Stock is the abbreviation of share certificate, which is a kind of securities issued by a joint-stock company to shareholders as a holding certificate to raise funds and obtain dividends and bonuses. Each share represents the shareholder's ownership of the basic unit of the enterprise. Every stock in the same category represents the equal ownership of the company. The share of ownership of the company owned by each shareholder depends on the proportion of shares held by each shareholder to the total share capital of the company. Shares are part of the capital of a joint-stock company and can be transferred, traded or mortgaged at a fixed price. It is the main long-term credit tool in the capital market, but the company cannot be required to return its capital contribution.