Lehman Brothers’ collapse on 15 September 2008 intensified the September 2008 stock-market crash.
Lehman Brothers was a major American investment bank with heavy exposure to mortgage-related assets and real-estate financing. After losses increased and potential rescue discussions failed, the firm filed for the largest bankruptcy in U.S. history at that time.
The failure amplified fears about counterparty risk and the stability of the global banking system. Credit markets tightened, financial shares plunged, and governments responded with emergency lending, guarantees, and bank-rescue measures. The stock-market decline was part of the broader global financial crisis, not an isolated reaction to one company.
Bear Stearns had already collapsed earlier in 2008 and was acquired by JPMorgan Chase, while Washington Mutual failed later that September. Those events are closely related, but Lehman Brothers is the bank most directly associated with the dramatic mid-September shock.