Reading 9: The Firm and Market Structures

50 questions available

Perfect Competition5 min
Perfect competition involves many firms selling identical products with no pricing power. Firms are price takers, meaning they face a horizontal demand curve at the market equilibrium price. Profit maximization occurs where marginal revenue equals marginal cost. In the short run, firms operate if price covers average variable costs. In the long run, free entry and exit force economic profits to zero, and firms produce at the minimum of their average total cost curves.

Key Points

  • Many firms, identical products, low barriers to entry.
  • Firms are price takers with perfectly elastic demand.
  • Profit maximization condition: P = MR = MC.
  • Short-run supply curve is MC above AVC.
  • Long-run equilibrium: Price = Minimum ATC; zero economic profit.
Monopolistic Competition5 min
This structure combines elements of competition and monopoly. Many firms exist, but they sell differentiated products, giving them some pricing power and facing downward-sloping demand curves. Differentiation occurs through quality, features, and marketing. While firms can earn short-run profits, low entry barriers ensure zero economic profits in the long run. Unlike perfect competition, firms operate with excess capacity and prices exceed marginal cost.

Key Points

  • Many firms, differentiated products, low barriers to entry.
  • Downward-sloping, elastic demand curves.
  • Product differentiation via innovation and marketing.
  • Long-run equilibrium: Price = ATC > MC (markup exists).
  • Economic profits are zero in the long run.
Oligopoly7 min
Oligopolies consist of a few large firms with high barriers to entry. The defining characteristic is interdependence: one firm's actions directly affect others. Models to explain pricing and output include the Kinked Demand Curve (suggesting price rigidity), Cournot (competition on quantity), and Stackelberg (sequential decision making). Firms may collude to act like a monopoly, though this is illegal in many jurisdictions. The Dominant Firm model suggests one large firm sets the price while smaller firms act as price takers.

Key Points

  • Few firms, high barriers, interdependence.
  • Kinked demand curve explains price stickiness.
  • Nash equilibrium: No firm gains by unilaterally changing strategy.
  • Collusion is more successful with fewer firms and similar costs.
  • Dominant firm sets price; competitive fringe follows.
Monopoly and Regulation6 min
A monopoly is a single seller of a product with no close substitutes. High barriers to entry protect long-run economic profits. Monopolists maximize profit where MR = MC, charging a price determined by the demand curve. Price discrimination can increase profits by capturing consumer surplus. Natural monopolies, often utilities, have falling average costs over the relevant range of demand and are regulated to improve efficiency, often through average cost pricing.

Key Points

  • Single seller, unique product, very high barriers.
  • Profit maximizer: Produce where MR = MC, price from demand curve.
  • Price discrimination requires preventing resale and distinct customer groups.
  • Natural monopoly: Economies of scale lead to a single supplier.
  • Regulation aims to reduce deadweight loss (e.g., average cost pricing).
Concentration Measures4 min
To assess market structure and potential pricing power, analysts use concentration measures. The N-firm concentration ratio is the sum of market shares of the top N firms. The Herfindahl-Hirschman Index (HHI) sums the squared market shares of all firms (or top firms), placing greater weight on larger firms. While useful, these measures fail to account for barriers to entry or potential competition.

Key Points

  • N-firm concentration ratio: Sum of top N market shares.
  • HHI: Sum of squared market shares; more sensitive to mergers.
  • Concentration does not guarantee pricing power.
  • Barriers to entry are crucial for true market power.
  • Market definitions (e.g., global vs. local) affect measures.

Questions

Question 1

Which of the following market structures is characterized by a large number of firms producing identical products?

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Question 2

In a perfectly competitive market, the demand curve faced by an individual firm is best described as:

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Question 3

A profit-maximizing firm in any market structure will expand production until:

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Question 4

Under perfect competition, a firm's short-run supply curve is represented by:

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Question 5

In the long run, firms in a perfectly competitive market will earn:

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Question 6

A firm in perfect competition should shut down in the short run if price is less than:

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Question 7

Which of the following is a key characteristic of monopolistic competition?

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Question 8

In monopolistic competition, the demand curve faced by each firm is:

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Question 9

Long-run equilibrium in monopolistic competition results in:

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Question 10

Advertising expenses are typically high for firms in monopolistic competition because:

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Question 11

Which market structure is characterized by a few firms and high interdependence?

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Question 12

The kinked demand curve model of oligopoly assumes that:

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Question 13

In the Cournot duopoly model, each firm determines its profit-maximizing quantity assuming that:

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Question 14

A Nash equilibrium is reached when:

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Question 15

In the Stackelberg dominant firm model, the market price is determined by:

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Question 16

Which of the following factors makes a collusive agreement in an oligopoly more likely to be successful?

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Question 17

A monopolist maximizes profit by producing the quantity where:

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Question 18

Which of the following is a necessary condition for a monopolist to practice price discrimination?

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Question 19

Compared to a single-price monopoly, perfect price discrimination results in:

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Question 20

A natural monopoly is characterized by:

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Question 21

Regulating a natural monopoly by forcing it to set price equal to marginal cost usually requires:

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Question 22

The N-firm concentration ratio is calculated as:

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Question 23

Calculate the 4-firm concentration ratio for an industry with five firms having market shares of 30 percent, 20 percent, 15 percent, 10 percent, and 25 percent.

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Question 24

Which of the following is a limitation of the N-firm concentration ratio?

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Question 25

The Herfindahl-Hirschman Index (HHI) is calculated as:

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Question 26

If two firms in an industry with market shares of 25 percent and 15 percent merge, the HHI will:

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Question 27

One limitation shared by both the N-firm concentration ratio and HHI is that they:

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Question 28

Which market structure generally has the lowest barriers to entry?

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Question 29

An industry with many firms, differentiated products, and some pricing power is best classified as:

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Question 30

A market with a single seller and no close substitutes is a:

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Question 31

In the long run, a firm in perfect competition produces at a quantity where:

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Question 32

Which of the following is true about the supply function in an oligopoly?

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Question 33

If a monopolist engages in rent seeking, the social cost of monopoly:

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Question 34

A permanent increase in demand in a perfectly competitive industry will eventually result in:

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Question 35

In the short run, if a perfectly competitive firm's marginal revenue is less than its marginal cost, it should:

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Question 36

Product innovation in monopolistic competition allows firms to:

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Question 37

Over time, the market share of a dominant firm in an oligopoly is likely to:

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Question 38

A firm operating in an oligopoly with a kinked demand curve believes that if it raises its price:

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Question 39

In the context of the kinked demand curve model, the marginal revenue curve:

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Question 40

According to the Cournot model, as the number of firms in an oligopoly increases, the equilibrium market price:

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Question 41

Under the Stackelberg model, the 'leader' firm:

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Question 42

Collusive agreements in an oligopoly are most likely to be successful when:

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Question 43

In the Dominant Firm Model, the dominant firm calculates its demand by:

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Question 44

Average cost pricing regulation for a natural monopoly typically forces the firm to:

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Question 45

Compared to perfect competition, a monopoly creates a deadweight loss because:

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Question 46

If a market has an HHI of 0.1950, this indicates:

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Question 47

Which pricing strategy allows a monopolist to capture more consumer surplus?

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Question 48

Game theory is most useful for analyzing which market structure?

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Question 49

In the short run, a firm in perfect competition will earn a normal profit when:

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Question 50

Which of the following is true regarding the long-run supply curve for a firm in perfect competition?

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