This paper provides a comprehensive overview of the principal measures economists and regulators use to assess market concentration, with particular attention to their application in U.S. agricultural markets. As the FAT framework considers adding an Economic Concentration category, understanding these tools—their strengths, limitations, and regulatory context—is essential to informed category design.

The paper examines four primary measures: the Herfindahl-Hirschman Index (HHI), Concentration Ratios (CR4/CR8), the Lerner Index, and the Gini Coefficient as applied to market share. It then addresses the critical limitations of all existing measures when applied to vertically integrated industries such as U.S. meatpacking, and surveys the current regulatory and legislative landscape.

Key findings suggest that while HHI remains the gold standard for horizontal concentration analysis, no single existing measure adequately captures the compounding effects of vertical integration, geographic market constraints, or the bargaining power asymmetries that define modern agricultural supply chains. A robust FAT Economic Concentration category will likely need to draw on multiple measures and incorporate qualitative assessments of vertical market structure.

1. Introduction

Market concentration—the degree to which a small number of firms control production, processing, or sales within an industry—is one of the foundational concepts in competition economics. High concentration can enable firms to exercise market power: raising prices above competitive levels, suppressing payments to suppliers, reducing output, or deterring entry by potential competitors.

For over a century, economists have developed quantitative tools to measure concentration and its effects. These measures serve multiple purposes: they inform antitrust enforcement decisions, guide merger review, support academic research on market structure and performance, and increasingly, help policymakers and advocacy organizations identify sectors where competitive conditions may be deteriorating.

The U.S. agricultural sector—and meatpacking in particular—has become a focal point for concentration concerns. With four firms controlling more than 80% of U.S. beef processing and the top three pork processors controlling approximately 60% of output, agricultural markets present some of the most extreme examples of industrial concentration in the American economy. Understanding the tools available to measure and assess this concentration is therefore both practically important and timely.

2. The Herfindahl-Hirschman Index (HHI)

2.1 Origins and Formula

The HHI is named after economists Orris C. Herfindahl, who used the measure in his 1950 doctoral dissertation on the U.S. steel industry, and Albert O. Hirschman, who independently developed a related statistic in his 1945 study of international trade patterns.^[1]^[2]

The formula is straightforward: the HHI equals the sum of the squares of each firm’s market share in the relevant market. Expressed mathematically:

HHI = S₁² + S₂² + S₃² + … + Sₙ²

Where S represents each firm’s market share expressed as a whole number percentage. The index ranges from near zero (a huge number of tiny firms) to 10,000 (a single-firm monopoly). A market with 10 equal-sized firms produces an HHI of 1,000; one with 4 equal-sized firms yields 2,500; and one with 2 equal-sized firms produces 5,000.

2.2 Regulatory Thresholds

The HHI is the primary concentration measure used by the U.S. Department of Justice (DOJ) and Federal Trade Commission (FTC) in merger review. The 2023 Merger Guidelines establish the following classification:^[3]

HHI Range	Classification	Merger Scrutiny
Below 1,000	Unconcentrated	Generally no concern
1,000 – 1,800	Moderately Concentrated	Merits further analysis
Above 1,800	Highly Concentrated	Presumed to enhance market power

Table 1: DOJ/FTC HHI Classification Thresholds (2023 Merger Guidelines)

Notably, the 2023 guidelines lowered the “highly concentrated” threshold from the previous standard of 2,500 to 1,800, reflecting a more aggressive posture toward concentration. Additionally, any merger that increases the HHI by more than 100 points in a highly concentrated market is presumed likely to enhance market power.^[4]

2.3 The “Effective Competitors” Interpretation

One intuitive way to interpret the HHI is through its inverse, which yields the number of “effective competitors”—that is, the number of hypothetical equal-sized firms that would produce the same HHI value. An HHI of 2,000 corresponds to 5 effective competitors; 2,500 corresponds to 4; and 3,333 corresponds to 3.^[5]

2.4 Theoretical Foundations

The HHI’s significance extends beyond mere description. Under the Cournot model of oligopolistic competition—where firms compete by choosing output quantities rather than prices—the HHI is directly related to the industry’s average price-cost margin (the Lerner Index, discussed in Section 4). This theoretical linkage means the HHI is not just measuring the number and size of firms; it is functioning as a proxy for the degree to which firms can profitably raise prices above competitive levels.^[6]

2.5 Worked Example: U.S. Pork Processing

Consider a simplified version of the U.S. pork processing market with approximate market shares: Smithfield (25%), JBS USA Pork (20%), Tyson Foods (15%), Seaboard/Triumph (10%), Clemens Food Group (5%), and all remaining firms collectively (25%, distributed across many small producers). The HHI would be calculated as:

25² + 20² + 15² + 10² + 5² + (small firms) ≈ 625 + 400 + 225 + 100 + 25 + ~65 = approximately 1,440

This places the national pork processing market near the “moderately concentrated” threshold. However, as discussed in Section 6, this national figure may significantly understate regional concentration.

2.6 Strengths

The HHI offers several advantages as a concentration measure. Its calculation is simple and requires only market share data. It gives proportionally more weight to larger firms, capturing the outsized influence of dominant players. It has direct theoretical grounding in oligopoly models. It is the legally recognized standard in U.S. and EU merger review, and its inverse provides an intuitive “effective competitors” interpretation.

2.7 Limitations

Despite its wide acceptance, the HHI has significant blind spots. It does not account for barriers to entry—a high-HHI market with low entry barriers may still be competitive. It ignores demand elasticity and therefore cannot predict profitability. It is sensitive to market definition: a national HHI may mask severe regional concentration. It captures only horizontal structure at a single supply chain stage, missing the effects of vertical integration. And it treats all market share as fungible, ignoring product differentiation, geographic segmentation, and buyer-supplier power dynamics.

3. Concentration Ratios (CR4, CR8)

3.1 Definition and Calculation

Concentration ratios are the simplest measures of market structure. The CRₙ is the sum of the market shares of the ‘n’ largest firms in a market. The most commonly used versions are CR4 (top four firms) and CR8 (top eight firms).

For example, if the top four beef packers hold market shares of 30%, 25%, 20%, and 10%, the CR4 is 85%. The USDA has historically tracked CR4 for meat processing, and it is the measure most commonly cited in public policy discussions of agricultural concentration.^[7]

3.2 Historical Trends in U.S. Meatpacking

Sector	CR4 (1980s)	CR4 (2024 est.)
Beef Packing	~36%	~85%
Pork Packing	~34%	~65–70%
Broiler Processing	~35%	~54%

Table 2: Four-Firm Concentration Ratios in U.S. Meat Processing (approximate)

The increase in beef CR4 from roughly 25% in 1971 to over 85% today represents one of the most dramatic consolidation trends in any U.S. industry over the past half century.^[8]

3.3 Strengths and Limitations

The CR4’s primary strength is its intuitive clarity—the statement “four firms control 85% of beef processing” is immediately comprehensible to policymakers, journalists, and the public. However, it suffers a critical flaw: it is blind to the distribution of shares among the top firms. Four firms each holding 20% (CR4 = 80%, HHI = 1,600) represents a very different competitive situation from one firm at 65% and three at 5% (CR4 = 80%, HHI = 4,300). The HHI captures this distinction; the CR4 does not. Additionally, the CR4 completely ignores the competitive fringe—the remaining firms outside the top four—which may or may not exert meaningful competitive pressure.

4. The Lerner Index

4.1 Measuring Power Through Prices

While HHI and CR4 measure market structure, the Lerner Index measures market conduct—specifically, the degree to which firms are able to charge prices above their marginal cost of production. Developed by economist Abba Lerner in 1934, it is calculated as:^[9]

L = (P – MC) / P

Where P is the price charged and MC is the marginal cost of production. A perfectly competitive firm earns zero economic profit, so its Lerner Index is 0. A monopolist facing inelastic demand can charge well above marginal cost, pushing the index toward 1.

4.2 Application to Livestock Markets

Agricultural economists have applied Lerner-style analysis to livestock markets by estimating the “markdown”—the gap between what packers pay producers for cattle or hogs and what they would pay under perfectly competitive conditions. The 2024 USDA report on meatpacking concentration found that packers were able to exercise market power to pay lower prices for cattle than they would have faced with more competitors, even as consolidation also contributed to lower processing costs that benefited consumers.^[10]

4.3 Strengths and Limitations

The Lerner Index’s great strength is that it measures what ultimately matters—the exercise of market power through pricing—rather than relying on structural proxies. However, it is extremely difficult to apply in practice. Marginal cost is notoriously hard to observe, especially in vertically integrated operations where costs are allocated internally across stages. The index also provides a snapshot of current conduct without indicating whether market structure could enable future abuse. For these reasons, the Lerner Index is more commonly used in academic research than in regulatory practice.

5. The Gini Coefficient Applied to Market Structure

5.1 From Income Inequality to Market Inequality

The Gini Coefficient, developed by Italian statistician Corrado Gini in 1912, is best known as a measure of income or wealth inequality. However, it can be applied to any distribution—including the distribution of market share across firms in an industry.^[11]

The Gini ranges from 0 (perfect equality, where all firms have identical market shares) to 1 (perfect inequality, where a single firm holds the entire market). It is constructed from the Lorenz curve, which plots the cumulative percentage of market share held by the bottom x% of firms ranked by size.

5.2 When the Gini Adds Value

The Gini is particularly useful when an industry has many firms but a highly skewed distribution. Consider a market with 100 firms where three hold 70% of output: the HHI might register as moderate (depending on the distribution among the remaining 97 firms), but the Gini would be very high, signaling that the industry’s structure is far from egalitarian. The Gini thus complements the HHI by highlighting inequality of market share even in markets that are not technically “highly concentrated” by HHI standards.

5.3 Limitations

The Gini is less commonly used in antitrust contexts because it lacks the direct theoretical connection to market power that the HHI possesses through the Cournot model. It also does not have established regulatory thresholds, making it harder to apply as a brightline enforcement tool. Its primary value is as an analytical complement to other measures, rather than a standalone indicator.

6. Critical Gaps: What Existing Measures Miss

6.1 Vertical Integration

Perhaps the most significant limitation of all standard concentration measures is their inability to capture vertical integration—the control of multiple stages of a supply chain by a single firm. In U.S. pork, a company like Smithfield Foods controls genetics, feed production, hog farming, slaughter, processing, branding, and distribution. Standard HHI analysis measures concentration at one stage (e.g., processing) without accounting for the compounding effect of control across the entire chain.

The concept of “chickenization”—coined to describe how the poultry industry’s vertical contract model amplifies processor bargaining power far beyond what market share alone would suggest—is increasingly applied to pork as well. Under this model, a contract grower may nominally be an independent business, but in practice the integrator owns the animals, specifies the inputs, dictates the facility design, and determines the payment formula.^[12]

6.2 Geographic Market Definition

National HHI figures can dramatically understate the concentration that individual producers actually experience. A hog farmer in eastern North Carolina may have effectively one buyer (Smithfield) within practical shipping distance. Similarly, a contract grower who has invested hundreds of thousands of dollars in facilities built to one integrator’s specifications faces a de facto monopsony regardless of how many other integrators exist nationally.

6.3 Buyer Power (Monopsony)

Standard concentration measures typically focus on seller-side market power—the ability of firms to raise consumer prices. But in agricultural markets, the more pressing concern is often buyer-side power (monopsony)—the ability of processors to depress prices paid to farmers and ranchers. The HHI does not distinguish between these two dimensions of market power.

6.4 Foreign Ownership

None of the standard economic measures account for the ownership nationality of dominant firms. In U.S. meatpacking, the two largest pork processors (Smithfield, owned by China’s WH Group, and JBS USA, a subsidiary of Brazilian JBS S.A.) are foreign-controlled. This raises distinct concerns about national food security, supply chain resilience, and sovereign economic influence that are entirely separate from concentration per se. A FAT category framework may need to address foreign ownership as a distinct dimension.

7. The Regulatory and Legislative Landscape

7.1 The Packers and Stockyards Act

The primary competition statute for meatpacking remains the Packers and Stockyards Act of 1921 (PSA), enacted after FTC investigations between 1918 and 1920 revealed extensive price-fixing and market manipulation by the era’s dominant meatpackers. The PSA prohibits practices that manipulate or control prices or create monopolies in the livestock and meat industries.^[13]

7.2 Legislative Proposals Using HHI

Senator Josh Hawley’s Strengthening Antitrust Enforcement for Meatpacking Act (S.2818, introduced 2023) would amend the PSA to establish specific HHI-based thresholds: any acquisition that would produce an HHI above 1,800 or increase the HHI by more than 100 points in any relevant market would be automatically prohibited, without requiring proof of actual competitive harm. This represents a significantly more aggressive use of the HHI than current general merger guidelines.^[14]

In March 2026, Senators Welch and Schumer introduced the Family Grocery and Farmer Relief Act, which goes further by seeking structural breakups of the largest meatpacking companies—a remedy that goes beyond the preventive approach of merger screening.

7.3 DOJ Investigation

In November 2025, President Trump directed the DOJ to investigate major meatpacking companies for potential price-fixing and collusion. The DOJ Antitrust Division and USDA subsequently executed a Memorandum of Understanding committing to joint monitoring of competitive conditions in agricultural markets. This represents the most significant federal enforcement action targeting meatpacking concentration in decades, and signals bipartisan recognition that existing market structure may be generating anticompetitive outcomes.

8. Comparative Summary of Measures

Measure	What It Captures	Primary Use	Key Limitation
HHI	Number and size distribution of firms at one supply chain stage	DOJ/FTC merger review; legislative thresholds	Misses vertical integration, geographic markets, barriers to entry
CR4/CR8	Combined share of top firms	Public policy discussion; USDA reporting	Blind to distribution among top firms; ignores competitive fringe
Lerner Index	Price-cost margin as proxy for market power exercise	Academic research; litigation support	Marginal cost is unobservable in practice; snapshot only
Gini Coefficient	Inequality of market share distribution	Academic research; complementary analysis	No regulatory thresholds; no direct link to market power theory

Table 3: Comparative Summary of Economic Concentration Measures

9. Recommendations for the FAT Framework

Based on this review, we offer the following recommendations for the development of a FAT Economic Concentration category:

First, the HHI should serve as the primary quantitative measure, given its regulatory acceptance, theoretical grounding, and established thresholds. However, it should be calculated at both the national and relevant regional/geographic levels, as national figures may dramatically understate the concentration experienced by individual market participants.

Second, the CR4 should be reported alongside HHI for its intuitive communicative value, particularly in public-facing analysis and policy advocacy.

Third, the FAT framework should develop a qualitative Vertical Integration Score that assesses the degree to which dominant firms control multiple supply chain stages. This score would complement the horizontal HHI by capturing the compounding effects of vertical control that standard measures miss.

Fourth, a separate Foreign Ownership dimension should be established within or adjacent to the Economic Concentration category, tracking the nationality of controlling interests for dominant firms in critical industries.

Fifth, any concentration assessment should specify the relevant geographic market explicitly, acknowledging that practical market boundaries for agricultural commodities are constrained by shipping distances, perishability, and the sunk costs of relationship-specific investments.

Finally, the FAT framework should track concentration dynamically over time rather than relying on snapshots, as the trajectory of concentration—whether improving or deteriorating—is as important as the current level.

10. References

Douglas, E. (2024). “Antitrust Abandonment.” Yale Journal on Regulation.

Gini, C. (1912). Variabilità e mutabilità. Bologna: C. Cuppini.

Herfindahl, O.C. (1950). Concentration in the U.S. Steel Industry. Ph.D. dissertation, Columbia University.

Herrine, L. (2024). Article on meatpacking consolidation. North Carolina Law Review.

Hirschman, A.O. (1945). National Power and the Structure of Foreign Trade. University of California Press.

Lerner, A.P. (1934). “The Concept of Monopoly and the Measurement of Monopoly Power.” Review of Economic Studies, 1(3), 157–175.

Macheel, W. (2024). “An Explainer on How Market Concentration Is Measured.” ProMarket, Stigler Center.

Mehra, S.K. (2024). “Chickenization.” South Dakota Law Review.

U.S. Department of Justice & FTC. (2023). Merger Guidelines.

USDA Economic Research Service. (2024). “Concentration and Competition in U.S. Agribusiness.”

USDA Economic Research Service. (2024). “Concentration in the U.S. Meatpacking Industry and How it Affects Competition and Cattle Prices.”

^[1]Herfindahl, O.C. (1950). Concentration in the U.S. Steel Industry. Ph.D. dissertation, Columbia University.

^[2]Hirschman, A.O. (1945). National Power and the Structure of Foreign Trade. University of California Press.

^[3]U.S. Department of Justice & FTC, Merger Guidelines § 2.1 (2023).

^[4]The 2023 Merger Guidelines lowered the “highly concentrated” threshold from 2,500 to 1,800 HHI points.

^[5]Macheel, W. (2024). “An Explainer on How Market Concentration Is Measured.” ProMarket, Stigler Center.

^[7]USDA Economic Research Service, “Concentration and Competition in U.S. Agribusiness,” 2024.

^[8]USDA, “Concentration in the U.S. Meatpacking Industry and How it Affects Competition and Cattle Prices,” 2024.

^[9]Lerner, A.P. (1934). “The Concept of Monopoly and the Measurement of Monopoly Power.” Review of Economic Studies, 1(3), 157–175.

^[11]Gini, C. (1912). Variabilità e mutabilità. Originally applied to income distribution; subsequently adapted for market share analysis.

^[12]Mehra, S.K. (2024). “Chickenization,” South Dakota Law Review. Describes how vertical contracts amplify processor bargaining power.

^[13]Douglas, E. (2024). “Antitrust Abandonment,” Yale Journal on Regulation.

^[14]Senator Hawley’s Strengthening Antitrust Enforcement for Meatpacking Act of 2023 (S.2818) proposed an HHI threshold of 1,800 for meatpacking acquisitions.

Table of Contents

Executive Summary

1. Introduction

2. The Herfindahl-Hirschman Index (HHI)

2.1 Origins and Formula

2.2 Regulatory Thresholds

2.3 The “Effective Competitors” Interpretation

2.4 Theoretical Foundations

2.5 Worked Example: U.S. Pork Processing

2.6 Strengths

2.7 Limitations

3. Concentration Ratios (CR4, CR8)

3.1 Definition and Calculation

3.2 Historical Trends in U.S. Meatpacking

3.3 Strengths and Limitations

4. The Lerner Index

4.1 Measuring Power Through Prices

4.2 Application to Livestock Markets

4.3 Strengths and Limitations

5. The Gini Coefficient Applied to Market Structure

5.1 From Income Inequality to Market Inequality

5.2 When the Gini Adds Value

5.3 Limitations

6. Critical Gaps: What Existing Measures Miss

6.1 Vertical Integration

6.2 Geographic Market Definition

6.3 Buyer Power (Monopsony)

6.4 Foreign Ownership

7. The Regulatory and Legislative Landscape

7.1 The Packers and Stockyards Act

7.2 Legislative Proposals Using HHI

7.3 DOJ Investigation

8. Comparative Summary of Measures

9. Recommendations for the FAT Framework

10. References

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