The margin ratio of an exchange is different from that of a futures company, and it will generally increase by several percentage points. For example, the exchange needs 10%, and the futures company needs 20%. When trading, half of the funds will be kept by the futures company. This part of the funds actually exists in the account opened by the futures company in the bank, and the bank will of course pay interest to the futures company. This is on the one hand, as long as the overall position changes little, the amount stability is high.