CA Foundation Business Economics Study Material – Oligopoly

CA Foundation Business Economics Study Material Chapter 4 Price Determination in Different Markets – Oligopoly



  • ‘Oligo’ means few and ‘Poly’ means seller. Thus, oligopoly refers to the market structure where there are few sellers or firms.
  • They produce and sell such goods which are either differentiated or homogeneous products.
  • Oligopoly is an important form of imperfect/competition.
  • E.g.- Cold drinks industry; automobile industry; Idea; Airtel. Hutch, BSNL mobile services in Nagpur; tea industry; etc.

Types of Oligopoly:

  • Pure or perfect oligopoly occurs when the product is homogeneous in nature, e.g. Aluminum industry.
  • Differentiated or imperfect oligopoly where products are differentiated. E.g. toilet products.
  • Open oligopoly where new firms can enter the market and compete with already existing firm.
  • Closed oligopoly where entry of new firm is restricted.
  • Collusive oligopoly when some firms come together with some common understanding and act in collusion with each other in fixing price and output.
  • Competitive oligopoly where there is no understanding or collusion among the firms.
  • Partial oligopoly where the industry is dominated by one large firm which is looked upon by other firms as the leader of the group. The dominating firm will be the price leader.
  • Full oligopoly where there is absence of price leadership.
  • Syndicated oligopoly where the firms sell their products through a centralized syndicate.
  • Organized oligopoly where the firms organize themselves into a central association for fixing prices, output, quotas, etc.

Characteristics of Oligopoly Market:

Following are the special features of oligopoly market:

1. Interdependence

  • In an oligopoly market, there is interdependence among firms.
  • A firm cannot take independent price and output decisions.
  • This is because each firm treats other firms as rivals.
  • Therefore, it has to consider the possible reaction to its rivals price-output decisions.

2. Importance of advertising and selling costs

  • Due to interdependence, the various firms have to use aggressive and defensive marketing tools to achieve larger market share.
  • For this the firms spend heavily on advertisement, publicity, sales promotion, etc. to attract large number of customers.
  • Firms avoid price-wars but are engaged in non-price competition. E.g.- free set of tea mugs with a packet of Duncan’s Double Diamond Tea.

3. Indeterminate Demand Curve

  • The nature and position of the demand curve of the oligopoly firm cannot be determined.
  • This is because it cannot predict its sales correctly due to indeterminate reaction patterns of rival firms.
  • Demand curve goes on shifting as rivals too change their prices in reaction to price changes by the firm.

4. Group behaviour

  • The theory of oligopoly is a theory of group behaviour.
  • The members of the group may agree to pull together to promote their mutual interest or fight for individual interests or to follow the group leader or not.
  • Thus the behaviour of the members is very uncertain.

Price and output decisions in an Oligopolistic Market:

As seen earlier, an oligopolistic firm does not know how rival firms react to each other decisions. Therefore, it has to be very careful when it makes decision about its price. Rival firms retaliate to price change by an oligopolistic firm. Hence, its demand curve indeterminate. Price and output cannot be fixed. Some of the important oligopoly models are:

  1. Some economists assume that oligopolistic firms make their decisions independently. Therefore, the demand curve becomes definite and hence equilibrium level of output can be determined.
  2. Some believe that oligopolistic can predict the reaction of rivals on the basis of which he makes decisions about price and quantity.
  3. Cornet considers OUTPUT is the firm’s controlled variable and not price.
  4. In a model given by Stackelberg, the leader firm commits to an output before all other firms. The rest of firms follow it and choose their own level of output.
  5. Bertrand model states PRICE is the control variable for firms and therefore each firm sets the price independently.
  6. In order to pursue common interests, oligopolistic enter into enter into agreement and jointly act as monopoly to fix quantity and price.

Price Leadership:

A large or dominant firm may be surrounded by many small firms. The dominant firm takes the lead to set the price taking into account of the small firms. Dominant firm may adopt any one of the following strategies—

  1. ‘Live and let live’ strategy where dominant firm accepts the presence of small firms and set the price. This is called price-leadership,
  2. In another strategy, the price leader sets the price in such a way that it allows some profits to the follower firms.
  3. Barometric price leadership where an old, experienced, respectful, largest acts as a leader and sets the price. It makes changes in price which are beneficial from all firm’s and industry’s view point. Price charged by leader is accepted by follower firms.

Kinked Demand Curve:

  • In many oligopolistic industries there is price rigidity or stability.
  • The prices remains sticky or inflexible for a long time.
  • Oligopolists do not change the price even if economic conditions change.
  • Out of many theories explaining price rigidity, the theory of kinked demand curve hypothesis given by American economist Paul M. Sweezy is most popular.
  • According to kinked demand curve 4 hypothesis, the demand curve faced by an oligopolist have a ‘Kink’ at the prevailing price level.
  • A kink is formed at the prevailing price because —
    – the portion of the demand curve above the prevailing price is elastic, and
    – the portion of the demand curve below the prevailing price is inelastic

Consider the following figure.
CA Foundation Business Economics Study Material Oligopoly 1

  • In the fig., OP is the prevailing price at which the firm is producing and selling OQ output.
  • At prevailing price OP, the upper portion of demand curve dK is elastic and lower portion of demand curve KD is inelastic.
  • This difference in elasticities is due to the assumption of particular reactions by kinked demand curve theory.

The assumed reaction pattern are –

  1. If the oligopolist raises the price above the prevailing price OP, he fears that none of his rivals will follow him.
    – Therefore, he will loose customers to them and there will be substantial fall in his sales.
    – Thus, the demand with respect to price rise above the prevailing price is highly elastic as indicated by the upper portion of demand curve dK.
    – The oligopolist will therefore, stick to the prevailing prices.
  2. If the oligopolist reduces the price below the prevailing price OP to increase his sales, his rivals too will quickly reduce the price.
    – This is because the rivals fear that their customers will get diverted to price cutting oligopolist’s product.
    – Thus, the price cutting oligopolist will not be able to increase his sales very much.
    – Hence, the demand with respect to price reduction below the prevailing price is inelastic as indicated by the lower portion of demand curve KD.
    – The oligopolist will therefore, stick to the prevailing prices.
    – Each oligopolist will, thus, stick to the prevailing price realising no gain in changing the price.
    – A kink will, therefore, be formed at the prevailing price which remains rigid or sticky or stable at this level.

Other Important Market Forms:

  1. Duopoly in which there are only TWO firms in the market. It is subset of oligopoly.
  2. Monopoly is a market where there is a single buyer. It is generally in factor market.
  3. Oligopsony market where there are small number of large buyers in factor market.
  4. Bilateral monopoly market where there is a single buyer and a single seller. It is mix of monopoly and monopsony markets