Since February 2013, there have been market-wide circuit breakers that respond to single-day declines in the S&P 500 index. When the index falls by 7% below its previous close, it is considered a Level 1 decline. A Level 2 decline refers to a drop of 13%. Finally, a Level 3 decline refers to a drop of 20%.2 These levels have not changed as of March 2022.3

Level 1 or 2 circuit breakers halt trading on all exchanges for 15 minutes unless they are triggered at or after 3:25 PM (in which case trading is allowed to continue). Level 3 circuit breakers halt trading for the remainder of the trading day (from 9:30 a.m to 4:00 p.m.).41