2. Small and medium-sized board, that is, small and medium-sized enterprise board, refers to the growth enterprise market with a circulation of about 1 billion, which is relative to the main board market. Some enterprises can't meet the requirements of the main board market and can only be listed in the small and medium-sized board market. Small and medium-sized board market is the transition of GEM, and the market code of small and medium-sized board in China begins with 002.