Under normal circumstances, the fund invests at least 80% of its net assets in debt securities and in derivatives and other instruments that have economic characteristics similar to such securities. The fund primarily invests in securities that have a dollar-weighted average portfolio maturity between three to 10 years. The fund will invest primarily in investment-grade securities, but may invest up to 20% of its net assets in below-investment-grade securities which are sometimes referred to as high-yield or “junk” bonds.