According to the research on foreign stock markets, if the P/E ratio is around 30 or below, the stock market will rise in the short term after the introduction of stock index futures. In a market with high P/E ratio, the stock index will fall. China stock market mostly belongs to the latter.

1. Stock index futures can be provided to the main short-selling mechanism. Simply put, before the introduction of stock index futures, the main force can only make money by raising the stock index (that is, doing more), and after the introduction of stock index futures, when the stock index falls, the main force can also make rich profits.

2. Since China introduced the CSI 300 stock index futures for the first time, institutions have bought a large number of CSI 300 heavyweights to control the future trend of CSI 300 stock index. Simply put, stock index futures are a bit like gambling. If the Shanghai and Shenzhen 300 Index is 5000 points today, I estimate that the index will fall to 4000 points in one month, so I will buy bearish futures contracts. If it really drops to 4000 points after one month, I will make money. Therefore, in order to accurately grasp the trend of the Shanghai and Shenzhen 300 stock indexes, the main force has bought the heavyweights of the Shanghai and Shenzhen 300 to prepare for the stock index futures. This is the origin of the phenomenon of 2.8 some time ago. Many non-CSI 300 stocks have been neglected.