Futures: It is a contract, a contract that must be fulfilled in the future, not a specific commodity. This kind of contract stipulates in a unified and standardized way that at some time in the future, both parties to the contract will buy and sell an item at a certain price.

Size: Non-tradable shares, which were not allowed to circulate in the market before the share-trading reform. Small non-small restricted shares, accounting for less than 5% of the total share capital.

Large-scale restricted shares circulation. It accounts for more than 5% of the total share capital.

Hedge funds: refers to some funds that not only hold high-quality securities in the investment market for a long time, but also combine short selling and financial derivatives trading to hedge and reduce risks. These risks include market risk, financial risk and economic risk. This kind of fund is called hedge fund because its operation mode is different from the long-term one-way operation mode held by many traditional investment funds.