How Stocks Nearly Triggered a Market-Wide Trading Freeze Thursday

On Thursday, the S&P 500 fell as much as 3.8% as chip stocks sold off, and another 3.3% drop would have triggered a market-wide circuit breaker that halts all U.S. stock trading for 15 minutes. Circuit breakers are automatic pauses tied to the S&P 500’s prior close of 7,688.62; a 7% fall to 7,150.41 triggers a 15-minute halt, and the first two pause levels apply only before 3:25 p.m. Eastern Time. The Philadelphia Semiconductor Index fell 10.2% as investors worried that Democratic control of Congress would slow growth for data centers that buy AI chips. By midday, the S&P 500 had recovered to about 7,400, leaving roughly 285 points of room.