Sociology Index


Oligopoly is the situation where a small number of companies own or control the production of a particular good or provision of services within a market economy. Oligopoly arises from the concentration of ownership and provides a challenge to liberal theory which claims benefit from a plurality of producers in a competitive market. Recognised interdependence is the hallmark of oligopoly. Oligopoly inter-dependence can foster anti-competitive co-ordination.

High barriers to market entry can consist of administrative restrictions of market entry, actual restrictions such as limited resources concentrated only in the hands of the members of the oligopoly, a large degree of vertical integration of the members of the oligopoly, exclusive dealing contracts of the oligopoly members with their respective customers.
But this is not the case if certain barriers to market entry exist , like patent law and licences.

If a dominant oligopoly already exists, the merger between two of its members will lead to the oligopoly becoming even tighter. The tighter the oligopoly is, the more transparent competitive conduct will become and the easier it will be for conscious parallelism to occur. Oligopolies are markets where profit maximising competitors set their strategies by paying close attention to how their rivals are likely to react. Firms might differentiate their products, which can benefit some consumers, but at a price.

Oligopoly is a market structure with a small number of sellers and each seller is required to take into account rivals’ current actions and likely future responses to rivals' actions. An oligopoly exists, if the variation of a behavioral parameter by one of a group of competing firms leads to a perceptible change in selling conditions for the other competing firms, thus causing them to respond by changing their own market behavior. - Kantzenbach and Kruse.

Competition laws prohibit collusion that raises prices, restricts output or divides markets. But the laws do not prohibit conscious parallelism. Thus firms in an oligopoly might imitate their rivals’ pricing and other competitive behavior in a process that harms consumer welfare, yet without reaching an explicit agreement. - The OECD Competition Committee debated oligopolies in 1999.

The greater the likelihood of conscious parallelism appears, the more evidence is needed to refute the presumption of a dominant oligopoly. If an examination of the conditions of competition it appears that there is no indication of a dominant oligopoly, the competitive process need not be examined further. It must be examined whether, and to what extent, the members of the oligopoly actually make use of possible parameters of competition.

If no substantial competition is evident even in the oligopoly, it is also less likely that it will exist in the relationship to the oligopoly outsiders. In oligopoly settings, parallel price movements for example could arise simply through independent rational behavior. When firms know they are highly interdependent, how can competition authorities help ensure they compete instead of find various ways to co-operate? That is the oligopoly problem confronting competition offices everywhere.

Some competition laws prohibit certain facilitating practices in oligopoly markets even when such practices are not being used in concert with any anti-competitive act.

If market entry did not occur, in the past, this may indicate a dominant oligopoly and acts as a deterrent to enterprises that would in principle be interested in entering a market.

Oligopoly theory does indeed have a useful role to play in the investigation of mergers. Oligopoly theory can be useful at identifying the factors which need to be considered in the assessment of a merger. The only oligopoly where competition did not appear to be effective post-merger was one where no buyer power was present.

The US antitrust laws combat anticompetitive oligopoly behavior in three ways. The Sherman Act prohibits horizontal agreements among competitors that restrain trade unreasonably. Section 7 of the Clayton Act prevents mergers or acquisitions whose effect may be to create or strengthen oligopoly structures in markets that are conducive to coordination. These laws provide a unified approach to dealing with the oligopoly problem.

Standard economic analysis identifies a number of factors which are generally considered relevant for ascertaining the existence of an oligopoly. The presence of links between the members of an alleged oligopoly constitutes simply an additional factor which reinforces the risks of oligopolistic dominance. An oligopoly can thus be proved on the basis of the analysis of the features of the market, even in the absence of structural links between the members of the alleged oligopoly.

BAKER, Jonathan B. (1993) "Two Sherman Act section 1 dilemmas: parallel pricing, the oligopoly problem, and contemporary economic theory", The Antitrust Bulletin, Vol. 38, No. 1 (Spring), pp. 143-219.

MONTI, Giorgio (1996) "Oligopoly: Conspiracy? Joint monopoly? Or Enforceable Competition?", World Competition, Vol. 19, No. 3 (March), pp. 59-102.

STIGLER, George J. (1964) A Theory of Oligopoly, Journal of Political Economy, Vol. 72. Reprinted as Chapter 5 in The Organization of Industry (Homewood, Ill.: Richard D. Irwin, 1968), pp. 39-63.

Posner, R.A. (1969) “Oligopoly and the Antitrust Laws: A Suggested Approach,” 21 Stanford Law Review 1562.
Stigler, G.J. (1964) “A Theory of Oligopoly,” 72 Journal of Political Economy 44.
Baker, J.B. (1993) “Two Sherman Act Section 1 Dilemmas: Parallel Pricing, the Oligopoly Problem, and Contemporary Economic Theory,” 38 Antitrust Bulletin 143.
Yao, D.A. and S.S. DeSanti (1993) Game Theory and the Legal Analysis of Tacit Collusion, 38 Antitrust Bulletin 113.
Posner, R.A. (1976) “Price Fixing and the Oligopoly Problem,” in his Antitrust Law: An Economic Perspective (Chicago, University of Chicago Press).
Shapiro, C. (1989) “Theories of Oligopoly Behavior,” in Handbook of Industrial Organization, Vol. 1, eds. R. Schmalensee and R. Willig (Amsterdam, North-Holland). Economic Approaches to Identifying Collusion
Shughart, W.F. (1997) “Oligopoly and Collusive Behavior” and “Coordinating Oligopolistic Activity” in his The Organization of Industry (Houston, Dame).
Carlton, D.W. and J.M. Perloff (1994) “Cartels: Oligopoly Joint Decision Making” in their Modern Industrial Organization (New York, Harper Collins).