On what date did the S&P 500 reach its closing low during the 2008 financial crisis?

The S&P 500 reached its closing low during the 2008 financial crisis on March 9, 2009.

The index closed at 676.53, ending a bear market that had begun after the record closing high of 1,565.15 on October 9, 2007. The decline reflected the collapse of housing-related finance, severe credit stress, bank losses, recession, and fear about the stability of the global financial system.

Although the crisis is commonly associated with events in 2008, the stock-market low came in 2009. Markets began a powerful recovery after that point, supported by policy interventions, financial rescues, improving confidence, and later economic stabilization.

The closing low should not be confused with the intraday low, which was reached on March 6, 2009. Nor is March 9 the date of the Lehman Brothers bankruptcy; that filing occurred on September 15, 2008, a major earlier shock in the crisis.