Since their adoption in 1988, market-wide circuit breakers have only been activated once, in 1997, in both countries. But new U.S. rules could see them triggered far more often.

The S&P 500 traded as low as 5,101.75 on Friday, down more than 5%. While this certainly feels like a significant decline, the index would have to drop to 5,018.76 to trigger the first circuit ...

A big drop in the S&P 500 could lead to a pause on trading Traders woke up to a sharply lower stock market on Monday morning and a spike in volatility. The Dow DJIA opened 2.7% lower, the S&P 500 ...

The Investment Industry Regulatory Organization of Canada (IIROC) announced that it’s revising circuit breaker trigger levels for Wednesday amid expectations of heightened market volatility in the ...

Major stock market indexes fell sharply on Monday, leaving some traders wondering if a circuit breaker could be triggered. Circuit breakers are built into the market structure and temporarily halt ...

Here's a breakdown of what it takes to trigger the circuit breakers: -- A Level 1 circuit breaker stops trade for a minimum of 15 minutes if the S&P 500 falls 7% before 3:25 p.m. Eastern time.

The S&P 500 traded as low as 5,101.75 on Friday, down more than 5%. While this certainly feels like a significant decline, the index would have to drop to 5,018.76 to trigger the first circuit ...

A circuit breaker will be triggered if the S&P 500 falls 7%, 13% or 20%. Photo: Getty Images/iStockphoto Traders woke up to a sharply lower stock market on Monday morning and a spike in volatility.