The specific reasons are as follows:

When the trading day of a futures contract closes, the fluctuation range of the second and third consecutive trading days will temporarily expand, which is called expansion. For example, the fluctuation range of futures products of Zhengshang Institute for three consecutive days is 4%-7%- 10%. If there is a daily limit or a daily limit for three consecutive trading days, the exchange will suspend trading for one day.

The futures varieties listed and traded on the first day are also subject to the price limit, which is twice the price limit in future trading days. The scope of the futures contract is not fixed. The exchange will make temporary adjustments according to the fluctuation of futures prices and the change of positions.