Close position refers to the behavior of futures investors buying or selling stock index futures contracts of the same variety, quantity and delivery month as the stock index futures contracts they hold but with opposite trading directions to close stock index futures transactions. Closing a position in futures trading is equivalent to selling in stock trading. Since futures trading has a two-way trading mechanism, corresponding to opening a position, there are two types of position closing: buying and closing (corresponding to selling and opening) and selling and closing (corresponding to buying and opening). Positions: Contracts that stock index futures investors have not closed after opening a position are called open contracts, also called positions. After opening a position, stock index futures investors have two ways to close the stock index futures contract: either choose an opportunity to close the position in advance, or hold it until the last trading day for cash delivery. Change of hands transaction: Change of hands can be divided into "long change of hands" and "short change of hands". When the original long investor sells and closes the position, but a new long position opens and buys, it is called "long change of hands". "; "Short changing hands" means that the original short-sold investors are buying and closing their positions, and new short-sellers are opening and selling.