The fund seeks to provide diversified investment exposure to the U.S. high yield bond market. Under normal circumstances, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in high yield securities and ETFs providing exposure to such securities. It's policy with respect to the investment of at least 80% of its net assets may be changed by the fund's board, upon 60 days' prior notice to shareholders. The fund's managers consider high yield securities to be securities with ratings that qualify for inclusion in the index.