The fund uses a rules-based, systematic investment strategy that seeks to track an index designed to measure the performance of the high yield bond market. To pursue its goal, the fund normally invests substantially all of its assets in bonds comprising the Bloomberg US Corporate High Yield Total Return Index (index). The fund may also invest in derivatives with economic characteristics similar to such bonds or the index. The fund's derivatives investments may include credit default swap indexes, total return swaps, structured notes and futures. 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. The fund considers high yield securities to be securities with ratings that qualify for inclusion in the index.