Antitrust Merger Screener & HHI Analyzer

DOJ / FTC 2023 Guidelines

Evaluate market concentration thresholds, calculate pre- and post-merger Herfindahl-Hirschman Index (HHI), and stress-test structural divestiture remedies for antitrust clearance under DOJ/FTC Horizontal Merger Guidelines and State AG enforcement standards.

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Antitrust Screening & Regulatory Clearance

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Presumed Anticompetitive (DOJ/FTC 2023)

Post-merger HHI exceeds 1,800 points with an increase (ΔHHI) over 100 points, triggering a legal presumption of substantial lessening of competition under 2023 Guidelines.

Pre-Merger HHI 1,624 Moderately Concentrated
Post-Merger HHI 2,234 High Concentration
Delta HHI (Δ) +610 > 100 pt threshold
Combined Entity Market Share 31.5% Exceeds 30% Clayton Act Sec 7 threshold
Estimated GUPPI (Unilateral Effect) 9.8% Elevated upward pricing incentive
Pro Forma Market Distribution Total: 100.0%

2023 DOJ/FTC Guidelines Presumed Anticompetitive

Threshold: Post-merger HHI > 1,800 AND ΔHHI > 100, OR combined market share > 30%.

2010 Traditional Guidelines Likely Scrutiny

Threshold: Highly concentrated if Post-HHI > 2,500; presumption if ΔHHI > 200.
6 Market Participants • Ready for Regulatory Review

Antitrust Legal Framework & State AG Powers

Under Section 7 of the Clayton Act (15 U.S.C. § 18), mergers that may "substantially lessen competition, or tend to create a monopoly" are unlawful. State Attorneys General hold parens patriae authority under Section 4C to seek injunctions and consumer restitution independently from federal agencies.

  • DOJ / FTC 2023 Guidelines: Lowered presumption triggers to a post-merger HHI of 1,800 + ΔHHI of 100, or a standalone merged share exceeding 30%.
  • State AG Settlements: Often mandate structural remedies (e.g., carving out broadcast licenses, production hubs, or catalog licensing) to preserve regional choice and wage competition.

Economic Indices: HHI & GUPPI

The Herfindahl-Hirschman Index (HHI) sums the squares of individual firm market shares:

HHI = ∑ (s_i)²   |   ΔHHI = 2 × s_acquirer × s_target

The Gross Upward Pricing Pressure Index (GUPPI) estimates the post-merger incentive for the acquirer to raise prices unilaterally without relying on market definition:

GUPPI = Diversion Ratio × (P_target / P_acquirer) × Gross Margin

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