Under normal conditions, the fund will invest at least 80 percent of its net assets (including any borrowings for investment purposes) in U.S. bonds. The funds overall investment strategy is to provide total returns (after all of the funds expenses have been deducted) that exceed the total returns of its benchmark index, the Bloomberg U.S. Aggregate Bond Index (Index). The Index is a broadly diversified index that typically consists of investment-grade, fixed income instruments with intermediate- to long-term maturities. Consistent with the Index, the funds holdings will normally include U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, municipal securities, and U.S. dollar-denominated securities of foreign issuers.