Detailed rules for delivery of stock index futures. Different from commodity futures, because it is cash delivery, the last trading day and the last settlement date are the same day, which is the third Friday of the maturity month. So how is the settlement price determined? It is stipulated that the settlement price of stock index futures delivery is the arithmetic average price of the last two hours of the Shanghai and Shenzhen 300 spot index on the previous trading day (and the settlement price of the day refers to the weighted average price of the transaction price of a futures contract in the last hour according to the volume). This is the reason why the price returns to the spot forcibly, and the trading time of the last trading day is consistent with the spot. An obvious advantage of this provision is that it can prevent excessive speculation in futures. For long-term traders and hedgers, there is no need to worry too much about short-term futures price fluctuations. Another question is, will the contract deposit increase after entering the spot? CICC did not specify this point. Our understanding is that if there is no major abnormality in the market, the margin will not increase even on the last trading day, but the Exchange reserves the right to adjust the margin ratio.