Second, when hedging, it is inevitable that there will be incomplete hedging. All incomplete hedging means that future positions and spot positions will have profit or loss after hedging. The reason for incomplete hedging is that the tonnage of futures is fixed and the contract time is fixed, so the spot position can only find a relatively close futures contract to buy a considerable future positions in the futures market, but there will always be differences, so there will be incomplete hedging. There are many reasons for incomplete hedging, such as substitutes.