Lehman Brothers filed for bankruptcy on 15 September 2008 during the global financial crisis.
The filing was the largest bankruptcy in US history at the time, with Lehman reporting hundreds of billions of dollars in assets. The investment bank had built substantial exposure to mortgage-related securities and was badly damaged when the US housing market deteriorated.
Lehman’s collapse intensified fear about counterparty risk: financial institutions could no longer be sure which partners were safe. Credit markets froze, stock markets plunged, and governments and central banks introduced emergency measures. Barclays acquired much of Lehman’s North American investment-banking operation.
Bear Stearns had already required a rescue in March 2008, which is why the two firms are sometimes conflated. Lehman, however, was the major Wall Street firm whose September bankruptcy became the crisis’s defining corporate failure.