2. 제11장의 독점시장에서는 가격차별과 독점이 사회적 후생에 미치는 영향과 같은 토픽을 중심으로 독점시장에 대해서 다룬다.
다이아몬드 독점기업인 드비어스(De Beers)와 같은 대표적인 기업을 예로 들어 설명하고, 캘리포니아 전력 발전소의 가격 조작과 비행기 티켓팅의 가격에 대해서도 학습한다.

3. What you will learn in this chapter:
➤ The significance of monopoly, where a single monopolist is the only producer of a good
➤ How a monopolist determines its profit-maximizing output and price
➤ The difference between monopoly and perfect competition, and the effects of that difference on society’s welfare
➤ How policy makers address the problems posed by monopoly
➤ What price discrimination is, and why it is so prevalent when producers have market power
Got stones?

4. Types of Market Structure
Economists have developed four principal models of market structure: perfect competition, monopoly, oligopoly, and monopolistic competition.
This system of market structures is based on two dimensions:
■ The number of producers in the market (one, few, or many)
■ Whether the goods offered are identical or differentiated

5. Types of Market Structure

6. The Meaning of Monopoly
A monopolist is a firm that is the only producer of a good that has no close substitutes. An industry controlled by a monopolist is known as a monopoly.

7. The Meaning of Monopoly
Monopoly: Our First Departure from Perfect Competition
In practice, true monopolies are hard to find in the modern American economy.
Monopolies do, however, play an important role in some sectors of the economy.

8. The Meaning of Monopoly
What Monopolists Do

9. The Meaning of Monopoly
What Monopolists Do
Market power is the ability of a producer to raise prices.
Why Do Monopolies Exist?
To earn profits, a monopolist must be protected by a barrier to entry—something that prevents other firms from entering the industry.

10. The Meaning of Monopoly
Why Do Monopolies Exist?
Control of a Scarce Resource or Input
A monopolist that controls a resource or input crucial to an industry can prevent other firms from entering its market.
Economies of Scale
A natural monopoly exists when economies of scale provide a large cost advantage to having all of an industry’s output produced by a single firm.

11. The Meaning of Monopoly
Why Do Monopolies Exist?
Economies of Scale

12. The Meaning of Monopoly
Why Do Monopolies Exist?
Technological Superiority
A firm that maintains a consistent technological advantage over potential competitors can establish itself as a monopolist.
We should note, however, that in certain high-tech industries, technological superiority is not a guarantee of success against competitors.
Government-Created Barriers
The most important legally created monopolies today arise from patents and copyrights.

13. How a Monopolist Maximizes Profit
The Monopolist’s Demand and Marginal Revenue Curves

14. Marginal revenue MR = ΔTR/ΔQ
How a Monopolist Maximizes Profit
The Monopolist’s Demand and Marginal Revenue Curves
TABLE 11-1
Demand, Total Revenue, and Marginal Revenue for the De Beers Monopoly
Price of diamond P
Quantity of diamonds Q
Total revenue TR = P x Q
Marginal revenue MR = ΔTR/ΔQ
$1,000 $0
$950
950 1
850
900 2
1,800
750 3
2,550
650
800 4
3,200
550 5
3,750
450
700 6
4,200
350 7
4,550
250
600 8
4,800
150 9
4,950 50
500 10
5,000
-50

15. Marginal revenue MR = ΔTR/ΔQ
How a Monopolist Maximizes Profit
The Monopolist’s Demand and Marginal Revenue Curves
TABLE 11-1 cont’d.
Demand, Total Revenue, and Marginal Revenue for the De Beers Monopoly
Price of diamond P
Quantity of diamonds Q
Total revenue TR = P x Q
Marginal revenue MR = ΔTR/ΔQ
450 11
4,950
–150
400 12
4,800
–250
350 13
4,550
–350
300 14
4,200
–450
250 15
3,750
–550
200 16
3,200
–650
150 17
2,550
–750
100 18
1,800
–850 50 19
950
–950 20

16. How a Monopolist Maximizes Profit
The Monopolist’s Demand and Marginal Revenue Curves
An increase in production by a monopolist has two opposing effects on revenue:
■ A quantity effect. One more unit is sold, increasing total revenue by the price at which the unit is sold.
■ A price effect. In order to sell that last unit, the monopolist must cut the market price on all units sold. This decreases total revenue.

17. How a Monopolist Maximizes Profit

18. How a Monopolist Maximizes Profit
The Monopolist’s Profit-Maximizing Output and Price

19. How a Monopolist Maximizes Profit
The Monopolist’s Profit-Maximizing Output and Price
The monopolist maximizes its profit by using the optimal output rule:
(11-1)
MR = MC at the monopolist’s profit-maximizing quantity of output
Monopoly versus Perfect Competition
(11-2)
P = MC at the perfectly competitive firm’s profit-maximizing quantity of output
(11-3)
P > MR = MC at the monopolist’s profit-maximizing quantity
of output

20. How a Monopolist Maximizes Profit
Monopoly: The General Picture

21. How a Monopolist Maximizes Profit
Monopoly: The General Picture
Profit is equal to the difference between total revenue and total cost.
(11-4)
Profit = TR – TC
= (PM x QM) – (ATCM x QM)
= (PM – ATCM) x QM

22. Monopoly and Public Policy
Welfare Effects of Monopoly

23. Monopoly and Public Policy
Preventing Monopoly
Policy toward monopoly depends crucially on whether or not the industry in question is a natural monopoly, one in which economies of scale ensure that bigger producers have lower average total cost.

24. Monopoly and Public Policy
Dealing with Natural Monopoly
Breaking up a monopoly that isn’t natural is clearly a good idea: the gains to consumers outweigh the loss to the producer.
It is not so clear whether a natural monopoly should be broken up, because this would raise average total cost.
Yet even in the case of a natural monopoly, a profit-maximizing monopolist acts in a way that causes inefficiency.

25. Monopoly and Public Policy
Dealing with Natural Monopoly
Public Ownership
In public ownership of a monopoly, the good is supplied by the government or by a firm owned by the government.
Regulation
Price regulation limits the price that a monopolist is allowed to charge.

26. Monopoly and Public Policy
Dealing with Natural Monopoly
Regulation

27. Price Discrimination
A single-price monopolist offers its product to all consumers at the same price.
Sellers engage in price discrimination when they charge different prices to different consumers for the same good.

28. Price Discrimination
The Logic of Price Discrimination

29. Price Discrimination Price Discrimination and Elasticity
On many airline routes, the fare you pay depends on the type of traveler you are.

30. Price Discrimination Perfect Price Discrimination
Perfect price discrimination takes place when a monopolist charges each consumer his or her willingness to pay—the maximum that consumer is willing to pay.

31. Price Discrimination
Perfect Price Discrimination

32. Price Discrimination Perfect Price Discrimination
Monopolists do try to move in the direction of perfect price discrimination through a variety of pricing strategies. Common techniques for price discrimination include the following:
■ Advance purchase restrictions.
■ Volume discounts.
■ Two-part tariffs.

33. K E Y T E R M S
Monopolist
Monopoly
Market power
Barrier to entry
Natural monopoly
Public ownership
Price regulation
Single-price monopolist
Price discrimination
Perfect price discrimination