The rules are covered here: https://www.sec.gov/oiea/investor-alerts-bulletins/investor-alerts-circuitbreakersbulletinhtm.html https://www.sec.gov/oiea/investor

The rules are covered here: https://www.sec.gov/oiea/investor-alerts-bulletins/investor-alerts-circuitbreakersbulletinhtm.html https://www.sec.gov/oiea/investor-alerts-bulletins/investor-... LULD is the one that applies to single stocks. It only results in a five minute halt, as I said. The market-wide circuit breaker can halt the entire market for a full day, but only in response to a 20% move in S&P500, not a single stock.