What Happened: On April 4, 2025, Washington was the first state to enact the Uniform Antitrust Pre-Merger Notification Act (the Act). The Act requires certain parties with a nexus to the state that make a Hart-Scott-Rodino (HSR) filing to also submit the filing to the state’s attorney general (AG).

The Bottom Line: Adoption of the Act requires direct notice of large transactions to the state AG’s office. The Act also promotes sharing of the information submitted among states that have enacted the Act. As more states pass their own versions of the Act, state involvement in the review of such transactions may increase. Recently, some state AGs have taken a more active role in merger enforcement, including filing their own state court cases separately from the federal antitrust agencies. Certain state AGs have also said they stand ready to fill in gaps, if the federal agencies under President Trump become more lenient on antitrust enforcement.

The Full Story: Washington’s law requires a person making a Hart-Scott-Rodino (HSR) filing that (a) has its principal place of business in the state; (b) has annual net sales of 20 percent of the HSR threshold (adjusted annually, currently $126.4 million) of the goods or services involved in the transaction in the state; or (c) is a healthcare provider conducting business in the state, to also submit the HSR filing and attachments to the state AG’s office. The statute requires notice only, does not require payment of a filing fee and does not include additional enforcement powers or impose a waiting period on the transaction before the parties can close (as under HSR). Nor does the statute require both parties to submit their HSR filings to the state AG, as they must under HSR to the Federal Trade Commission (FTC) and Antitrust Division of the Department of Justice (DOJ). The statute authorizes a civil penalty of $10,000 per day of noncompliance. The statute contains confidentiality measures, including exempting the information submitted from the state FOIA law. In certain merger investigations where state AGs join their federal enforcer counterparts (FTC or DOJ), state AGs will request waivers from the merging parties to allow for the federal enforcers to share material obtained from the merging parties (including their HSR filings) with state AG offices. Washington’s law is mandatory and obviates the need for the Washington AG to obtain a waiver to gain access to the HSR filing of a party with one of the above connections to the state.

Washington is the first state to enact the Uniform Antitrust Pre-Merger Notification Act (the “Act”), which was adopted last year by the Uniform Law Commission. Other states have introduced bills with versions of the Act, including California, Nevada, Utah, Colorado, West Virginia, and the District of Columbia. This is in addition to other state laws requiring pre-merger notification (baby HSRs) for certain transactions in the healthcare industry including in California, Colorado, Connecticut, Hawaii, Illinois, Indiana, Massachusetts, Minnesota, Nevada, New York, New Mexico, Oregon, Rhode Island, Vermont, and Washington.

Conclusion: As state-specific pre-merger notification regimes are adopted, state antitrust review of mergers is expected to become more active. During the first Trump administration, several blue state AGs challenged the T-Mobile/Sprint merger after DOJ and several red state AGs settled the case. Also, during the Trump 1.0, the California AG challenged Valero’s proposed acquisition of petroleum terminals from Plains All American Pipeline and obtained a settlement in the Cedars-Sinai/Huntington Memorial Hospital transaction after the FTC declined to take action. Under the Biden administration, the Washington AG and Colorado AG challenged the Kroger/Albertsons merger separately in state courts and chose not to join the FTC (and nine other state AG co-plaintiffs) in the FTC’s case brought in federal court. The New York AG just recently won its challenge of Intermountain Management’s acquisition of Toggenburg Mountain ski resort, a case brought under New York state antitrust law. AGs from Colorado, California, and Michigan have stated that they are committed to take independent enforcement action if warranted regardless of what their federal enforcer counterparts decide to do. Companies need to stay apprised of new state merger filing requirements, as well as increased state antitrust review of transactions. This is especially true for industries that are localized in nature such as healthcare and retail.