Why is the daily turnover of the stock market the sum of two volumes?

According to the development needs of the country at that time, China's first stock exchange was established in Shanghai. It was established on November 26th, 199 and opened on December 19th of the same year. It is a non-profit legal person and directly managed by China Securities Regulatory Commission. Adhering to the eight-character policy of "legal system, supervision, self-discipline and standardization", Shanghai Stock Exchange is committed to creating a transparent, open, safe and efficient market environment and effectively protecting the rights and interests of investors. Its main functions include: providing places and facilities for securities trading; To formulate the business rules of the stock exchange; Accepting listing applications and arranging the listing of securities; Organizing and supervising securities trading; Supervise members and listed companies; Manage and publish market information. Shenzhen Stock Exchange (hereinafter referred to as "Shenzhen Stock Exchange") was established on December 1, 199. It is a legal person that provides places and facilities for centralized securities trading, organizes and supervises securities trading, and implements self-discipline management. It is directly supervised and managed by China Securities Regulatory Commission. Shenzhen Stock Exchange is committed to the construction of multi-level securities market and strives to create an open, fair and just market environment. The main functions include: providing places and facilities for securities trading; To formulate the business rules of this firm; Accepting listing applications and arranging the listing of securities; Organizing and supervising securities trading; Supervise members and listed companies; Manage and publish market information; Other functions permitted by China Securities Regulatory Commission. They are all trading places in China stock market, so add up their trading volume.

Recently, the state officially approved the establishment of OTC market in Tianjin, which is another qualitative leap of China's economy. In Europe, the OTC market is the main trading place.