Chapter 6
The Two
Extremes: Perfect Competition and Pure Monopoly
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-2
Learning Objectives
• List the four characteristics of a perfectly
competitive market.
• Describe how a perfect competitor makes the decision to stay in business or to go out of business.
• List the characteristics of monopoly. • Explain the difference between marginal
revenue for a perfect competitor and
marginal revenue for a pure monopolist.
Market Structures
• Market structure relates to the number, size, and interaction of firms in a
particular market.
• One extreme market structure is perfect competition, when there are literally thousands of sellers.
Market Structures (cont.)
• At the other extreme is pure monopoly, when there is only one seller of a good for which there are no close substitutes. • In between, there are varying degrees
of what is called imperfect competition (duopoly, oligopoly, and monopolistic competition).
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-5
Characteristics of a Perfectly
Competitive Market
• There are a very large number of relatively small buyers and sellers. • The product sold by each seller is
virtually identical to the product sold by other sellers.
• Firms can easily enter or exit the industry.
• Everybody involved has good information about price and product qualities.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-6
Demand Curve Faced by
a Perfect Competitor
• A perfect competitor is a price taker. • He takes the prices determined by
market forces. Therefore, the demand curve faced by the individual firm in this market is perfectly elastic.
• This means that customers will buy all that any individual firm might want to produce at the going market price and none at a higher price.
Figure 6-2: Demand Curve Facing
the Perfect Competitor
How Much Should You Produce?
• The decision on how much to produceis similar to all decisions in economics. Never do anything past the point at which marginal benefit equals marginal cost.
• A perfect competitor produces up to the point at which marginal benefit equals marginal cost, or the point at which the price per unit equals marginal cost.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-9
Profit Maximization
• This decision-making process is really one in which the perfect competitor maximizes
profits.
• If the perfect competitor produced a larger quantity, marginal costs would exceed the price per unit.
• If the firm stops producing before marginal benefit equals marginal cost, then it is forgoing potential profits on additional units of output.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-10
Marginal Revenue
• Marginal benefit here refers to the firm’s
marginal revenue, defined as the change in
total revenues when there is a one-unit change in production and sales.
• Marginal revenue is equal to unit price at all rates of output for perfect competitors.
Change in total revenues Marginal revenue =
Change in output
Figure 6-3: The Perfect Competitor
Determines How Much to Produce
Maximizing Profits
• Profit maximization occurs at the rate of output at which marginal revenue equals marginal cost.
• For a perfectly competitive firm, this is at the intersection of the demand schedule, d, and the marginal cost curve, MC. As was seen in Figure 6-3.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-13
Figure 6-4: Showing Short-Run
Economic Profits
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-14
When Should a Perfect Competitor
Shutdown?
• Whenever a perfect competitor is sustaining economic losses in the short run, it must compare the cost of
producing, while incurring these losses, with the cost of shutting down.
• Whenever total revenues exceed total variable costs, the perfect competitor should still keep production going.
Perfect Competitors Generally
Make Zero Economic Profits
• In the short run, even in a perfectlycompetitive industry, an individual firm might make positive economic profits. • These profits tend to disappear in the
long run. That is, in the long run, because of so much competition, those who remain in a perfectly competitive industry end up making zero economic profits.
Pure Monopoly
• A pure monopoly is a market with a sole producer of a specific good or service for which there are no close substitutes and, no competitors.
• By definition, the pure monopolist is the entire industry. Therefore, this firm faces the entire market demand curve.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-17
Types of Monopolies
1. Natural Monopoly: usually arises when there are large economies of scale relative to the market demand, such that one firm can produce at a lower average cost than can be achieved by multiple firms.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-18
Types of Monopolies
2. Technological Monopoly: Someone who invents something that allows for the creation of a unique product often has a technological monopoly. Normally, the government provides a patent that gives the creator exclusive right to manufacture, rent, or sell that invention for 20 years.
Types of Monopolies
3. Government Monopoly:Governments—federal, state, and local—often create their own
monopolies. That is, they decide that no one else but them lawfully may provide the production of a good or service.
Barriers to Entry
• For any amount of monopoly power to continue to exist in the long run, the market must be closed to entry in some way.
• Two of the barriers to entry that have allowed firms to reap monopoly profits in the long run are:
– Ownership of Resources – Government Regulations.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-21
What Kind of Demand Curve Does
the Monopolist Face?
• A pure monopolist is the sole supplier of one product, good, or service.
• It represents the entire industry. • Consequently, a pure monopolist faces
a demand curve that is the one for the entire market. This is a downward sloping demand curve.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-22
Marginal Revenue for the
Monopolist
• Because a pure monopolist faces the market downward-sloping demand curve, it can only sell more by charging less for all units sold. Consequently, for a pure monopolist, marginal revenue is always less than price.
How the Monopolist Maximizes
Profits
• A monopolist always produces at that rate at which marginal revenue equals marginal cost.
• However, for the monopolist, marginal revenue is always less than price.
Why Monopolies Are Considered
“Bad”
• Competition leads to lower prices. • Monopoly, in contrast, implies no
competition. The result, then, is that monopolists tend to charge higher prices than would competitors, if they existed.
Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 6-25
Key Terms and Concepts
• barriers to entry • economies of scale • government monopoly • marginal revenue • market structure • natural monopolies • patent • perfect competition • price setter • price taker • pure monopoly • technological monopoly