The U.S. stock market has suffered a sharp two-day decline after President Trump announced new tariffs. The S&P 500 dropped 4.8% on Thursday and fell another more than 5% on Friday, trading as low as 5,101.75. To trigger a circuit breaker, the index would need to fall further to 5,018.76, representing a 7% decline.
Circuit breakers are automatic trading halts that activate during dramatic market downturns. Introduced after the 1987 market crash to help curb panic selling, they operate at three thresholds: a 7% decline triggers a 15-minute pause, a 13% decline triggers another 15-minute pause, and a 20% decline halts trading for the remainder of the day. These mechanisms were most recently activated in March 2020 at the onset of the COVID-19 pandemic.
Other major U.S. indexes are also seeing steep losses: the Dow Jones Industrial Average is down about 4%, and the Nasdaq Composite has fallen roughly 4.6%. Investors are watching whether further market stress will push indexes to the circuit-breaker thresholds or prompt policy responses aimed at stabilizing markets.