The investment seeks investment results that track the total return of the debt securities that comprise the Bloomberg U.S. Aggregate Bond Index (the "benchmark index"). The fund normally invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in securities included in the benchmark index and, using sampling techniques, a portfolio of securities designed to give the fund the relevant comparable attributes of the benchmark index. The index includes over 12,000 securities and covers the U.S. investment grade bond market, including corporate bonds, government securities, mortgage-backed securities.