Several prominent hedge fund managers made bigger bets on U.S. automaker General Motors (GM.N) during the second quarter, despite the company’s battling a deadly ignition defect and tangling with shareholders over its stock price. Greenlight Capital’s David Einhorn bought 7.9 million shares between April and the end of June, raising his investment to 14.6 million shares. Einhorn had told investors about the stake but details on how much he actually bought were only released on Friday in a regulatory filing.