The fund, under normal circumstances, invests in swap agreements, futures contracts, short positions or other financial instruments that, in combination, provide inverse (opposite) or short leveraged exposure to the index equal to at least 80% of the fund's net assets (plus borrowing for investment purposes). The index is a market value weighted index that includes publicly issued U.S. Treasury securities that have a remaining maturity of greater than 20 years. It is non-diversified.