The investment seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, emerging market bonds. The fund invests at least 80% of its net assets in U.S. dollar-denominated emerging market bonds, in one or more underlying funds that principally invest in emerging market bonds and in U.S. Treasury securities. It may also invest in other ETFs, U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.