March 9, 2020, was the first date in March 2020 when U.S. stock-market circuit breakers halted trading during the COVID-19 crash.
The S&P 500 fell more than 7% shortly after trading began, triggering a Level 1 market-wide circuit breaker. Trading paused for 15 minutes. The halt was designed to give investors time to assess rapidly changing information rather than stop markets for the entire day.
The March 9 sell-off followed growing concern about the spread of COVID-19 and a sharp collapse in oil prices after a dispute between Saudi Arabia and Russia. Further U.S. circuit-breaker halts occurred on March 12, March 16, and March 18.
The 2020 crash was unusually fast. After reaching a record high in February, major U.S. indexes entered a bear market in March. Massive fiscal and monetary support helped markets recover later that year.