The investment seeks daily investment results that correspond to the inverse (-1x) of the daily performance of the Markit iBoxx $Liquid High Yield Index. The fund invests in financial instruments that ProShare Advisors believes, in combination, should produce daily returns consistent with the fund's investment objective. The index is a market-value weighted index designed to provide a balanced representation of U.S. dollar denominated high yield corporate bonds for sale within the U.S. by means of including the most liquid high yield corporate bonds available as determined by a set of transparent and objective index rules. The fund is non-diversified.