A 7% loss by the S&P 500 on March 9, 2020, triggered a circuit breaker during the 2020 stock-market crash.
The market opened sharply lower as investors reacted to the rapid spread of COVID-19, rising economic uncertainty, and a collapse in oil prices after an OPEC+ production agreement broke down. The S&P 500’s fall reached the threshold for a Level 1 market-wide trading halt, temporarily pausing trading.
The U.S. circuit-breaker system uses percentage declines in the S&P 500 to slow panic selling. A 7% fall before 3:25 p.m. Eastern Time triggers a 15-minute halt; a 13% fall triggers another Level 2 halt, while a 20% decline closes the market for the day.
March 9 was the first of three major U.S. market sell-offs that month. The episode is sometimes called Black Monday, but that nickname also commonly refers to the separate October 19, 1987 crash.