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Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Focused Portfolio Risk. The Fund's portfolio tends to be invested in a relatively small number of stocks—thirty to sixty rather than hundreds. As a result, the appreciation or depreciation of any one security held by the Fund will have a greater impact on the Fund's net asset value than it would if the Fund invested in a larger number of securities. Although that strategy has the potential to generate attractive returns over time, it also increases the Fund's volatility. Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular sector or industry, changes affecting that sector or industry, or the perception of that sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's average annual returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.253 0.1173 -0.0131 0.1826 -0.0364 -0.3261 0.4477 0.1218 0.0182 0.2097 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20004 column dei_LegalEntityAxis compact ck0000872323_S000002758Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 23.2%, during the quarter ended June 30, 2009 Lowest quarterly return: -23.0%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.232 2009-06-30 Lowest quarterly return: -0.230 2008-12-31 0.2097 0.0616 0.0782 0.2029 0.0580 0.0738 0.1453 0.0523 0.0682 0.2064 0.0585 0.0748 0.1600 0.0166 0.0710 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20005 column dei_LegalEntityAxis compact ck0000872323_S000002758Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's average annual returns compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. Average Annual Total Returns for Periods Ended December 31, 2012 PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in a diversified portfolio of common stocks of U.S. companies. The Fund generally invests in the securities of larger capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. The Adviser believes that holding a relatively small number of stocks allows its "best ideas" to have a meaningful impact on the Fund's performance. Therefore, the Fund's portfolio typically holds thirty to sixty stocks rather than hundreds, and a higher percentage of the Fund's total assets may also be invested in a particular sector or industry. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 27% of the average value of its portfolio. 0.27 INVESTMENT OBJECTIVE Oakmark Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0087 0.0087 0.0000 0.0000 0.0016 0.0043 0.0103 0.0130 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20001 column dei_LegalEntityAxis compact ck0000872323_S000002758Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20002 column dei_LegalEntityAxis compact ck0000872323_S000002758Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 105 132 328 412 569 713 1259 1568 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20003 column dei_LegalEntityAxis compact ck0000872323_S000002758Member row primary compact * ~ Oakmark Select OAKLX OARLX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Non-Diversification Risk. A non-diversified fund (generally, a fund that may invest in a limited number of issuers) may be subject to greater risk than a diversified fund because changes in the financial condition or market assessment of a single issuer may cause greater fluctuation in the value of a non-diversified fund's shares. The Fund could hold as few as twelve securities, but generally will have approximately twenty securities in its portfolio. Lack of broad diversification also may cause a non-diversified fund to be more susceptible to economic, political or regulatory events than a diversified fund. A non-diversification strategy may increase the Fund's volatility. Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular sector or industry, changes affecting that sector or industry, or the perception of that sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Mid Cap Securities Risk. Investments in mid cap companies may be riskier than investments in larger, more established companies. Mid cap companies may have limited product lines, markets or financial resources or may depend on a few key employees, and may be more susceptible to particular economic events or competitive factors than large capitalization companies. The securities of mid cap companies may trade less frequently and in smaller volumes, and as a result, may be less liquid than securities of larger companies. In addition, mid cap companies may be more vulnerable to economic, market and industry changes. As a result, share price changes may be more sudden or erratic than the prices of other equity securities, especially over the short term. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. A non-diversified fund (generally, a fund that may invest in a limited number of issuers) may be subject to greater risk than a diversified fund because changes in the financial condition or market assessment of a single issuer may cause greater fluctuation in the value of a non-diversified fund's shares. The Fund could hold as few as twelve securities, but generally will have approximately twenty securities in its portfolio. Lack of broad diversification also may cause a non-diversified fund to be more susceptible to economic, political or regulatory events than a diversified fund. A non-diversification strategy may increase the Fund's volatility. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.29 0.0973 0.0484 0.136 -0.1404 -0.3622 0.5246 0.1324 0.0215 0.2174 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20011 column dei_LegalEntityAxis compact ck0000872323_S000002759Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:0pt .7pt 9pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:0pt .7pt 9pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 25.7%, during the quarter ended June 30, 2009 Lowest quarterly return: -20.2%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.257 2009-06-30 Lowest quarterly return: -0.202 2008-12-31 0.2174 0.0649 0.0709 0.2009 0.0612 0.0644 0.1628 0.0557 0.0616 0.2139 0.0623 0.0681 0.1600 0.0166 0.0710 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20012 column dei_LegalEntityAxis compact ck0000872323_S000002759Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. Average Annual Total Returns for Periods Ended December 31, 2012 PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in common stocks of U.S. companies. The Fund is non-diversified, which means that it may invest a greater portion of its assets in a more limited number of issuers than a diversified fund. The Fund could own as few as twelve securities, but generally will have approximately twenty securities in its portfolio and as a result, a higher percentage of the Fund's total assets may also be invested in a particular sector or industry. The Fund generally invests in the securities of large- and mid-capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 32% of the average value of its portfolio. 0.32 INVESTMENT OBJECTIVE Oakmark Select Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0092 0.0092 0.0000 0.0000 0.0013 0.0044 0.0105 0.0136 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20008 column dei_LegalEntityAxis compact ck0000872323_S000002759Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20009 column dei_LegalEntityAxis compact ck0000872323_S000002759Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 107 138 334 431 579 745 1283 1635 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20010 column dei_LegalEntityAxis compact ck0000872323_S000002759Member row primary compact * ~ Oakmark Equity and Income OAKBX OARBX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Focused Portfolio Risk. The equity portion of the Fund's portfolio tends to be invested in a relatively small number of stocks—thirty to sixty rather than hundreds. As a result, the appreciation or depreciation of any one security held by the Fund will have a greater impact on the Fund's net asset value than it would if the Fund invested in a larger number of securities. Although that strategy has the potential to generate attractive returns over time, it also increases the Fund's volatility. Small and Mid Cap Securities Risk. Investments in small and mid cap companies may be riskier than investments in larger, more established companies. The securities of smaller companies may trade less frequently and in smaller volumes, and as a result, may be less liquid than securities of larger companies. In addition, smaller companies may be more vulnerable to economic, market and industry changes. As a result, share price changes may be more sudden or erratic than the prices of other equity securities, especially over the short term. Because smaller companies may have limited product lines, markets or financial resources or may depend on a few key employees, they may be more susceptible to particular economic events or competitive factors than large capitalization companies. Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular sector or industry, changes affecting that sector or industry, or the perception of that sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Debt Securities Risk. Debt securities are subject to credit risk, interest rate risk and liquidity risk. Credit risk is the risk the issuer or guarantor of a debt security will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. Interest rate risk is the risk of losses due to changes in interest rates. In general, the prices of debt securities rise when interest rates fall, and the prices fall when interest rates rise. Liquidity risk is the risk a particular security may be difficult to purchase or sell and that the Fund may be unable to sell illiquid securities at an advantageous time or price. The Fund's investments in government-sponsored entity securities also exhibit these risks, although the degree of such risks may vary significantly among the different government-sponsored entity securities. Some securities issued or guaranteed by U.S. government agencies or instrumentalities are not backed by the full faith and credit of the U.S. and may only be supported by the right of the agency or instrumentality to borrow from the U.S. Treasury. There can be no assurance that the U.S. government will always provide financial support to those agencies or instrumentalities. Foreign sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt. There is no legal process for collecting sovereign debt that a government does not pay, nor are there bankruptcy proceedings through which all or part of the sovereign debt that a government entity has not repaid may be collected. Below investment grade securities (commonly referred to as junk bonds) are regarded as having predominately speculative characteristics and may be more susceptible to credit, interest rate or liquidity risk than a debt security rated investment grade. Inflation-Indexed Securities Risk. The principal value of an investment is not protected or otherwise guaranteed by virtue of the Fund's investments in inflation-indexed bonds. If the index measuring inflation falls, the principal value of inflation-indexed bonds will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-indexed bonds. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal value. The value of inflation-indexed bonds is expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation indexed bonds. Short-term increases in inflation may lead to a decline in value. Any increase in the principal amount of an inflation-indexed bond will be considered taxable ordinary income, even though investors do not receive their principal until maturity. Periodic adjustments for inflation to the principal amount of an inflation-indexed bond may give rise to original issue discount, which will be includable in the Fund's gross income. Due to original issue discount, the Fund may be required to make annual distributions to shareholders that exceed the cash received, which may cause the Fund to liquidate certain investments when it is not advantageous to do so. Also, if the principal value of an inflation-indexed bond is adjusted downward due to deflation, amounts previously distributed in the taxable year may be characterized in some circumstances as a return of capital. Non-U.S. Securities Risk. Investments in securities issued by entities based outside the United States involve risks relating to political, social and economic developments abroad, as well as risks resulting from the differences between the regulations to which U.S. and non-U.S. issuers and markets are subject. These risks may result in the Fund experiencing rapid and extreme value changes due to currency controls; different accounting, auditing, financial reporting, and legal standards and practices; political and diplomatic changes and developments; expropriation; changes in tax policy; a lack of available public information regarding non-U.S. issuers; greater market volatility; a lack of sufficient market liquidity; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. These risks may be heightened in connection with investments in issuers located in developing and emerging countries, and in issuers in more developed countries that conduct substantial business in such developing and emerging countries. Fluctuations in the exchange rates between currencies may negatively affect an investment in non-U.S. securities. Investments in securities issued by entities domiciled in the United States also may be subject to many of these risks. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.2321 0.1036 0.086 0.1082 0.1197 -0.1618 0.1984 0.095 0.0064 0.0905 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20018 column dei_LegalEntityAxis compact ck0000872323_S000002760Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:0pt .7pt 9pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:0pt .7pt 9pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 13.2%, during the quarter ended June 30, 2003 Lowest quarterly return: -12.8%, during the quarter ended September 30, 2011 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.132 2003-06-30 Lowest quarterly return: -0.128 2011-09-30 0.0905 0.0384 0.0826 0.0849 0.0339 0.0764 0.0661 0.0320 0.0714 0.0875 0.0351 0.0793 0.1194 0.0282 0.0651 0.1600 0.0166 0.0710 0.0482 0.0606 0.0525 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20019 column dei_LegalEntityAxis compact ck0000872323_S000002760Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ Lipper Balanced Funds Index is an index of the thirty largest balanced funds tracked by Lipper, Inc. All returns reflect reinvested dividends. This information shows how the Fund's returns compare with the returns of an index comprised of the thirty largest balanced funds tracked by Lipper, Inc. The S&P 500 Index is a widely quoted, unmanaged, market weighted index that includes 500 of the largest publicly traded companies in the U.S. All returns reflect reinvested dividends. This information shows how the Fund's returns compare with a broad-based securities market index. The Barclays U.S. Government & Credit Index measures the performance of U.S. dollar-denominated U.S. Treasury bonds, government-related bonds and investment grade U.S. corporate bonds that have a remaining maturity of greater than or equal to one year. This information shows how the Fund's returns compare with a broad-based securities market index. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. Average Annual Total Returns for Periods Ended December 31, 2012 PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in a diversified portfolio of U.S. equity and debt securities (although the Fund may invest up to 35% of its total assets in equity and debt securities of non-U.S. issuers). The Fund is intended to present a balanced investment program between growth and income by investing approximately 40-75% of its total assets in common stock, including securities convertible into common stock, and up to 60% of its assets in U.S. government securities and debt securities, including inflation-indexed securities, rated at time of purchase within the two highest grades assigned by Moody's Investors Service, Inc. or by Standard & Poor's Corporation Ratings Group, a division of The McGraw-Hill Companies. The Fund also may invest up to 20% of its total assets in unrated or lower rated debt securities, sometimes called junk bonds. The types of equity securities in which the Fund may invest include common and preferred stocks and warrants or other similar rights and convertible securities. The types of debt securities in which the Fund may invest include debt securities of both governmental and corporate issuers. The Fund may invest in the securities of large-, mid-, and small-capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy—Equity Portion of the Fund: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. The Adviser believes that holding a relatively small number of stocks allows its "best ideas" to have a meaningful impact on the Fund's performance. Therefore, the Fund's portfolio typically holds thirty to sixty stocks rather than hundreds, and a higher percentage of the Fund's total assets may also be invested in a particular sector or industry. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 29% of the average value of its portfolio. 0.29 INVESTMENT OBJECTIVE Oakmark Equity and Income Fund seeks income and preservation and growth of capital. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0067 0.0067 0.0000 0.0000 0.0011 0.0042 0.0078 0.0109 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20015 column dei_LegalEntityAxis compact ck0000872323_S000002760Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20016 column dei_LegalEntityAxis compact ck0000872323_S000002760Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 80 111 249 347 433 601 966 1329 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20017 column dei_LegalEntityAxis compact ck0000872323_S000002760Member row primary compact * ~ Oakmark Global OAKGX OARGX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Focused Portfolio Risk. The Fund's portfolio tends to be invested in a relatively small number of stocks, thirty to sixty rather than hundreds. As a result, the appreciation or depreciation of any one security held by the Fund will have a greater impact on the Fund's net asset value than it would if the Fund invested in a larger number of securities. Although that strategy has the potential to generate attractive returns over time, it also increases the Fund's volatility. Region, Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular region, sector or industry, changes affecting that region, sector or industry, or the perception of that region, sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Non-U.S. Securities Risk. Investments in securities issued by entities based outside the United States involve risks relating to political, social and economic developments abroad, as well as risks resulting from the differences between the regulations to which U.S. and non-U.S. issuers and markets are subject. These risks may result in the Fund experiencing rapid and extreme value changes due to currency controls; different accounting, auditing, financial reporting, and legal standards and practices; political and diplomatic changes and developments; expropriation; changes in tax policy; a lack of available public information regarding non-U.S. issuers; greater market volatility; a lack of sufficient market liquidity; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. These risks may be heightened in connection with investments in issuers located in developing and emerging countries, and in issuers in more developed countries that conduct substantial business in such developing and emerging countries. Fluctuations in the exchange rates between currencies may negatively affect an investment in non-U.S. securities. Investments in securities issued by entities domiciled in the United States also may be subject to many of these risks. The Fund may hedge its exposure to foreign currencies. Although hedging may be used to protect the Fund from adverse currency movements, the use of such hedges may reduce or eliminate the potentially positive effect of currency revaluations on the Fund's total return, and there is no guarantee that the Fund's hedging strategy will be successful. Small and Mid Cap Securities Risk. Investments in small and mid cap companies may be riskier than investments in larger, more established companies. The securities of smaller companies may trade less frequently and in smaller volumes, and as a result, may be less liquid than securities of larger companies. In addition, smaller companies may be more vulnerable to economic, market and industry changes. As a result, share price changes may be more sudden or erratic than the prices of other equity securities, especially over the short term. Because smaller companies may have limited product lines, markets or financial resources or may depend on a few key employees, they may be more susceptible to particular economic events or competitive factors than large capitalization companies. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's average annual returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.4898 0.1563 0.1323 0.2418 0.0733 -0.3878 0.4019 0.1574 -0.1165 0.2016 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20025 column dei_LegalEntityAxis compact ck0000872323_S000002761Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:8.5pt .7pt 6pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:8.5pt .7pt 6pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 33.5%, during the quarter ended June 30, 2003 Lowest quarterly return: -24.1%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.335 2003-06-30 Lowest quarterly return: -0.241 2008-12-31 0.2016 0.0107 0.1061 0.1978 0.0084 0.1000 0.1338 0.0086 0.0945 0.1986 0.0072 0.1023 0.1583 -0.0118 0.0751 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20026 column dei_LegalEntityAxis compact ck0000872323_S000002761Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com Average Annual Total Returns for Periods Ended December 31, 2012 After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in a diversified portfolio of common stocks of U.S. and non-U.S. companies. The Fund invests in the securities of companies located in at least three countries. Typically, the Fund invests between 25-75% of its total assets in securities of U.S. companies and between 25-75% of its total assets in securities of non-U.S. companies. There are no geographic limits on the Fund's non-U.S. investments, and the Fund may invest in securities of companies located in developed or emerging markets. The Fund may invest in the securities of large-, mid-, and small-capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. The Adviser believes that holding a relatively small number of stocks allows its "best ideas" to have a meaningful impact on the Fund's performance. Therefore, the Fund's portfolio typically holds thirty to sixty stocks rather than hundreds, and a higher percentage of the Fund's total assets may also be invested in a particular region, sector or industry. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 26% of the average value of its portfolio. 0.26 INVESTMENT OBJECTIVE Oakmark Global Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0100 0.0100 0.0000 0.0000 0.0016 0.0050 0.0116 0.0150 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20022 column dei_LegalEntityAxis compact ck0000872323_S000002761Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20023 column dei_LegalEntityAxis compact ck0000872323_S000002761Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 118 153 368 474 638 818 1409 1791 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20024 column dei_LegalEntityAxis compact ck0000872323_S000002761Member row primary compact * ~ Oakmark Global Select OAKWX OARWX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Non-U.S. Securities Risk. Investments in securities issued by entities based outside the United States involve risks relating to political, social and economic developments abroad, as well as risks resulting from the differences between the regulations to which U.S. and non-U.S. issuers and markets are subject. These risks may result in the Fund experiencing rapid and extreme value changes due to currency controls; different accounting, auditing, financial reporting, and legal standards and practices; political and diplomatic changes and developments; expropriation; changes in tax policy; a lack of available public information regarding non-U.S. issuers; greater market volatility; a lack of sufficient market liquidity; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. These risks may be heightened in connection with investments in issuers located in developing and emerging countries, and in issuers in more developed countries that conduct substantial business in such developing and emerging countries. Fluctuations in the exchange rates between currencies may negatively affect an investment in non-U.S. securities. Investments in securities issued by entities domiciled in the United States also may be subject to many of these risks. The Fund may hedge its exposure to foreign currencies. Although hedging may be used to protect the Fund from adverse currency movements, the use of such hedges may reduce or eliminate the potentially positive effect of currency revaluations on the Fund's total return, and there is no guarantee that the Fund's hedging strategy will be successful. Non-Diversification Risk. A non-diversified fund (generally, a fund that may invest in a limited number of issuers) may be subject to greater risk than a diversified fund because changes in the financial condition or market assessment of a single issuer may cause greater fluctuation in the value of a non-diversified fund's shares. The Fund could hold as few as twelve securities, but generally will have approximately twenty securities in its portfolio. Lack of broad diversification also may cause a non-diversified fund to be more susceptible to economic, political or regulatory events than a diversified fund. A non-diversification strategy may increase the Fund's volatility. Region, Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular region, sector or industry, changes affecting that region, sector or industry, or the perception of that region, sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. A non-diversified fund (generally, a fund that may invest in a limited number of issuers) may be subject to greater risk than a diversified fund because changes in the financial condition or market assessment of a single issuer may cause greater fluctuation in the value of a non-diversified fund's shares. The Fund could hold as few as twelve securities, but generally will have approximately twenty securities in its portfolio. Lack of broad diversification also may cause a non-diversified fund to be more susceptible to economic, political or regulatory events than a diversified fund. A non-diversification strategy may increase the Fund's volatility. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) -0.0116 -0.3249 0.5358 0.1106 -0.0587 0.2395 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20032 column dei_LegalEntityAxis compact ck0000872323_S000013607Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="bottom" width="329"> Since 2007, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 26.6%, during the quarter ended June 30, 2009 Lowest quarterly return: -16.3%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.266 2009-06-30 Lowest quarterly return: -0.163 2008-12-31 0.2395 0.0609 0.0593 0.2352 0.0575 0.0547 0.1601 0.0510 0.0492 0.1583 -0.0118 0.0171 2006-10-02 2006-10-02 2006-10-02 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20033 column dei_LegalEntityAxis compact ck0000872323_S000013607Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com Average Annual Total Returns for Periods Ended December 31, 2012 After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in common stocks of U.S. and non-U.S. companies. The Fund invests in the securities of companies located in at least three countries. The Fund is non-diversified, which means that it may invest a greater portion of its assets in a more limited number of issuers than a diversified fund. The Fund could own as few as twelve securities, but generally will have approximately twenty securities in its portfolio and as a result, a higher percentage of the Fund's total assets may also be invested in a particular region, sector or industry. Typically, the Fund will invest at least 40% of its total assets in securities of non-U.S. companies (unless Harris Associates L.P., the Fund's investment adviser (the "Adviser"), deems market conditions and/or company valuations less favorable to non-U.S. companies, in which case the Fund will invest at least 30% of its total assets in securities of non-U.S. companies). There are no geographic limits on the Fund's non-U.S. investments, and the Fund may invest in securities of companies located in developed or emerging markets. The Fund generally invests in the securities of larger capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Adviser uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 36% of the average value of its portfolio. 0.36 INVESTMENT OBJECTIVE Oakmark Global Select Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0099 0.0099 0.0000 0.0000 0.0024 0.0049 0.0123 0.0148 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20029 column dei_LegalEntityAxis compact ck0000872323_S000013607Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20030 column dei_LegalEntityAxis compact ck0000872323_S000013607Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 125 151 390 468 676 808 1489 1768 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20031 column dei_LegalEntityAxis compact ck0000872323_S000013607Member row primary compact * ~ Oakmark International OAKIX OARIX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Focused Portfolio Risk. The Fund's portfolio tends to be invested in a relatively small number of stocks, thirty to sixty rather than hundreds. As a result, the appreciation or depreciation of any one security held by the Fund will have a greater impact on the Fund's net asset value than it would if the Fund invested in a larger number of securities. Although that strategy has the potential to generate attractive returns over time, it also increases the Fund's volatility. Region, Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular region, sector or industry, changes affecting that region, sector or industry, or the perception of that region, sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Non-U.S. Securities Risk. Investments in securities issued by entities based outside the United States involve risks relating to political, social and economic developments abroad, as well as risks resulting from the differences between the regulations to which U.S. and non-U.S. issuers and markets are subject. These risks may result in the Fund experiencing rapid and extreme value changes due to currency controls; different accounting, auditing, financial reporting, and legal standards and practices; political and diplomatic changes and developments; expropriation; changes in tax policy; a lack of available public information regarding non-U.S. issuers; greater market volatility; a lack of sufficient market liquidity; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. These risks may be heightened in connection with investments in issuers located in developing and emerging countries, and in issuers in more developed countries that conduct substantial business in such developing and emerging countries. Fluctuations in the exchange rates between currencies may negatively affect an investment in non-U.S. securities. The Fund may hedge its exposure to foreign currencies. Although hedging may be used to protect the Fund from adverse currency movements, the use of such hedges may reduce or eliminate the potentially positive effect of currency revaluations on the Fund's total return, and there is no guarantee that the Fund's hedging strategy will be successful. Small and Mid Cap Securities Risk. Investments in small and mid cap companies may be riskier than investments in larger, more established companies. The securities of smaller companies may trade less frequently and in smaller volumes, and as a result, may be less liquid than securities of larger companies. In addition, smaller companies may be more vulnerable to economic, market and industry changes. As a result, share price changes may be more sudden or erratic than the prices of other equity securities, especially over the short term. Because smaller companies may have limited product lines, markets or financial resources or may depend on a few key employees, they may be more susceptible to particular economic events or competitive factors than large capitalization companies. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.3804 0.1909 0.1412 0.306 -0.0051 -0.4106 0.563 0.1622 -0.1407 0.2922 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20039 column dei_LegalEntityAxis compact ck0000872323_S000002762Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:8.5pt .7pt 9pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 33.2%, during the quarter ended June 30, 2009 Lowest quarterly return: -21.4%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.332 2009-06-30 Lowest quarterly return: -0.214 2008-12-31 0.2922 0.0352 0.1123 0.2884 0.0299 0.1033 0.1955 0.0283 0.0991 0.2870 0.0321 0.1085 0.1641 -0.0343 0.0860 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20040 column dei_LegalEntityAxis compact ck0000872323_S000002762Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in a diversified portfolio of common stocks of non-U.S. companies. The Fund may invest in non-U.S. markets throughout the world, including emerging markets. Ordinarily, the Fund will invest in the securities of at least five countries outside the U.S. There are no geographic limits on the Fund's non-U.S. investments. The Fund may invest in securities of large-, mid-, and small-capitalization companies. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. The Adviser believes that holding a relatively small number of stocks allows its "best ideas" to have a meaningful impact on the Fund's performance. Therefore, the Fund's portfolio typically holds thirty to sixty stocks rather than hundreds, and a higher percentage of the Fund's total assets may also be invested in a particular region, sector or industry. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 38% of the average value of its portfolio. 0.38 INVESTMENT OBJECTIVE Oakmark International Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0088 0.0088 0.0000 0.0000 0.0018 0.0051 0.0106 0.0139 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20036 column dei_LegalEntityAxis compact ck0000872323_S000002762Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20037 column dei_LegalEntityAxis compact ck0000872323_S000002762Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 108 142 337 440 585 761 1294 1669 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20038 column dei_LegalEntityAxis compact ck0000872323_S000002762Member row primary compact * ~ Oakmark International Small Cap OAKEX OAREX PRINCIPAL INVESTMENT RISKS As an investor in the Fund, you should have a long-term perspective and be able to tolerate potentially wide fluctuations in the value of your Fund shares. Your investment in the Fund is subject to risks, including the possibility that the value of the Fund's portfolio holdings may fluctuate in response to events specific to the companies in which the Fund invests, as well as economic, political or social events in the U.S. or abroad. As a result, when you redeem your Fund shares, they may be worth more or less than you paid for them. Although the Fund makes every effort to achieve its objective, it cannot guarantee it will attain that objective. The principal risks of investing in the Fund are: Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to market or economic news and conditions, and securities markets also tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as "volatility," which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events and conditions that may not readily appear to directly relate to such securities, the securities' issuer or the markets in which they trade. Common Stock Risk. Common stocks are subject to greater fluctuations in market value than other asset classes as a result of such factors as a company's business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company's assets including debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed. Value Style Risk. Investing in "value" stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies' true business values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform growth stocks during given periods. Focused Portfolio Risk. The Fund's portfolio tends to be invested in a relatively small number of stocks, thirty to seventy rather than hundreds. As a result, the appreciation or depreciation of any one security held by the Fund will have a greater impact on the Fund's net asset value than it would if the Fund invested in a larger number of securities. Although that strategy has the potential to generate attractive returns over time, it also increases the Fund's volatility. Region, Sector or Industry Risk. If the Fund has invested a higher percentage of its total assets in a particular region, sector or industry, changes affecting that region, sector or industry, or the perception of that region, sector or industry, may have a significant impact on the performance of the Fund's overall portfolio. Non-U.S. Securities Risk. Investments in securities issued by entities based outside the United States involve risks relating to political, social and economic developments abroad, as well as risks resulting from the differences between the regulations to which U.S. and non-U.S. issuers and markets are subject. These risks may result in the Fund experiencing rapid and extreme value changes due to currency controls; different accounting, auditing, financial reporting, and legal standards and practices; political and diplomatic changes and developments; expropriation; changes in tax policy; a lack of available public information regarding non-U.S. issuers; greater market volatility; a lack of sufficient market liquidity; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. These risks may be heightened in connection with investments in issuers located in developing and emerging countries, and in issuers in more developed countries that conduct substantial business in such developing and emerging countries. Fluctuations in the exchange rates between currencies may negatively affect an investment in non-U.S. securities. The Fund may hedge its exposure to foreign currencies. Although hedging may be used to protect the Fund from adverse currency movements, the use of such hedges may reduce or eliminate the potentially positive effect of currency revaluations on the Fund's total return, and there is no guarantee that the Fund's hedging strategy will be successful. Small Cap Securities Risk. Investments in small cap companies may be riskier than investments in larger, more established companies. The securities of smaller companies may trade less frequently and in smaller volumes, and as a result, may be less liquid than securities of larger companies. Therefore, when purchasing and selling smaller cap securities, the Fund may experience higher transactional costs due to the length of time that might be needed to purchase or sell such securities. Additionally, if the Fund is forced to sell securities to meet redemption requests or other cash needs, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. Smaller companies also may be more vulnerable to economic, market and industry changes. As a result, share price changes may be more sudden or erratic than the prices of other equity securities, especially over the short term. Because smaller companies may have limited product lines, markets or financial resources or may depend on a few key employees, they may be more susceptible to particular economic events or competitive factors than large capitalization companies. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. You may lose money by investing in the Fund. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. PERFORMANCE INFORMATION The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. This information can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund's Class I Shares from year to year. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with a broad measure of market performance. Updated performance information is available at oakmark.com or by calling 1-800-OAKMARK. Class I Shares Total Returns for Years Ended December 31 (%) 0.5241 0.2895 0.2126 0.349 -0.0833 -0.4571 0.6745 0.2153 -0.1644 0.1839 ~ http://oakmark.com/20130128/role/ScheduleAnnualTotalReturnsBarChart20046 column dei_LegalEntityAxis compact ck0000872323_S000002763Member row primary compact * ~ <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" colspan="3" style="padding:8.5pt .7pt 6pt 0pt;" valign="top" width="8"> </td> <td colspan="1"> </td> <td align="left" colspan="3" style="padding:8.5pt .7pt 6pt 0pt;" valign="bottom" width="329"> Since 2003, the highest and lowest quarterly returns for the Fund's Class I Shares were: Highest quarterly return: 43.7%, during the quarter ended June 30, 2009 Lowest quarterly return: -27.3%, during the quarter ended December 31, 2008 </td> <td colspan="1"> </td> </tr> </table> Highest quarterly return: 0.437 2009-06-30 Lowest quarterly return: -0.273 2008-12-31 0.1839 0.0180 0.1241 0.1823 0.0128 0.1103 0.1241 0.0135 0.1094 0.1813 0.0151 0.1221 0.1748 -0.0070 0.1204 ~ http://oakmark.com/20130128/role/ScheduleAverageAnnualReturnsTransposed20047 column dei_LegalEntityAxis compact ck0000872323_S000002763Member column rr_PerformanceMeasureAxis compact * row primary compact * ~ After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Class I shares. After-tax returns for Class II shares will vary from returns shown for Class I. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The information illustrates the volatility of the Fund's historical returns and shows how the Fund's annual average returns compare with a broad measure of market performance. The Fund's past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. After-tax returns are shown only for Class I shares. 1-800-OAKMARK oakmark.com Average Annual Total Returns for Periods Ended December 31, 2012 After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. PRINCIPAL INVESTMENT STRATEGY The Fund invests primarily in a diversified portfolio of common stocks of non-U.S. companies. Under normal market conditions, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in the stocks of "small cap companies." A small cap company is one whose market capitalization is less than $5 billion at the time of investment. The Fund may invest in non-U.S. markets throughout the world, including emerging markets. Ordinarily, the Fund will invest in the securities of at least five countries outside the U.S. There are no geographic limits on the Fund's non-U.S. investments. The Fund uses a value investment philosophy in selecting equity securities. This investment philosophy is based upon the belief that, over time, a company's stock price converges with the company's intrinsic or true business value. By "true business value," we mean an estimate of the price a knowledgeable buyer would pay to acquire the entire business. We believe that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective. The Fund's investment adviser, Harris Associates L.P. (the "Adviser"), uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, the Adviser looks for the following characteristics, although not all of the companies selected will have all of these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership. Key Tenets of the Oakmark Investment Philosophy: 1.  Buy businesses that are trading at a significant discount to the Adviser's estimate of the company's intrinsic value. At the time the Adviser buys a company, the Adviser wants the company's stock to be inexpensive relative to what it believes the entire business is worth. 2.  Invest with companies expected to grow shareholder value over time. Value investors can sometimes fall into the trap of buying a stock that is inexpensive for a reason—because the company just does not grow. The Adviser looks for good quality, growing businesses with positive free cash flow and intelligent investment of cash. 3.  Invest with management teams that think and act as owners. The Adviser seeks out companies with management teams that understand the dynamics of per share value growth and are focused on achieving such growth. Stock ownership and incentives that align managements' interests with those of shareholders are key components of this analysis. In making its investment decisions, the Adviser uses a "bottom-up" approach focused on individual companies, rather than focusing on specific economic factors or specific industries. In order to select investments that meet the criteria described above, the Adviser uses independent, in-house research to analyze each company. As part of this selection process, the Adviser's analysts typically visit companies and conduct other research on the companies and their industries. Once the Adviser determines that a stock is selling at a significant discount and that the company has the additional qualities mentioned above, the Adviser may consider buying that stock for the Fund. The Adviser usually sells a stock when the price approaches its estimated worth. This means the Adviser sets specific "buy" and "sell" targets for each stock held by the Fund. The Adviser also monitors each holding and adjusts those price targets as warranted to reflect changes in a company's fundamentals. The Adviser believes that holding a relatively small number of stocks allows its "best ideas" to have a meaningful impact on the Fund's performance. Therefore, the Fund's portfolio typically holds thirty to seventy stocks rather than hundreds, and as a result, a higher percentage of the Fund's total assets may also be invested in a particular region, sector or industry. Portfolio Turnover The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 33% of the average value of its portfolio. 0.33 INVESTMENT OBJECTIVE Oakmark International Small Cap Fund seeks long-term capital appreciation. FEES AND EXPENSES OF THE FUND Below are the fees and expenses that you would pay if you buy and hold shares of the Fund. 0.0000 0.0000 0.0000 0.0000 -0.02 -0.02 0.0000 0.0000 0.0115 0.0115 0.0000 0.0000 0.0026 0.0054 0.0141 0.0169 ~ http://oakmark.com/20130128/role/ScheduleShareholderFees20043 column dei_LegalEntityAxis compact ck0000872323_S000002763Member row primary compact * ~ ~ http://oakmark.com/20130128/role/ScheduleAnnualFundOperatingExpenses20044 column dei_LegalEntityAxis compact ck0000872323_S000002763Member row primary compact * ~ Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Shareholder Fees (fees paid directly from your investment) Example. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual returns and costs may be higher or lower, based on these assumptions your expenses would be: 144 172 446 533 771 918 1691 1998 ~ http://oakmark.com/20130128/role/ScheduleExpenseExample20045 column dei_LegalEntityAxis compact ck0000872323_S000002763Member row primary compact * ~