Closing Price: The price of the last reported trade on the fund's primary exchange.

Bid Ask Midpoint: The midpoint between the highest bid and the lowest offer on the primary listing exchange, as of the time that the Fund's NAV is calculated, generally around 4 p.m. (Eastern time).

Premium Discount: A premium is the amount that the fund is trading above the reported NAV, expressed as a percentage of the NAV. A discount is the amount that the fund is trading below the reported NAV, expressed as a percentage of the NAV.

ETF Market Performance (Inception to Date): The fund's per share Net Asset Value (NAV) is the value of one share of the fund. Market Price is determined by using the midpoint between the highest bid and the lowest offer on the primary stock exchange on which the shares of the fund are listed for trading, as of the time that the fund's NAV is calculated. The NAV Return is based on the NAV of the fund, and the Market Price Return is based on the market price per share of the fund. Since shares of the fund did not trade in the secondary market until after the fund's inception, for the period from inception to the first day of secondary market trading in shares of the fund, the NAV of the fund is used as a proxy for the Market Price to calculate market returns. Market Price and NAV returns assume that dividends and capital gain distributions have been reinvested in the fund at Market Price and NAV, respectively.

Weighted Average Coupon: The weighted average interest rate paid by the securities in the pool.

Option Adjusted Duration (OAD): OAD is the effective duration. It is a duration calculation for bonds that have embedded options. This measure of duration takes into account the fact that expected cash flows will fluctuate as interest rates change. The effective duration measures the percentage change in price for a 100 basis points parallel shift in the yield curve. Positive duration means that as rates rise, the price decreases, and negative duration means that as rates rise, the price increases.

Option Adjusted Spread (OAS): The measurement of the spread (in basis points) of a fixed-income security rate and the risk-free rate of return, which is adjusted to take into account an embedded option.

Holdings: The number of holdings in the fund excluding cash positions and derivatives such as futures and currency forwards.

Investment Blend: Reflects the blend of securities owned by a fund. For example, the percentage of foreign or domestic stocks held by an equity fund or the percentage of corporate and government securities owned by a bond fund. The U.S./Foreign Convertibles grouping includes Convertible Bonds, Equity Linked Securities and Convertible Preferred securities.

Top Holdings: This value represents the top holdings included in the portfolio on a percent of assets basis. Holding weights are rounded to the nearest whole number, which may result in the display of less than ten holdings. Holdings are subject to change without notice. Shares are units of ownership interest in a corporation or financial asset that provide for an equal distribution in any profits, if any are declared, in the form of dividends. In the context of debt instruments, principal can refer to the face value, or par value, of a bond—that is, the actual amount listed on the bond itself. American Century Investments publishes this listing of identities and quantities of each position held by the fund on each business day, before commencement of trading. Securities are reported at market value. The portfolio data and its presentation here may differ from the complete schedules of investments in regulatory filings due to differing accounting and reporting requirements.

Quality: Describes the portfolio of the fund in terms of the quality ratings of the securities it holds. Cash and cash equivalents include payable amounts related to securities purchased but not settled at period end. Credit quality ratings on underlying securities of a fund are obtained from three Nationally Recognized Statistical Rating Organizations ("NRSROs"), Standard & Poor's, Moody's and Fitch. Ratings are converted to the equivalent Standard & Poor's rating category for purposes of presentation. The median rating is used for securities rated by all three NRSROs. The common rating is used when two of the three NRSROs agree. The lower rating is used when only two NRSROs rate a security. A "nonrated" designation is assigned when a public rating is not available for a security. This designation does not necessarily indicate low credit quality. The letter ratings are provided to indicate the credit worthiness of the underlying bonds in the portfolio and generally range from AAA (highest) to D (lowest). Includes payable amounts related to securities purchased but not settled at period end.

Maturity: Describes the portfolio of the fund in terms of the different maturities of the securities it holds.
Weighted Average Life to Maturity (WALM): Is a measure of the sensitivity of a fixed income portfolio to interest rate changes. WALM is the average time in years to receive the principal repayments. Accordingly, WALM reflects how a portfolio would react to deteriorating credit or tightening liquidity conditions.

Duration: Describes the portfolio of the fund in terms of the different durations of the securities it holds.

For detailed descriptions of indices or investing terms referenced above, refer to our glossary.