Energy firms fall as oil prices edge lower

S&P 500 energy index .SPNY falls 0.8% as oil prices edge lower

Brent crude futures LCOc1 down 0.4% at $71.73 per barrel; U.S. West Texas Intermediate (WTI) crude CLc1 falls 0.2% to $67.91 per barrel

Oil prices fell slightly on Friday but were headed for second consecutive weekly gain as fresh U.S. sanctions on Iran and latest output plan from OPEC+ producer group raised expectations of tighter supply

Oil majors Chevron CVX.N and Exxon Mobil XOM.N down 0.4% and 0.5%, respectively

Valero Energy VLO.N, Marathon Petroleum MPC.N, Phillips 66 PSX.N down between 1.2% and 1.7%, among top pct. losers on energy index

Oilfield equipment and services operators Baker Hughes BKR.O down 1%