OTC refers to the OTC market, that is, OTC trading. Completely different from the exchange market, OTC has no fixed place, no prescribed members, no strictly controllable rules and regulations, no prescribed trading varieties and restrictions, mainly one-on-one transactions conducted by counterparties through private consultations. Over-the-counter transactions are mainly in the financial industry.

An empty OTC is an outfield short sale. For example, a pen was sold to a third party in 10 yuan, and then bought back when it fell to 8 yuan. Then the 2 yuan price difference in the middle is the profit you earn. The same is true for futures.