The S&P 500 took 33 calendar days to fall about 34% during the COVID-19 market crash.
The decline ran from the index’s February 19, 2020 record close to its March 23, 2020 low. That made the episode one of the fastest bear-market collapses in modern U.S. market history. Investors reacted to the spread of COVID-19, business shutdowns, travel restrictions, uncertainty about earnings, and stress in credit markets.
Trading was halted several times in March when major U.S. indexes hit market-wide circuit breakers. The Federal Reserve and other authorities introduced large monetary and fiscal measures, while governments supported households, businesses, and financial markets.
The decline was followed by a powerful rebound, although the economic recession continued and many sectors remained disrupted. The 33-day figure measures calendar time between the closing peak and closing trough; different definitions can produce slightly different statistics.