Lehman Brothers' September 2008 bankruptcy intensified the worldwide stock-market crash.
Lehman Brothers filed for Chapter 11 bankruptcy protection on September 15, 2008, after suffering heavy losses connected to U.S. housing and mortgage-related securities. It was the largest bankruptcy filing in U.S. history at that time.
The failure shocked financial markets because Lehman was a major global investment bank with extensive relationships and obligations. Interbank lending became more difficult as institutions reassessed the creditworthiness of counterparties. Equity markets fell sharply as investors feared a broader systemic crisis.
Lehman's collapse is often treated as a turning point in the 2007–2008 financial crisis, but it was not its beginning. The crisis had already involved the collapse or rescue of other firms, including Bear Stearns, and later led to extraordinary government interventions.