The S&P 500 plummeted 3.8%, and Wall Street is closely monitoring the market-wide circuit breaker thresholds. Under U.S. circuit breaker rules, the S&P 500 trigger levels are as follows: a 7% drop to 7,150.41 triggers a 15-minute trading halt; a 13% drop to 6,689.09 halts trading for another 15 minutes; and a 20% drop to 6,150.89 halts trading for the rest of the day. Notably, the 7% and 13% circuit breakers apply only before 3:25 PM Eastern Time, while the 20% threshold remains in effect throughout the entire trading day.