California’s New “Mini-HSR” Law: Key Takeaways for Deal Makers

California has joined the growing number of states adopting their own premerger-notification regimes. On February 10, 2026, Governor Newsom signed SB 25, the California Uniform Antitrust Premerger Notification Act, requiring certain parties making federal Hart-Scott-Rodino (HSR) filings to submit a copy of that filing to the California Attorney General.[1] The law applies to premerger notifications filed on or after January 1, 2027.[2]

For dealmakers, the significance is practical. California’s new law does not replace HSR and does not create a separate California waiting period or state clearance requirement. But it does add another filing obligation for certain HSR-reportable transactions, gives California earlier visibility into qualifying deals, and creates a fresh issue that both buyers and sellers should address early in transaction planning.

What Does the New Law Require?

SB 25 requires a person filing under the federal HSR Act to submit an electronic copy of the HSR filing to the California Attorney General within one business day after the federal filing if either of two statutory triggers is met. The first trigger is met if the filing person has its principal place of business in California.[3] The second trigger is met if the filing person, or a controlled entity, has California annual net sales of the goods or services involved in the transaction equal to at least 20% of the HSR filing threshold.[4]

The documents required to be filed depend on which trigger is met. If the filing obligation is based on the filer’s principal place of business in California, the filer must provide both the HSR form and the additional documentary material. If the filing obligation is based only on the California sales test, the filer initially submits the HSR form and then provides the additional documentary material only if the Attorney General requests it, in which case the documents must be submitted within seven business days. The statute also authorizes filing fees and civil penalties, including up to $25,000 per day after notice and a three-business-day cure period.[5]

Which Deals are Covered?

SB 25 does not apply to every merger or acquisition. It applies only where a party is already required to file under the federal HSR Act. For 2026, the FTC announced that the adjusted federal size-of-transaction threshold is $133.9 million, effective February 17, 2026. Because California’s sales trigger is pegged to 20% of the HSR filing threshold, the current California benchmark is roughly $26.8 million in annual California net sales of the goods or services involved in the transaction, although that figure will change as the HSR thresholds are adjusted.[6]

In practical terms, the law is most relevant where a transaction is already large enough to trigger HSR and one or both filing parties has a meaningful California nexus. That nexus may be based on headquarters, California operations, or California sales tied to the relevant goods or services. Because the statute applies to the filing “person,” the analysis should be made carefully for each of the filing parties in a transaction.

Why Both M&A Buyers and Sellers Should Care

For buyers, SB 25 is another execution and diligence issue. It should now be part of the early antitrust and closing analysis for transactions where HSR may be required and there is a California nexus. Buyers will want to understand whether the law applies, whether California document production may be required, and whether the transaction could attract additional state-level attention.

For sellers, the law can be just as important. Sellers planning on negotiating a sale may want to identify early whether the company’s California footprint could make SB 25 relevant to any likely bidders or to the seller itself. Evaluating the applicability of SB 25 early on in the process would help inform process planning, diligence preparation, document management, and discussions around timing and regulatory obligations. Sellers also have a strong interest in avoiding preventable timing friction late in the process, especially when HSR compliance and filings are already on the path to closing.

In short, SB 25 is not just a buyer-side filing issue. It is also an issue during the sale process for companies seeking to position themselves for a smooth transaction.

How Should Parties Build SB 25 into Deal Planning?

The right time to analyze California’s new law is not when the HSR form is nearly complete. Getting ahead of the filing requirements is important – the parties should consider their California obligations early on when building the transaction timetable and identifying regulatory workstreams.

For buyers, that means assessing early on whether the buyer or target has a California principal place of business or sufficient California sales in the relevant goods or services to trigger the filing. For sellers, that means understanding whether the company’s California profile is likely to matter in a future HSR-reportable transaction and being prepared to respond adeptly if a buyer or its counsel raises the issue. For both sides, early analysis can improve coordination around filing timing, document preparation, and allocation of regulatory responsibilities.

A Note for Advertising and Creative-Services Transactions

The law may be particularly relevant in service-heavy sectors such as advertising, marketing, digital media, and related creative-services businesses. One reason is that the California sales test refers to California annual net sales of the “goods or services involved in the transaction” – understanding what falls under this definition may be more of a challenge to analyze. The law’s language is easier to apply in a business selling discrete products than in a services business with multiple offerings, bundled work, retainer relationships, media buying, creative production, strategy, and platform or subscription revenue.

The potential ambiguity of applicability matters for both sides of a deal. Buyers evaluating an agency platform or creative-services business may need to understand how California revenue maps onto the service lines implicated by the transaction. Sellers in those sectors may likewise benefit from understanding in advance how their California client base or service mix could affect the regulatory analysis in a sale process.

Why the Law May Matter for Food, Beverage, and Wine Deals

The new law is relevant to transactions in the food, beverage, and wine sectors, where California often plays an outsized commercial role. For branded products businesses, the California sales analysis may be more straightforward than in some services sectors because the relevant products involved in the transaction may map more directly onto product sales by state.

That can matter for both buyers and sellers. A buyer evaluating a beverage brand, winery, food manufacturer, or distribution business may want to test California revenue early in diligence. A seller in those sectors should also understand before going to market whether California product sales or operations could make SB 25 part of the transaction landscape. Even where one side of the deal is headquartered elsewhere, California may still be important because of production, brand identity, distribution, or consumer demand.

How California Compares with HSR

HSR remains the primary federal merger-notification regime. California’s law does not replace HSR, and it does not create a separate California approval requirement. Instead, SB 25 is derivative of HSR: if there is no HSR filing, there is no California filing under this statute.

California’s law is also generally described as “non-suspensory,” meaning that it does not independently impose a separate California waiting period before closing. But that does not make it insignificant. It still gives the California Attorney General earlier notice of certain transactions and adds another compliance step that parties must address alongside HSR.

How California Fits into the Broader State-Law Trend

California is the third state, after Washington and Colorado, to adopt a mini-HSR law modeled on the Uniform Antitrust Premerger Notification Act. That broader trend is important because it suggests that merger-control compliance may increasingly require a state-by-state lens, not just a federal one.

For active buyers, that may mean more multijurisdictional filing analysis. For potential sellers, it means that regulatory preparedness has become part of transaction readiness. In either case, California’s adoption of SB 25 is a reminder that state-level merger oversight continues to expand.

What Should Companies Do Now?

Companies that are likely to be involved in HSR-reportable transactions should begin treating California nexus as an early merger-planning issue. Buyers should consider whether the target or the buyer itself may trigger the California filing, while sellers should consider whether their California footprint may affect how a future transaction is structured, timed, and diligenced. Both sides should be prepared to coordinate California filing obligations with the federal HSR process.

As state-level merger-control regimes continue to expand, early planning can help parties avoid unnecessary delay, reduce last-minute filing issues, and better allocate regulatory risk in transaction documents. For both buyers and sellers, the most effective approach is to evaluate these issues early – before the HSR filing is underway and before timing assumptions are baked into the deal process.

California’s new law may not create a separate state waiting period, but it does create a new compliance obligation for certain HSR-reportable deals. For both companies pursuing acquisitions and preparing for a sale, that means state-level merger-control analysis is becoming a more important part of transaction planning. Thoughtful counsel can help parties identify these issues early, integrate them into the deal timeline, and manage the regulatory process with greater predictability and ease.

If your company needs assistance, Coblentz’s Corporate attorneys can help. Please reach out to Peter Wang at pwang@coblentzlaw.com or Hunter Moss at hmoss@coblentzlaw.com for further information or assistance.

[1] Governor Newsom Signs Legislation 2.10.26, https://www.gov.ca.gov/2026/02/10/governor-newsom-signs-legislation-2-10-26/.

[2] SB 25, Uniform Antitrust Pre-Merger Notification Act, Section 16787.

[3] Id. at Section 16782(a)(1).

[4] Id. at Section 16782(a)(2).

[5] Id. at Section 16785.

[6] Federal Trade Commission, Current Thresholds, https://www.ftc.gov/enforcement/premerger-notification-program/current-thresholds.