Petrobras shares lag in Sao Paulo after loss By: MarketWatch August 06, 2012 at 14:48 PM EDT A loss from Brazil’s state-run oil company cuts into shares of Petrobras Read More >> Related Stocks: Companhia Siderurgica Nacional ADR Petrobras - Petroleo Brasileiro S.A. Standard & Poors 500 Vale ADR Representing One Ord Shs