On what date did Lehman Brothers file for bankruptcy, helping trigger the 2008 financial crash?

Lehman Brothers filed for bankruptcy on September 15, 2008, helping trigger the 2008 financial crash.

The filing was the largest bankruptcy in U.S. history at that time, with Lehman reporting hundreds of billions of dollars in assets. The investment bank had accumulated heavy exposure to mortgage-related securities and real-estate financing. As housing prices fell and mortgage defaults rose, those assets became difficult to value and sell.

Lehman's collapse intensified fears that other financial institutions could fail. Credit markets tightened, stock markets plunged, and governments intervened to stabilize banks and insurers. The crisis had already begun before the filing, but Lehman's bankruptcy became one of its defining turning points.

Lehman Brothers is sometimes confused with Bear Stearns, another major investment bank rescued earlier in 2008. Bear Stearns was acquired by JPMorgan Chase in March, while Lehman entered bankruptcy after no rescue buyer was found.