The Department of Justice's Antitrust Division, along with the State of Texas, has initiated a civil merger case (Case Open Date: December 5, 2025) against Constellation Energy Corporation, Calpine Corporation, and CPN CS Holdco Corp. The core of the complaint centers on alleged violations of antitrust laws due to a horizontal merger within the Electric Power Distribution, Fossil Fuel Electric Power Generation, and Natural Gas Distribution sectors. Key documents filed include the Complaint, an Asset Preservation and Hold Separate Stipulation and Order, a Proposed Final Judgment, and a Competitive Impact Statement, all dated in early December 2025.

This action signifies a substantive challenge to the merger, requiring the involved entities to comply with the terms of the Proposed Final Judgment and the Stipulation and Order. Compliance likely involves divesting certain assets or adhering to specific operational restrictions to mitigate anticompetitive effects. Regulated entities in the energy sector, particularly those involved in mergers, should review the details of this case and the filed judgments to understand the DOJ's current enforcement priorities and potential implications for future transactions. Failure to comply with the stipulated orders and final judgment could result in significant legal and financial penalties.