The COVID-19 bear market in US stocks began in February 2020.
The S&P 500 reached a record closing high on February 19, 2020, but then fell rapidly as the global spread of COVID-19 threatened economic activity. The index entered bear-market territory on March 12, after a decline of at least 20 percent from its peak.
March contained the most dramatic trading sessions, including several days when market-wide circuit breakers halted trading. Governments and central banks responded with emergency fiscal and monetary measures, while lockdowns disrupted travel, employment, supply chains, and consumer spending.
People sometimes call the episode the March 2020 crash because that month contained the steepest portion of the decline. Strictly speaking, however, the downturn began in February, and the S&P 500 reached its pandemic-era trough on March 23 before rebounding sharply.