The fund generally invests at least 90% of its assets in securities of the underlying index. The index measures the performance of U.S. dollar-denominated U.S. Treasury bonds, government-related bonds (i.e., U.S. and non-U.S. agencies, sovereign, supranational and local authority debt) and investment-grade U.S. corporate bonds that have a remaining maturity of greater than one year and less than ten years.