ProShares UltraShort DJ-UBS Crude Oil (the Fund), formerly known as ProShares UltraShort DJ-AIG Crude Oil, seeks daily investment results that correspond to twice (200%) the inverse (opposite) of the daily performance of The Dow Jones—UBS Crude Oil Sub-Index (the Index). The Index, a sub-index of DJ—UBS Commodity Index, is intended to reflect the crude oil segment of the commodities market. The Index consists of futures contracts on crude oil only. The Index is valued using the settlement prices for the underlying futures contracts.