Skip to main content
Back

Monopoly and Antitrust Policy: Study Notes

NotesPracticeVideo lessons

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Chapter 15: Monopoly and Antitrust Policy

Introduction

This chapter explores the concept of monopoly, the sources of monopoly power, how monopolies determine price and output, the economic consequences of monopoly, the practice of price discrimination, and the role of government policy in regulating monopolies and promoting competition.

15.1 Is Any Firm Ever Really a Monopoly?

Definition and Importance

  • Monopoly: A firm that is the only seller of a good or service for which there is not a close substitute.

  • Monopolies are studied because some firms are true or near-monopolists, and because firms may collude to act like monopolists.

Market Power

  • Even if a firm is not a pure monopoly, it may have market power—the ability to raise prices and earn economic profit due to a lack of close substitutes.

Example

  • A single pizzeria in a small town may or may not be a monopoly, depending on the availability of close substitutes (other restaurants or grocery stores).

15.2 Where Do Monopolies Come From?

Barriers to Entry

Monopolies arise due to barriers that prevent other firms from entering the market. The four main sources are:

  1. Government Restrictions on Entry

    • Patents, copyrights, and trademarks: Legal protections that grant exclusive rights to produce or sell a product, encouraging innovation by allowing firms to recover high fixed costs.

    • Public franchises: Government designates a single firm as the only legal provider of a good or service (e.g., U.S. Postal Service).

  2. Control of a Key Resource

    • Owning or controlling a vital input (e.g., Alcoa's control of bauxite for aluminum production, NFL's contracts with top athletes).

  3. Network Externalities

    • The value of a product increases as more people use it (e.g., social networks, operating systems).

    • Can create a virtuous cycle for the firm, but may lock consumers into inferior products.

  4. Natural Monopoly

    • Occurs when economies of scale are so large that one firm can supply the entire market at a lower average total cost than multiple firms.

    • Common in industries with high fixed costs (e.g., electricity distribution).

Figure 15.1: Illustrates that a single firm can deliver electricity at a lower cost than two firms due to economies of scale.

15.3 How Does a Monopoly Choose Price and Output?

Profit Maximization

  • Monopolists maximize profit by choosing the quantity where marginal revenue (MR) equals marginal cost (MC):

  • The demand curve determines the price at this quantity.

  • The average total cost (ATC) curve determines the average cost.

  • Profit is .

Revenue Calculation Example (USPS)

Stamps per Day (Q)

Price (P)

Total Revenue (TR)

Average Revenue (AR)

Marginal Revenue (MR)

1

$0.85

$0.85

$0.85

$0.85

2

$0.80

$1.60

$0.80

$0.75

3

$0.75

$2.25

$0.75

$0.65

4

$0.70

$2.80

$0.70

$0.55

5

$0.65

$3.25

$0.65

$0.45

6

$0.60

$3.60

$0.60

$0.35

7

$0.55

$3.85

$0.55

$0.25

8

$0.50

$4.00

$0.50

$0.15

9

$0.45

$4.05

$0.45

$0.05

10

$0.40

$4.00

$0.40

-$0.05

Additional info: Marginal revenue is always below the demand curve for a monopolist because lowering price to sell more units reduces revenue from existing customers.

Long-Run Profits

  • Barriers to entry allow monopolists to earn profits in the long run, unlike in monopolistic competition.

15.4 Does Monopoly Reduce Economic Efficiency?

Economic Efficiency and Deadweight Loss

  • Monopoly leads to higher prices and lower quantities compared to perfect competition.

  • Consumer surplus falls, producer surplus rises, but total economic surplus (consumer + producer surplus) falls due to deadweight loss.

Figure 15.5: Illustrates the deadweight loss (areas B and C) resulting from monopoly pricing.

  • Market power is common, but the overall efficiency loss in the U.S. due to market power is estimated to be less than 1% of total production.

Market Power and Innovation

  • Market power can incentivize innovation, as firms seek to earn and maintain economic profits ("creative destruction").

15.5 Price Discrimination: Charging Different Prices for the Same Product

Definition and Conditions

  • Price discrimination: Charging different prices to different customers for the same good or service when price differences are not due to cost differences.

  • Conditions for price discrimination:

    1. Firm has market power (not a price-taker).

    2. Identifiable groups of consumers with different willingness to pay.

    3. Arbitrage (resale) is not possible or is costly.

Examples

  • Student and senior discounts at movie theaters.

  • Airlines charging different prices based on booking time and trip duration.

Perfect Price Discrimination

  • Also called first-degree price discrimination: Each consumer is charged their maximum willingness to pay.

  • Consumer surplus is zero; the firm captures all surplus.

  • May increase efficiency by eliminating deadweight loss, but reduces consumer welfare.

Legal Aspects

  • Price discrimination is generally legal unless it reduces competition (Robinson-Patman Act).

15.6 Government Policy Toward Monopoly

Antitrust Laws and Regulation

  • Antitrust laws: Laws aimed at eliminating collusion and promoting competition (e.g., Sherman Act, Clayton Act).

  • Collusion: Firms agree not to compete, acting as a monopoly.

  • Antitrust authorities also review mergers, especially horizontal mergers (between firms in the same industry).

Merger Guidelines

  • Market definition: Identifying the relevant market for competition analysis.

  • Measure of concentration: Using the Herfindahl-Hirschman Index (HHI) to assess market concentration.

  • Merger standards: Mergers that substantially increase market power may be challenged unless efficiency gains are proven.

Regulating Natural Monopolies

  • Natural monopolies are often regulated by government commissions, which may set prices to allow zero economic profit or to maximize efficiency.

  • Setting prices at marginal cost may result in losses for the firm, so a compromise is often used.

Summary Table: Key Concepts

Concept

Definition

Example

Monopoly

Single seller, no close substitutes

USPS, local utilities

Barriers to Entry

Obstacles preventing new firms

Patents, control of resources

Price Discrimination

Different prices for same product

Airline tickets, movie discounts

Deadweight Loss

Lost economic surplus due to inefficiency

Monopoly pricing

Antitrust Laws

Promote competition, prevent collusion

Sherman Act, Clayton Act

Pearson Logo

Study Prep