Oil firms fall as Moody's downgrades US credit rating, slow growth in China

U.S.-listed shares of oil firms fall premarket, tracking falling oil prices O/R

Brent crude futures LCOc1 down 0.7% at $64.95/barrel, U.S. West Texas Intermediate crude CLc1 fall 0.4% to $62.23/barrel

Oil prices fell after Moody's downgraded the U.S. sovereign credit rating and official data showed slowing growth in China's industrial output and retail sales

Energy majors Chevron CVX.N and Exxon XOM.N down 1.9% and 0.7%, respectively

APA Corp APA.O down nearly 1%, Devon Energy DVN.N dips 1.4%, ConocoPhillips COP.N falls 2%

Oilfield service companies Halliburton HAL.N and Baker Hughes BKR.O slip 1.2% and 1.8%, respectively

Refiners Valero Energy VLO.N and Marathon Petroleum MPC.N down 1% each