An oligopoly is a market structure in which two or more firms make strategically interdependent decisions about quantities, prices, or other actions. In contrast to a monopoly, in which a single firm is the sole seller, an oligopoly has multiple firms whose decisions affect one another. It is modeled as a game whose players are firms and whose payoffs depend on the actions of all firms. A predicted outcome is therefore usually a Nash equilibrium.
Cournot competition is an oligopoly model in which firms choose quantities simultaneously. Other oligopoly models differ in the actions available to firms and in the timing with which the actions are chosen.
