The DME has asked the CFTC to ease margin-calculation rules for traders on its markets, cutting trading costs for its flagship Oman Sour Crude contract. The DME’s sour crude futures contract, launched in June 2007, is among a host of products aimed at establishing a pricing mechanism for the heavier crude oil produced in the Middle East. The CFTC rule requiring customer margin levels to be calculated on a two-day holding period may be making it about 30% more expensive for investors to trade Oman crude oil contracts versus global benchmark crude contracts.