1, short position: When the investor's margin is insufficient to offset the losses caused by market fluctuation, the exchange will force the investor to close the position, which is a short position. In other words, the short position is because the market changes rapidly, and investors fail to increase the margin in time, resulting in the margin in the account being unable to maintain the original contract, thus being forced to close the position. Short positions often occur when the market is unfavorable, and the losses caused are often greater than those caused by investors' independent liquidation.

2. Closing positions: refers to the behavior of futures traders to buy or sell futures contracts with the same variety, quantity and delivery month, but in the opposite direction, thus ending futures trading. The liquidation can be achieved by hedging liquidation or forced liquidation. Hedging liquidation is the behavior of traders buying and selling futures contracts according to their own situation; Forced liquidation is the behavior of a third party other than the position holder to forcibly liquidate the position holder under the condition of insufficient margin.