Lehman Brothers’ bankruptcy on September 15, 2008, became a key event in the global financial crisis and stock-market crash.
Lehman Brothers was a major American investment bank with extensive exposure to mortgage-related assets, especially securities linked to the U.S. housing market. After housing prices fell and mortgage defaults increased, the value of those assets declined and confidence in the firm's finances deteriorated.
Lehman filed for Chapter 11 bankruptcy protection after efforts to arrange a rescue or sale failed. It was the largest bankruptcy filing in U.S. history at that time. The failure intensified uncertainty about the stability of banks and financial institutions around the world.
Lehman's collapse was important, but it was not the sole cause of the crisis. The turmoil also involved excessive leverage, complex mortgage securities, weak underwriting, falling house prices, and stress across the global banking system. Governments and central banks later used emergency lending, guarantees, and stimulus measures.