Black market refers to a market illegally formed without the approval of the government, which is characterized by trading goods that are not allowed to be listed or secretly buying and selling at a price higher than the open market price. Such as ticket black market, gold and silver black market, smuggled goods black market and so on. If it is to avoid the state's restrictions on commodity prices, exchange rates, securities market prices, interest rates, etc. This is called black market trading. The price traded on the black market is called the black market price.