The United States Oil FundÂź LP (USO) is an exchange-traded security whose shares may be purchased and sold on the NYSE Arca. USOâs investment objective is for the daily changes, in percentage terms, of its sharesâ net asset value (NAV) to reflect the daily changes, in percentage terms, of the spot price of light sweet crude oil delivered to Cushing, Oklahoma, as measured by the daily changes in the Benchmark Oil Futures Contract. Specifically, USO seeks for the average daily percentage change in USOâs net asset value, for any period of 30 successive valuation days, to be within plus/minus 10% of the average daily percentage change in the price of the Benchmark Oil Futures Contract over the same period.