In the 2008 financial crisis, which U.S. mortgage-market collapse triggered the wider credit crisis?

The subprime mortgage crisis triggered the wider credit crisis that became central to the 2008 financial crisis.

Subprime mortgages were home loans made to borrowers with weaker credit histories or higher repayment risks. Many were bundled into mortgage-backed securities and more complex financial products. When U.S. house prices fell and borrowers began defaulting, the value of these securities became difficult to assess, damaging banks and credit markets.

The crisis intensified in 2007 and 2008, with failures and rescues involving major financial institutions. Lehman Brothers filed for bankruptcy on September 15, 2008, but that event was a consequence and accelerator of the wider crisis rather than its sole starting point. The turmoil spread internationally through interconnected banks, markets, and economies.