Mankiw Principles of Economics (3rd ed)

O L I G O P O L Y

If you go to a store to buy tennis balls, it is likely that you will come home with one of four brands: Wilson, Penn, Dunlop, or Spalding. These four companies make almost all of the tennis balls sold in the United States. Together these firms determine the quantity of tennis balls produced and, given the market demand curve, the price at which tennis balls are sold.

How can we describe the market for tennis balls? The previous two chapters discussed two types of market structure. In a competitive market, each firm is so small compared to the market that it cannot influence the price of its product and, therefore, takes the price as given by market conditions. In a monopolized market, a single firm supplies the entire market for a good, and that firm can choose any price and quantity on the market demand curve.

The market for tennis balls fits neither the competitive nor the monopoly model. Competition and monopoly are extreme forms of market structure. Competition occurs when there are many firms in a market offering essentially identical products; monopoly occurs when there is only one firm in a market. It is

IN THIS CHAPTER YOU WILL . . .

See what market str uctur es lie between monopoly and competition

Examine what outcomes ar e possible when a market is an oligopoly

Learn about the prisoners’ dilemma and how it applies to oligopoly and other issues

Consider how the antitr ust laws tr y to foster competition in oligopolistic markets

oligopoly

a market structure in which only a few sellers offer similar or identical products

monopolistic competition a market structure in which many firms sell products that are similar but not identical

natural to start the study of industrial organization with these polar cases, for they are the easiest cases to understand. Yet many industries, including the tennis ball industry, fall somewhere between these two extremes. Firms in these industries have competitors but, at the same time, do not face so much competition that they are price takers. Economists call this situation imperfect competition.

In this chapter we discuss the types of imperfect competition and examine a particular type called oligopoly. The essence of an oligopolistic market is that there are only a few sellers. As a result, the actions of any one seller in the market can have a large impact on the profits of all the other sellers. That is, oligopolistic firms are interdependent in a way that competitive firms are not. Our goal in this chapter is to see how this interdependence shapes the firms’ behavior and what problems it raises for public policy.

BETWEEN MONOPOLY AND PERFECT COMPETITION

The previous two chapters analyzed markets with many competitive firms and markets with a single monopoly firm. In Chapter 14, we saw that the price in a perfectly competitive market always equals the marginal cost of production. We also saw that, in the long run, entry and exit drive economic profit to zero, so the price also equals average total cost. In Chapter 15, we saw how firms with market power can use that power to keep prices above marginal cost, leading to a positive economic profit for the firm and a deadweight loss for society.

The cases of perfect competition and monopoly illustrate some important ideas about how markets work. Most markets in the economy, however, include elements of both these cases and, therefore, are not completely described by either of them. The typical firm in the economy faces competition, but the competition is not so rigorous as to make the firm exactly described by the price-taking firm analyzed in Chapter 14. The typical firm also has some degree of market power, but its market power is not so great that the firm can be exactly described by the monopoly firm analyzed in Chapter 15. In other words, the typical firm in our economy is imperfectly competitive.

There are two types of imperfectly competitive markets. An oligopoly is a market with only a few sellers, each offering a product similar or identical to the others. One example is the market for tennis balls. Another is the world market for crude oil: A few countries in the Middle East control much of the world’s oil reserves. Monopolistic competition describes a market structure in which there are many firms selling products that are similar but not identical. Examples include the markets for novels, movies, CDs, and computer games. In a monopolistically competitive market, each firm has a monopoly over the product it makes, but many other firms make similar products that compete for the same customers.

Figure 16-1 summarizes the four types of market structure. The first question to ask about any market is how many firms there are. If there is only one firm, the market is a monopoly. If there are only a few firms, the market is an oligopoly. If there are many firms, we need to ask another question: Do the firms sell identical or differentiated products? If the many firms sell differentiated products, the market is monopolistically competitive. If the many firms sell identical products, the market is perfectly competitive.

Figur e 16-1

THE FOUR TYPES OF MARKET

STRUCTURE. Economists who study industrial organization divide markets into four types— monopoly, oligopoly, monopolistic competition, and perfect competition.

Table 16-1

THE DEMAND SCHEDULE

FOR WATER

small quantity of output and charging a price above marginal cost. Yet because each oligopolist cares about only its own profit, there are powerful incentives at work that hinder a group of firms from maintaining the monopoly outcome.

A DUOPOLY EXAMPLE

To understand the behavior of oligopolies, let’s consider an oligopoly with only two members, called a duopoly. Duopoly is the simplest type of oligopoly. Oligopolies with three or more members face the same problems as oligopolies with only two members, so we do not lose much by starting with the case of duopoly.

Imagine a town in which only two residents—Jack and Jill—own wells that produce water safe for drinking. Each Saturday, Jack and Jill decide how many gallons of water to pump, bring the water to town, and sell it for whatever price the market will bear. To keep things simple, suppose that Jack and Jill can pump as much water as they want without cost. That is, the marginal cost of water equals zero.

Table 16-1 shows the town’s demand schedule for water. The first column shows the total quantity demanded, and the second column shows the price. If the two well owners sell a total of 10 gallons of water, water goes for $110 a gallon. If they sell a total of 20 gallons, the price falls to $100 a gallon. And so on. If you graphed these two columns of numbers, you would get a standard downwardsloping demand curve.

The last column in Table 16-1 shows the total revenue from the sale of water. It equals the quantity sold times the price. Because there is no cost to pumping water, the total revenue of the two producers equals their total profit.

Let’s now consider how the organization of the town’s water industry affects the price of water and the quantity of water sold.

COMPETITION, MONOPOLIES, AND CARTELS

Before considering the price and quantity of water that would result from the duopoly of Jack and Jill, let’s discuss briefly the two market structures we already understand: competition and monopoly.

Consider first what would happen if the market for water were perfectly competitive. In a competitive market, the production decisions of each firm drive price equal to marginal cost. In the market for water, marginal cost is zero. Thus, under competition, the equilibrium price of water would be zero, and the equilibrium quantity would be 120 gallons. The price of water would reflect the cost of producing it, and the efficient quantity of water would be produced and consumed.

Now consider how a monopoly would behave. Table 16-1 shows that total profit is maximized at a quantity of 60 gallons and a price of $60 a gallon. A profitmaximizing monopolist, therefore, would produce this quantity and charge this price. As is standard for monopolies, price would exceed marginal cost. The result would be inefficient, for the quantity of water produced and consumed would fall short of the socially efficient level of 120 gallons.

What outcome should we expect from our duopolists? One possibility is that Jack and Jill get together and agree on the quantity of water to produce and the price to charge for it. Such an agreement among firms over production and price is called collusion, and the group of firms acting in unison is called a cartel. Once a cartel is formed, the market is in effect served by a monopoly, and we can apply our analysis from Chapter 15. That is, if Jack and Jill were to collude, they would agree on the monopoly outcome because that outcome maximizes the total profit that the producers can get from the market. Our two producers would produce a total of 60 gallons, which would be sold at a price of $60 a gallon. Once again, price exceeds marginal cost, and the outcome is socially inefficient.

A cartel must agree not only on the total level of production but also on the amount produced by each member. In our case, Jack and Jill must agree how to split between themselves the monopoly production of 60 gallons. Each member of the cartel will want a larger share of the market because a larger market share means larger profit. If Jack and Jill agreed to split the market equally, each would produce 30 gallons, the price would be $60 a gallon, and each would get a profit of $1,800.

THE EQUILIBRIUM FOR AN OLIGOPOLY

Although oligopolists would like to form cartels and earn monopoly profits, often that is not possible. As we discuss later in this chapter, antitrust laws prohibit explicit agreements among oligopolists as a matter of public policy. In addition, squabbling among cartel members over how to divide the profit in the market sometimes makes agreement among them impossible. Let’s therefore consider what happens if Jack and Jill decide separately how much water to produce.

At first, one might expect Jack and Jill to reach the monopoly outcome on their own, for this outcome maximizes their joint profit. In the absence of a binding agreement, however, the monopoly outcome is unlikely. To see why, imagine that Jack expects Jill to produce only 30 gallons (half of the monopoly quantity). Jack would reason as follows:

collusion

an agreement among firms in a market about quantities to produce or prices to charge

car tel

a group of firms acting in unison

IN THE NEWS

Modern Pirates

“This is one of the last legalized price-setting arrangements in existence,” says Robert Litan, a former Justice Department antitrust official. Airlines and banks couldn’t do this, he says, “but if you’re an ocean shipping line, there’s nothing to stop you from price fixing.”

You could call them the OPEC of shipping, though not quite as powerful because they can’t keep members from building too many ships. To get more business, some of the shipping cartels’ own members undercut cartel rates or make special deals with big customers. They also face the emergence of new competitors, which are keeping rates down in some markets.

Nonetheless, the industry is playing a bigger role now in the U.S. economy as American companies plunge more deeply into world trade. Exports over the seas have jumped 26% in the past two years and 50% since the start of the decade.

For consumers, the impact is hard to measure. Transportation costs make up 5% to 10% of the price of most goods, and increases in shipping rates are usually passed on to consumers. A limited 1993 survey by the Agriculture Department, examining $5 billion of U.S. farm exports, concluded that the cartels were raising ocean shipping rates as much as 18%. A different report, by the Federal Trade Commission in 1995, found that when shipping lines broke

of cartel rates, contract prices were 19% lower.

“The cartels’ whole makeup is anticonsumer,” says John Taylor, a transion professor at Wayne State iversity in Detroit. “They’re designed

keep prices up.”

Some moves are afoot to change all The U.S. Senate is considering a bill for the first time in a decade, would

weaken the cartels, by reducing their power to police their members. The bill, sponsored by Sen. Kay Bailey Hutchison of Texas, has the support of some other high-ranking Republicans, including Majority Leader Trent Lott. . . .

For eight decades, shipping cartels have been protected by Congress under the Shipping Act of 1916, passed at the behest of American shipping customers, who thought cartels would guarantee reliable service. The law was revised significantly only twice, in 1961 and 1984, but both times the industry’s antitrust immunity was left intact.

The most recent major review was done in 1991 by a congressional commission. It heard more than 100 witnesses, produced a 250-page re- port—and offered no conclusions or recommendations. . . .

The real reasons for years of inaction in Congress may be apathy and the lobbying by various groups. Dockside labor, for example, fears that secret contracts would enable ship lines to divert cargo to nonunion workers without the union knowing it. David Butz, a University of Michigan economist who has studied shipping, thinks voters aren’t likely to weigh in; the cartels aren’t a hot topic. “It’s below the radar screen,” he says. “Consumers don’t realize the impact they have.”

SOURCE: The Wall Street Journal, October 7, 1997, p. A1.

“I could produce 30 gallons as well. In this case, a total of 60 gallons of water would be sold at a price of $60 a gallon. My profit would be $1,800 (30 gallons $60 a gallon). Alternatively, I could produce 40 gallons. In this case, a total of 70 gallons of water would be sold at a price of $50 a gallon. My profit would be $2,000 (40 gallons $50 a gallon). Even though total profit in the market would fall, my profit would be higher, because I would have a larger share of the market.”

Of course, Jill might reason the same way. If so, Jack and Jill would each bring 40 gallons to town. Total sales would be 80 gallons, and the price would fall to $40. Thus, if the duopolists individually pursue their own self-interest when deciding how much to produce, they produce a total quantity greater than the monopoly quantity, charge a price lower than the monopoly price, and earn total profit less than the monopoly profit.

Although the logic of self-interest increases the duopoly’s output above the monopoly level, it does not push the duopolists to reach the competitive allocation. Consider what happens when each duopolist is producing 40 gallons. The price is $40, and each duopolist makes a profit of $1,600. In this case, Jack’s selfinterested logic leads to a different conclusion:

“Right now, my profit is $1,600. Suppose I increase my production to 50 gallons. In this case, a total of 90 gallons of water would be sold, and the price would be $30 a gallon. Then my profit would be only $1,500. Rather than increasing production and driving down the price, I am better off keeping my production at 40 gallons.”

The outcome in which Jack and Jill each produce 40 gallons looks like some sort of equilibrium. In fact, this outcome is called a Nash equilibrium (named after economic theorist John Nash). A Nash equilibrium is a situation in which economic actors interacting with one another each choose their best strategy given the strategies the others have chosen. In this case, given that Jill is producing 40 gallons, the best strategy for Jack is to produce 40 gallons. Similarly, given that Jack is producing 40 gallons, the best strategy for Jill is to produce 40 gallons. Once they reach this Nash equilibrium, neither Jack nor Jill has an incentive to make a different decision.

This example illustrates the tension between cooperation and self-interest. Oligopolists would be better off cooperating and reaching the monopoly outcome. Yet because they pursue their own self-interest, they do not end up reaching the monopoly outcome and maximizing their joint profit. Each oligopolist is tempted to raise production and capture a larger share of the market. As each of them tries to do this, total production rises, and the price falls.

At the same time, self-interest does not drive the market all the way to the competitive outcome. Like monopolists, oligopolists are aware that increases in the amount they produce reduce the price of their product. Therefore, they stop short of following the competitive firm’s rule of producing up to the point where price equals marginal cost.

In summary, when firms in an oligopoly individually choose production to maximize profit, they produce a quantity of output greater than the level produced by monopoly and less than the level produced by competition. The oligopoly price is less than the monopoly price but greater than the competitive price (which equals marginal cost).

HOW THE SIZE OF AN OLIGOPOLY

AFFECTS THE MARKET OUTCOME

Nash equilibrium

a situation in which economic actors interacting with one another each choose their best strategy given the strategies that all the other actors have chosen