An illegal exchange or marketplace is a place where transactions take place without the knowledge or approval of government officials or regulatory bodies. These issues usually arise when specific commodities and services are in short supply or when supply and pricing are regulated by the government. Cash-only transactions are often unrecorded, making them even more difficult to track.

A black market refers to an illicit or illegal economic system in which goods, services, or commodities are bought and sold outside the purview of government regulations and without the oversight of legal authorities. Participants in the black market often engage in activities such as smuggling, counterfeiting, or trading prohibited items. These activities typically circumvent legal channels, taxation, and quality controls. Black markets can emerge in response to government restrictions, high taxes, or shortages of certain goods.

Participants in black market transactions may include individuals seeking to avoid legal repercussions, organized crime groups, or even legitimate businesses operating in violation of regulations. The consequences of black market activities can range from economic distortions to social issues, and they pose challenges for law enforcement and regulatory bodies attempting to curb such illicit trade.