The investment seeks daily investment results that correspond to three times (3x) the daily performance of the S&P MidCap400®. The fund invests in securities and derivatives that ProShare Advisors believes, in combination, should have similar daily return characteristics as three times (3x) the daily return of the index. The index is a measure of mid-size company U.S. stock market performance. It is a float-adjusted, market capitalization-weighted index of 400 U.S. operating companies and real estate investment trusts selected through a process that factors criteria such as liquidity, price, market capitalization and financial viability. It is non-diversified.