Strategy. Under normal market conditions, the portfolio managers will invest at least 80% of the funds net assets, plus any borrowings for investment purposes, in high-yield debt securities. A high-yield security is one that has been rated below the four highest categories used by a nationally recognized statistical rating organization (for example, below BBB by Standard & Poors Corporation or below Baa by Moodys Investors Service, Inc.), or, if unrated, determined by the investment advisor to be of similar quality. High-yield securities are also referred to as junk bonds. The portfolio managers generally operate a long-only strategy using a bottom-up investment philosophy by investing in companies that they believe can carry debt loads through different economic cycles. The portfolio managers look … Show more… Under normal market conditions, the portfolio managers will invest at least 80% of the funds net assets, plus any borrowings for investment purposes, in high-yield debt securities. A high-yield security is one that has been rated below the four highest categories used by a nationally recognized statistical rating organization (for example, below BBB by Standard & Poors Corporation or below Baa by Moodys Investors Service, Inc.), or, if unrated, determined by the investment advisor to be of similar quality. High-yield securities are also referred to as junk bonds. The portfolio managers generally operate a long-only strategy using a bottom-up investment philosophy by investing in companies that they believe can carry debt loads through different economic cycles. The portfolio managers look for companies that demonstrate the ability to generate strong, sustainable cash flow, which may enable them to decrease leverage and improve their ratings. The portfolio managers also use a top-down investment overlay to identify areas of the high yield market that they believe are undervalued relative to the rest of the market. The portfolio managers decide which debt securities to buy and sell by, among other things: identifying debt securities that satisfy the funds credit quality standards; considering the price of the security and the issuers financial history, condition, management and prospects; assessing current and anticipated interest rates; evaluating current economic conditions and the risk of inflation; or evaluating special features of the debt securities that may make them more or less attractive to alternatives. The portfolio managers will actively allocate the funds assets in a range of high-yield corporate bonds. The fund also may invest in preferred securities, convertible securities and cash and cash equivalents. The fund will invest primarily in securities rated BB or B, but may invest a portion of its portfolio in securities rated BBB and above, or CCC and below. The fund has no average maturity limitations. The fund typically invests in debt securities with maturities of 3-10 years, but may also hold securities maturing in less than 3 years and more than 10 years. The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. American Century Investment Management, Inc. (the advisor) has hired Nomura Corporate Research and Asset Management Inc. (the subadvisor) to make investment recommendations for the fund by delivering a model portfolio together with portfolio parameters to the advisor. The advisor has investment discretion to implement the model portfolio delivered by the subadvisor. When deciding whether to buy or sell a security, and how and when to implement a trade, portfolio managers may consider the expected implementation costs and tax consequences of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, minimize tax impact, and/or enhance fund returns. Show less