The investment seeks daily investment results, before fees and expenses, that correspond to three times the inverse (-3x) of the daily performance of the NASDAQ-100 Index®. The fund invests in derivatives that ProShare Advisors believes, in combination, should have similar daily return characteristics as three times the inverse (-3x) of the daily return of the index. The index, a modified market capitalization-weighted index, includes 100 of the largest non-financial domestic and international issues listed on the NASDAQ Stock Market. The fund is non-diversified.