Futures margin means that futures clearing members deposit a certain amount of funds or a certain amount of securities that meet the standards in an account established according to the settlement rules as a guarantee for futures trading settlement and performance. Under the time deposit system, there are two concepts of deposit: original deposit (deposit for opening an account) and maintenance deposit (maintenance deposit). The original margin is the fixed minimum capital charged by the exchange for opening positions, while the maintenance margin is a certain discount of the fixed margin and is also fixed. Margin refers to the opening margin dynamically calculated according to the contract value in a fixed proportion, that is, the margin is calculated according to the following formula: opening margin = stock index futures point × contract multiplier × margin ratio × number of transactions, where the contract multiplier represents the equivalent value of 1 index point.