March 16, 2020, marked the largest single-day percentage fall in the S&P 500 during the COVID-19 crash.
The index dropped 12.0% as investors reacted to rapidly spreading coronavirus infections, travel restrictions, business closures, and emergency monetary and fiscal measures. Trading was halted by the S&P 500’s Level 1 circuit breaker after the index fell 7% shortly after the opening.
The 2020 crash was unusually fast. U.S. equities entered a bear market in March, then rebounded sharply after central-bank liquidity, government relief programs, vaccine progress, and expectations of reopening improved sentiment. Energy markets added stress when an oil-price dispute between Saudi Arabia and Russia intensified.
March 9 and March 12 were also major decline days, which can cause date confusion. March 23 became the approximate low for the S&P 500 before the powerful recovery that followed.