Here's what to know about so-called “circuit breakers" and when they're used to halt trading on stock markets.

The S&P 500 was trading around 5,470 on Thursday, down about 3.6%. While this certainly feels like a significant decline, the index would have to drop to 5,274.01 to trigger the f ...

During the regular hours of 9:30 a.m. ET to 4 p.m. ET, trading in equities may be paused market-wide if declines in the S&P 500 trigger a "circuit breaker." These occur when the benchmark index falls ...