The S&P 500 lost about 57% from its 2007 peak to its 2009 trough during the global financial crisis.
The index reached a closing high of 1,565.15 on October 9, 2007. It eventually fell to a closing low of 676.53 on March 9, 2009, a decline of roughly 56.8%, commonly rounded to 57%. The fall reflected the bursting of the U.S. housing bubble, mortgage defaults, bank losses, and a severe contraction in credit.
The S&P 500’s decline was larger than an ordinary correction and met the conventional definition of a bear market many times over. The index later recovered, but the crisis had already produced a global recession and major government interventions in financial markets.