The essence of futures is to sign a sales contract. The short must be long, and the quantity is the same.

If 80% people are short, 20% people are long, but there are as many short orders as long orders. Then the stock index fell and 80% people made money. The money comes from 20% people.

Suppose you always have 100W, and you have bought stock index futures for three months. At this time, the stock index is 5000. According to the margin rate of 15%, the margin for each lot is 5000×300× 15% = 225000 yuan, 100. Three months later, the stock index was 2500. In the futures market in China, you can earn: (5000-2500) × 4× 3000 = 3 million yuan.