"Buying" refers to judging that the stock index will rise, that is, you can open a position at the buying price and close the position according to the latest selling price;

"Selling" refers to judging that the stock index will fall, that is, you can open a position at the selling price, and the closing position is calculated according to the latest buying price.

Opening a position, also known as opening a position, refers to investors buying or selling a certain number of stock index futures contracts. If investors hold stock index futures contracts until the last trading day, they must settle futures transactions by cash delivery.

Closing position refers to the futures investors buying or selling stock index futures contracts with the same variety, quantity and delivery month, but in the opposite direction, so as to close the stock index futures trading.