Stock index futures refer to standardized futures contracts with stock indexes as the underlying assets. Both parties to the futures contract agree to buy and sell the underlying index at a certain time in the future according to the size of the stock price index determined in advance.

Stock index futures can be used to hedge and reduce the systemic risk of portfolio. For institutional investors such as various investment funds, stock index futures is an important and flexible asset allocation and management tool. Moreover, there is a close price relationship between stock index futures and stock indexes, and between different stock index futures. And because of the leverage effect of futures investment, buying and selling stock index futures has the function of double income.