Estimated Profit: Golden State Is the Latest to Enact Premerger Filing Requirements

In February 2026, California became the third state (after Colorado and Washington) to pass a version of the Uniform Antitrust Premerger Notification Act (UAPNA). Effective on January 1, 2027, the new law gives the California Attorney General’s (AG’s) Office quick access to copies of parties’ submissions under the Hart-Scott-Rodino Act (HSR) to the Federal Trade Commission and the U.S. Department of Justice, Antitrust Division.

Under the , companies or persons must file a copy of their HSR Act filing forms with the California AG within one business day of their federal filing, if they have a principal place of business in California or net sales of goods and services in California of 20 percent of the HSR threshold (so currently $26.8 million).

California-based filers must also submit to the AG’s Office all other HSR documents—like Item 4(c) and (d) studies and reports—provided to the FTC and Antitrust Division, while parties filing under the size-of-the-transaction test may be requested by the AG’s Office to submit additional documentary materials within seven days.

Analysis: Active State Antitrust Enforcers Get Information Sooner

At a time when state AGs have begun to enforce antitrust laws more aggressively with regard to transactions—such as in the separate state court challenges in Colorado and Washington to the proposed Kroger-Albertsons supermarket merger—the California UAPNA adds an additional administrative layer on some transactions and perhaps additional investigatory coordination with the largest state AG antitrust enforcer in the country. The law will allow the AG’s Office to avoid seeking subpoenas of HSR filings and documents when starting an investigation into a transaction already filed with federal antitrust enforcers.

But the California UAPNA has no “waiting period” or requirement of approval before a transaction can be consummated. Nor does the new law change the legal standard for evaluating transactions or expand the premerger notification document requirements beyond what is required by the HSR Act. 

Further, the UAPNA protects the confidentiality of any HSR forms or documentary materials, although those submissions can be shared with AGs in states with similar premerger notification laws. At present, those are only Washington and Colorado, but Hawaii, West Virginia, New York, and Washington, D.C., are also considering “mini-HSR” laws.