Antitrust Merger Review: HSR Thresholds, Waiting Period, and Penalties

If your transaction is valued at $133.9 million or more in 2026, Hart-Scott-Rodino filing requirements mean you must submit a premerger notification to both the Federal Trade Commission and the Department of Justice Antitrust Division, pay a graduated filing fee, and wait at least 30 days before closing. Both sides of the deal file separately, and neither can integrate operations during the waiting period. What follows is what triggers a filing, what the form now demands after the February 2025 overhaul, what it costs, and what happens after you submit.

Which Deals Have to Be Filed

The trigger is the size of the transaction. For 2026, any deal valued at $133.9 million or more may require a filing. At $535.5 million or more, both parties must file regardless of their individual size. Between $133.9 million and $535.5 million, a second test applies: one party must have at least $267.8 million in total assets or annual net sales while the other has at least $26.8 million.¹ These thresholds adjust annually based on changes in gross national product.²

Not every deal above those dollar figures triggers a filing. Federal regulations exempt acquisitions of new facilities, unproductive real property that generated less than $5 million in revenue over the preceding three years, and purchases of goods or current supplies in the ordinary course of business, as opposed to buying an entire operating unit.³ The key distinction is between routine commercial purchases and acquisitions that give you a meaningful stake in a competitor or adjacent business.

Both the FTC and DOJ receive every filing, though only one agency ends up investigating any given deal. Which one does not change what you submit.

What Goes Into the Filing

The HSR notification form was substantially rewritten effective February 10, 2025. For the first time, the FTC created separate forms for acquiring and acquired persons, each with its own instructions.⁴ Both sides identify their ultimate parent entity and provide annual reports or audited financial statements.⁵

Revenue data must be broken out by six-digit NAICS industry codes so regulators can see where the two companies’ product lines overlap.⁵ Beyond the numbers, the 2025 overhaul added several narrative and disclosure requirements. Filers now must:

Describe overlapping products and services in narrative form.
Identify their top ten customers for each overlap product.
Report geographic information for locations where both parties compete.
Disclose minority interest holders in certain entities.
Identify officers or directors who serve on the boards of companies in the same industry as the target.⁴

Each filer also provides a brief written description of the strategic rationale for the transaction. Regulators read this carefully. A board presentation explaining that the deal will “eliminate our biggest competitor” tells a different story than one describing supply-chain efficiencies.

The Document Production

The most scrutinized part of the filing is the documents. Item 4(c) requires all internal studies, analyses, and presentations prepared for officers or directors that evaluate market shares, competition, or growth potential related to the deal. Items 4(d)(i) through 4(d)(iii) capture confidential information memoranda, third-party advisor reports, and synergy analyses.⁵

The revised form also captures documents prepared for or by the “supervisory deal team lead,” meaning the person with primary responsibility for evaluating the strategic merits of the deal, even if that person is not a director or officer.⁴ Draft documents shared with even a single board member must be submitted.

Filing Fees

The acquiring person pays a graduated filing fee based on total transaction value. The 2026 tiers are:⁶

Less than $189.6 million: $35,000
$189.6 million to under $586.9 million: $110,000
$586.9 million to under $1.174 billion: $275,000
$1.174 billion to under $2.347 billion: $440,000
$2.347 billion to under $5.869 billion: $875,000
$5.869 billion or more: $2,460,000

Payment goes by electronic wire transfer to the U.S. Treasury through the Federal Reserve Bank of New York. The FTC discourages check payments but will accept certified or cashier’s checks if a wire cannot be arranged.⁶ Both parties must file before the review clock starts, so timing the two submissions together matters.

The 30-Day Waiting Period

Once both completed notifications are on file with the FTC and DOJ, a 30-day waiting period begins. For cash tender offers and bankruptcy acquisitions, it is 15 days.⁷ You cannot close during this window. If the agencies take no action by the time the period expires, you’re free to close.

The statute allows the agencies to grant early termination when they conclude the deal is unlikely to harm competition, but early termination has not been routinely available in recent years. Plan around the full 30 days.

Withdrawing and Refiling

If timing slips, the acquiring person can withdraw and refile within two business days without paying a new fee, but only if the withdrawal happens before the waiting period expires, before early termination is granted, and before the agency issues a second request.⁸ The option is available only once, and only if the proposed deal has not changed in any material way. You must notify both the FTC Premerger Notification Office and the DOJ Premerger Unit by email, specifying the withdrawal date and your intended refile date.

Parties commonly pull and refile when they learn informally that the reviewing agency has concerns. Restarting the clock buys another window to negotiate with staff, submit white papers, or propose remedies before a second request lands.

Second Requests

If the reviewing agency’s preliminary analysis raises competitive concerns during the initial waiting period, it can issue a Request for Additional Information and Documentary Material, commonly called a second request.⁹ That stops the clock entirely. You cannot close until you have substantially complied with the request and an additional 30-day period has run (10 days for cash tender offers and bankruptcy sales).⁷

The scope of a second request is enormous, typically covering transaction data, pricing records, cost information, customer communications, and strategic planning documents from a broad set of employees, along with executive depositions. In the third quarter of 2025, investigations involving second requests averaged roughly 13 months from start to resolution; deals that ultimately cleared without enforcement action averaged nearly 15 months.

Parties can petition a designated senior official at the FTC or DOJ, one not directly responsible for the enforcement recommendation, to determine whether the second request is unreasonably burdensome, duplicative, or already substantially satisfied.⁹ These appeals are rare in practice.

What You Cannot Do During the Wait

Buyer and seller must continue operating as independent competitors until the deal legally closes. Jumping ahead on integration violates the HSR Act. Regulators call it “gun jumping,” and it covers two categories: prematurely transferring control of the target business, and sharing competitively sensitive information beyond what due diligence needs.

Prohibited conduct includes the buyer directing the target’s pricing, output, or customer relationships; shutting down or redirecting the target’s operations; and sharing current or forward-looking data about customers, costs, or marketing strategy. In January 2025, the FTC imposed a record $5.6 million civil penalty on three oil companies after finding that the acquiring parties had ordered a halt to the target’s planned drilling activities and coordinated on customer pricing during the 94-day waiting period.¹⁰

The line between legitimate pre-closing planning and illegal coordination is narrower than many dealmakers expect. Merger agreements themselves can create problems if they give the buyer approval rights over ordinary-course business decisions, or allow the buyer to control the target’s inventory at signing. The safest approach: no operational decisions flow between the parties until the deal legally closes.

Penalties for Failing to File or Closing Too Early

Closing a deal without filing the required notification, or closing before the waiting period expires, exposes both parties to substantial civil penalties. The maximum is adjusted annually for inflation and currently exceeds $50,000 per day of violation.

If you discover you have consummated a reportable transaction without filing, the FTC expects you to contact the Premerger Notification Office immediately and submit a corrective filing along with a detailed explanation letter signed by a company official.¹¹ A separate filing and filing fee are required for each violation. Corrective filings are processed like standard filings, but the FTC will not grant early termination, and the agency investigates every late filing to decide whether to seek civil penalties. A deal that closes even a few weeks early without proper clearance can generate penalties in the hundreds of thousands of dollars.

Filing Is Not the Whole Review

Clearing the HSR process only means you have satisfied the premerger notification statute. The substantive antitrust question, whether the deal may substantially lessen competition under Section 7 of the Clayton Act, is what the agencies actually investigate during the waiting period and, if issued, the second request.¹² A deal that clears federal review can still face challenge from state attorneys general, who have independent authority under both federal and state antitrust laws and who sometimes coordinate multistate challenges through the National Association of Attorneys General. HSR filing is the entry point to that review, not the end of it.

1
Federal Trade Commission. New HSR Thresholds and Filing Fees for 2026
2
Federal Trade Commission. Hart-Scott-Rodino Antitrust Improvements Act of 1976
3
eCFR. 16 CFR Part 802 – Exemption Rules
4
Federal Trade Commission. 2025 HSR Form Updates – What Filers Need to Know
5
Federal Trade Commission. HSR Form Instructions
6
Federal Trade Commission. Filing Fee Information
7
Federal Trade Commission. Premerger Notification and the Merger Review Process
8
Federal Trade Commission. Tips on Withdrawing and Refiling an HSR Premerger Notification Filing
9
Office of the Law Revision Counsel. 15 USC 18a – Premerger Notification and Waiting Period
10
Federal Trade Commission. Oil Companies Pay Record FTC Gun-Jumping Fine for Antitrust Law Violation
11
Federal Trade Commission. Procedures for Submitting Post-Consummation Filings
12
Federal Trade Commission. Guide to Antitrust Laws