Trading Halts & Circuit Breakers
Mechanisms that pause trading in stress: market-wide circuit breakers halt all equity trading when the S&P 500 falls 7% (Level 1), 13% (Level 2), or 20% (Level 3) from the prior close; single-stock halts pause one issue for news or volatility.
Limit-up/limit-down (LULD) bands curb single-stock moves by pausing trading when prices push outside set percentage bands. Open orders generally remain live through a halt and may execute when trading resumes.