The investment seeks daily investment results that correspond to the inverse (-1x) of the daily performance of the Dow Jones U.S. Oil & GasSM Index. The fund invests in derivatives that ProShare Advisors believes, in combination, should have similar daily return characteristics as the inverse (-1x) of the daily return of the index. The index measures the performance of the oil and gas sector of the U.S. equity market. Component companies include, among others, exploration and production, integrated oil and gas, oil equipment and services, pipelines, renewable energy equipment companies and alternative fuel producers. The fund is non-diversified.