The Dow Jones industrial average would have to fall 1,100 points in a day to trigger the first halt. If that point is reached before 2 p.m., the market would shut down for an hour. If the threshold is breached between 2 p.m. and 2:30 p.m., the halt will last 30 minutes. No trading stops will take place if the plunge occurs after 2:30 p.m.
Based on Thursday’s Dow close of 8,579, the threshhold number to cause the market stop in one day would be 7,479.
If the index were to fall 2,200 points before 1 p.m., the market would close for two hours. If such a decline took place between 1 p.m. and 2 p.m., there would be a one-hour pause. The market would close for the day if stocks sank to that level after 2 p.m.
In the event of a 3,350-point decline, the market would close for the day, regardless of the time.
The thresholds are computed at the beginning of each quarter to establish a specific point value for the quarter. The 1,100-point drop represented a 10 percent decline at that time; the 2,200 level, a 20 percent drop and the 3,350 level is a 30 percent drop.
The rules would halt trading on the major securities and futures exchanges in a coordinated cross-market halt if the circuit breaker is enacted.
