Understanding U.S. Stock Market Circuit Breakers
Circuit breakers are market-protection mechanisms designed to slow extreme price movements and give investors time to assess rapidly changing conditions. When a stock's price movement reaches the specified circuit breaker threshold, the exchange will suspend trading as a risk control measure. In the United States, protections operate at both the market-wide level and the individual-security level.
Market-Wide Circuit Breakers
U.S. market-wide circuit breakers are tied to a one-day decline in the S&P 500 Index. The thresholds are calculated each day using the previous day’s closing value of the index:
Level 1: S&P 500 declines by 7%
Level 2: S&P 500 declines by 13%
Level 3: S&P 500 declines by 20%
When a severe decline reaches one of these levels, coordinated trading halts may apply across U.S. securities markets. These mechanisms are intended to address conditions in which liquidity may be overwhelmed by unusually intense selling pressure. Depending on the timing and severity of the decline, trading may pause temporarily or the markets may close before the normal end of the session.
Single Stock Circuit Breaker
The United States also uses the Single Stock Circuit Breaker mechanism for individual securities. Rather than responding to a broad market decline, Single Stock Circuit Breaker is designed to prevent trades in a particular stock from occurring outside a defined price band.
for any trading halts due to the single stock circuit breaker, please check https://www.nasdaqtrader.com/Trader.aspx?id=TradeHalts
