A type of economic activity that takes place outside of government-sanctioned channels. Black-market transactions typically occur as a way for participants to avoid government price controls or taxes, conducting transactions 'under the table'. The black market is also the means by which illegal substances or products - such as illicit drugs, firearms or stolen goods - are bought and sold.

While the black market is commonly associated with criminal activities involving drugs or weapons, it also has a financial component: black currency-exchange markets almost always appear when government controls on exchange rates prevent the use of natural exchange rates in the global marketplace.