Which 2008 collapse of a major investment bank intensified the global financial crisis?

The bankruptcy of Lehman Brothers on September 15, 2008, intensified the global financial crisis and triggered severe turmoil in stock markets.

Lehman was a major American investment bank with extensive exposure to mortgages and mortgage-related securities. After the U.S. housing market weakened, losses increased and confidence in the bank deteriorated. The firm filed for Chapter 11 protection with more than $600 billion in debt, making it the largest U.S. bankruptcy filing at that time.

The failure froze credit markets and raised fears that other financial institutions could collapse. Stock indexes plunged worldwide, while governments and central banks adopted emergency measures. The crisis had begun earlier through housing and credit problems, so Lehman’s bankruptcy was a major escalation rather than the sole original cause.