Why did Washington mutual bank close?

Washington Mutual Bank closed due to significant financial instability stemming from high levels of mortgage defaults and poor risk management practices. By 2008, it faced a liquidity crisis, leading to heavy losses and a plummeting stock price. The bank was ultimately seized by the Office of Thrift Supervision and its banking assets were sold to JPMorgan Chase during the financial crisis, marking one of the largest bank failures in U.S. history.