Put option is also called put option, seller option, put option, put option or elimination option. Put option means that the buyer of the option has the right to sell a certain number of the subject matter at the execution price within the validity period of the option contract, but does not undertake the obligation of selling.

Stock option contract refers to the standardized contract formulated by the exchange, and the buyer of the agreed contract has the right to buy and sell the agreed contract object (stock or ETF listed on the Shanghai Stock Exchange) at the agreed time and price. The subject matter of contract is the basic component of option contracts, and it is an important factor that affects the success of stock options.