Washington State Enacts First‑Of-Its-Kind Antitrust Pre-Merger Notification Law

May 1, 2025 - In a significant development for antitrust regulation in the United States, Washington state has become the first state to enact a mandatory pre-merger notification regime that mirrors aspects of the federal Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act). Gov. Bob Ferguson recently signed into law the Uniform Antitrust Pre-Merger Notification Act (APNA). While several states (besides Washington) already have healthcare-focused merger review laws in place, the new Washington state law is the first comprehensive state merger notification law. The new law will require certain mergers and acquisitions involving entities with a nexus to Washington to be reported to the state's attorney general before they are consummated. The law's filing requirements will apply to any transaction for which an HSR filing is made on or after the law's effective date of July 27, 2025.