The investment seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays U.S. Aggregate Bond Index (the "underlying index"). The fund generally seeks to track the performance of the underlying index by investing approximately 90% of its assets in the bonds represented in the underlying index and in securities that provide substantially similar exposure to securities in the underlying index. The underlying index measures the performance of the total U.S. investment grade bond market.