Petrobras shares lower; Mexico stocks up By: MarketWatch September 24, 2010 at 15:31 PM EDT Brazilian stocks fall, with Petrobras down after massive share offering Read More >> Related Stocks: Brazil Ishares MSCI ETF Cemex S.A.B. DE C.V. ADR Gerdau S.A. ADR Petrobras - Petroleo Brasileiro S.A. Standard & Poors 500 Vale ADR Representing One Ord Shs