Oligopoly Study Notes

Overview of Chapter 12: Oligopoly

  • Focus of Chapter
    • Oligopoly recognized as a significant challenge for microeconomists
    • Analysis rests on strategic interaction among a few firms in the market
    • Key concepts include duopoly, barriers to entry, and equilibrium analysis

Fundamental Concepts of Oligopoly

  • Definition of Oligopoly
    • Market structure with a limited number of firms (usually two or more).
    • Firms produce either identical or slightly differentiated products.
    • Examples of oligopoly include various industries where a few firms dominate the market.

Key Characteristics of Oligopoly

  • Strategic Interaction
    • Firms make decisions based on expectations of competitors' actions.
  • Barriers to Entry
    • Factors preventing new competitors from easily entering the market.
    • Ensures profits are maintained and not eroded by new entrants.
  • Equilibrium Analysis
    • Goal is to identify equilibrium states in the market.

Methodological Approaches

  • Sequential and Simultaneous Models
    • Firms can make decisions either successively (one after another) or simultaneously.
    • Resulting equilibrium can be analyzed through various models.

Nash Equilibrium

  • Definition
    • A state where all market participants are satisfied with their strategies given the strategies of others.
  • Example with Two Firms
    • In a duopoly, when each firm makes decisions based on the anticipated response of the other, neither has incentive to deviate from their strategy.

Classic Duopoly Model

  • Assumptions of the Classic Model
    • Two firms produce an identical product with zero marginal costs.
    • Historical example of firms selling water from springs during the 1800s.
  • Market Demand & Pricing
    • Demand must be shared between firms.
    • If one firm acts alone, it would equate marginal revenue to marginal costs (set as zero) to find market price.

Potential Collusion

  • Collusion Definition
    • When firms agree to set production levels and prices together, which is illegal.
  • Hypothetical Scenario
    • Two firms could theoretically agree to produce a total of 5 units, charge a price of 5, yielding total revenue of 25, leading to profits split in half (12.5 each).

Reaction Functions and Isoprofit Curves

  • Reaction Function
    • Describes how one firm's output responds to the output of the other firm.
  • Isoprofit Curves
    • Curves representing combinations of outputs that provide the same profit level.
    • The maximum profit occurs at the intersection of the reaction functions.

Stackelberg Model

  • Price Leadership Model
    • One firm (the leader) sets production levels, while the other firm (the follower) reacts.
  • Strategic Maximization
    • The leader chooses output levels to maximize profits based on follower's reaction function.

Application: Reaction Function Derivation

  1. Market Demand Equation
    • Price equals
      P = A - B(QA + QB)
    • Analyze reaction functions for both firms (A and B).
  2. Marginal Revenue Calculation
    • Derive marginal revenue equations by differentiating total revenue and setting equal to zero.
  3. Solving the Reaction Functions
    • Example using symmetric conditions suggests equal production outputs for both firms under Nash equilibrium.

Bertrand Solution

  • Price Discrimination
    • If products are identical, price competition drives price to marginal cost ($= 0$).
  • Differentiated Products Scenario
    • Analysis when products are slightly different; both can maintain some price elevation above marginal costs.

Market Dynamics of Oligopoly

  • Sticky Prices
    • Firms may maintain stable prices despite market conditions.
  • Sweasy’s Model
    • Analyzes scenarios where firms retain profits while avoiding drastic price changes, despite external cost fluctuations.

Conclusion of Oligopoly Models

  • Price Leadership Model

    • Describes industries where one dominant firm sets prices, e.g., OPEC's dynamics.
    • Followers adjust based on leader's price without direct communication between firms, reflecting a non-collusive market structure.

  • Potential Prisoner’s Dilemma

    • Individual firms have an incentive to cheat on production levels for individual gain, posing risks to the overarching market framework.

  • Excess Capacity Implications

    • Holding excess production capacity can intimidate competitors, enabling market leaders to maintain control through the threat of increased output.

  • Final Note

    • The examination of oligopoly dynamics reveals the complexity and interplay between competitive behaviors versus collusion, and the ethical implications surrounding market practices.

  • Upcoming Topics

    • Future lectures will delve deeper into game theory for enhanced insights into oligopolistic strategies and interactions.