The trading system is a market maker system, which is different from the bidding trading system and is generally adopted by the OTC market. Market maker refers to a securities business legal person with certain strength and credibility as a franchise dealer in the securities market, constantly reporting the buying and selling price of a certain securities to public investors, making two-way quotations, accepting the buying and selling requirements of public investors at this price, and trading securities with investors with their own funds and securities. Market makers maintain market liquidity and meet the investment needs of public investors through this continuous trading. Market makers compensate the cost of providing services through appropriate bid-ask spreads and realize certain profits.