Concentration Ratio: Definition, Examples, and Application


The concentration ratio is a vital economic indicator that assesses the size of firms within an industry relative to the industry’s entirety. This article delves into the definition, calculation, interpretation, and significance of concentration ratios. Learn how to determine if an industry is highly competitive or monopolistic, and explore the Herfindahl-Herschman Index as an alternative measure of market concentration.

Concentration ratio definition

The concentration ratio is a pivotal concept in economics used to evaluate the structure and competitiveness of industries. It quantifies the proportion of market share held by a specific number of large firms within an industry. In essence, it offers insights into whether an industry is dominated by a few giants or characterized by numerous smaller players.

Understanding the concentration ratio

The four-firm concentration ratio

The four-firm concentration ratio, often abbreviated as CR4, focuses on the market share of the four largest firms in an industry. Expressed as a percentage, CR4 can indicate whether these top four firms hold a significant sway over the industry. Typically, the higher the CR4, the less competitive the industry.

Other concentration ratios

Apart from CR4, economists also employ the eight-firm, three-firm, and five-firm concentration ratios. These ratios consider the market share of the eight, three, or five largest firms, respectively, to gain a nuanced understanding of industry competition.

Concentration ratio formula and interpretation

The concentration ratio is calculated by summing up the market share percentages held by the specified number of firms in the industry. The result ranges from 0% to 100%. A low concentration ratio suggests a highly competitive industry, while a high ratio indicates reduced competition.

Example calculation

To illustrate, consider the biotechnology industry. ABC Inc., XYZ Corp., GHI Inc., and JKL Corp. are its four largest companies with market shares of 10%, 15%, 26%, and 33%, respectively. The four-firm concentration ratio for this industry is calculated as 84%. This high ratio implies that the biotech industry operates as an oligopoly, with the top four firms exerting substantial control.

Herfindahl-Herschman Index (HHI)

The Herfindahl-Herschman Index (HHI) serves as an alternative measure of market concentration. It’s calculated by squaring the percentage share of each firm in the industry and then summing these squared market shares. HHI can provide insights similar to the concentration ratio but with a different methodology.

Pros and cons of using concentration ratios

Weigh the risks and benefits

Here is a list of the benefits and drawbacks of using concentration ratios:

  • Provides a quick snapshot of industry competitiveness.
  • Easy to calculate and understand.
  • Useful for policymakers and analysts assessing market structures.
  • Doesn’t account for market dynamics and innovation.
  • May oversimplify complex market scenarios.
  • Relies heavily on available data accuracy.

Examples of concentration ratios

Let’s explore some real-world examples to better understand how concentration ratios work:

Example 1: Retail industry

In the retail industry, consider four major players: Retailer A, Retailer B, Retailer C, and Retailer D. Their respective market shares are 20%, 15%, 10%, and 5%. To calculate the four-firm concentration ratio (CR4), sum the market shares of the top four retailers: 20% + 15% + 10% + 5% = 50%. This indicates moderate concentration in the retail market.

Example 2: Tech giants

Examining the tech industry, let’s focus on four tech giants: Company X, Company Y, Company Z, and Company W. Their market shares are 30%, 25%, 20%, and 15%. Calculating CR4: 30% + 25% + 20% + 15% = 90%. This high CR4 suggests a significant concentration of market power among these tech giants.

Subheadings to enhance understanding

The significance of market structure

Understanding the significance of market structure is crucial when interpreting concentration ratios. A highly concentrated market may lead to reduced competition and potential antitrust concerns, while a competitive market benefits consumers through lower prices and innovation.

Measuring industry changes over time

Industries are dynamic, and concentration ratios can change over time due to mergers, acquisitions, or shifts in market share. Regularly updating concentration ratios is essential for businesses and policymakers to adapt to evolving market conditions.

Comparing concentration ratios globally

Concentration ratios can vary across countries and regions. Comparing concentration ratios globally can provide insights into market competitiveness on a broader scale. It helps identify industries where regulatory intervention may be necessary to promote competition.

Using concentration ratios for investment

Investors can leverage concentration ratios as part of their investment research. A high concentration ratio may indicate stability but also potential vulnerability to regulatory changes, while a low ratio may signal a volatile but competitive market with growth potential.


In the world of economics, the concentration ratio is a valuable tool for assessing market dynamics. By analyzing the market share of the top firms, economists, policymakers, and business analysts can gain insights into the level of competition within an industry. Whether it’s CR4, CR8, CR3, or CR5, these concentration ratios provide a quick snapshot of market structure. However, it’s important to remember that concentration ratios have their limitations and should be used in conjunction with other market analysis tools for a comprehensive understanding.

Frequently Asked Questions

What is the purpose of the concentration ratio?

The concentration ratio serves the purpose of assessing the level of competition within an industry. It helps determine whether a few large firms dominate the market or if there’s a more competitive landscape.

How is the concentration ratio different from market share?

While both concepts involve percentages, market share typically focuses on a single firm’s portion of the market, whereas the concentration ratio considers the combined market share of a specified number of firms in an industry.

What does a high concentration ratio imply?

A high concentration ratio, often above 60%, suggests that a small number of firms exert significant control over the industry. This can indicate reduced competition and potential antitrust concerns.

How can businesses use concentration ratios in strategic planning?

Businesses can use concentration ratios to assess the competitiveness of the industry they operate in. A high concentration ratio might signal stability but also the need to monitor potential regulatory changes, while a low ratio could present growth opportunities.

Are there limitations to using concentration ratios?

Yes, concentration ratios have limitations. They provide a snapshot but may not account for dynamic market changes, innovation, or other factors affecting competition. It’s advisable to complement concentration ratio analysis with other market research tools.

What is the significance of the Herfindahl-Herschman Index (HHI) as an alternative measure?

The HHI offers an alternative approach to measuring market concentration. It squares the market shares of each firm and sums them, providing a different perspective on concentration. It can be valuable when used alongside concentration ratios for a more comprehensive analysis of market structure.

Key takeaways

  • The concentration ratio measures the dominance of a few large firms in an industry.
  • A high concentration ratio indicates reduced competition, while a low ratio suggests a competitive market.
  • CR4, CR8, CR3, and CR5 are common variants of the concentration ratio.
  • The Herfindahl-Herschman Index (HHI) offers an alternative measure of market concentration.
  • Consider the pros and cons of using concentration ratios for industry analysis.
View article sources
  1. Concentration Ratios – Economics helps
  2. Concentration Ratio & Other Industry Data – Econ 332 – University of St. Thomas
  3. Does The Choice Of Concentration Ratio Really Matter? – Federal Trade Commission