Antitrust Merger Scrutiny & HHI Analyzer
Model market concentration shifts, Herfindahl-Hirschman Index (HHI) deltas, structural divestiture carve-outs, and State Attorney General legal challenges under official antitrust merger standards.
Regulatory Impact Dossier
DOJ / FTC 2023 Merger Guidelines (§ 2.1 Structural Presumption)Market Share Concentration (Pre- vs. Post-Merger)
State AG Coalition Exposure (Rob Bonta Test)
Active coalition of 12 State Attorneys General (led by CA AG Rob Bonta) possess independent enforcement standing under Clayton Act § 16. Even if federal authorities settle, states frequently refuse consent decrees when local economic impacts, movie theater exhibition windows, and studio job cuts threaten consumer welfare.
Labor & Talent Monopsony Index
High risk of buyer-side monopsony power. A consolidated entity reduces bidding competition for screenplays, IP acquisition, and guild compensation (WGA/SAG-AFTRA/DGA). Under Guideline 10, mergers that substantially lessen competition for workers are evaluated as independent statutory violations regardless of consumer pricing.
Understanding Antitrust Merger Review
Under Section 7 of the Clayton Act (15 U.S.C. § 18), transactions are unlawful if their effect "may be substantially to lessen competition, or to tend to create a monopoly." Both federal enforcers (DOJ Antitrust Division & FTC) and State Attorneys General exercise jurisdiction to seek preliminary injunctions in federal district court.
Why State Attorneys General Matter
As demonstrated in major entertainment, healthcare, and telecommunications mergers (e.g., California AG Rob Bonta leading multi-state coalitions against studio consolidations), states have distinct statutory authority under Section 16 of the Clayton Act. Even when federal regulators contemplate behavioral consent decrees or divestiture carve-outs, state AGs can reject settlements and litigate independently to block transactions that harm local labor, consumer choice, or regional production infrastructure.
Key Regulatory Thresholds
The 2023 FTC / DOJ Merger Guidelines
In December 2023, the FTC and DOJ restored the historical structural presumption: any merger resulting in a post-merger HHI greater than 1,800 with an increase in HHI (ΔHHI) greater than 100 points is presumed to substantially lessen competition. Additionally, a merger creating a firm with over 30% market share with an HHI increase over 100 points triggers the structural presumption.
The Herfindahl-Hirschman Index (HHI) Formula
HHI is calculated by summing the squares of the individual market shares of all market participants:
HHI = s₁² + s₂² + ... + sₙ²
When Firm A ($s_A$) and Firm B ($s_B$) combine, the increase in concentration is:
ΔHHI = 2 × s_A × s_B (less any structural divestiture remedy).
Divestiture Remedies & "Fix-It-First" Settlements
Merging parties frequently offer asset divestitures (such as selling cable networks, catalog libraries, or studio lots) to reduce market overlap. However, under current antitrust enforcement policy, behavioral conditions are disfavored, and structural divestitures must replace competitive intensity completely to overcome the presumption of illegality.