The S&P 500 lost nearly 34% between February 19 and March 23, 2020, during the 2020 stock market crash.
The decline followed the global spread of COVID-19, which led governments to impose travel restrictions, business closures, and social-distancing measures. Investors rapidly reassessed corporate earnings, economic activity, energy demand, and credit conditions.
The sell-off was unusually fast. The S&P 500 reached a record closing high on February 19 before entering a bear market and reaching its 2020 closing low on March 23. Trading was interrupted by market-wide circuit breakers several times during the most volatile period.
Central banks and governments then introduced extensive monetary, fiscal, and public-health responses. The index recovered strongly later in 2020, but the episode remains distinct from earlier crashes because the initial shock came from a global health emergency rather than a conventional financial-sector failure.