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Market Power in Perfect Competition

Jun 19, 2025

Overview

This lesson covers the characteristics of a perfectly competitive market, including definitions, key features, and exam-related distinctions from other market structures.

Definition and Key Features of Perfect Competition

  • A perfectly competitive market has many buyers and sellers selling a homogeneous (identical) product.
  • No single firm or buyer can influence the market price; all are "price takers."
  • Examples include agricultural markets like maize and apples.

Criteria for Identifying Perfect Competition

  • Do not rely on only one criterion (e.g., many sellers); check for multiple features like homogeneous products and free entry.
  • Other market structures can also have many buyers and sellers.

Nature of Product

  • The product is standardized or homogeneous (e.g., apples from different provinces are indistinguishable).
  • Heterogeneous products (e.g., branded food) are not part of perfect competition.

Market Entry and Exit

  • Entry and exit from the market are free and easy; no significant barriers exist.
  • Firms can join or leave the market without restriction.

Collusion and Price Setting

  • Collusion is nearly impossible due to the large number of firms.
  • Firms cannot control prices; market price is set by demand and supply.

Information and Price Control

  • Information is complete and perfectly shared among buyers and sellers.
  • Firms have no control over price and must accept the prevailing market price.

Demand Curve

  • The individual firm faces a horizontal demand curve (perfectly elastic demand).

Long-Run Profits and Efficiency

  • In the long run, firms make only normal profit due to free entry and exit.
  • Firms achieve both productive and allocative efficiency.

Decision Making and Market Power

  • A single firm's decisions do not affect other firms in the market.
  • No individual firm possesses market power.

Key Terms & Definitions

  • Perfect Competition — A market with many buyers and sellers offering a homogeneous product and no firm controlling price.
  • Homogeneous Product — An identical product offered by all firms in the market.
  • Price Taker — A firm that must sell at the prevailing market price.
  • Normal Profit — The minimum profit necessary to keep a firm in business in the long run.
  • Productive Efficiency — Producing goods at the lowest possible cost.
  • Allocative Efficiency — Resources are allocated such that consumer and producer surplus are maximized.

Action Items / Next Steps

  • Complete the activity: With reference to the number of buyers and sellers in perfectly competitive markets, explain where market power exists.
  • Answer: Is the JSE (Johannesburg Stock Exchange) an example of a perfectly competitive market? Motivate your answer.