The investment seeks to track changes, whether positive or negative, in the level of the DBIQ Optimum Yield Silver Index Excess ReturnTM over time, plus the excess, if any, of the sum of the fund?s Treasury Income, Money Market Income and T-Bill ETF Income, over the expenses of the fund. The Advisor invests in futures contracts in an attempt to track its Index. The fund pursues its investment objective by investing in a portfolio of exchange-traded futures on the index commodity. The index is composed of the notional amount of the underlying index commodity.