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 typically arises from the concentration of ownership and provides a
challenge to liberal theory which claims benefit from a plurality of producers operating
in a very competitive market.
A formal definition of oligopoly is: ...a market structure with a small
number of sellers - small enough to require each seller to take into account its
rivalscurrent actions and likely future responses to its actions. - Recognised
interdependence is the hallmark of oligopoly.
Kantzenbach and Kruse offer a more technical definition asserting that an oligopoly
exists, if the variation of a behavioural 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 behaviour.
If a dominant oligopoly already exists, the merger between two of its members or between
an oligopolist and an outsider 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. In these conditions,
firms might differentiate their products, which can benefit some consumers, but at a
price. Oligopoly inter-dependence can also foster anti-competitive co-ordination.
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 behaviour in a
process that harms consumer welfare, yet without reaching an explicit agreement. - The
OECD Competition Committee debated oligopolies in 1999. - Extracts.
The greater the likelihood of conscious parallelism appears on the basis of these
criteria, the more evidence is needed to refute the presumption of a dominant oligopoly.
If as a result of 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. If such indications do exist, however, it must be examined whether, and to what
extent, the members of the oligopoly actually make use of possible parameters of
There is often no price competition under these conditions due to the high degree of
oligopolistic interdependence among the suppliers. That is why residual competition in the
form of competition in services, terms, R&D and the provision of advice to customers
is particularly important. On the other hand, competition in terms of price and quality
currently often exists in the case of heterogeneous products.
The trend to oligopolistic behaviour is less in this case. If the conditions of the
oligopolistic presumption are satisfied, the existence of substantial competition before
the merger is not sufficient to refute the presumption of market dominance. 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. The conscious parallelism in
the oligopoly could otherwise not be sustained in the long run.
In oligopoly settings, parallel price movements for example could arise simply through
independent rational behaviour. To convince courts that parallel behaviour has arisen
through some kind of agreement rather than merely resulting from oligopolistic
interdependence, competition authorities must usually demonstrate that something more has
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.
When firms know they are highly interdependent, how can competition authorities help
ensure they compete instead of find various ways to co-operate? That, in essence, is the
oligopoly problem confronting competition offices everywhere, especially in
markets where collusion is particularly profitable and easy.
The Finnish competition legislation and the commentaries to it display a fairly standard
position in dealing with the oligopoly problem. The Finnish Competition Authority has the
same legislative tools to tackle the possible oligopoly problem as most other competition
authorities in Europe. The Finnish competition legislation covers all three aspects
relevant to the oligopoly problem discussed in the paper: tacit collusion, abuse of
joint/collective dominance and merger control.
In retrospect, it appears that due to structural and institutional factors, the problems
involved with explicit collusion and market dominance and the abuse thereof have been more
important than the oligopoly problem in Finland.
Nevertheless, there are many indicators in the Finnish economy, which attest that the
oligopoly problem is becoming more relevant. Companies in Finland and in Europe have been
reconstructing their strategies through an increasing number of mergers and acquisitions.
This would speak for a more sensitive attitude towards the oligopoly problem. Also, the
launching of the control of concentrations to Finland adds relevance to the potential
market dominance of oligopolistic companies.
Barriers to market entry
High barriers to market entry can for example consist of administrative restrictions of
market entry (entry restrictions for environmentally harmful plants or drugs), actual
restrictions such as limited resources concentrated only in the hands of the members of
the oligopoly, economies of scale in various departments, a large degree of vertical
integration of the members of the oligopoly, exclusive dealing contracts of the oligopoly
members with their respective customers, demarcation and concession agreements, industrial
standards as well as of high advertising and inter-brand competition in a market.
Oligopolies tend to be more contestable in new and dynamically growing markets than in
stagnating or declining markets with overcapacities since the former offer greater
opportunities to achieve profits.
But this is not the case if certain barriers to market entry exist (patents, licences). If
market entry did not occur, or was not successful, in the past despite objectively good
opportunities, 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.
Correctly applied, oligopoly theory can be useful at identifying the factors which need to
be considered in the assessment of a merger e.g. sunk costs, the nature of the product,
and the relative efficiencies of firms. However, the report warns that oligopoly theory is
of limited use in predicting how a market is likely to behave following a merger. This is
in part due to the vast number of competing models and the sensitivity of these models to
small changes in assumptions. However, it is also because the structure of the oligopoly,
and indeed the nature of competition, is often endogenous and likely to evolve over time.
Notably, 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 basic 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. And section 5 of the FTC Act prohibits practices that tend to facilitate
collusion. Combined, these laws provide a unified approach to dealing with the oligopoly
The concept of oligopolistic dominance generally acknowledged in standard antitrust
economics is not primarily founded on the presence of links between their members. In
particular 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.
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