In many oil-producing countries, the government receives a physical share of production, and that oil is then typically sold by the national oil company (NOC). These trading transactions are currently subject to limited regulation and even fewer reporting requirements.

The sale of crude oil by national oil companies (NOCs) generates a large share of government revenue in oil-producing countries. NOC export sales bring in more than two-thirds of total government income in countries such as Angola, Azerbaijan, Congo-Brazzaville, Iraq, Saudi Arabia and Yemen.