What Is the HSR Premerger Notification Process?

The Hart-Scott-Rodino Antitrust Improvements Act of 1976 requires parties to certain large mergers, acquisitions, and transfers of assets or voting securities to notify the FTC and DOJ before completing the transaction. Whether a filing is required depends on annually adjusted monetary thresholds, the size of the transaction, the size of the parties, applicable exemptions, and the structure of the deal.

Once complete filings are submitted, the parties generally must observe a 30-day waiting period. The initial period is usually 15 days for cash tender offers and certain bankruptcy transactions. During that window, the agencies decide whether the deal appears unlikely to harm competition or whether it deserves a deeper investigation through a request for additional information, commonly called a Second Request.

The process is preventive rather than merely punitive. Regulators are supposed to evaluate a transaction before the corporate wedding cake is cut, not months later when the businesses, employees, computer systems, and customer contracts have already been combined.

Why the FTC and DOJ Revised the HSR Form

The agencies argued that the earlier form no longer provided enough information to evaluate modern transactions during the short statutory waiting period. Corporate structures had become more complicated, private equity ownership had become more common, supply chains had become more interconnected, and acquisition strategies increasingly involved serial purchases of smaller businesses.

According to the FTC, the former form could leave important information gaps concerning who controlled the parties, where they competed, whether they bought products from or sold products to one another, and whether the transaction was part of a broader consolidation strategy. The DOJ similarly emphasized that merger practices and global markets had changed substantially during the four decades following the original HSR program.

The agencies therefore wanted more useful information at the beginning of the review. Their basic theory was simple: asking better questions on day one could reduce frantic information requests on day twenty-seven.

Major Changes Under the Final HSR Rule

1. Separate Forms for Buyers and Targets

The final rule recognized that an acquiring person and an acquired person do not always possess the same information or create the same competition risks. It therefore established different reporting obligations for the two sides instead of treating every filer identically.

The acquiring person generally faced broader disclosure requirements, particularly concerning its ownership structure, minority investors, officers, directors, prior acquisitions, and post-transaction control. Some simplified requirements applied to qualifying transactions in which the buyer would not obtain control and had no agreement or board appointment rights.

2. A Narrative Explanation of the Transaction

Filing parties were required to describe the transaction and explain the strategic rationales considered in pursuing it. They also needed to identify documents included with the filing that supported those rationales.

This was a meaningful change. The old HSR form was often described as largely technical and objective. The revised form asked parties to explain the commercial story behind the deal. That meant legal teams could no longer focus only on corporate entities, revenue codes, and transaction values; they also needed input from executives, finance teams, corporate development personnel, and business leaders.

3. Descriptions of Products, Services, and Competitive Overlaps

Parties had to describe their principal products and services and identify current or planned products that competed with those of the other party. When an overlap existed, the form requested additional information about sales, customers, geographic operations, and the business entities responsible for the overlapping activities.

The goal was to help regulators identify horizontal concerns, such as one direct competitor purchasing another, without spending the opening weeks of the review learning the basic vocabulary of the industry. A filing involving two software businesses, for example, could not simply say both parties operated in “technology.” It needed to explain which products performed similar functions, which customers purchased them, and where the products competed.

4. Information About Supply Relationships

The revised filing also sought information about vertical and supply relationships. Parties could be required to identify products or services sold to the other party, purchased from the other party, or supplied to businesses that competed with the other party.

This information could reveal whether the merged company might control an input, distribution channel, technology, service, or customer relationship that competitors needed. In plain English, regulators wanted to know whether the deal might allow the combined company to squeeze a rival by raising its costs or cutting off access to something important.

5. More Transaction-Related Documents

The final rule expanded the group of individuals whose transaction-related documents could be responsive. In addition to relevant materials prepared by or for officers and directors, parties needed to search for documents prepared by or for the supervisory deal team lead.

The rule defined that person as the individual with primary responsibility for supervising the strategic assessment of the transaction who was not otherwise an officer or director. The final version limited the requirement to one such person, narrowing a broader proposal that could have required searches involving several deal-team members.

6. Ordinary-Course Competition Reports

Certain regularly prepared reports discussing markets, competitors, competition, or market shares had to be submitted when they concerned overlapping products and had been provided to the chief executive officer or board during the previous year.

This requirement reached beyond documents written specifically to promote or evaluate the transaction. A routine annual strategy report could become relevant if it discussed the same market in which the buyer and target competed. Companies therefore had to think about HSR readiness as an information-governance issue, not merely a form that outside counsel completed after signing.

7. Expanded Ownership and Investor Information

The acquiring side could be required to provide additional details about its ownership structure, minority investors, and investors with management or governance rights. These obligations were especially relevant to private equity firms, investment consortia, special-purpose acquisition entities, and layered holding-company structures.

Regulators were not collecting investor names simply to create the world’s least exciting address book. Ownership and governance rights can reveal who may influence the combined business, whether related portfolio companies operate in overlapping markets, and whether individuals hold positions with competing companies.

8. Prior Acquisition Disclosures

The final rule expanded information concerning acquisitions completed during the previous five years in business lines related to identified competitive overlaps. The requirement applied to relevant prior acquisitions by both the buyer and the target, while retaining certain limitations intended to reduce the burden of reporting very small transactions.

The agencies said this information would help them detect roll-up strategies in which a company purchases multiple smaller competitors over time. Any one acquisition might appear modest, but a long series of modest deals can transform a market as effectively as one blockbuster transaction.

9. Foreign Subsidies and Government Contracts

The revised form implemented statutory requirements concerning subsidies received from certain foreign entities or governments. It also requested information in specified circumstances about substantial defense or intelligence procurement contracts connected to areas of competitive overlap or supply relationships.

These disclosures reflected growing concern that government support, national-security relationships, and international industrial policies may affect how companies compete.

10. English Translations and More Complete Agreements

Non-English documents submitted with the filing generally needed English translations. Parties also had to provide transaction agreements, relevant exhibits and schedules, and sufficiently detailed preliminary agreements when filing before executing a definitive contract.

The agencies did not want an initial filing based on an agreement so vague that the actual transaction remained a mystery. A letter of intent needed enough substance to show the parties, structure, assets or interests being acquired, and material deal terms.

How Much Additional Work Did the Revised HSR Form Create?

The FTC estimated that the final amendments would add an average of 68 hours to the preparation of a non-index HSR filing, with an estimated average additional cost of approximately $39,644 per filing. The projected burden ranged from about 10 extra hours for certain simpler acquired-person filings to as many as 121 extra hours for an acquiring person in a transaction involving overlaps or supply relationships.

Those figures were averages, not promises. A repeat buyer with updated ownership records and a centralized acquisition database might respond efficiently. A multinational business with decentralized records, numerous product lines, multiple portfolio companies, and a folder structure last organized during the era of dial-up internet could face a much longer process.

Leading antitrust practitioners consequently advised parties to begin HSR preparation weeks before signing, especially for complex strategic transactions. Some recommended adding two to four weeksor moreto transaction schedules and maintaining frequently requested information on an ongoing basis.

What the Rule Meant for M&A Planning

Start Antitrust Work Earlier

Under the revised process, waiting until the definitive agreement was signed could create avoidable delays. Parties needed to begin identifying overlaps, supply relationships, prior acquisitions, ownership data, and potential document custodians during preliminary due diligence.

Coordinate Business and Legal Teams

Many answers could not be produced by lawyers alone. Product managers understood product road maps. Sales leaders knew the largest customers. Procurement teams knew key suppliers. Finance teams controlled revenue data. Corporate secretaries maintained director information. The revised filing turned HSR preparation into a company-wide scavenger hunt, except the prize was permission to keep waiting.

Review Deal Documents for Consistency

The strategic rationale described in the filing needed to align with board presentations, investment committee memoranda, valuation materials, and ordinary-course plans. Inconsistencies could create questions about whether the filing was complete or whether the parties had accurately described the transaction.

Improve Acquisition Recordkeeping

Companies pursuing frequent acquisitions benefited from maintaining a searchable database of past transactions, acquired products, transaction dates, values, business lines, and retained entities. Reconstructing five years of acquisitions days before an HSR deadline is possible, but so is assembling furniture without instructions. Neither activity improves with panic.

Build Flexibility Into the Deal Timeline

Because form preparation could take longer, merger agreements needed realistic filing covenants and deadlines. Parties also had to consider how filing delays might affect financing commitments, employee communications, foreign merger-control filings, customer announcements, and outside closing dates. These recommendations were practical inferences from the expanded information requirements and the preparation timelines reported by antitrust practitioners.

Early Termination Returned With the Revised Process

Alongside the final rule, the agencies announced that they would resume granting early termination in eligible transactions after suspending the practice in 2021. Early termination allows a transaction presenting little apparent antitrust risk to close before the ordinary waiting period expires.

This provided at least one spoonful of sugar with the larger filing package. Although parties might spend more time preparing the filing, a sufficiently clear submission could help the agencies identify an uncomplicated transaction and end the waiting period early. Early termination remained discretionary rather than guaranteed.

Current Status of the Revised HSR Final Rule

The expanded form remained in effect from February 10, 2025, until litigation changed the landscape in 2026. On February 12, 2026, the U.S. District Court for the Eastern District of Texas vacated the rule, concluding that the expanded requirements exceeded the FTC’s delegated authority and were arbitrary and capricious. The court briefly stayed its decision while the FTC sought appellate relief.

The Fifth Circuit initially entered a temporary administrative stay, but on March 19, 2026, it denied the FTC’s request for a stay pending appeal. The FTC then announced that it was again accepting filings under the form and instructions used before February 10, 2025. Parties that had already prepared the expanded form could submit it voluntarily.

On May 26, 2026, the Fifth Circuit granted an unopposed request to pause the appeal through December 31, 2026, while the FTC and DOJ considered possible revisions to the HSR form. Accordingly, as of August 5, 2026, the pre-February 2025 form is the operative filing framework, while the future of the expanded requirements remains subject to agency action and appellate proceedings.

This later legal development does not erase the significance of the 2024 rule. Many of its underlying concernsserial acquisitions, complex ownership, vertical relationships, incomplete market information, and modern investment structuresare likely to remain central to future merger-review policy.

A Deal-Team Experience: What Preparing the Expanded Filing Felt Like

The following is an illustrative composite based on the practical demands described in agency guidance and antitrust commentary. It does not describe a specific client or confidential transaction.

Imagine a private equity sponsor agreeing to acquire a regional software company. At first glance, the transaction looks straightforward. The buyer owns several portfolio businesses, but none appears to sell precisely the same software. The parties expect to sign on Friday, file their HSR notifications the following week, and begin the waiting period before anyone has time to forget where the celebratory champagne was stored.

Under the expanded HSR form, that schedule quickly becomes optimistic. Outside antitrust counsel first asks the sponsor for a description of its ownership structure, minority investors with management rights, relevant controlled entities, officers, directors, and recent acquisitions. The deal team responds with three organizational charts, two of which disagree, and a spreadsheet named “Ownership_Final_v7_REALLY_FINAL.xlsx.”

The target’s product team must then describe each principal software service, including products still in development. The buyer’s portfolio companies are asked whether they offer competing tools, purchase services from the target, sell products to the target’s competitors, or share important customers. A portfolio company initially says there is no relationship. Two days later, its sales director remembers a pilot program involving the target’s second-largest customer.

Next comes document collection. The legal team identifies the supervisory deal team lead and searches for presentations discussing competition, market share, growth opportunities, and the transaction’s strategic rationale. A board presentation says the acquisition will provide “entry into an adjacent market.” An investment memorandum calls the same market “a natural extension of an existing platform.” Neither statement is necessarily problematic, but the filing narrative must explain the relationship accurately rather than pretending the wording is identical.

The target discovers that its chief executive received a quarterly market report discussing three rivals. Because the report covers an overlapping product and was regularly prepared for the CEO, it may need to be submitted. Counsel reviews the document carefully, along with a collection of emails in which executives use the sort of colorful language that makes antitrust lawyers suddenly interested in herbal tea.

The teams also compile customer and supplier information. Sales data is organized by product, but the HSR narrative uses a slightly different product taxonomy. Finance calls the product team. The product team calls sales operations. Sales operations asks whether anyone remembers why one legacy product has four internal names. Eventually, the parties create a cross-reference table and agree on consistent descriptions.

Meanwhile, the merger agreement requires filing within seven business days. Everyone realizes the deadline was drafted using assumptions from the former HSR process. The parties amend their internal timetable, prioritize information requests, and hold daily calls involving antitrust counsel, corporate counsel, finance, IT, tax, procurement, and business executives.

The experience produces several lessons. First, filing preparation should begin before signing whenever a transaction may be reportable. Second, repeat acquirers should maintain current ownership and acquisition records instead of rebuilding them for every deal. Third, business descriptions must be consistent across the form, supporting documents, and internal data. Fourth, executives should write strategy materials clearly and accurately because casual exaggeration can create serious regulatory questions later.

Most importantly, HSR compliance is not merely a legal formality. It is a structured explanation of who the parties are, what they sell, why they are combining, and how the transaction may change competition. The expanded rule made that explanation more demanding, but it also revealed how much smoother the process becomes when corporate records, product data, and deal documentation are managed before a regulator asks for them.

Conclusion

The FTC and DOJ’s revised HSR premerger notification rule represented a fundamental shift from a relatively narrow notification form toward a broader initial antitrust submission. It required more detailed narratives, ownership information, product descriptions, supply-relationship data, prior-acquisition records, ordinary-course reports, and transaction documents.

Supporters viewed the rule as a necessary modernization that could help regulators identify dangerous mergers during the short initial waiting period. Critics focused on its cost, subjectivity, preparation burden, and potential to delay transactions that presented little competitive risk. Both sides had a point: the older form often provided limited information, while the revised process could turn a routine filing into a substantial diligence project.

Although the expanded rule was vacated in 2026 and the previous form returned, its practical lessons remain relevant. Companies contemplating significant acquisitions should evaluate antitrust risks early, maintain accurate ownership and acquisition records, coordinate legal and business teams, and treat internal strategy documents with appropriate care. Merger rules may change again, but regulators’ interest in understanding how deals affect competition is unlikely to disappear.