The 2026 HSR Reset: New Thresholds, a Vacated Rule, and a Patchwork of State Filings
The Hart-Scott-Rodino premerger notification regime has rarely been this unsettled. As of February 17, 2026, the initial HSR filing threshold rose to $133.9 million, up from $126.4 million. The change is a modest but operationally important adjustment that will take some small- and middle-market deals out of the filing perimeter. At the same time, the expansive 2024 HSR Rule that dramatically widened the scope of required filings and accompanying documentation was vacated by a federal court in February 2026, then stayed through February 19, 2026, pending potential appeal. Parties now face genuine uncertainty about which filing regime will govern transactions signed in the second half of the year, at the same moment that states are layering new filing obligations on top of the federal system. For clients in deal-making mode, the near-term path requires careful planning on both jurisdictional analysis and document preparation.
What Changed at the Federal Level
The 2026 threshold increase follows the statutory indexing formula tied to changes in gross national product. The revised numbers: $133.9 million initial size-of-transaction threshold, with the size-of-person test continuing to apply to deals valued between $133.9 million and $535.5 million (requiring one party to have at least $267.8 million in sales or assets and the other at least $26.8 million). Filing fees, tiered by deal value, also rose across all brackets. More consequential, however, is the status of the October 2024 HSR Rule. That rule, which took effect February 10, 2025 and significantly expanded narrative disclosures, document production requirements, and information on competitive overlaps, was vacated by the U.S. District Court for the Eastern District of Texas in February 2026. The FTC’s potential appeal, and the stay set to expire February 19, 2026, will determine whether parties revert to the pre-2025 short-form filing or continue under the expanded regime.
State-Level Filing Obligations Emerge
Even as the federal picture shifts, states are expanding their own premerger oversight. California’s Senate Bill 25, signed in 2025, will require parties making federal HSR filings to submit copies to the California Attorney General beginning January 1, 2027, when at least one party has its principal place of business in California. Other states, including Washington and New York, have introduced similar proposals. The practical effect is that deal teams can no longer assume a single federal filing will discharge their premerger obligations. A jurisdictional mapping exercise is now part of every deal plan.
Practical Steps for Deal Teams
The changes require taking some threshold actions, some of which may result in less work in the long run. First, confirm HSR jurisdiction using the new $133.9 million threshold for any deal signing after February 17, 2026. Previously reportable transactions may now fall below the line. Second, plan document productions to accommodate both the expanded 2024-rule format and the pre-2025 format until the appellate status clarifies. Consider collecting the broader universe of materials defensively, then narrow as required. Third, if California law is implicated, begin building state-level filing checklists for California and watch for similar legislation in other jurisdictions where clients have principal offices. Fourth, update deal timelines and representations and warranties in purchase agreements to reflect the possibility of state-level follow-on filings and the continuing 30-day federal waiting period.
The firm is monitoring the court decisions and state legislative activity and will issue updates as the picture clarifies. Clients negotiating LOIs should reach out early so we can align diligence and filing strategy to the current landscape.
