This is the way to buy it: when you are at 5,000 points in stock index futures, you can sign a contract with others, stipulating that you can sell the stock index to him at the price of 5,000 points (selling the first-hand stock index contract, the first-hand value is 5000× 300 = 1.5 million yuan), and you pay 1.5 to the exchange (futures brokerage company).

When the stock index drops to 4000 points, you buy goods in the market and give them to the buyer at the price of 5000 points (buy a stock index contract). The first-hand profit is (5000-4000) × 300 = 300,000 yuan.