After the futures contract is signed, before it expires or before the trading obligation is terminated through the hedging system, the clearing house of the exchange will calculate the profit and loss balance of each trader's open position according to the settlement price of each project, and increase or decrease the balance of his margin account. If there is a profit, so that the balance of the margin account exceeds the prescribed initial margin, the trader can withdraw the surplus. If there is a loss and the balance of the margin account falls below the required maintenance margin, the trader must pay an additional margin as required to restore it to the initial margin level; Otherwise, the exchange or clearing house will forcibly dispose of its open position. This is the daily settlement system in futures trading. It makes every surplus or loss of futures trading parties be liquidated in time, and avoids the accumulation of risks.