The price of crude oil in the U.S. never exceeded $40 per barrel until mid-2004. By 2006 it reached$70, and in July 2008 it peaked at $145. By late 2008 it had plummeted to about $30 before increasingto $110 in 2011. Are speculators at least partly to blame for these sharp price changes? We...

If commercial producers or financial investors use futures contracts to hedge against commodity price risk, the arbitrageurs who take the other side of the contracts may receive compensation for their assumption of nondiversifiable risk in the form of positive expected returns from their...