ST system means that the Shanghai and Shenzhen Stock Exchanges give special treatment to the stock transactions of listed companies that have suffered losses for two consecutive years since1April 22, 1998. The abbreviation of "special treatment" begins with "ST". The implementation of "ST" system by regulators on loss-making companies is not only a warning to loss-making listed companies, but also a risk warning to investors. ST can only be a transitional institutional arrangement and a flexible and organic part of a complete market exit mechanism.

ST is the abbreviation of English specialtreatment. S stands for special, T stands for transaction, and st stands for special transaction. In the stock market, some stocks may be inoperable for business reasons. The exchange shall, according to its specific circumstances, add st before the abbreviation of its stock to remind investors that the stock is risky, so as to warn investors of the risk. The daily limit of risk warning stocks in A-share market, namely st shares, is set at 5%.

A contract is a clause that two or more people, or two or more parties, abide by in order to determine their respective rights and obligations when dealing with something.