Washington Mutual shares rose more than 12 percent on Tuesday amid speculation of a possible capital infusion by Goldman Sachs or Warren Buffett. The shares closed down about 2 percent at $11.64 on the New York Stock Exchange on Wednesday. Last week, shares of WaMu, the largest U.S. savings and loan which has been battered by mortgage losses, fell after a report in The Wall Street Journal said it has approached private equity firms and sovereign wealth funds about possible cash infusions. Neither WaMu nor Toscafund were immediately available.