OILK holds WTI oil futures in an open-ended ETF wrapper. The underlying index provides equal exposure to three separate WTI Oil futures at each semi-annual reset in March and September. The portfolio exposure is divided into thirds. The first portion follows a monthly roll schedule while the second and third portion holds June and December contracts that are rolled annually each March and September, respectively. OILK is organized as an open-ended ETF, rather than a commodities pool, so investors avoid receiving a complicated K-1 form at tax time. The fund pulls this off by getting its oil futures exposure through a wholly-owned Cayman Islands subsidiary, an increasingly common structure in the commodity space. Prior to May 17, 2021, the fund was actively managed. Before September 27, 2024, the fund was named ProShares K-1 Free Crude Oil Strategy ETF.