TMF provides daily leveraged (3x) exposure to the ICE U.S. Treasury 20+ Year Bond Index. Using a combination of swaps and futures, TMF gives investors 3x exposure to daily moves in T-bonds with more than 20 years left to maturity. The daily reset means investors shouldn't expect the leverage factor to hold constant over investment horizons greater than one day. In short, the fund is a valid option for tactical positioning/hedging against rising interest rates, but it's important to keep in mind that the 3x leverage results in greater impact from the effects of compounding. As a levered product, TMF is not a buy-and-hold ETF, it's a short-term tactical instrument. Prior to May 2, 2016, TMF tracked the NYSE 20+ Year Treasury Bond Index. The change had minimal impact on investors exposure.