Washington Mutual, Inc—abbreviated to WaMu—was a savings bank holding company and the former owner of WaMu Bank, which was the United States' largest savings and loan association until its collapse in 2008. Regarding total assets under management, WaMu's closure and receivership is the largest bank failure in American financial history.Before the receivership action, it was the sixth-largest bank in the United States.According to WaMu Inc.'s 2007 SEC filing, the holding company held assets valued at $327.9 billion.