Washington Mutual, Inc. (OTC Pink: WAMUQ), abbreviated to WaMu, was a savings bank holding company and the former owner of Washington Mutual Bank, which was the United States' largest savings and loan association until its collapse in 2008.^{[2][3][4][5][6]}

On Thursday, September 25, 2008, the United States Office of Thrift Supervision (OTS) seized Washington Mutual Bank from Washington Mutual, Inc. and placed it into receivership with the Federal Deposit Insurance Corporation (FDIC). The OTS took the action due to the withdrawal of $16.7 billion in deposits during a 9-day bank run (amounting to 9% of the deposits it had held on June 30, 2008).^[7] The FDIC sold the banking subsidiaries (minus unsecured debt and equity claims) to JPMorgan Chase for $1.9 billion, which JPMorgan Chase had been planning to acquire as part of a confidential plan internally nicknamed Project West.^[8][9][10] All WaMu branches were rebranded as Chase branches by the end of 2009. The holding company, Washington Mutual, Inc., was left with $33 billion in assets, and $8 billion debt, after being stripped of its banking subsidiary by the FDIC.^{[3][4][11][12]} The next day, September 26, Washington Mutual, Inc. filed for Chapter 11 voluntary bankruptcy in Delaware, where it is incorporated.^[4][11]

With respect to total assets under management, Washington Mutual Bank's closure and receivership is the largestbank failure in American financial history.^[3][4] Before the receivership action, it was the sixth-largest bank in the United States.^[13] According to Washington Mutual Inc.'s 2007 SEC filing, the holding company held assets valued at $327.9 billion.^[14]

On March 20, 2009, Washington Mutual Inc. filed suit against the FDIC in the United States District Court for the District of Columbia, seeking damages of approximately $13 billion for what it claims was an unjustified seizure and an extremely low sale price to JPMorgan Chase. JPMorgan Chase promptly filed a counterclaim in the Federal Bankruptcy Court in Delaware, where the Washington Mutual bankruptcy proceedings had been continuing since the Office of Thrift Supervision's seizure of the holding company's bank subsidiaries.