Does your deal trigger HSR?
The Hart Scott Rodino size of transaction and size of person tests in one quick check, using the 2025 thresholds.
The HSR Act premerger notification thresholds are adjusted annually. In 2025, the size of transaction threshold sits at about $126.4 million and the automatic threshold (above which the size of person test does not apply) sits at about $505.8 million. The size of person test catches deals between the floor and the automatic threshold where one party is large.
The HSR threshold checker runs the math. Input the transaction value, the buyer’s and seller’s annual sales or total assets, and the tool tells you whether notification is likely required.
What the tool is good for
A quick sanity check on a new deal. If the transaction value is well under the floor or well above the automatic threshold, the answer is straightforward. The size of person test is where most of the analysis lives, and the tool handles the threshold comparison cleanly.
A first-pass scope decision. If the answer is "likely required," you know to budget for the new HSR rule’s expanded document production and to start the diligence collection early. If the answer is "likely not required," you can move faster.
What the tool is not good for
A definitive answer. The HSR rules include a long list of exemptions (certain real estate, certain banking, certain foreign issuer thresholds), aggregation rules (multiple acquisitions over time can be combined), and special tests for particular industries. The new substantive notification requirements (deal rationale documents, business plans, customer lists) add cost even when the threshold answer is unchanged.
For any actual transaction, the threshold question is the first conversation with antitrust counsel, not the last. The tool gives you the conversation starter.
Walter Allison is a corporate attorney in Denver. He writes here about M&A, private equity, and venture capital structure.
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