First of all, it is clear that the delivery price is fixed and is part of the contract, which is 100 yuan in the example. Refer to the value formula of futures/forwards: f=(F-K)e-rT(-rT is the prescription, please forgive me), where f is the present value of futures, f is the real-time price of futures, k is the delivery price of futures, r is the risk-free rate of return, and t is the time from now to the delivery date. F is also the opening/closing price when you trade futures, which is constantly changing according to the supply and demand relationship of the exchange. If you open a position at t0, you open a position at the delivery price. Because F0=K, which will be explained later. In addition, we should understand the difference between futures and forwards. There is no cash exchange at the beginning of the contract signing, and its value will be realized only at the end of the contract, that is, the delivery date (K-S or physical delivery according to K). In futures, cash transactions occur at the time of opening, and the buyer of futures can take delivery directly on the delivery date. At the same time, due to the existence of the daily mark-to-market system, its value (profit and loss changes) can be realized daily (reflected in deposits). Therefore, the futures price tends to be consistent with the spot price when it is close to delivery, that is, F and S, not K. So how is the delivery price K of futures/forwards determined? Let's break down the pricing formula of futures/forwards: K=F0=S0e(r-q+u)T where s is the spot price, q is the convenient rate of return, and u is the storage cost rate. Only in this way can the contract be guaranteed to be worthless at the beginning (f0=0), because it is a zero-sum game between long and short sides. After the contract started, F and F changed with the constant changes of spot price S and various interest rates. Therefore, on the final delivery date, it is also a forward or futures contract with the delivery price of 100 (assuming that the spot price is 120 at this time), and the profit of the bulls is 20, but the profit of the futures bulls is constantly changing every day during the contract period. It should be noted that it is assumed that futures bulls open positions from the beginning of the contract signing and hold them until the delivery date. If a bull opens a position near the delivery date and finally accepts delivery, then you can understand that he just bought the spot at a price very close to the spot.