board noted that the Fund’s one-year, three-year, and five-year performance was below its category median.

Costs of Services by the Adviser. The Board reviewed the expenses borne by the Fund. The Adviser does not charge a management fee to the Fund; however, the Adviser collects indirect management fees from the Fund’s Underlying Funds. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load conservative allocation funds with comparable asset levels and distribution features. After discussions with the Board, the Adviser has agreed to contractually waive fees and/or reimburse the Fund for certain expenses in order to limit “Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement” (including the combined direct (Fund level) and indirect (Underlying Fund level) expenses, but excluding (i) interest and fees from borrowing, interest and related expenses from inverse floaters, taxes, dividends tied to short sales, brokerage commission, and other expenditures which are capitalized in accordance with generally accepted accounting principles; (ii) certain other expenses attributable to, and incurred as a result of, a Fund’s investments; and (iii) other extraordinary expenses (including litigation expenses) not incurred in the ordinary course of the Fund’s business) to annual rates of 1.25% for Class A shares, 2.00% for Class B shares, 2.00% for Class C shares, 1.50% for Class R shares, and 1.00% for Class Y shares as calculated on the daily net assets of the Fund. This fee waiver and/or expense reimbursement may be amended or withdrawn at any time without prior notice to shareholders. After discussions with the Board, the Adviser has also 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 may apply, and may not be

amended or withdrawn until one year from the date of the Fund’s prospectus, unless approved by the Board. The Adviser is not required to waive or reimburse Fund expenses in excess of the amount of indirect management fees earned from investments in the Underlying Funds. 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 Fund’s total expenses were lower than its peer group median and category median.

Economies of Scale and Profits Realized by the Adviser and Sub-Adviser. The Board considered information regarding OFI Global’s costs in serving as the Fund’s investment adviser, including the costs associated with the personnel and systems necessary to manage the Fund, and information regarding the Managers’ profitability from their relationship with the Fund. The Board reviewed whether the Managers may realize economies of scale in managing and supporting the Fund 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. The Board also considered that the Managers must be able to pay and retain experienced professional personnel at competitive rates to provide quality services to the Fund.

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

Based on its review of the information it received and its evaluations described above, the Board, including a majority of the independent Trustees, decided to continue the Agreements through September 30, 2015. 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.

The Fund has adopted Portfolio Proxy Voting Policies and Procedures under which the Fund votes proxies relating to securities (“portfolio proxies”) held by the Fund. A description of the Fund’s Portfolio Proxy Voting Policies and Procedures is available (i) without charge, upon request, by calling the Fund toll-free at 1.800.CALL OPP (225.5677), (ii) on the Fund’s website at 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.

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.

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).

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

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

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

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

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

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

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.

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 financial services or educational material that may be of interest to you. If this requires us to provide you with an opportunity to “opt in” or “opt out” of such information sharing with a firm not affiliated with us, you will receive notification on how to do so, before any such sharing takes place.

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.

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

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

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.

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

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 November 2014. 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, write to us at P.O. Box 5270, Denver, CO 80217-5270, email us by clicking on the Contact Us section of our website at oppenheimerfunds.com or call us at 1.800.CALL OPP (225.5677).

*January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements. Index returns are calculated through January 31, 2015.

During the reporting period, the Fund’s Class A shares (without sales charge) produced a total return of 6.67%. On a relative basis, the Fund underperformed the Barclays U.S. Aggregate Bond Index and the S&P 500 Index, which returned 6.61% and 14.22%, respectively.

the second and third quarters of 2014, with Gross Domestic Product (“GDP”) growing at 4.6% and 5.0%, respectively. According to estimates as of the reporting period’s end, GDP in the fourth quarter slowed with an increase of 2.2%.

especially the Russian ruble, Brazilian real, the euro, and Japanese yen. In many cases, the large move in currencies represented buying of the U.S. dollar due to a positive U.S. economic outlook compared to weakening growth prospects elsewhere, in addition to anticipated higher rates in the U.S. The euro was challenged by persistent weakness in Europe and elevated concerns about deflation. Other nations faced headwinds as well. Japan’s economy remained moribund and falling commodity prices pressured natural resource exporters such as Brazil, Russia and Australia. Russia was also under pressure due to sanctions related to hostilities in eastern Ukraine and Crimea, and the precipitous drop in oil prices. Even countries with positive economic fundamentals saw their currencies drop versus the dollar.

FUND REVIEW

value stocks, as well as mid-cap and small-cap stocks. Oppenheimer Capital Appreciation Fund received its best results from holdings in the information technology and health care sectors. Relative to its benchmarks, this underlying fund outperformed the S&P 500 Index and the Russell 1000 Growth Index. Oppenheimer Value Fund also experienced its strongest contribution to performance from the information technology and health care sectors. This underlying fund underperformed the S&P 500 Index and the Russell 1000 Value Index, due largely to weaker relative stock selection in the financials sector. Oppenheimer Main Street Mid Cap Fund underperformed its benchmark, the Russell Midcap Index. Its performance was driven by holdings in the information technology and health care sectors, with relative underperformance in the financials sector. Oppenheimer Main Street Small Cap Fund outperformed its benchmark, the Russell 2000 Index. This underlying fund’s performance was driven by holdings in the industrials and financials sectors.

The Fund’s investment in foreign equity funds was the largest detractor from absolute performance this period, as equities outside of the U.S. experienced volatility. The Fund’s largest foreign equity underlying funds at period end were Oppenheimer International Growth Fund and Oppenheimer International Value Fund. Both underlying funds produced negative returns this reporting period, and

underperformed their benchmark, the MSCI All Country World ex-U.S. Index. The performance of these underlying funds was negatively impacted by their exposure to certain European stocks. The Fund also had smaller allocations to Oppenheimer Developing Markets Fund and Oppenheimer International Small Company Fund. Oppenheimer Developing Markets Fund produced a positive total return but underperformed its benchmark, the MSCI Emerging Markets Index. This underlying fund received strong contributions to return from the financials and information technology sectors, but investments in the United Kingdom and Russia drove its underperformance. Oppenheimer International Small Company Fund produced a positive return and outperformed the negative return of its benchmark, the MSCI All Country World Ex U.S. Small Cap Net Index. Investments in the health care, information technology and materials sectors drove this underlying fund’s performance.

Relative to its benchmarks, this underlying fund outperformed the Barclays U.S. Aggregate Bond Index and the Citigroup Broad Investment Grade Bond Index, but underperformed the Barclays Credit Index.

underweights in the Japanese yen and the euro were beneficial, as was its overweight to international credit exposure, especially in high grade emerging market sovereign and high yield European credit. This underlying fund’s overall short duration exposure detracted from performance as rates declined in most developed countries. Its underweight duration positions in Europe detracted the most.

seeks to offer the benefit of four major alternative strategy categories: Global Macro, Equity Market Neutral, Fixed-Income Alternatives and Volatility. It produced a positive return, with contributions from three of its four major alternative strategy categories, Equity Market Neutral, Global Macro and Fixed Income Alternatives. Relative to its benchmark, this underlying fund outperformed the BofA Merrill Lynch 3-Month U.S. Treasury Bill Index as absolute return strategies generally outpaced short-term U.S. Government securities. The Fund also had exposure to Oppenheimer Real Estate Fund, Oppenheimer Gold & Special Minerals Fund and Oppenheimer Commodity Strategy Total Return Fund. Oppenheimer Real Estate Fund produced positive performance in an environment of solid real estate fundamentals that were supported both by macroeconomic factors and the capital markets. Relative to its benchmark, this underlying fund outperformed the FTSE/NAREIT Equity REIT Index. Oppenheimer Gold & Special Minerals Fund produced negative returns as the stocks of most gold producers fell sharply in response to plummeting commodity prices in an environment of sluggish global economic growth and intensifying geopolitical tensions.

Oppenheimer Commodity Strategy Total Return Fund experienced declines for the same reason, with energy in particular falling over the second half of 2014. Oppenheimer Gold & Special Minerals Fund

underperformed its benchmark, the MSCI World Index, but performed more in line with other gold and special minerals stocks within the Philadelphia Gold & Silver Index. Oppenheimer Commodity Strategy Total Return Fund underperformed the Bloomberg Commodity Index for the reporting period.

Mark Hamilton

Portfolio Manager

Dokyoung Lee¹

Portfolio Manager

1. Dokyoung Lee became a Portfolio Manager in May 2014.

ASSET CLASS ALLOCATION


Domestic Equity Funds		41.9%
Domestic Fixed Income Funds		25.7
Foreign Equity Funds		15.2
Alternative Funds		10.0
Foreign Fixed Income Funds		6.5
Money Market Funds		0.7
Portfolio holdings and allocations are subject to change. Percentages are as of January 30, 2015, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Value Fund, Cl. I		18.0%
Oppenheimer Capital Appreciation Fund, Cl. I		17.7
Oppenheimer Core Bond Fund, Cl. I		15.7
Oppenheimer Limited-Term Government Fund, Cl. I		7.0
Oppenheimer International Bond Fund, Cl. I		6.5
Oppenheimer International Growth Fund, Cl. I		5.9
Oppenheimer International Value Fund, Cl. I		5.2
Oppenheimer Master Inflation Protected Securities Fund, LLC		4.5
Oppenheimer Main Street Mid Cap Fund, Cl. I		3.3
Oppenheimer Main Street Small Cap Fund, Cl. I		3.0

*January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements.

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

The examples are based on an investment of $1,000.00 invested at the beginning of the period and held for the entire

* January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

b. Prior to June 30, 2014, this Fund was named Oppenheimer Main Street Small- & Mid-Cap Fund.

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

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

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

2. 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.

3. Effective July 1, 2014, Class N shares were renamed Class R. See Note 1 of the accompanying Notes.

1. January 30, 2015 represents the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

2. Effective July 1, 2014, Class N shares were renamed Class R. See Note 1 of the accompanying Notes.

1. January 30, 2015 represents the last business day of the Fund’s 2015 reporting period. See Note 2 of the accompanying Notes.

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

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

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

1. January 30, 2015 represents the last business day of the Fund’s 2015 reporting period. See Note 2 of the

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. The returns do not include

adjustments in accordance with generally accepted accounting principles required at the period end for financial

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

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


Year Ended January 30, 2015	1.83	%
Year Ended January 31, 2014	1.89	%
Year Ended January 31, 2013	1.93	%
Year Ended January 31, 2012	1.98	%
Year Ended January 31, 2011	1.99	%

1. January 30, 2015 represents the last business day of the Fund’s 2015 reporting period. See Note 2 of the accompanying Notes.

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

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

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


Year Ended January 30, 2015		1.83%
Year Ended January 31, 2014		1.87%
Year Ended January 31, 2013		1.85%
Year Ended January 31, 2012		1.88%
Year Ended January 31, 2011		1.90%

1. January 30, 2015 represents the last business day of the Fund’s 2015 reporting period. See Note 2 of the accompanying Notes.

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

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

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


Year Ended January 30, 2015		1.33%
Year Ended January 31, 2014		1.36%
Year Ended January 31, 2013		1.35%
Year Ended January 31, 2012		1.38%
Year Ended January 31, 2011		1.38%

1. January 30, 2015 represents the last business day of the Fund’s 2015 reporting period. See Note 2 of the accompanying Notes.

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

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

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

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

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

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.

1. As of January 30, 2015, the Fund had $124,089,170 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.

2. During the fiscal year ended January 30, 2015, the Fund utilized $89,872,417 of capital loss carryforward to offset capital gains realized in that fiscal year.

3. During the fiscal year ended January 31, 2014, the Fund utilized $19,134,269 of capital loss carryforward to offset capital gains realized in that fiscal year.

Accordingly, the following amounts have been reclassified for January 30, 2015. Net assets of the Fund were unaffected by the reclassifications.

The tax character of distributions paid during the years ended January 31, 2015 and January 31, 2014 was as follows:

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.

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 Fund classifies each of its investments in those Underlying Funds which are publicly offered and reported on an exchange as Level 1, and those Underlying Funds which are not

publicly offered as Level 2, without consideration as to the classification level of the specific investments held by the Underlying Funds.

The table below categorizes amounts that are included in the Fund’s Statement of Assets and Liabilities as of January 30, 2015 based on valuation input level:

Investment in Oppenheimer Master Funds. The Fund is permitted to invest in entities sponsored and/or advised by the Manager or an affiliate. Certain of these entities in which the Fund invests are mutual funds registered under the Investment Company Act of 1940 that expect to be treated as partnerships for tax purposes, specifically Oppenheimer Master Loan Fund, LLC and Oppenheimer Master Inflation Protected Securities Fund, LLC (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.

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 in an amount equal to the indirect management fees incurred through the Fund’s investment in the Master Funds.

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:

The aggregate cost of purchases and proceeds from sales of securities, other than short-term obligations and investments in IMMF, for the year ended January 30, 2015 were as follows:

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 period ended January 30, 2015 was 0.53%. This amount is gross of any waivers or reimbursements of management fees implemented at the Underlying Fund level.

Trustees’ Compensation. 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 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.

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.

Waivers and Reimbursements of Expenses. The Manager has contractually agreed to waive fees and/or reimburse 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 1.30%, 2.05%, 2.05%, 1.55% and 1.05%, for Class A, Class B, Class C, Class R and Class Y, respectively. The expense limitations do not include extraordinary expenses and other expenses not incurred in the ordinary course of the Fund’s business. Notwithstanding the foregoing limits, the Manager is not required to waive or reimburse Fund expenses in excess of the amount of indirect management fees earned from investments in the Underlying Funds.

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 year ended January 30, 2015, the Manager waived fees and/or reimbursed the Fund $1,082,169.

These undertakings may be modified or terminated as set forth according to the terms in the prospectus.

judgment approving the settlements as fair, reasonable and adequate. The settlements do not resolve a seventh outstanding lawsuit relating to Oppenheimer Rochester California Municipal Fund (the “California Fund Suit”). OFI believes the California Fund Suit is without legal merit and is defending the suit vigorously. While it is premature to render any opinion as to the outcome in the California Fund Suit, or whether any costs that OFI may bear in defending the California Fund Suit might not be reimbursed by insurance, OFI believes the California Fund Suit should not impair the ability of OFI or the Distributor to perform their respective duties to the Fund, and that the outcome of the California Fund Suit should not have any material effect on the operations of any of the Oppenheimer funds.

We have audited the accompanying statement of assets and liabilities of Moderate Investor Fund (a series of Oppenheimer Portfolio Series), including the statement of investments, as of January 30, 2015, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the years in the two-year period then ended, and the financial highlights for each of the years in the five-year period then ended. These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Moderate Investor Fund as of January 30, 2015, 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.

In early 2015, if applicable, shareholders of record received information regarding all dividends and distributions paid to them by the Fund during calendar year 2014.

Dividends, if any, paid by the Fund during the fiscal year ended January 30, 2015 which are not designated as capital gain distributions should be multiplied by the maximum amount allowable but not less than 32.36% to arrive at the amount eligible for the corporate dividend-received deduction.

A portion, if any, of the dividends paid by the Fund during the fiscal year ended January 30, 2015 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 $11,519,543 of the Fund’s fiscal year taxable income may be eligible for the lower individual income tax rates. In early 2015, shareholders of record received information regarding the percentage of distributions that are eligible for lower individual income tax rates.

Recent tax legislation allows a regulated investment company to designate distributions not designated as capital gain distributions, as either interest related dividends or short-term capital gain dividends, both of which are exempt from the U.S. withholding tax applicable to non U.S. taxpayers. For the fiscal year ended January 30, 2015, the maximum amount allowable but not less than $9,524,106 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 $422,890 of foreign income taxes were paid by the Fund during the fiscal year ended January 30, 2015. 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 $3,248,904 was derived from sources within foreign countries or possessions of the United States.

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

services and risk management, and information the Board has received regarding the experience and professional qualifications of the Managers’ key personnel and the size and functions of its staff. In its evaluation of the quality of the portfolio management services provided, the Board considered the experience of Mark Hamilton and Dokyoung Lee, the portfolio managers for the Fund, and the experience of the portfolio managers and the investment performance of the investment companies in which the Fund invests (the “Underlying Funds”). The Board members also considered the totality of their experiences with the Managers as directors or trustees of the Fund and other funds advised by the Managers. The Board considered information regarding the quality of services provided by affiliates of the Managers, which its members have become knowledgeable about in connection with the renewal of the Fund’s service agreements. The Board concluded, in light of the Managers’ experience, reputation, personnel, operations and resources that the Fund benefits from the services provided under the Agreement.

Investment Performance of the Fund, the Adviser and the Sub-Adviser. Throughout the year, the Adviser and the Sub-Adviser provided information on the investment performance of the Fund, the Adviser and the Sub-Adviser, including comparative performance information. The Board also reviewed information, prepared by the Adviser, the Sub-Adviser and the independent consultant, comparing the Fund’s historical performance to its benchmark and to the performance of other retail funds in the moderate allocation category. The Board noted that the Fund’s one-year, three-year, and five-year performance was below its category median.

Costs of Services by the Adviser. The Board reviewed the expenses borne by the Fund. The Adviser does not charge a management fee to the Fund; however, the Adviser collects indirect management fees from the Fund’s Underlying Funds. The independent consultant provided comparative data in regard to the fees and expenses of the Fund and other retail front-end load moderate allocation funds with comparable asset levels and distribution features. After discussions with the Board, the Adviser has agreed to contractually waive fees and/or reimburse the Fund for certain expenses in order to limit “Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement” (including the combined direct (Fund level) and indirect (Underlying Fund level) expenses, but excluding (i) interest and fees from borrowing, interest and related expenses from inverse floaters, taxes, dividends tied to short sales, brokerage commission, and other expenditures which are capitalized in accordance with generally accepted accounting principles; (ii) certain other expenses attributable to, and incurred as a result of, a Fund’s investments; and (iii) other extraordinary expenses (including litigation expenses) not incurred in the ordinary course of the Fund’s business) to annual rates of 1.30% for Class A shares, 2.05% for Class B shares, 2.05% for Class C shares, 1.55% for Class R shares, and 1.05% for Class Y shares as calculated on the daily net assets of the Fund. This fee waiver and/or expense reimbursement may be amended or withdrawn at any time without prior notice to shareholders. After discussions with the Board, the Adviser has also 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 may apply, and may not be amended or withdrawn until one year from the date of the Fund’s prospectus, unless

approved by the Board. The Adviser is not required to waive or reimburse Fund expenses in excess of the amount of indirect management fees earned from investments in the Underlying Funds. 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 Fund’s total expenses were lower than its peer group median and category median.

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

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

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.

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.

*January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements. Index returns are calculated through January 31, 2015.

During the reporting period, the Fund’s Class A shares (without sales charge) produced a total return of 6.26%. On a relative basis, the Fund underperformed the Barclays U.S. Aggregate Bond Index and the S&P 500 Index, which returned 6.61% and 14.22%, respectively.

MARKET OVERVIEW

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, Oppenheimer Master Inflation Protected Securities Fund, LLC and Oppenheimer Master Loan Fund, LLC, which do not offer Class I shares.

FUND REVIEW

At period end, the Fund had roughly 20% of its assets invested in an “active allocation” that seeks to take advantage of short- to mid-term market conditions, and 80% invested in a “static allocation.” Both allocations are comprised of Oppenheimer funds.

During the reporting period, the active allocation continued to have its largest allocation to equities, with roughly 53% invested in domestic equity underlying funds and 32% in foreign equity underlying funds. It also had approximately 9% in alternatives and 6% invested in fixed-income. The static allocation had roughly 50% invested in

domestic equity, 27% in foreign equity, 18% in fixed-income and 5% in alternatives. Domestic equity was the strongest performing asset class for both allocations, as U.S. stocks rallied this reporting period. Foreign equity underlying funds detracted from performance for both allocations. Market volatility outside of the U.S. and particularly in Europe was the primary driver behind the negative results. The underperformance of foreign equities had a greater impact on the active allocation, which had a larger investment in foreign equity funds. Fixed-income and alternatives produced positive results for both allocations. In the next section, we discuss the performance of underlying investments for both the active and static allocations.

UNDERLYING INVESTMENTS REVIEW

The largest underlying domestic equity holdings of both the active and static allocations were Oppenheimer Value Fund and Oppenheimer Capital Appreciation Fund. They also had allocations to Oppenheimer Main Street Mid Cap Fund and Oppenheimer Main Street Small Cap Fund. All of these underlying funds produced positive absolute performance, but Oppenheimer Capital Appreciation Fund was the top performer as large-cap U.S. growth stocks generally outperformed large-cap U.S. value stocks, as well as mid-cap and small-cap stocks. Oppenheimer Capital Appreciation Fund received its best results from holdings in the information technology and health care sectors. Relative to its benchmarks, this underlying fund outperformed the S&P 500 Index and the Russell 1000 Growth Index.

Oppenheimer Value Fund also experienced its strongest contribution to performance from the information technology and health care sectors. This underlying fund underperformed the S&P 500 Index and the Russell 1000 Value Index, due largely to weaker relative stock selection in the financials sector. Oppenheimer Main Street Mid Cap Fund underperformed its benchmark, the Russell Midcap Index. Its performance was driven by holdings in the information technology and health care sectors, with relative underperformance in the financials sector. Oppenheimer Main Street Small Cap Fund outperformed its benchmark, the Russell 2000 Index. This underlying fund’s performance was driven by holdings in the industrials and financials sectors.

Among foreign equity underlying funds, the active and static allocations both had their largest exposure to Oppenheimer International Growth Fund and Oppenheimer International Value Fund. Both underlying funds produced negative returns this reporting period, and underperformed their benchmark, the MSCI All Country World ex-U.S. Index. The performance of these underlying funds was negatively impacted by their exposure to certain European stocks. Both allocations also had smaller investments in Oppenheimer Developing Markets Fund and Oppenheimer International Small Company Fund. Oppenheimer Developing Markets Fund produced a positive total return but underperformed its benchmark, the MSCI Emerging Markets Index. This underlying fund received strong contributions to return from

the financials and information technology sectors, but investments in the United Kingdom and Russia drove its underperformance. Oppenheimer International Small Company Fund produced a positive return and outperformed the negative return of its benchmark, the MSCI All Country World Ex U.S. Small Cap Net Index. Investments in the health care, information technology and materials sectors drove this underlying fund’s performance.

The active and static allocations had different fixed-income exposures. The active allocation’s largest fixed-income investments were Oppenheimer Master Event-Linked Bond Fund, LLC, Oppenheimer International Bond Fund and Oppenheimer Master Loan Fund, LLC. Oppenheimer Master Event-Linked Bond Fund, LLC provides the Fund with exposure to catastrophe bonds, which performed positively. This underlying fund underperformed its benchmark, the Swiss Re Cat Bond Total Return Index. Oppenheimer International Bond Fund produced a positive return this reporting period. This underlying fund outperformed its Reference Index, which is a customized weighted index comprised of 50% of the Citigroup Non-U.S. Dollar World Government Bond Index, 30% of the J.P. Morgan Government Bond Index and 20% of the J.P. Morgan Emerging Markets Bond Index. This underlying fund’s lower than typical foreign currency exposure helped performance as the U.S. dollar strengthened against most other currencies. In addition, this underlying fund’s underweights in the Japanese yen and the euro were beneficial, as

was its overweight to international credit exposure, especially in high grade emerging market sovereign and high yield European credit. This underlying fund’s overall short duration exposure detracted from performance as rates declined in most developed countries. Its underweight duration positions in Europe detracted the most. Oppenheimer Master Loan Fund, LLC, which invests primarily in senior loans, produced a modest positive return and underperformed its benchmark, the J.P. Morgan Leveraged Loan Index. This underlying fund’s relative underperformance stemmed from the energy sector, as a result of the sudden and precipitous drop in oil prices.

The static allocation had its largest fixed-income exposure in Oppenheimer Core Bond Fund, Oppenheimer Limited-Term Government Fund and Oppenheimer International Bond Fund. Oppenheimer Core Bond Fund continued to favor corporate bonds, mortgages and other securitized products over government bonds this reporting period, which benefited performance as these investments outperformed U.S. Treasuries. Relative to its benchmarks, this underlying fund outperformed the Barclays U.S. Aggregate Bond Index and the Citigroup Broad Investment Grade Bond Index, but underperformed the Barclays Credit Index. Oppenheimer Limited-Term Government Fund produced a muted return during the reporting period, as U.S. Government bonds lagged higher-yielding fixed-income sectors and

equities. An allocation to mortgage-backed securities benefited this underlying fund during the reporting period. Relative to its benchmarks, the underlying fund outperformed the Barclays U.S. 1-3 Year Government Bond Index, but underperformed the Barclays U.S. Government Bond Index.

Both the static and active allocations received positive contributions to return from underlying alternative funds. Positions within alternatives for both allocations included Oppenheimer Master Inflation Protected Securities Fund, LLC and Oppenheimer Global Multi Strategies Fund. Oppenheimer Master Inflation Protected Securities Fund, LLC, invests primarily in Treasury Inflation Protected Securities (TIPS), whose performance is closely correlated to U.S. inflation rates. This underlying fund produced positive performance, but underperformed its benchmark, the Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index. Oppenheimer Global Multi Strategies Fund seeks to offer the benefit of four major alternative strategy categories: Global Macro, Equity Market Neutral, Fixed-Income Alternatives and Volatility. It produced a positive return, with contributions from three of its four major alternative strategy categories, Equity Market Neutral, Global Macro and Fixed Income Alternatives. Relative to its benchmark, this underlying fund outperformed the BofA Merrill Lynch 3-Month U.S. Treasury Bill Index as absolute return strategies generally outpaced short-term U.S. Government securities. Both allocations also had exposure to

Oppenheimer Real Estate Fund, Oppenheimer Gold & Special Minerals Fund and Oppenheimer Commodity Strategy Total Return Fund. Oppenheimer Real Estate Fund produced positive performance in an environment of solid real estate fundamentals that were supported both by macroeconomic factors and the capital markets. Relative to its benchmark, the Fund outperformed the FTSE/NAREIT Equity REIT Index. Oppenheimer Gold & Special Minerals Fund produced negative returns as the stocks of most gold producers fell sharply in response to plummeting commodity prices in an

LOGO

Mark Hamilton

Portfolio Manager

LOGO

Dokyoung Lee

Portfolio Manager

environment of sluggish global economic growth and intensifying geopolitical tensions. Oppenheimer Commodity Strategy Total Return Fund experienced declines for the same reason, with energy in particular falling over the second half of 2014. Oppenheimer Gold & Special Minerals Fund underperformed its benchmark, the MSCI World Index, but performed more in line with other gold and special minerals stocks within the Philadelphia Gold & Silver Index. Oppenheimer Commodity Strategy Total Return Fund underperformed the Bloomberg Commodity Index for the reporting period.

LOGO

Caleb Wong

Portfolio Manager


ASSET CLASS ALLOCATION
Domestic Equity Funds	50.3	%
Foreign Equity Funds	28.3
Domestic Fixed Income Funds	12.0
Alternative Funds	5.6
Foreign Fixed Income Funds	3.4
Money Market Funds	0.4

Portfolio holdings and allocations are subject to change. Percentages are as of January 30, 2015, and are based on the total market value of investments.

TOP TEN HOLDINGS


Oppenheimer Value Fund, Cl. I	21.4	%
Oppenheimer Capital Appreciation Fund, Cl. I	20.6
Oppenheimer International Growth Fund, Cl. I	11.0
Oppenheimer International Value Fund, Cl. I	9.6
Oppenheimer Core Bond Fund, Cl. I	7.3
Oppenheimer Main Street Small Cap Fund, Cl. I	4.5
Oppenheimer Developing Markets Fund, Cl. I	4.4
Oppenheimer Main Street Mid Cap Fund, Cl. I	3.9
Oppenheimer International Bond Fund, Cl. I	3.4
Oppenheimer International Small Company Fund, Cl. I	3.3

*January 30, 2015, was the last business day of the Fund’s fiscal year. See Note 2 of the accompanying Notes to Financial Statements.

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 (“CDSC”) of 1% for the 1-year period. Prior to 7/1/14, Class R shares were named Class N shares. Beginning 7/1/14, new purchases of Class R shares will no longer be subject to a CDSC upon redemption (any CDSC will remain in effect for purchases prior to 7/1/14). There is no sales charge for Class Y shares. Because Class B shares convert to Class A shares 72 months after purchase, the 10-year return for Class B shares uses Class A performance for the period after conversion.

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

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

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 30, 2015.

*January 30, 2015, was the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.

b. Prior to June 30, 2014, this Fund was named Oppenheimer Main Street Small- & Mid-Cap Fund.

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

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

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

1. January 30, 2015, was the last business day of the Fund’s reporting period. See Note 2 of the accompanying Notes.