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Lerner Index Calculator

Measure market power and competition levels with the Lerner Index

Market Power Analysis

Calculation Method

Price & Cost Information

$

Market price per unit

$

Cost of producing one additional unit

Formula Used:

Lerner Index = (Price - Marginal Cost) / Price

Lerner Index = ($500.00 - $350.00) / $500.00 = 0.300

Market Power Analysis Results

0.300
Lerner Index
30.0%
Profit Margin
42.9%
Markup over MC

Market Structure: Oligopolistic

Moderate to high market power

Economic Implications

• Moderate market power

• Some pricing flexibility

• Potential for economic profit

• May warrant monitoring

Competitive Analysis

Market Power Level:Moderate
Competition Intensity:Moderate
Regulatory Concern:Medium
Consumer Welfare:Medium

Industry Benchmarks

Agriculture/Commodities: 0.00-0.10 (highly competitive)
Retail/Manufacturing: 0.10-0.25 (competitive)
Technology/Branded goods: 0.25-0.50 (moderate power)
Utilities/Pharmaceuticals: 0.50+ (high market power)

Your Lerner Index: 0.300

Example: Alpha Machineries

Company Information

Company: Alpha Machineries

Product: Industrial equipment

Market Price: $500 per unit

Marginal Cost: $350 per unit

Lerner Index Calculation

Formula: Lerner Index = (Price - Marginal Cost) / Price

Calculation: ($500 - $350) / $500 = 0.30

Result: Lerner Index = 0.30 (30% profit margin)

Interpretation: Oligopolistic market with moderate market power

Markup: 42.9% above marginal cost

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Interpretation Guide

0.00 - Perfect Competition
  • • Price = Marginal Cost
  • • No market power
  • • Maximum efficiency
0.01-0.25 - Competitive
  • • Low market power
  • • Many competitors
  • • Limited pricing flexibility
0.25-0.50 - Oligopolistic
  • • Moderate market power
  • • Few large competitors
  • • Strategic pricing
0.50-1.00 - Monopolistic
  • • High market power
  • • Limited competition
  • • Price setting ability

Calculation Methods

Basic Formula

L = (P - MC) / P

Uses price and marginal cost directly

Elasticity Method

L = -1 / ε

Uses price elasticity of demand (ε)

Applications

Antitrust analysis and regulation

Competition policy assessment

Market structure analysis

Merger evaluation

Strategic pricing decisions

Academic research in economics

Understanding the Lerner Index

What is the Lerner Index?

The Lerner Index, developed by economist Abba Lerner, is a fundamental measure in economics that quantifies a firm's market power. It indicates how much a company can price its products above marginal cost, serving as a key indicator of market competition and monopoly power.

Economic Significance

  • Measures degree of market power
  • Indicates competition intensity
  • Guides regulatory decisions
  • Helps analyze market efficiency

Key Formulas

Basic Formula:

L = (P - MC) / P

Where P = Price, MC = Marginal Cost

Elasticity Formula:

L = -1 / ε

Where ε = Price Elasticity of Demand

Market Structure Analysis

Perfect Competition

Lerner Index = 0

  • • Price = Marginal Cost
  • • No market power
  • • Maximum efficiency

Monopolistic Competition

Lerner Index: 0.1-0.3

  • • Product differentiation
  • • Limited market power
  • • Many competitors

Oligopoly

Lerner Index: 0.3-0.6

  • • Few large firms
  • • Strategic interdependence
  • • Moderate market power

Monopoly

Lerner Index: 0.6-1.0

  • • Single seller
  • • High barriers to entry
  • • Maximum market power
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