The S&P 500 declined 56.8% from its 2007 peak to its March 2009 low during the Global Financial Crisis.
The index reached a closing high of 1,565.15 on October 9, 2007, before the housing and credit crisis intensified. It reached a closing low of 676.53 on March 9, 2009, producing a fall of roughly 56.8%.
The decline reflected widespread stress in mortgage lending, securitized debt, banks, insurers, and credit markets. The bankruptcy of Lehman Brothers in September 2008 accelerated panic, while governments and central banks introduced emergency interventions.
The S&P 500 measures large U.S. companies and is capitalization-weighted, so the percentage describes the index rather than every share. The market’s low also marked the beginning of a long recovery, though economic conditions remained difficult afterward.