Understanding Price Behavior in Oligopoly Models

Oligopoly describes a market structure characterized by a small number of large firms that dominate the industry. The decisions made by one firm significantly impact the others, leading to strategic interactions. This interdependence makes pricing behavior in oligopoly complex and gives rise to various economic models explaining different outcomes.

The question asks in which models the oligopolists will not vary their prices despite differences in production costs. Let's analyze each model listed:

Analysis of Oligopoly Pricing Models

• (a) Collusion Model:

  In a collusion model, firms cooperate, often secretly, to behave like a single monopolist. They might form a cartel, agreeing on a common price and output levels to maximize their joint profits. Once the cartel price is established, member firms are expected to adhere to it. Even if there are differences in the production costs among the member firms, the agreed-upon cartel price typically remains fixed for all, at least until the agreement is renegotiated. Individual firms do not change their price based on their unique cost structure.

• (b) Cournot’s Model:

  Cournot's model is a model of quantity competition. Each firm decides the quantity of output to produce, assuming the output of its rivals is fixed. The market price is then determined by the total quantity supplied by all firms. If a firm's production cost changes, its optimal output level (reaction function) will change. This change in output will affect the total market output and consequently lead to a change in the market price. Therefore, in Cournot's model, prices do vary when production costs change.

• (c) Kinked Demand Model:

  The Kinked Demand model attempts to explain price rigidity in oligopoly. It assumes that rivals will follow price cuts to prevent losing market share but will not follow price increases, hoping to gain market share from the firm raising its price. This creates a demand curve with a "kink" at the current price and a discontinuous marginal revenue curve. As long as a firm's marginal cost curve intersects the marginal revenue curve within this discontinuity, the firm will find it optimal to keep its price and output stable. While it predicts price rigidity, a sufficiently large change in production costs (shifting the marginal cost curve outside the gap) can still lead to a price change. It focuses on rigidity around an existing price rather than stating prices never vary despite differing costs across firms.

• (d) Price Leadership Model:

  In a Price Leadership model, one firm (the leader, which could be the dominant firm or the low-cost firm) sets the market price, and the other firms (followers) adopt this price. The follower firms act as price takers, accepting the leader's price and deciding how much to produce at that price. Crucially, the follower firms do not set their prices based on their own production costs; they simply match the leader's price. Thus, prices for follower firms do not vary despite their potentially different cost structures.

Identifying Models with Price Stability Despite Cost Differences

Reviewing the models based on the behavior of price variation despite cost differences:

• In the Collusion model (a), a common price is agreed upon and maintained by members, ignoring individual cost differences.
• In Cournot's model (b), prices change in response to cost changes.
• The Kinked Demand model (c) explains rigidity but not necessarily the absence of variation despite fundamental cost differences across firms or large cost changes.
• In the Price Leadership model (d), follower firms adopt the leader's price, and their own prices do not vary based on their individual cost differences.

Therefore, the models where oligopolists will not vary the prices of their products as per differences in cost of production are the Collusion model (a) and the Price Leadership model (d).

Revision Table: Oligopoly Model Comparison

Additional Information on Oligopoly

Understanding the assumptions and predictions of different oligopoly models is key to analyzing real-world industries. These models provide frameworks for understanding competitive strategies, pricing decisions, and market stability. While simple, they highlight the crucial role of interdependence and strategic thinking in markets with a few dominant firms. Other factors like product differentiation, advertising, and entry barriers also play a significant role in shaping oligopolistic markets.