Six minutes after trading began on the New York Stock Exchange on Monday, it was suddenly halted. That's when the S&P 500 index had plummeted 7% and marketwide circuit breakers kicked in. Trading ...

Forbes contributors publish independent expert analyses and insights. I show you how to save and invest. In 1987 the markets fell over 20% in a single day. Separately, in 1989 the markets had a 6% one ...

But many investors and others may not know what the market circuit breaker is and why it is so important. What is a market circuit breaker? How does a circuit breaker work? What are single-stock ...

Six minutes after trading began on the New York Stock Exchange on Monday, it was suddenly halted. That's when the S&P 500 index had plummeted 7% and marketwide circuit breakers kicked in. Trading ...