Circuit Breaker
Also called: trading halt, limit up limit down, market halt
A circuit breaker pauses trading after a sharp move, giving participants time to assess and letting the order book rebuild. US markets halt for 15 minutes on 7% and 13% index declines and close for the day at 20%. Single stocks have their own bands. The debate is whether pauses calm panic or intensify it by making participants rush to trade before the next halt.