10 stocks leading today’s S&P 500 decline By: MarketWatch September 28, 2015 at 16:08 PM EDT Drug companies take a beating as Congress looks into price increases. Read More >> Related Stocks: Allergan Plc Chesapeake Energy Endo Int'l Plc Energy Transfer Equity LP Freeport-McMoRan Mallinckrodt plc Mylan Qorvo Inc Regeneron Pharmaceuticals Standard & Poors 500 Tenet Healthcare Valeant Pharmaceuticals International, Inc. Williams Companies Williams Partners LP