Oligopoly is a market where the supply is controlled by a small group of companies. In this condition, the actions of one company will have a material effect on the entire market for a product.
Several characteristics of an Oligopoly:
1) Substantial barriers to entry
2) Market dominated by a few large firms
3) Differentiated products
4) Price rigidity
An example of this type of monopoly would be the corporations Visa and MasterCard. They are in the business of card securities and hold major market share. However, it could be noted that Visa holds more of a pure monopoly status; MasterCard does have a high level of control to create a competitive market situation.
