Due to the large demand for arbitrage, hedging and other investment strategies, stock index futures will increase the demand for stock trading, thus increasing the liquidity of the stock market. The stock index period will change the pattern of unilateral market in the past, and the investment subjects and investment models will be diversified.

The bull market of stock index futures helps the bear market to rise and fall, which has the characteristics of high leverage and low cost. In the bull market, investors buy stock index futures, and arbitrageurs will sell futures to buy stocks, thus accelerating the rise of stock index; In a bear market, investors who are bearish on the market outlook will sell a lot of stock index futures, and arbitrageurs will buy stock index futures and sell the spot, thus accelerating the decline of the spot index. However, the introduction of stock index futures can only be said to amplify the rise and fall of the stock market, and does not determine the rise and fall.