GM shares hurt as investors question whether automaker can deal with slowing US market

``GM posted its second most profitable quarter ever, earning $2.4 billion and beating earnings estimates by a wide margin. But the stock failed to pop as questions grow over whether GM will be able to adjust to a slowing market in the U.S. -- specifically, whether the automaker will ditch several car models and retool some of its plants to build crossovers and SUVs.'' -- More good news = bad news...