This term refers to index futures. For Hong Kong, the object of index futures is the Hang Seng Index. Theoretically, index futures is a financial derivative tool to hedge the unsystematic risks in the stock market. For example, if you decide that the market will go up, you want to buy stocks, and at the same time you are worried that the trend of the stocks you buy is inconsistent with the market, you can open a futures index in the buying direction; And the object of your opening position is another bearish person, and his opening period refers to selling. Next, everyone uses the index as a reference. The index went up. You are right. If you have more money in your account, he will lose it to you. If it goes up badly, all the money in his account will go to you. If he can't add money to his account, he must close the position. At the same time, this term refers to a settlement date, on which it must also be closed. Whether the stock index will fall again after liquidation has nothing to do with him. This product is not available in China market, but it is available in many mature foreign securities markets, including Hongkong. At present, China is also developing this variety, and it is estimated that it will appear in a few years.