The investment seeks daily investment results, before fees and expenses, that correspond to two times (2x) the daily performance of the S&P MidCap 400®. The fund invests in securities and derivatives that ProShare Advisors believes, in combination, should have similar daily return characteristics as two times (2x) 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. The fund is non-diversified.