The price difference between futures and cash on the last trading day of stock index futures is meaningless. The futures spread on the last trading day of stock index futures, some people will refer to the futures spread, which generally means that the futures price is much higher or lower than the spot price. Then according to the value regression theory, the futures price should fall to the spot, or the futures should rise to the spot. However, in practice, the spot price may follow the futures price, and the stop loss is meaningless.