Last Week in Antitrust Litigation (#039)

Week of December 8, 2025

Top Takeaways

1. Merger Scrutiny Expands Beyond Government Enforcement: The DOJ and Texas AG moved to block Constellation’s $26.6B Calpine deal—showing that federal and state regulators are continuing to press merger challenges.

2. Courts Tighten Collusion Pleading Standards: The dismissal of the Manufactured Home Lot Rents case underscores that data sharing and parallel conduct, without specific “plus factors,” are insufficient to infer conspiracy.

3. Remedies and Settlements Shape Modern Enforcement: From UnitedHealth–Amedisys divestitures to major labor and food-industry settlements, courts continue to favor structural and compliance-based solutions delivering tangible market relief.

New Cases Filed

United States v. Constellation Energy Corp. (D.D.C. Dec. 5, 2025): The Department of Justice and the Texas Attorney General sued to block Constellation Energy’s proposed $26.6 billion acquisition of Calpine Corporation, alleging it would substantially lessen competition in violation of Section 7 of the Clayton Act. The complaint asserts the merger would create the nation’s largest wholesale power generator, giving Constellation market power to raise wholesale prices in Texas’s ERCOT grid and the PJM Coastal Mid-Atlantic region by strategically withholding generation to force higher auction clearing prices. The government contends the merged firm would control over 12% of ERCOT’s total capacity and 20% of its natural-gas capacity, enabling it to profit from higher market-wide prices, potentially increasing consumer costs by more than $100 million annually.

The follow-on cases that were filed are:

• Borough of Roseland v. Fire Apparatus Mfr.'s' Ass'n (D.N.J. Dec. 9, 2025) (alleging defendants conspired to inflate the price of fire trucks like in City of La Crosse v. Oshkosh Corp. (E.D. Wis. Aug. 20, 2025))

• Yell-O-Glow Corp. v. Cal-Maine Foods, Inc. (N.D. Ill. Dec. 11, 2025) (alleging conspiracy to fix prices of conventional fresh shell eggs like in King Kullen Grocery Co. v. Cal-Maine Foods, Inc. (S.D. Ind. Nov. 6, 2025))

• Price v. Cal-Maine Foods, Inc. (W.D. Wis. Dec. 11, 2025) (same)

Dispositive Orders and Verdicts

In re Manufactured Home Lot Rents Antitrust Litig. (N.D. Ill. Dec. 4, 2025): In this nationwide class action alleging that major manufactured-home community operators conspired to fix lot rents through Datacomp’s rent reports, the court granted defendants’ motion to dismiss. The court held that (a) plaintiffs failed to plead direct evidence or plausible circumstantial evidence of an agreement under Section 1 of the Sherman Act because the alleged rent increases and data sharing were consistent with independent, competitive conduct amid rising demand and limited supply; (b) the alleged “plus factors” such as information exchanges, trade association membership, and market concentration did not plausibly indicate collusion; and (c) the separate information-exchange claim failed under the rule-of-reason because plaintiffs did not allege a plausible geographic market.

United Healthcare Servs., Inc. v. Merck & Co., Inc. (D. Minn. Dec. 9, 2025): In this antitrust action alleging that Merck unlawfully restrained competition and caused overcharges for its cholesterol-lowering drugs Zetia and Vytorin, the court denied United HealthCare’s motion for partial judgment on the pleadings. The court held that Rule 12(c) is not a proper vehicle to strike affirmative defenses, explaining that such challenges must be brought under Rule 12(f). Because UHS sought only to eliminate certain of Merck’s affirmative defenses regarding assigned claims—without seeking judgment on any claim—the motion was procedurally improper and was denied in full.

United States v. Unitedhealth Grp. (D. Md. Dec. 9, 2025): In this case alleging that UnitedHealth Group’s proposed acquisition of Amedisys would substantially lessen competition for home health and hospice services in violation of Section 7 of the Clayton Act, the court entered a Final Judgment requiring UnitedHealth and Amedisys to divest numerous home health and hospice branches and related assets to approved buyers, including BrightSpring Health Services and The Pennant Group. The decree mandates transfer of facilities, contracts, personnel, and customer data; imposes firewall, monitoring, and compliance requirements; prohibits reacquisition of divested assets; and assesses a $1.1 million civil penalty against Amedisys for a Hart-Scott-Rodino Act violation. The judgment, approved December 9, 2025, resolves the government’s antitrust claims and will remain in effect for ten years.

Class Actions and Other Settlements

Tobler v. 1248 Holdings, LLC (D. Kan. Dec. 5, 2025): In this case alleging defendants entered into unlawful “no-poach” agreements that suppressed employee compensation across the wealth management industry, the court granted final approval of a $25.5 million settlement. The certified settlement class comprises roughly 4,400 affected employees. Finding the agreement fair, reasonable, and adequate under Rule 23(e), the court awarded class counsel one-third of the fund in attorneys’ fees, $396,212 in litigation expenses, and $15,000 service awards to each class representative for taking professional risks in suing their former employer. Two individuals who opted out were excluded from recovery, and the court retained jurisdiction over settlement administration.

Carefirst of Md. v. Johnson & Johnson (E.D. Va. Dec. 5, 2025): In this case alleging Johnson & Johnson unlawfully delayed biosimilar competition for Stelara, the court granted class certification in part for third-party payors who indirectly purchased Stelara as part of a prescription drug benefit. The court found numerosity, typicality, adequacy, ascertainability, and predominance was satisfied for the federal and state antitrust claims. It approved A.B. Data as notice administrator and the proposed notice plan, deferring approval of the claim form.

In re Cattle & Beef Antitrust Litig. (D. Minn. Dec. 10, 2025): The court granted preliminary approval of consumer indirect purchaser settlements with Cargill and Tyson resolving claims of price-fixing and output restrictions in the beef market from 2014 to 2019. The settlements cover consumers in numerous repealer jurisdictions who indirectly purchased specified beef products. Finding the agreements fair, reasonable, and negotiated at arm’s length, the court certified provisional settlement classes, appointed Hagens Berman and Lockridge Grindal Nauen as co-lead counsel, and approved Epiq Class Action & Claims Solutions as notice administrator. The plan of allocation distributes funds based on qualifying beef purchases, allowing claims submitted by mail or online with payment options such as digital transfers or checks, and the court set June 30, 2026, as the claim deadline.

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If you have any antirust questions or would like more information about any of these matters, please contact one of the following authors:

Christian Lorenz Zach Martin  christian@kressinpowers.com zach@kressinpowers.com

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