Call it a USO abduction. The United States Oil Fund, ticker USO, remains one of Wall Street's most popular vehicles for betting on oil prices. The exchange-traded fund, which invests in oil futures, has had average assets of $2.2bn since the start of 2009, according to Morningstar, meaning a payday for USO's managers of roughly $23m given the 0.45% management fee.

And yet, the USO and oil have inhabited different universes when it comes to performance. Front-month futures on West Texas Intermediate oil, USO's benchmark, have risen 123% since the start of 2009, while the ETF has risen a mere 19%.