Except for futures in non-US session, there is a fuse mechanism for the decline in US session.
During trading hours in the United States, the fuse mechanism can be divided into three levels.
The primary market is blown, which means that the market has fallen by 7%.
The secondary market is blown, which means that the market is down 13%.
The melting of the tertiary market means that the market has fallen by 20%.
The market decline here refers to the decline of the index point of the S&P 500 index relative to the closing point of the previous day during the regular trading hours (9: 30- 16: 00 EST). (If the trading day is half a day, the closing time is 13: 00).
During non-US trading hours, if the price of stock index futures rises or falls by 5%, it will trigger the fuse mechanism.