The fund seeks to track the investment results of the Bloomberg Barclays U.S. Universal Index (the Underlying Index), which measures the performance of U.S. dollar-denominated taxable bonds that are rated either investment-grade or high yield (as determined by Bloomberg Index Services Limited). The Underlying Index includes U.S. Treasury bonds, government-related bonds (i.e., U.S. and non-U.S. agencies, sovereign, quasi-sovereign, supranational and local authority debt), investment-grade and high yield U.S. corporate bonds, mortgage-backed pass-through securities, commercial mortgage-backed securities, asset-backed securities, Eurodollar bonds, bonds registered with the SEC or exempt from registration at the time of issuance or offered pursuant to Rule 144A with or without registration rights and U.S. dollar-denominated emerging market bonds. The securities in the Underlying Index must be denominated in U.S. dollars.