HSR Premerger Notification
The federal antitrust premerger notification regime under the Hart-Scott-Rodino Act (15 U.S.C. § 18a). Parties to certain mergers and acquisitions must notify the FTC and DOJ Antitrust Division and observe a waiting period, generally 30 days, before closing. The 2026 "size of transaction" threshold is $133.9 million (effective February 17, 2026), with a "size of person" test for transactions under $535.5 million. Failure to file properly carries civil penalties up to $53,088 per day.
HSR premerger notification is the federal antitrust regime requiring parties to certain mergers and acquisitions to notify the Federal Trade Commission (FTC) and the Department of Justice Antitrust Division and observe a waiting period before consummating the transaction. Codified in the Hart-Scott-Rodino Antitrust Improvements Act of 1976, the regime gives the antitrust agencies an opportunity to review transactions for potential anticompetitive effects before closing. Thresholds adjust annually based on changes in gross national product, and fee amounts adjust based on changes in the Consumer Price Index; 2026 thresholds took effect February 17, 2026.
The 2026 jurisdictional thresholds
Effective February 17, 2026, the HSR thresholds are: (1) Size of Transaction: $133.9 million (up from $126.4 million in 2025). Transactions below this threshold are not reportable. (2) Size of Person: applies to transactions valued between $133.9 million and $535.5 million; one party must have annual net sales or total assets of $267.8 million, the other party $26.8 million. (3) All transactions above $535.5 million: reportable regardless of party size. The thresholds are adjusted annually based on changes in gross national product.
The 30-day waiting period
HSR-reportable transactions trigger an initial waiting period, 30 calendar days in most cases and 15 for cash tender offers and bankruptcy section 363 sales, during which the parties may not close. The agencies use the period for preliminary review. Possible outcomes: (1) expiration of waiting period, most common; transaction can close; (2) early termination, available on request at the agencies' discretion; suspended by the FTC in 2021 and since reinstated, with grants published by the FTC; (3) second request, formal request for additional information triggering an extended waiting period (typically 30 days from substantial compliance with the request). Second requests are time-consuming and expensive and signal substantive antitrust concern.
Filing fees (2026)
The 2026 filing fees, adjusted under the Merger Filing Fee Modernization Act (effective Feb. 17, 2026): six-tier structure based on transaction value, ranging from $35,000 for transactions under $189.6 million to $2,460,000 for transactions of $5.869 billion or more. The fee is paid by the acquiring party at the time of filing.
The revised HSR form (2025)
The FTC and DOJ implemented a substantially revised HSR form effective February 10, 2025, the first major form overhaul in decades. The revised form expanded required disclosures regarding competitive overlaps, vertical relationships, sales data, customer information, and document production. On February 12, 2026, a federal district court vacated the new form, with the court staying its decision for seven days. On March 19, 2026, the Fifth Circuit denied the FTC's motion for a stay pending appeal, and the agencies began accepting filings on the form in use before February 10, 2025.
Common exemptions
Several exemptions apply to otherwise-reportable transactions: (1) acquisitions of certain assets in the ordinary course of business (e.g., inventory, used equipment); (2) acquisitions of certain real property and unproductive assets; (3) investment-only acquisitions of voting securities solely for the purpose of investment, where the acquirer will hold 10% or less of the issuer's outstanding voting securities; (4) certain acquisitions of foreign assets and securities; (5) intracompany transactions; (6) certain bankruptcy reorganizations; (7) certain bank and savings association transactions that require federal banking agency approval, and transactions specifically exempted from the antitrust laws by federal statute. Each exemption has specific technical requirements.
Civil penalties for noncompliance
Failure to file when required, or failure to observe the waiting period before closing, carries civil penalties up to $53,088 per day of noncompliance (as adjusted annually). Penalties accrue for each day a person is in violation of the Act. 15 U.S.C. § 18a(g)(1). The DOJ has actively enforced HSR violations in recent years, including multimillion-dollar settlements for failures to notify successive transactions, technical violations of waiting periods, and failures to update prior filings.
Section 8 of the Clayton Act
HSR practice often involves analysis of Section 8 of the Clayton Act, which prohibits interlocking directorates between competing corporations meeting threshold conditions. The 2026 Section 8 thresholds: $54,402,000 minimum size (capital, surplus, undivided profits) and $5,440,200 minimum competitive sales. The de minimis exceptions exclude small interlocks. Recent DOJ enforcement focus on Section 8 has expanded its practical importance for board appointments by activist investors and private equity sponsors.
For Texas businesses involved in M&A above the threshold range, HSR review affects deal timing and documents. Recurring issues include which thresholds apply at the expected closing date, whether an exemption applies, how the waiting period and any second request fit the timeline, how antitrust risk is allocated (reverse break fees, "hell-or-high-water" covenants, divestiture obligations), and whether board appointments raise Section 8 questions. Transactions below the thresholds do not require an HSR filing, but Section 7 of the Clayton Act still applies, and the agencies can challenge an anticompetitive deal whether or not it was reportable.
Companion article: Business Divorces in Texas