The trading terms of stock index futures include margin, long position, short position, daily mark to market, opening position, closing position and holding position. When buying and selling futures contracts, both parties need to pay a small sum of money to the clearing house as a performance bond, which is called a deposit. Buying bulls for the first time is called building bulls. Short position The first time a contract is sold, it is called establishing a short position. Mark the market every day. The contract at hand should be settled daily, that is, the market should be marked day by day. Open a position to establish a trading position. After closing a trading position (called opening a position), it is not necessary to hold it until maturity. You can reverse trade at any time before the expiration of the stock index futures contract, which is called liquidation. A contract that has not been closed after a day's trading is called a position. For example, you sell the 10 stock index futures contract on the first day and buy back the 10 contract on the second day. Then the first one is the short position of opening 10 stock index futures, and the second one is the short position of closing 10 stock index futures. The next day I bought 20 lots of stock index futures contracts, and then I became a long position in 20 lots of stock index futures. Then sell 10 lots, which is called liquidation 10 stock index futures bulls, leaving 10 stock index futures bulls. A contract that is not closed at the end of a day's trading is called a position. In this example, on the first day after trading, the stock index futures with the position of 10 are short, and on the second day after trading, the stock index futures with the position of 10 are long.