Energy stocks drag down S&P 500 By: MarketWatch October 10, 2012 at 13:52 PM EDT Shares of energy stocks move lower Wednesday, with the sector the worst performing in the S&P 500 index amid steep losses for Chevron and Tesoro. Read More >> Related Stocks: BP Plc ADR Chevron Corp ConocoPhillips Energy Select Sector SPDR Exxon Mobil Marathon Petroleum Phillips 66 Tesoro Petroleum Co