An incomplete futures trading system. The trading system in China is to buy on the same day and sell the next day. In this way, this loophole was exploited, and people were suppressed, but they could not ship, causing losses.
There is no limit to the short selling mechanism. The introduction of stock index futures is to reduce or even avoid unilateral rise, but because the short-selling mechanism is not restricted, it will put pressure on the stock market, investors will reduce their positions and cut their meat, and finally let others take the opportunity to make profits.
Speculation in the futures trading market is serious. Some investors use leverage to make more profits.