Why is the rise and fall of futures the difference between the closing price of the day and the settlement price of yesterday? Why is it not between the settlement price of the day and the settlement price of yesterday? If a certain variety fluctuates greatly on the same day, the settlement price often cannot reflect the real market trend, such as the late plunge or skyrocketing, but the settlement price for the whole day will not be too low or too high. Therefore, it is most appropriate to compare the closing price of the day with the settlement price of yesterday, which can best reflect the actual trend of the market.