“Mini-HSR Acts” Multiply in the States; Merger Enforcement Developments in Washington, Colorado and More

Parties to transactions should be aware of new requirements for state-level merger reporting – so-called “mini-HSR Acts” – modeled on the Uniform Antitrust Pre-Merger Notification Act (“UAPNA”). Washington and Colorado have enacted UAPNA-based merger control frameworks requiring submission of certain federal HSR Act filings to state enforcers, with new laws in California, New York, and several other states on the horizon. Washington’s new merger control requirement took effect on July 27, 2025, while Colorado’s will take effect on August 6, 2025.

The UAPNA, a model statute developed by the Uniform Law Commission, provides additional state-level notice requirements for transactions that are reportable under the HSR Act. Washington and Colorado have each passed merger control frameworks based on the UAPNA that will require filing parties with sufficient nexus to the state to share their as-submitted HSR filings with each state’s Attorney General. California and other states are developing their own UAPNA-based frameworks, while New York is considering a non-UAPNA merger control regime. Washington’s new law took effect on July 27, 2025, while Colorado’s will take effect August 6, 2025. Other states are actively working towards their own UAPNA-inspired frameworks.

The Uniform Antitrust Pre-Merger Notification Act (“UAPNA”)

The Uniform Antitrust Pre-Merger Notification Act (“UAPNA”) is a model law published in 2024 by the Uniform Law Commission, a non-profit association founded in 1892 and best known for its work on the Uniform Commercial Code (“UCC”).¹ Under the UAPNA, transactions that trigger a filing obligation under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (“HSR Act” and “HSR-reportable” transactions)² also trigger a state-level merger control filing where parties bear a nexus to the state in question.

The UAPNA model law aims to streamline the merger review process for state Attorneys General (“AGs”) by giving them access to HSR filings at the beginning of the federal review process and by facilitating information sharing among the Department of Justice (“DOJ”), Federal Trade Commission (“FTC”), and the state AGs.³ A party required to file under the UAPNA must submit a copy of its HSR filing (the form and documentary attachments) but is not required to compile or draft any additional information for state notification.⁴ A state AG may request additional information. Unlike the HSR regime, which imposes a 30-day waiting period (or in some situations 15 days), the UAPNA does not create a waiting period.

The UAPNA also allows for information sharing between the receiving state AG and their counterparts in other states that have adopted the UAPNA or substantially equivalent laws. The UAPNA allows for sharing of not only the HSR filing form and materials but also any state-level work product related to those filings.⁵

The New Washington and Colorado Merger Review Frameworks

Washington

Washington state’s UAPNA-based merger review framework, SB 5122, took effect on July 27, 2025. It requires parties to an HSR-reportable transaction to share their HSR filing with the Washington Attorney General if the party:

• has a principal place of business in Washington;
• had (or controls an entity that had) annual net sales in Washington of goods or services involved in the transaction of 20 percent or more of the current HSR filing threshold (for 2025, $25.28 million); or
• is a provider or provider organization (this involves health care, as defined by state law) active in Washington state.⁶

Filers must share their as-submitted HSR filing form and materials on the same day they file with the federal government. Although there is no filing fee, filers should take note that penalties of up to $10,000 per day may be issued for failure to file. Filers are not subject to any waiting period requirement, nor is clearance from the Washington Attorney General required prior to closing (although the federal HSR waiting period must expire prior to closing).

Colorado

Colorado’s state-level merger review framework, SB25-126, also modeled on the UAPNA, will go into effect on August 6, 2025. It will require HSR-reportable transaction parties to submit their HSR filing to the Colorado Attorney General if the party:

• has a principal place of business in Colorado; or
• had (or controls an entity that had) annual net sales in Colorado of goods or services involved in the transaction of 20 percent or more of the current HSR filing threshold (for 2025, $25.28 million).

Filers in Colorado must submit their HSR filing form and materials to the Colorado Attorney General on the same date they file HSR with the federal government. As in Washington, there is no associated filing fee, but parties may be fined up to $10,000 per day for noncompliance. There is no statutory waiting period, and clearance from the Colorado Attorney General is not required prior to closing.

For additional information on recent developments in Colorado, including the Colorado State Antitrust Act of 2023 and state-level enforcement actions, please refer to our recent article: Colorado Shifts to Robust State-Level Antitrust Enforcement Regime.

California, New York, and Other State Laws on the Horizon

California

California’s version of the UAPNA, CA SB-25, passed in the California Senate on June 2, 2025, and the bill has moved into the Assembly. If the Assembly passes the bill, it will be sent to the governor for enactment.

The California Law Revision Commission also recently recommended changes to the Cartwright Act, the state’s existing antitrust law, to address merger control and abuse of dominance practices.⁷

For additional information on these and other recent antitrust developments in California, please refer to our recent article: California Poised to Sharpen Antitrust Enforcement with New Penalties.

New York

New York is also considering an amendment to its antitrust law (known as the Donnelly Act), which, like many state antitrust laws, generally follows the Sherman Act. The bill, Assembly Bill A2015, was introduced in January 2025 and is currently in committee in the Assembly. This amendment would implement a merger control framework by requiring any party “conducting business” in the state to submit a copy of its full HSR documentation to the state AG when a transaction is HSR-reportable. This is a significantly looser nexus compared to the UAPNA.

The bill also provides for (i) a single-firm conduct framework under an “abuse of dominance” standard, (ii) a private right of action, and (iii) new avenues for class actions. Actions relating to single-firm conduct would be based on an abuse of dominance standard and would create a rebuttable presumption of market dominance for sellers with 40% or higher market share, or for buyers with 30% or higher market share. The bill also includes language stating that certain actions taken by dominant firms that would raise a “substantial risk” of harm to competition (as determined by the New York Attorney General) would be presumed illegal – the bill includes among these actions non-compete agreements, tying, certain kinds of refusals to deal, and certain kinds of exclusivity agreements. Lawsuits under the bill’s new private right of action also would be based on an abuse of dominance standard and would allow for treble damages and attorney’s fees. The amendment would allow the New York Attorney General to consider each transaction’s effects on the labor market.

This is the third attempt to amend the Donnelly Act since 2021. Previously, legislation containing similar provisions to this latest attempt passed through the Senate before failing in the Assembly at the end of the legislative term.

Other States

The Hawaii, Nevada, Utah, West Virginia, and District of Columbia legislatures are working toward their own enactments of the UAPNA.⁸

¹ Refer to the Uniform Law Commission’s website for the full text of the Act and additional information: https://www.uniformlaws.org/committees/community-home?CommunityKey=6bf5d101-d698-4c72-b7c1-0191302a6a95.

² The current lowest HSR Act filing threshold is for deals valued above $126.4 million. See our summary of HSR Act filing thresholds for 2025: https://www.velaw.com/insights/2025-annual-updates-to-the-united-states-pre-merger-notification-hsr-act-and-interlocking-directorates-thresholds/.

³ UAPNA at p. 2 (official comment).

⁴ Id. at p. 5 (official comment).

⁵ Id. §§ 4(d), 5; id. at p. 8-9 (official comment).

⁶ Various states, including Washington, have adopted industry-specific merger control laws, most often focused on the health care industry. The requirement that certain providers submit their HSR filings to the state AG is not new.

⁷ Cal. Bus. & Prof. Code § 16720.

⁸ Refer to the relevant section of the Uniform Law Commission’s Legislative Report by Act for the latest updates on these bills: https://www.uniformlaws.org/viewdocument/legislative-report-by-act.

This information is provided by Vinson & Elkins LLP for educational and informational purposes only and is not intended, nor should it be construed, as legal advice.