HSR Act: Pre-Merger Notification Filing Requirements

The Hart-Scott-Rodino Antitrust Improvements Act of 1976 requires parties to qualifying mergers and acquisitions to notify the Federal Trade Commission and the Department of Justice before closing a transaction. The notification process gives federal antitrust authorities a mandatory waiting period to review proposed deals for competitive harm. The rules governing which transactions must be reported, how filings are structured, and what exemptions apply are administered jointly by the FTC and DOJ under 16 C.F.R. Parts 801–803. Understanding these filing requirements is foundational to any corporate transaction above the statutory thresholds.

• Definition and scope
• Core mechanics or structure
• Causal relationships or drivers
• Classification boundaries
• Tradeoffs and tensions
• Common misconceptions
• Checklist or steps (non-advisory)
• Reference table or matrix

Definition and scope

The Hart-Scott-Rodino Act, codified at 15 U.S.C. § 18a, imposes a premerger notification obligation on acquiring and acquired persons when a transaction meets three cumulative tests: the commerce test, the size-of-transaction test, and (for smaller deals) the size-of-person test. All three must be satisfied before a filing obligation arises.

The commerce test requires that at least one party be engaged in commerce or in any activity affecting commerce within the United States. This is satisfied by virtually all companies with U.S. operations.

The size-of-transaction test is the primary numerical threshold. The FTC adjusts these figures annually based on changes in gross national product. For fiscal year 2024, the base transaction threshold is $119.5 million (FTC HSR Threshold Adjustments, February 2024). Transactions valued at or below this figure are not reportable regardless of party size.

The size-of-person test applies to transactions between the base threshold and $478.0 million (the 2024 upper threshold). At least one party must have annual net sales or total assets of $239.0 million or more, and the other party must have annual net sales or total assets of $23.9 million or more. Transactions exceeding $478.0 million are reportable without regard to party size.

The statute covers acquisitions of voting securities, non-corporate interests (such as LLC membership interests), and assets. It applies to both domestic transactions and foreign transactions that satisfy the nexus to U.S. commerce under the foreign commerce exemption criteria at 16 C.F.R. § 802.50–802.52.

Core mechanics or structure

Once a reportable transaction is identified, both the acquiring person and the acquired person must each submit a separate HSR Form to the FTC's Premerger Notification Office (PNO). The form requests documentary and financial information, including the acquiring person's principal business description, revenue breakdowns by 6-digit NAICS code, and overlapping products or services.

The standard initial waiting period is 30 calendar days from the date both parties' submissions are deemed complete. For cash tender offers and bankruptcy-related acquisitions, the initial waiting period is 15 calendar days (16 C.F.R. § 803.10).

During the waiting period, the reviewing agency may issue a Second Request — a civil investigative demand for additional documents and information. Second Requests extend the waiting period: the acquiring party has 30 days after substantial compliance to complete the review (10 days for cash tender offers). Second Requests are resource-intensive; compliance can require production of hundreds of thousands of documents and take 6–12 months in contested deals.

Filing fees are tiered by transaction size. Under 15 U.S.C. § 18a(a)(5), the fee structure for 2024 is:

• Transactions valued at $119.5 million to under $173.3 million: $30,000
• Transactions valued at $173.3 million to under $519.9 million: $105,000
• Transactions valued at $519.9 million to under $1.0399 billion: $260,000
• Transactions valued at $1.0399 billion to under $2.0798 billion: $420,000
• Transactions valued at $2.0798 billion or more: $1,310,000

(FTC HSR Filing Fee Schedule 2024)

Only one filing fee is paid per transaction — typically by the acquiring person.

Causal relationships or drivers

Congress enacted the HSR Act in response to a documented pattern of post-closing antitrust challenges that proved ineffective. Before 1976, the FTC and DOJ could only challenge mergers after closing, when unwinding integrated businesses imposed severe economic costs on both parties and third parties. The premerger notification requirement shifts antitrust review to a window before assets or control are transferred, making structural remedies viable without forced divestiture of operating businesses.

The annual threshold adjustments are causally tied to the GNP deflator mechanism mandated by statute. The FTC's PNO publishes revised thresholds each February. This indexing mechanism prevents bracket creep — without adjustment, inflation would cause the thresholds to cover a shrinking proportion of economically significant transactions over time.

Second Requests are triggered when the reviewing agency identifies overlapping markets that raise a facially credible competition concern. The probability of receiving a Second Request rises with horizontal overlap between the parties. According to the FTC's annual HSR report data, the vast majority of transactions clear the initial waiting period without a Second Request — in fiscal year 2022, the FTC and DOJ together issued Second Requests in approximately 2 to 3 percent of all reported transactions (FTC Annual HSR Report FY2022).

Classification boundaries

Not every large acquisition requires an HSR filing. The statute and implementing regulations carve out specific exemptions:

Exemptions by transaction type:
- Acquisitions of goods or realty in the ordinary course of business (16 C.F.R. § 802.1)
- Acquisitions of investment assets such as publicly traded securities held solely for investment purposes, provided the acquirer holds 10 percent or less of the issuer's shares without intent to influence control (16 C.F.R. § 802.9)
- Acquisitions within a single person, such as transactions between controlled subsidiaries (16 C.F.R. § 802.30)

Exemptions by party or industry:
- Acquisitions of foreign assets with limited U.S. nexus (16 C.F.R. § 802.50)
- Acquisitions by foreign persons of foreign issuers, where U.S. sales and assets are below the nexus thresholds

Voluntary early termination: Parties may request early termination of the waiting period if the reviewing agency concludes no investigation is warranted. The FTC suspended its practice of publicly announcing early terminations in 2021 (FTC Early Termination Announcement, February 2021), though early termination grants remain available internally.

The FTC's merger review process describes how cleared transactions proceed through the agency's substantive competitive analysis after the notification phase.

Tradeoffs and tensions

Compliance burden versus screening benefit. Filing fees, legal costs, and management time for HSR compliance impose real costs on transactions that ultimately raise no competitive concern. Because roughly 97–98 percent of reported deals are cleared without a Second Request, the mandatory reporting system imposes friction on a large volume of competitively benign transactions to identify the small fraction that warrant scrutiny.

Waiting period certainty versus investigative thoroughness. The fixed 30-day initial period prioritizes transactional certainty but constrains the agency's ability to conduct even basic competitive analysis before a deal closes or Second Request issues. In industries characterized by complex data ecosystems — such as healthcare or digital platforms — 30 days is often insufficient to assess market dynamics without a Second Request.

Threshold indexing versus policy flexibility. Annual GNP-based adjustments maintain consistent economic coverage but remove agency discretion from threshold-setting. Congress retains authority to legislate different thresholds, and proposals periodically emerge to lower thresholds for technology sector acquisitions involving substantial user bases but relatively low asset values.

Foreign commerce exemptions versus global market realities. Multinational transactions can sometimes structure asset transfers to minimize U.S. nexus, reducing HSR reportability for deals that nonetheless affect U.S. markets. The DOJ and FTC retain jurisdiction to challenge such transactions on substantive antitrust grounds regardless of whether HSR notification was required.

Common misconceptions

Misconception: If a transaction is below the size-of-transaction threshold, no analysis is required.
Correction: The thresholds trigger notification obligations, not antitrust liability. A non-reportable transaction can still be challenged under Section 7 of the Clayton Act or Section 5 of the FTC Act if it substantially lessens competition. The HSR filing requirement and substantive antitrust review are separate legal frameworks. The FTC's antitrust enforcement authority extends to all mergers regardless of size.

Misconception: Both parties pay separate filing fees.
Correction: Only one filing fee is paid per transaction, almost always by the acquiring party. Both parties do submit separate HSR Forms, but the fee is singular.

Misconception: Early termination of the waiting period means the deal is approved.
Correction: Early termination means the reviewing agency has concluded it will not challenge the transaction during the waiting period. It does not constitute agency approval and does not bar future challenge if the transaction substantially lessens competition.

Misconception: The HSR filing itself is confidential only after closing.
Correction: HSR filings are confidential by statute under 15 U.S.C. § 18a(h) from the moment of submission. The contents of a filing — including transaction documents and financial schedules — cannot be made public by the agencies.

Misconception: Second Requests are always followed by a merger challenge.
Correction: A substantial proportion of transactions that receive Second Requests ultimately close without a formal challenge, after parties provide the requested information or negotiate divestitures.

Checklist or steps (non-advisory)

The following sequence describes the procedural steps involved in an HSR filing. This is a factual description of the regulatory process, not legal guidance.

Step 1 — Determine reportability
Apply the three-part test: commerce test, size-of-transaction test, size-of-person test. Consult 15 U.S.C. § 18a and 16 C.F.R. Parts 801–803 for applicable definitions.

Step 2 — Identify the acquiring and acquired persons
Determine the "ultimate parent entity" for each side of the transaction using the control test at 16 C.F.R. § 801.1(b) (50-percent voting interest or contractual control over board composition).

Step 3 — Evaluate applicable exemptions
Review 16 C.F.R. §§ 802.1–802.64 for transaction-type, industry, and jurisdictional exemptions before preparing the form.

Step 4 — Prepare the HSR Form
Collect required documents: 4(c) and 4(d) documents (analyses prepared by or for officers or directors discussing the transaction in terms of competition), financial statements, revenue data by NAICS code, and executed transaction agreements.

Step 5 — Calculate and pay the filing fee
Determine the applicable fee tier based on the transaction value. The acquiring person submits payment through the FTC's electronic payment system.

Step 6 — Submit both filings electronically
Each party submits its own HSR Form via the FTC's e-filing portal. The waiting period begins the day after both submissions are complete.

Step 7 — Monitor for Second Request or early termination
Track the waiting period expiration date. If a Second Request issues, the waiting period is tolled until substantial compliance is certified.

Step 8 — Close or respond to remedy negotiations
Upon expiration of the waiting period without a Second Request, or upon grant of early termination, the transaction may close. If the agency identifies a concern, parties may negotiate a consent order involving divestitures before closing.

The FTC's pre-merger notification program page provides the official e-filing portal link and updated form instructions.

Reference table or matrix

HSR Threshold and Fee Structure (FY2024)

Source: FTC Premerger Notification Rules, 2024 Adjustments

Waiting Period Summary

Source: 16 C.F.R. § 803.10

The broader landscape of FTC enforcement authority — including how HSR review intersects with post-merger consent orders — is covered across the ftcauthority.com reference network, which addresses the full scope of the Commission's competition and consumer protection mandates. Parties and practitioners researching the relationship between HSR filings and substantive antitrust review can consult the FTC–DOJ coordination page for detail on how the two agencies allocate merger review responsibility.