Energy companies down on US economic concerns

S&P 500 energy index .SPNY falls 4% as oil prices edge lower

Brent crude LCOc1 down ~1% at $67.32/barrel and U.S. West Texas Intermediate (WTI) crude futures CLc1 down 1% at $63.39/barrel

Oil prices fall as traders focus more on concerns about the U.S. economy than the start of looser monetary policy after the U.S. Federal Reserve cut interest rates for the first time this year

Top oil and gas firms Exxon Mobil XOM.N and Chevron CVX.N down 1.2% and 1%, respectively

EQT EQT.N, Devon Energy DVN.N and APA Corp APA.O fall between 1.5% and 1.7%, among biggest pct loosers on the energy index

Refiners Phillips 66 PSX.N and Marathon Petroleum MPC.N down 1.6% and 1%, respectively

Oilfield services cos Halliburton HAL.N and SLB SLB.N both down marginally