California Adopts Uniform Antitrust Premerger Notification Act

Summary

On February 10, 2026, Governor Newsom signed into law Senate Bill 25 (“SB 25”), enacting the California Uniform Antitrust Premerger Notification Act (the “California APNA” or “Act”),[1] which will require certain parties that submit a premerger notification and report form under the federal Hart-Scott-Rodino Antitrust Improvements Act of 1976 (“HSR”) to also provide an electronic copy of the HSR filing to the California Attorney General within one business day of filing. The Act applies only to HSR premerger notifications filed on or after January 1, 2027.

Like similar legislation in Colorado and Washington that went into effect in 2025, the California APNA is non-suspensory; that is, it does not require filing parties to observe a state-specific waiting period that would prevent closing. But parties that are based in or have sales in California will soon need to obtain state-level sales revenue data as part of the HSR filing process to determine whether a California APNA filing is also required. Failure to make a required filing may result in a civil penalty of up to $25,000 per day of noncompliance.

The California APNA

The HSR Act[2] requires parties to transactions exceeding a certain value threshold to submit a premerger notification and report form (“HSR Form”) to the Federal Trade Commission and the Antitrust Division of the U.S. Department of Justice, which triggers a statutory waiting period (typically, 30 days) during which a reportable transaction may not be consummated.  HSR’s transaction thresholds adjust annually; as of February 17, 2026, the minimum size-of-transaction threshold is $133.9 million.[3]

SB 25 largely follows the model Uniform Antitrust Premerger Notification Act (the “Uniform APNA”), adopted by the Uniform Law Commission in 2024. SB 25 applies to any person or entity making an HSR filing if either (i) the filer “has its principal place of business in” California, or (ii) 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 percent of the [HSR] filing threshold.”[4] If either criteria is met, the person must provide the California Attorney General with a copy of the HSR Form within one business day of the federal filing.[5]

California is the third state to adopt a premerger notification law based on the Uniform APNA, following Washington and Colorado.[6] California’s law departs from the model in certain minor respects, including by authorizing filing fees and adopting a one-business-day submission deadline rather than requiring contemporaneous submission.

Principal place of business

SB 25 does not define “principal place of business,” the first of the two grounds for the law’s applicability. The Uniform APNA commentary suggests that states may look to the federal “nerve center” test used in assessing diversity jurisdiction, under which a corporation’s principal place of business is the place where its officers direct, control and/or coordinate corporate activities.[7] In practice, the “nerve center” will often be a company’s headquarters, but parties should be cautious in assuming that a nominal headquarters address is determinative if key executives and core operations are located elsewhere.

Annual net sales threshold

The second, sales-based test focuses on annual net sales in California of the “goods or services involved in the transaction,” rather than the filer’s total California revenues.[8] This “involved in the transaction” qualifier is undefined, but is likely to require a fact-specific product or service mapping exercise, particularly for diversified companies with multiple lines of business. The test reaches sales by persons (i.e., corporate entities) that the filer controls directly or indirectly.[9] Although SB 25 does not define “control,” the HSR rules contain a well-developed control framework that parties may use as a practical reference point in mapping corporate groups for purposes of this analysis.[10]

Because the threshold for California sales is defined as 20 percent of the federal HSR filing threshold, the dollar amount will adjust annually as the HSR threshold adjusts. Under the 2026 minimum HSR threshold of $133.9 million, SB 25 would apply if a company’s annual net sales in California sales exceed $26.78 million.

Additional documentary material

SB 25 distinguishes between the HSR Form and the “additional documentary material” submitted with the HSR filing.[11] Principal place of business filers must include the additional documentary material with their submission to California.[12] Sales-threshold filers must provide the additional documentary material only upon request, and then within seven business days after receipt of the request from California.[13]

Submission mechanism and fees

The California Attorney General must provide a secure means to receive and store submissions under the Act.[14] SB 25 authorizes the Attorney General to impose a $1,000 fee for principal place of business filings and a $500 fee for sales-threshold filings (including for providing additional documentary material in response to a request).[15]

Applicability and timing

The Act applies only to HSR Forms filed on or after January 1, 2027.[16] SB 25 requires submission to the California Attorney General “within one business day” after the federal HSR filing, rather than contemporaneously as other states’ laws require.[17] Parties should include within their HSR filing process (i) determining whether the Act applies, (ii) transmitting materials through the California Attorney General’s secure submission mechanism, and (iii) ensuring any required fee is paid on time.

Confidentiality and information sharing

SB 25 prohibits public disclosure of the submitted materials, the fact of filing, and the merger described in the HSR form, subject to limited exceptions, and expressly exempts covered materials and related information from disclosure under the California Public Records Act.[18] Subject to a protective order, the Attorney General may disclose materials in an administrative proceeding or judicial action if the proposed merger is relevant to that proceeding or action.[19] The Act permits information sharing with the federal antitrust agencies and with the attorneys general of other states that have enacted the Uniform APNA (or a substantively equivalent act), subject to confidentiality assurances and advance notice to the filer before disclosure to another state.[20] Unless otherwise directed by court order or law, the Attorney General must destroy or return submitted materials within 120 days after the later of closing or the conclusion of legal proceedings directly related to the transaction.[21]

Enforcement and penalties

After written notice and a three-business-day period to cure, the California Attorney General “may impose a civil penalty of up to [$25,000] per day of noncompliance on a person that fails to comply with” the Act’s filing obligations, including failures to timely provide requested additional documentary material.[22] While the cure period may mitigate inadvertent errors, the per-day penalty structure underscores the need for a reliable compliance process, particularly given the next-business-day deadline.

Implications

California’s enactment of the California APNA should be viewed in the context of broader efforts to expand California’s antitrust enforcement tools and to increase state-level participation in merger review. As noted in recent reporting, California policymakers have considered a range of antitrust reforms: the California APNA is one of the first enacted measures that affects deal execution mechanics for transactions reportable under the HSR Act.[23] For HSR-reportable transactions with a California nexus, SB 25 gives the California Department of Justice access to the same HSR materials provided to the federal agencies, which may facilitate earlier state engagement and coordination with federal and other state enforcers.Even absent a separate California waiting period, early access can matter where state enforcement priorities or sector-specific concerns prompt parallel inquiries.

Multi-state considerations

With Washington and Colorado already requiring similar submissions,[24] and California now joining, state-by-state jurisdictional analysis may become a more routine component of HSR preparation for many transactions. Indiana has a similar bill pending that, if passed and signed into law, would go into effect in July 2026.[25] Other jurisdictions such as Hawaii, Nevada, Utah, West Virginia, and Washington D.C. have proposed similar legislation.[26] Clients with active M&A teams should consider building a repeatable “state filing” workstream to reduce the risk of missed deadlines and inconsistent submissions.

Key takeaways

In advance of the January 1, 2027 applicability date, clients should consider the following near-term steps.

1. Develop a mechanism to identify sales and services in California by product or service line if California is not the parties’ principal place of business and where the parties have small business lines.

2. Maintain an internal record of what was submitted to federal agencies to ensure the California submission is complete.

3. Monitor California DOJ guidance on submission mechanics (including the secure submission process), and update compliance protocols as implementing details become available.