State premerger notification requirements take effect this summer

Washington and Colorado require submission of HSR filings to state attorneys general

Parties to acquisitions of voting shares, assets, and/or controlling interests in non-corporate entities must submit premerger filings under the HSR Act to the Federal Trade Commission (FTC) and Antitrust Division of the Department of Justice (DOJ) and observe a waiting period before closing if their transaction satisfies applicable HSR threshold tests and does not qualify for an HSR exemption.  During the waiting period, the federal antitrust agencies decide whether to allow the parties to close or whether to extend the initial waiting period by opening an investigation of the reported transaction.

In July 2024, the Uniform Law Commission (ULC) approved the Uniform Antitrust Premerger Notification Act (UAPNA), a model premerger notification law that requires parties submitting HSR filings to the federal antitrust agencies to contemporaneously submit a copy of their HSR filing with a state AG.  The UAPNA is meant to create “a simple, non-burdensome mechanism for a state AG to receive access to [HSR] filings at the same time as the federal agencies . . .”    While several states currently have laws requiring parties to file premerger notifications for certain healthcare transactions,¹ the UAPNA provides states with a model premerger notification law that is not limited to specific industries.

To date, Washington and Colorado are the only states to have passed premerger filing laws based on the UAPNA.  The Washington law will apply to HSR filings made on or after July 27th, and the Colorado law will apply to HSR filings made on or after August 6th.  The laws are summarized below:

Summary of state premerger filing requirements

Additional states may follow

Additional states are likely to pass premerger notification laws.  Legislation based on the UAPNA is being considered by lawmakers in Hawaii, West Virginia, and the District of Columbia.  Bills based on the UAPNA were also introduced in Nevada and Utah; however, they failed to pass in the most recent legislative session.

On June 2, 2025, the California State Senate advanced a bill based on the UAPNA that would give the California AG discretion to impose an $1,000 filing fee on parties that have their principal place of business in California and an $500 filing fee on parties to transactions that involve goods or services with annual net sales in the state of at least 20 percent of the HSR filing threshold.  The bill was referred to the California Assembly Committee on Appropriations on June 24, 2025.

New York is considering implementing a premerger notification law that would implement filing requirements that extend beyond requirements of the UAPNA.  The 21st Century Antitrust Act—passed by the New York State Senate on June 4, 2025, and pending approval by the State Assembly and the governor—would require “any person conducting business in the state” to concurrently submit HSR filings to the New York AG.  The legislation would also require the New York AG to consider a transaction’s impact on labor markets and establish a process to allow affected workers and their representatives to comment on a proposed transaction.

Implications

Going forward, parties to transactions that must submit an HSR notification will also need to assess whether their transaction triggers a concurrent state submission.  The state revenue thresholds will sometimes require an assessment of sales by state that could be burdensome to conduct.

These filing requirements could result in transactions being reviewed by state AGs who otherwise would not have been aware of the transaction and will allow for earlier information sharing and coordination among federal and state enforcers.  States have long been authorized to investigate mergers using their general subpoena power but have primarily focused their merger enforcement efforts on transactions that raise competitive concerns in state or local markets.  Although the UAPNA does not grant state AGs any new enforcement powers, certain state AGs may implement procedures for reviewing transactions that could lead to a state AG investigating a transaction that disproportionately impacts their state or in instances where a state believes the federal antitrust agencies are not adequately enforcing the federal antitrust laws.⁴

Parties should consult antitrust counsel to determine whether (and how) a proposed transaction will be implicated by state premerger notification statues and to monitor pending legislation.  As additional states adopt general or industry-specific premerger notification requirements, the regulatory landscape will become increasingly complex and challenging.

Authored by Robert Baldwin, John Hamilton, and Jill Ottenberg.