The investment seeks daily investment results that correspond to two times the inverse (-2x) of the daily performance of the Nasdaq Biotechnology Index®. The fund invests in derivatives that ProShare Advisors believes, in combination, should have similar daily return characteristics as two times the inverse (-2x) of the daily return of the index. The index is a modified capitalization weighted index that includes securities of NASDAQ listed companies that are classified as either biotechnology or pharmaceutical according to the Industry Classification Benchmark ("ICB") which also meet other eligibility criteria determined by NASDAQ. It is non-diversified.