CFTC Finds Oil Price Manipulation

By a company called Optiver Holdings. Only it appears not to have had much of an effect:

The alleged manipulation was attempted 19 times on 11 days in March 2007, the agency said. In at least five of those 19 times, traders succeeded in driving prices higher twice and lower three times, according to the CFTC.

Five out of Nineteen, about 26%...not so effective.