The S&P 500 entered a bear market in March 2020 after falling more than 20% from its February peak.
The index closed at a record high on 19 February 2020, then declined rapidly as the COVID-19 pandemic disrupted travel, business activity, supply chains, and consumer behavior. On 12 March, the S&P 500 closed more than 20% below its previous high, meeting the widely used definition of a bear market.
The 2020 stock-market crash was exceptionally fast. The S&P 500 reached its low on 23 March, after governments and central banks had announced large fiscal and monetary responses. Major indices then recovered sharply, although economic damage and uncertainty continued.
The Dow Jones and Nasdaq Composite also experienced major declines, so they are common alternative answers to broad questions about the crash. The S&P 500 is the specific index identified here by its February peak and March bear-market threshold.