What is Oligopoly?
A market structure in which a few large sellers dominate the market and each one's decisions on price or volume noticeably affect the others. The difference from monopoly: there is not one firm but several; the difference from free competition: there are few firms and they watch each other's actions. As Britannica notes, in oligopolistic industries market behaviour mixes monopolistic and competitive tendencies. Firms may engage in price wars as well as in open or tacit agreements, which is why such markets are under the supervision of competition authorities.