Monopoly: Origins, Price-Setting, and Efficiency in Microeconomics

Monopoly and How It Arises

Definition and Key Features

A monopoly is a market structure characterized by a single supplier that produces a good or service for which no close substitute exists. This supplier is protected from competition by barriers that prevent the entry of new firms.

• No Close Substitutes: The product offered by a monopoly has no close alternatives, so consumers cannot easily switch to another product.

• Barriers to Entry: These are constraints that protect the monopoly from potential competitors.

Types of Barriers to Entry

Barriers to entry are essential for the existence and persistence of monopoly power. They can be classified as:

• Natural Barriers: Arise when economies of scale allow one firm to supply the entire market at the lowest possible cost, creating a natural monopoly.

• Ownership Barriers: Occur when a firm controls a vital resource or infrastructure, restricting entry. Example: Luxottica's dominance in the eyewear market.

• Legal Barriers: Created by government action, such as public franchises, licenses, patents, or copyrights. Example: The U.S. Postal Service's exclusive right to deliver first-class mail.

Natural Monopoly

A natural monopoly exists when a single firm can supply the entire market at a lower cost than multiple competing firms due to economies of scale. The long-run average cost (LRAC) curve continues to slope downward even when market demand is met.

• Example: One firm produces 4 million units at 5 cents per unit, while two firms would produce at 10 cents per unit each.

Table: Comparison of Cost Structures

Number of Firms	Total Output	Cost per Unit
1	4 million	5 cents
2	4 million (2 million each)	10 cents

Ownership Barriers to Entry

Monopolies can be sustained by ownership of key resources or infrastructure. Examples include:

• Vertical Integration: Luxottica (Eyewear) controls brands and retail chains.

• Natural Resource Ownership: De Beers (Diamonds) controls mines and distribution.

• Proprietary Platform: Microsoft (Software) controls dominant OS ecosystem.

• Infrastructure Ownership: Comcast (Cable/Internet) controls broadband networks.

• State Resource Ownership: Saudi Aramco (Oil) has exclusive rights to Saudi oil extraction.

• Intellectual Property (Patent): Monsanto/Bayer (Agriculture) owns GM seed patents.

• Unique Infrastructure Ownership: Eurotunnel/Getlink (Transport) owns Channel Tunnel.

Legal Barriers to Entry

Legal monopolies are created by government intervention, such as:

• Public Franchise: Exclusive rights to provide a service (e.g., postal service).

• Government License: Required to practice certain professions (e.g., law, medicine).

• Patent or Copyright: Grants exclusive rights to produce or sell a product.

Monopoly Price-Setting Strategies

Single-Price Monopoly vs. Price Discrimination

• Single-Price Monopoly: Sells each unit of output at the same price to all customers.

• Price Discrimination: Sells different units of a good or service at different prices to different customers or groups.

A Single-Price Monopoly’s Output and Price Decision

Price and Marginal Revenue

A monopoly is a price setter, not a price taker. The demand for its output is the market demand. To sell more, it must lower the price.

• Total Revenue (TR): $TR = P imes Q$

• Marginal Revenue (MR): The change in total revenue from selling one more unit. For a single-price monopoly, $MR < P$ at each level of output.

Marginal Revenue and Elasticity

• If demand is elastic, a price decrease increases total revenue ($MR > 0$).

• If demand is inelastic, a price decrease reduces total revenue ($MR < 0$).

• If demand is unit elastic, a price decrease does not change total revenue ($MR = 0$). Total revenue is maximized when $MR = 0$.

Profit Maximization

• The monopoly produces the quantity where $MR = MC$ (marginal cost).

• The price is set at the highest level at which the profit-maximizing quantity can be sold.

• Economic Profit: The area between price and average total cost (ATC), multiplied by quantity.

Single-Price Monopoly and Competition Compared

Comparing Price and Output

• In perfect competition, equilibrium occurs where quantity demanded equals quantity supplied ($Q_C$, $P_C$).

• In monopoly, equilibrium output ($Q_M$) occurs where $MR = MC$, and price ($P_M$) is set on the demand curve at that quantity.

• Monopoly produces a smaller output and charges a higher price than perfect competition.

Efficiency Comparison

• In perfect competition, the market demand curve is the marginal social benefit (MSB) curve, and the market supply curve is the marginal social cost (MSC) curve. Equilibrium is efficient: $MSB = MSC$.

• Total surplus (consumer + producer surplus) is maximized in perfect competition.

• In monopoly, price exceeds marginal social cost, so $MSB > MSC$, and a deadweight loss arises, indicating inefficiency.

Table: Comparison of Perfect Competition and Monopoly

Market Structure	Output	Price	Efficiency
Perfect Competition	High ($Q_C$)	Low ($P_C$)	Efficient (MSB = MSC)
Monopoly	Low ($Q_M$)	High ($P_M$)	Inefficient (Deadweight loss)

Redistribution of Surpluses

• Some lost consumer surplus is transferred to the monopoly as producer surplus.

Summary

• Monopoly arises due to lack of close substitutes and barriers to entry.

• Monopolies set prices and output to maximize profit, resulting in $MR = MC$.

• Compared to perfect competition, monopolies produce less, charge more, and create inefficiency (deadweight loss).

• Price discrimination allows monopolies to increase profit by capturing consumer surplus.

Additional info: The notes are based on lecture slides for ECON 1000: Microeconomics for Managers, Week 9, Professor Irene Henriques.