Energy companies fall after Iran signals progress in nuclear talks

S&P 500 energy index .SPNY falls ~2% as oil prices ease

Brent crude LCOc1 futures down 1.4% at $67.71/barrel; U.S. West Texas Intermediate (WTI) crude futures CLc1 fall 0.2% to $62.79/barrel

Prices fall after Iran's foreign minister said the United States and Iran reached an understanding on the main "guiding principles" of their nuclear talks, easing investor concerns about tensions escalating O/R

Oil majors Exxon Mobil XOM.N and Chevron CVX.N down 1.5% and 1.2%, respectively

APA Corp APA.O, Diamondback Energy FANG.O, Expand Energy EXE.O and EQT Corp EQT.N among biggest percentage losers on the energy index, slip between 2.5% and 3.1%

Refiners Marathon Petroleum MPC.N and Valero Energy VLO.N dip 1.6% and ~1%, respectively

Oilfield services companies: SLB SLB.N down 1.3%, Baker Hughes BKR.O falls ~2% and Halliburton HAL.N dips 1.2%