OTC (over-the-counter market, also known as over-the-counter market ).

Completely different from the exchange market, OTC has no fixed place, no prescribed membership, no strictly controllable rules and regulations, no prescribed trading products and restrictions, mainly one-to-one transactions conducted by counterparties through private negotiations.

The more influential OTC markets in the world include the US OTC Securities Market (OTCBB), Pink sheets (Pink Sheets); UK alternative investment market (AIM); French over-the-counter market (CMF), Paris new market (New Market); over-the-counter market in South Korea and China's interbank bond market etc.

The United States has a huge OTC market, which accounts for about 3/4 of the securities traded in the United States.