Washington State First To Enact Broad Premerger Notification Law

Introduction

The state of Washington became the first to enact a broad premerger notification law covering transactions across all industries. The law, S.B. 5122, was enacted on April 4, 2025, and goes into effect July 27, 2025. S.B. 5122,¹ modeled after the Uniform Antitrust Premerger Notification Act, which was drafted and approved by the Uniform Law Commission (ULC) in July 2024, will require covered merging parties to provide copies of their Hart-Scott-Rodino (HSR) merger filings to the Washington State Office of the Attorney General. Multiple other states, including New York and California, are considering adopting their own premerger notification laws.²

Provisions of Washington’s Act

Unlike certain existing state premerger notification laws that require notification for mergers in specific industries, such as California’s Health Care Quality and Affordability Act,³ which requires notification for health care mergers, Washington’s S.B. 5122 covers eligible mergers across all industries. S.B. 5122 requires merging parties that submit a federal HSR filing after the act’s effective date of July 27, 2025 to contemporaneously submit a copy of the HSR form (but not the accompanying materials such as the transaction agreement and business documents) to the Washington State Office of the Attorney General if one of three thresholds are met:

• The party has a principal place of business in the state of Washington
• The party has net sales in the state of Washington of at least 20% of the federal HSR filing threshold (currently $25.3 million, 20% of $126.4 million HSR threshold)
• The party is a health care provider or provider organization as defined in the Revised Code of Washington 19.390.020⁴

However, companies with a principle place of business in Washington are required to submit the attachments to the HSR form as well,⁵ and the Washington Attorney General has the power to require any person that has submitted only the HSR form under the act to also provide the attachments within seven days of the Attorney General’s request.⁶

Unlike the HSR Act, S.B. 5122 prohibits charging parties a filing fee.⁷ Nor does S.B. 5122 include a mandatory waiting period after filing before closing the merger. The requirement that the Washington filing be made contemporaneously with the federal filing means that the Washington State Office of the Attorney General can review during the HSR 30-day waiting period (or any lesser time if the FTC grants early termination) before the parties are free to close.

S.B. 5122 preserves the confidentiality provisions of the HSR Act, prohibiting the Washington State Office of the Attorney General from disclosing a party’s HSR form and accompanying materials, as well as prohibiting disclosure of the fact an HSR filing was made or the terms of the merger laid out in the HSR form.⁸ However, S.B. 512 does permit disclosure to the attorneys general of other states that enact similar premerger notification laws, provided those state laws include equivalent confidentiality rules.⁹

Failure of a party required to submit a copy of its HSR filing can subject the party to a civil penalty of up to $10,000 per day.¹⁰

The First but Not Necessarily the Last

Washington is the first state to enact the Uniform Antitrust Premerger Notification Act, but multiple other states are considering legislation that would enact the model law or considering other legislation that would require premerger notification. States considering such bills include California,¹¹ New York,¹² New Jersey,¹³ Minnesota,¹⁴ Pennsylvania,¹⁵ Hawaii,¹⁶ Nevada,¹⁷ Utah,¹⁸ West Virginia,¹⁹ and the District of Columbia.²⁰

Although most of these states have proposed legislation modeled on the Uniform Antitrust Premerger Notification Act, California and New York are considering legislation that is broader.²¹

The California Law Revision Commission recommended drafting a new law to create its own premerger notification rules and to expand the California antitrust laws to allow the state to challenge mergers if there is an “appreciable risk” of harm.²² This “appreciable risk” standard would give California the ability to challenge mergers that do not meet the “may substantially lessen competition or tend to create a monopoly” standard for a violation of Section 7 of the Clayton Act.

The New York bill, requires filing a copy of the HSR with the state for any merging parties “conducting business in the state.”²³ As currently drafted, the bill does not define the phrase “conducting business in the state,” and empowers the New York Office of the Attorney General to define this term and other terms used in the premerger notification section of the bill.²⁴ If enacted with this language, the New York law could potentially be interpreted by the New York Office of the Attorney General to cover transactions where parties have even minimal amounts of sales or business within the state, greatly expanding the law’s jurisdictional reach.²⁵

Conclusion

Merging parties that have their principal place of business in Washington or otherwise conduct a substantial amount of business within the state must now consider whether they must submit a copy of any HSR filing to the state of Washington.

It is too soon to say if Washington’s adoption of a premerger notification law will be a one-off occurrence, or if the state is the vanguard in a coming wave of additional states enacting their own premerger notification regimes. Should multiple other states follow suit, merging parties will face a more complex regulatory landscape. They will have to consider not only if a federal filing is required, but also which states must receive a copy of the filing. This complexity could be further compounded if, following the lead of New York and California, multiple states depart from the Uniform Antitrust Premerger Notification Act framework and develop individualized filing thresholds with vagueness around what constitutes sufficient contacts with the state to trigger the filing requirement.

© Arnold & Porter Kaye Scholer LLP 2025 All Rights Reserved. This Advisory is intended to be a general summary of the law and does not constitute legal advice. You should consult with counsel to determine applicable legal requirements in a specific fact situation.