The management fee has been restated to reflect the decrease in the management fee schedule effective August 1, 2019. Returns or yields for the fund would have been lower if a portion of the management fee had not been waived. Review the annual or semiannual report for the most current information.

The value and/or returns of a portfolio will fluctuate with market and economic conditions.

Historically, small- and/or mid-cap stocks have been more volatile than the stock of larger, more-established companies. Smaller companies may have limited resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies.

International investing involves special risks, such as political instability and currency fluctuations.

Please see the prospectus for details about sales charges.

The gross expense ratio is the fund's total annual operating costs, expressed as a percentage of the fund's average net assets for a given time period. It is gross of any fee waivers or expense reimbursement. The net expense ratio is the expense ratio after the application of any waivers or reimbursement. This is the actual ratio that investors paid during the fund's most recent fiscal year. Please see the prospectus for more information.

Investor Class Shares: Minimum initial investment is $1,000 for IRA and CESA accounts, and $2,500 for non-retirement accounts, but these minimums are waived with an initial investment of at least $500 per account and automatic investments of at least $100 per month. Non-Retirement Accounts: If your account balance falls below the minimum, or if you cancel your automatic monthly investment plan prior to reaching the minimum, American Century Investments may redeem the account and send the proceeds to you. Prior to doing so, we will notify you and give you 90 days to meet the minimum or reinstate your automatic monthly investment plan.

Only Investor Class shares are made available to investors directly. Advisor, A, C, I, and Y Classes of shares are only available for purchase by institutions or other financial intermediaries. R, R5, and R6 Classes of shares are only available for purchase by group employer-sponsored retirement plans. Review definitions and minimums for all share classes.

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