he OPEC Conference is the supreme authority of the organization, and consists of delegations normally headed by the oil ministers of member countries. The chief executive of the organization is the OPEC Secretary General. The Conference ordinarily meets at the Vienna headquarters, at least twice a year and in additional extraordinary sessions when necessary. It generally operates on the principles of unanimity and "one member, one vote", with each country paying an equal membership fee into the annual budget. However, since Saudi Arabia is by far the largest and most-profitable oil exporter in the world, with enough capacity to function as the traditional swing producer to balance the global market, it serves as "OPEC's de facto leader".