11.7: Bertrand Competition

In a Bertrand oligopoly, companies compete by strategically setting prices rather than engaging in a continuous price-cutting war. Each company anticipates its rival's reaction and adjusts its prices accordingly. Because customers prefer lower prices, companies undercut one another until prices fall to marginal cost. No company can reduce its price any further without incurring losses, leading to a Bertrand equilibrium, where firms make zero economic profit.

Take two supermarkets selling the same type of milk. If one charges $3, the other lowers its price to $2.90 to attract customers. In response, the first supermarket reduces the price of its milk to $2.80, and this price reduction strategy continues. Here, companies don't reduce prices at random—they think about how their competitor will respond and whether further reducing the price will be profitable. Once the price reaches the marginal cost of supplying milk ($2.50 in this example), further price reductions are no longer viable, and both companies stabilize at that price.

This result occurs because companies know that setting the price too high means losing all customers, whereas setting the price too low leads to losses. Anticipating their competitors' actions, companies price their products to maximize sales while avoiding a price war. The Bertrand oligopoly assumes that companies have unlimited ability to satisfy demand at the current price; thus, the company with the lowest cost captures the entire market.

Companies tend to prevent this situation through product differentiation or customer loyalty. However, under strict Bertrand conditions, companies can only compete on price, and strategic choice forces them to a situation where prices equal marginal cost with no scope for economic profit.

A Bertrand Oligopoly is a market structure where a few firms compete on price, undercutting each other’s prices until they equal marginal cost.

Each firm has the same constant marginal cost (MC), assuming identical products and consumers choosing the cheaper option.

The firm with the lowest price captures the market until it reaches its capacity. As a result, firms set equal prices (P1 = P2 = P), which then become the market price.

For instance, two airlines, Delta and United, compete on the New York to Los Angeles route, and their marginal cost is $250.

Delta sets a one-way ticket price of $300, and United sets its price at $290 to attract more passengers.

Delta responds by lowering its price to $280; further, United lowers its price to $270.

This process continues back and forth until prices reach $250, and prices fall until they are equal to MC, the level at which further reductions would cause losses to both airlines. 

This outcome demonstrates that in Bertrand oligopoly, firms earn zero economic profit in equilibrium because price equals marginal cost

• Bertrand Oligopoly - Firms compete strategically by setting prices, avoiding a continuous price-cutting war.
• Bertrand Equilibrium - Prices in Bertrand competition fall to marginal cost, leading to zero economic profit.
• Marginal Cost - The cost at which further production or price reduction is no longer viable.
• Product Differentiation - Companies avoid price wars by differentiating their products.
• Customer Loyalty - A defensive strategy companies use to retain their customer base amidst competition.

• Define Bertrand Oligopoly – Explains firms' competitive pricing strategy that led to Bertrand Equilibrium (e.g., bertrand competition)
• Contrast Bertrand Equilibrium vs Oligopoly War – Explain key differences (e.g., continuous price-cutting vs strategic pricing).
• Explore Bertrand Equilibrium – Describe scenario when prices fall to marginal cost (e.g., supermarkets selling milk).
• Explain Marginal Cost Impact – Describe how it limits price reduction and production increase.
• Apply Product Differentiation and Customer Loyalty – Understand their role within a Bertrand framework.

• [Question 1] What is Bertrand Oligopoly and how it leads to Bertrand Equilibrium?
• [Question 2] How does marginal cost impact Bertrand competition?
• [Question 3] How can Product Differentiation and Customer Loyalty prevent a price war in Bertrand competition?

• Business Students – Understand how Bertrand competition shapes market pricing and equilibrium
• Economists – Insight into the dynamics of price competition and marginal cost
• Market Researchers – Applications of the Bertrand Oligopoly model in market studies
• Business Enthusiasts – Understanding strategic pricing strategies and their impact on profitability