Level 1 and 2 halts may only occur once per trading day. If the S&P 500 falls by 7% and the 15-minute halt is activated, trading would only be halted again if the Level 2 threshold of 13% is met.
If the Level 2 halt occurs on the same day as a Level 1 halt, only the Level 3 loss threshold of 20% would halt trading again.
Level 1 and 2 halts can only be triggered before 3:25 pm EST. After 3:25 pm, only a Level 3 trading halt (20% decline in the price of the S&P 500) would cause trading to stop for the remainder of the day.
Standard US stock market hours of operation are: 9:30 am - 4:00 pm EST.
