California becomes the third state to adopt the Uniform Antitrust Premerger Notification Act

On February 10, 2026, the California Uniform Antitrust Premerger Notification Act^[1]  was signed into law. California has thus become the third state to adopt the Uniform Antitrust Premerger Notification Act^[2]  (Uniform Act), following Colorado and Washington state. The Uniform Act requires parties filing premerger notification forms under the Hart-Scott-Rodino (HSR) Act with the Federal Trade Commission (FTC) and the Department of Justice (DOJ) to file copies of the forms with the adopting states, if certain jurisdictional requirements are satisfied. The California statute goes into effect on January 1, 2027.

The California statute for the most part adopts the Uniform Act, although there are a few differences as noted below. 

Following the Uniform Act, parties will be required to file their HSR forms with the California attorney general if either of these criteria are satisfied:
 

1. The filer has its principal place of business in California, in which case the HSR form with all documentary attachments must be filed in California.
2. The filer or a person it controls directly or indirectly had annual net sales in California of the goods or services involved in the transaction of at least 20% of the filing threshold, in which case the documentary attachments must also be filed in California within seven business days of request.

At the federal level, both parties to a transaction are required to file HSR forms with the FTC and the DOJ. Under the Uniform Act, including as adopted in California, it will sometimes be the case that only one of the parties satisfies the jurisdictional criteria and is therefore required to file.

The commentary to the Uniform Act looks to the definition of “principal place of business” in the U.S. Supreme Court case of Hertz Corp. v. Friend (2010). That decision associated the term with “the place where a corporation’s officers direct, control, and coordinate the corporation’s activities.”

Effective February 17, 2026, the minimum filing threshold under the HSR Act increased to $133.9 million.^[3] Were the California statute currently in effect, any filing party with net sales in California of goods and services that are of a type involved in the transaction of at least $26.78 million would be required to file its HSR form in California. The HSR filing threshold, which is adjusted annually for inflation based on the gross national product, will likely increase in February 2027, shortly after the California statute goes into effect. 

The limitation to “goods and services involved in the transaction” addresses the case of a parent company with multiple businesses. In assessing whether the in-state sales threshold is crossed, only the businesses of the filer in the particular transaction space need to be considered.

The confidentiality provisions of the California statute largely track the Uniform Act as well. HSR forms filed in California will be exempt from the California Public Records Act, and are otherwise protected from disclosure, subject to the exceptions specified in the Uniform Act. The exceptions include disclosure to an attorney general of another state that has enacted the Uniform Act or its equivalent, with the additional qualification in California that the other state must provide California with an express assurance of confidentiality.

There are a few other differences between the California statute and the Uniform Act, which are summarized below.
 

Conclusion

With California joining the ranks of states that have adopted the Uniform Act, momentum to enact the legislation in other states may grow. Currently, legislation to adopt the Uniform Act has been introduced and is pending in various stages of legislative review in eight additional states.^[4]  An increase in the number of states requiring filing of HSR forms with their attorneys general will not only impose an additional burden (though not a particularly heavy one) on filing parties; it may also increase the likelihood of state interest and potential intervention on antitrust grounds in their deals.^[5]  Developments in the area should therefore be of continuing interest.