Which 2008 event marked the bankruptcy of the investment bank whose failure intensified the global financial crisis?

The 2008 event marking the bankruptcy of the investment bank whose failure intensified the global financial crisis was the Lehman Brothers bankruptcy.

Lehman Brothers filed for Chapter 11 bankruptcy protection on September 15, 2008. It was the largest bankruptcy filing in U.S. history at that time. The firm had substantial exposure to mortgage-related assets and had been weakened by the collapse of the U.S. housing market and the broader subprime-mortgage crisis.

Lehman’s failure shocked financial markets because banks and investors were uncertain about their counterparties and the value of complex mortgage securities. Credit markets tightened sharply, stock markets fell, and governments around the world introduced emergency lending, guarantees, and recapitalization programs.

The bankruptcy was one part of a wider crisis rather than its sole cause. Bear Stearns had been rescued earlier in 2008, while American International Group received government support shortly after Lehman failed. The episode led to major financial reforms, including the U.S. Dodd–Frank Act of 2010.