An oligopoly is when a small number of firms have a large majority of market share in their respective industries. An oligopoly is similar to a monopoly, except instead of one firm controlling the market, two or more firms control the market.
An oligopoly (from Ancient Greek ὀλίγος (olígos) "few" + πωλεῖν (polein) "to sell") is a market form wherein a market or industry is dominated by a small number of sellers (oligopolists). Oligopolies can result from various forms of collusion which reduce competition and lead to higher prices for consumers. Oligopoly has its own market structure.
With few sellers, each oligopolist is likely to be aware of the actions of the others. According to game theory, the decisions of one firm therefore influence and are influenced by decisions of other firms. Strategic planning by oligopolists needs to take into account the likely responses of the other market participants.