Premerger Filings May Become More Extensive

Why Premerger Filings Are Suddenly a Bigger Deal

Premerger filings used to feel like the regulatory equivalent of filling out a long airport form: not exactly fun, but predictable. You gathered the deal documents, described the buyer and seller, checked the relevant boxes, paid the filing fee, and waited for the Federal Trade Commission and the Department of Justice to decide whether your merger deserved a closer look.

That calm little routine has changed. In recent years, U.S. antitrust agencies have pushed to modernize the Hart-Scott-Rodino Act filing process, better known as the HSR premerger notification system. The big idea is simple: if regulators have only a short window to review a major acquisition before it closes, they want more useful information at the start. The not-so-small catch is that “more useful information” can mean more narratives, more documents, more competitive analysis, more ownership details, and more late nights for deal teams.

The result is a practical reality for companies, investors, private equity sponsors, and M&A counsel: premerger filings may become more extensive, even if the exact form of those requirements remains unsettled. The 2025 expanded HSR form took effect, was later vacated by a federal court, and then became the subject of renewed agency review. In plain English, the old filing form is back for now, but the debate over a longer, deeper, more revealing HSR filing is very much alive.

What Is a Premerger Filing?

A premerger filing is a required notice submitted to federal antitrust agencies before certain mergers, acquisitions, asset purchases, voting securities acquisitions, or non-corporate interest acquisitions can close. Under the HSR Act, parties to reportable transactions must notify both the FTC and the DOJ and then observe a waiting period, usually 30 days. For certain cash tender offers and bankruptcy transactions, the waiting period is typically 15 days.

The purpose is not to punish companies for doing deals. The purpose is to give regulators a chance to review whether a transaction may substantially lessen competition before the eggs are scrambled, the companies are integrated, and everyone is standing in the kitchen wondering who invited the antitrust lawyers.

If the agencies see no obvious competitive concern, the waiting period expires and the parties can close. If the agencies need more information, they may issue a Second Request, which is a much deeper investigation. A Second Request can involve large document productions, data requests, interviews, depositions, and months of additional review. That is why the initial HSR filing matters so much: it helps determine whether the deal gets a quick green light or gets pulled into the regulatory inspection lane.

What Changed With the Expanded HSR Form?

The FTC finalized major changes to the HSR form and instructions in 2024, with the DOJ concurring. Those changes took effect in February 2025. The agencies said the old form no longer gave them enough information to assess modern transactions, especially deals involving complex ownership structures, private equity roll-ups, labor markets, overlapping business lines, vertical supply relationships, and serial acquisitions.

The expanded form was designed to provide more detail upfront. Instead of relying mainly on transaction documents and limited revenue classifications, the new approach required parties to explain more about the deal, the businesses involved, and potential competitive relationships. It moved the filing process closer to a mini-antitrust memo than a basic notification form.

Key Categories of Additional Information

The expanded requirements focused on several major areas:

• Transaction rationale: Parties had to describe why the deal was happening, not merely identify what was being bought.
• Business overlaps: Filers had to provide more detail about products or services where the buyer and target competed.
• Supply relationships: The form asked for information about vertical or supply-chain connections between the parties.
• Prior acquisitions: Certain previous deals by the acquiring person became more relevant, especially in industries where roll-up strategies may affect competition.
• Ownership and control: More information could be required about entities, officers, directors, and organizational structures.
• Ordinary-course documents: The scope of responsive documents expanded beyond the traditional core deal materials in some circumstances.

For antitrust agencies, this information can help spot competitive risks earlier. For companies, it can turn a filing that once took days into a project that requires cross-functional coordination among legal, finance, business development, tax, HR, operations, and outside counsel. The HSR form did not become a novel. But for some transactions, it certainly started reading like one with footnotes.

The 2026 Twist: The Expanded Form Was Vacated

Here is where the plot gets more interesting. In February 2026, a federal district court vacated the expanded HSR form. After a brief stay and further appellate activity, the Fifth Circuit denied the FTC’s request for a stay pending appeal in March 2026. As a result, the agencies began accepting filings using the pre-February 2025 form and instructions again.

That means the expanded 2025 form is not currently mandatory. Companies can generally use the older form, although the agencies have indicated they will continue to accept filings submitted under the 2025 form voluntarily. This creates a strange but important moment: the more extensive form is no longer the required default, yet the agencies are still actively evaluating whether and how the HSR process should be changed.

So, should deal teams breathe a sigh of relief? Yes, but only a modest one. Think of it as loosening your tie, not leaving the office. The current filing burden is lighter than it was under the 2025 expanded form, but the direction of travel still suggests that premerger reporting may become more detailed again in some form.

Why Regulators Want More Information Upfront

The main argument for more extensive premerger filings is timing. The agencies usually have only 30 days to decide whether a transaction deserves a deeper investigation. In large, complex deals, 30 days can pass faster than a CFO saying, “Can we close by quarter-end?”

Modern transactions may involve layered entities, minority investments, platform acquisitions, data assets, labor effects, vertical relationships, and prior roll-up strategies. Regulators argue that a basic filing may not reveal enough to understand how the deal affects competition. If the agencies do not receive meaningful information until late in the process, they may be more likely to issue Second Requests simply to get clarity.

In theory, a more detailed initial filing could help regulators separate harmless transactions from risky ones more efficiently. A well-prepared filing may answer obvious questions before they become formal demands. That sounds attractive, especially for deals that have a clear procompetitive explanation.

But there is another side. Many reportable transactions do not raise serious antitrust concerns. Requiring every filer to produce extensive narratives and document sets can increase cost, delay, and uncertainty for routine deals. Critics argue that a heavier form may impose large burdens on transactions that would never receive more than a quick look under the traditional process.

What More Extensive Filings Could Mean for Deal Teams

If premerger filings become more extensive again, companies should expect the filing process to start earlier in the deal timeline. Waiting until the purchase agreement is almost signed may no longer be enough. The antitrust team may need to join conversations during diligence, not after everyone else has already picked the closing dinner restaurant.

1. More Time Before Filing

A basic HSR filing can often be prepared relatively quickly when the parties are organized. A more extensive filing may require more factual development, internal interviews, business-unit input, customer and supplier analysis, and document collection. That means companies may need to build extra time into the signing-to-filing period.

2. More Coordination Across Departments

Legal teams cannot answer every competition question alone. They may need help from product leaders, sales teams, finance departments, corporate development teams, and executives who understand why the deal makes business sense. If labor market information or supply relationships are relevant, HR and procurement may also enter the chat.

3. More Attention to Deal Documents

HSR filings already require certain documents analyzing competition, markets, growth, synergies, and transaction rationale. Expanded requirements can make document discipline even more important. Companies should assume that strategy decks, board materials, banker books, and ordinary-course analyses may receive careful attention if they discuss market share, competitors, pricing, expansion, or customer switching.

4. More Risk for Inconsistent Narratives

If the business team says the acquisition is about “eliminating a fierce competitor,” while the legal filing describes the same target as a “small complementary asset,” regulators may notice. They have eyes. And coffee. A strong filing strategy requires consistency between the business rationale, board materials, public messaging, investor communications, and antitrust submissions.

Industries Most Likely to Feel the Pressure

More extensive premerger filings would affect all reportable industries, but some sectors may feel the impact more than others. Technology deals may face questions about data, platforms, artificial intelligence, ecosystems, and future competition. Healthcare transactions may draw scrutiny over local markets, physician groups, hospital systems, payer relationships, and patient access. Private equity deals may be reviewed in the context of serial acquisitions, management control, and platform strategies.

Consumer goods, energy, defense, agriculture, pharmaceuticals, and financial services can also raise complicated overlap or vertical issues. A deal does not need to be enormous to be interesting to regulators. Sometimes a smaller transaction matters because of local concentration, a narrow product market, a key supplier relationship, or a pattern of acquisitions over time.

The lesson is not that every deal is doomed. The lesson is that companies should stop treating HSR analysis as a last-minute administrative chore. The filing may be the first serious conversation regulators have with your transaction. First impressions count, even in antitrust.

Current 2026 Filing Thresholds and Fees Matter Too

Separate from the debate over the form itself, HSR thresholds and filing fees are adjusted annually. For 2026, the minimum size-of-transaction threshold increased to $133.9 million. In general, if a transaction results in holdings above that amount and no exemption applies, the parties must analyze whether an HSR filing is required.

Filing fees also vary based on transaction size. For 2026, fees range from $35,000 for smaller reportable transactions to $2.46 million for the largest deals. That is not exactly pocket change, unless your pockets are lined with private equity fund commitments.

Companies should remember that thresholds are only the starting point. HSR analysis can involve exemptions, size-of-person tests, aggregation rules, prior acquisitions, minority holdings, non-corporate interests, foreign assets, and other technical details. A deal that looks simple on the term sheet may become more complicated once the HSR rules enter the room wearing reading glasses.

How Companies Can Prepare for More Extensive Premerger Filings

Even while the older form is currently operative, smart deal teams can prepare for a future in which HSR filings become more detailed again. Preparation does not mean overreacting. It means building habits that make any filing process faster, cleaner, and less stressful.

Create an Antitrust Filing Checklist Early

Before signing, deal teams should identify whether HSR may apply, what exemptions might be relevant, who controls the filing process, what documents must be collected, and what business people will need to provide input. A checklist keeps the filing from becoming a scavenger hunt with billable hours.

Map Competitive Overlaps

Companies should identify where the buyer and target sell competing products or services, where they serve the same customers, and where they operate in adjacent markets. This does not require panic. It requires clarity. A good overlap map helps counsel anticipate agency questions and craft accurate filing narratives.

Review Strategic Documents Before They Become a Problem

Deal documents should be truthful, practical, and carefully worded. Overheated language can create unnecessary risk. A slide saying “crush the market by buying our only rival” may thrill nobody except a future regulator with a highlighter.

Coordinate Public Messaging

Press releases, investor decks, board presentations, and HSR filings should not tell conflicting stories. If a deal is described publicly as transformative because it consolidates market power, but privately as harmless and complementary, the inconsistency may create questions that slow review.

Build Extra Time Into Transaction Planning

Deal timelines should account for possible filing delays, agency questions, pull-and-refile strategies, Second Requests, or litigation risk. Even if a transaction appears low-risk, a realistic timeline helps avoid unpleasant surprises when closing is tied to financing, shareholder approvals, or regulatory deadlines.

Experience-Based Observations: What the HSR Filing Process Feels Like in Practice

In real-world transaction planning, the premerger filing process often feels less like filling out a form and more like assembling a miniature biography of a deal. The first challenge is usually not the legal standard itself; it is getting the right facts from the right people before the deadline starts breathing down everyone’s neck. Corporate development may know the strategic rationale. Finance may know the valuation model. Sales may know the actual competitors. Product teams may understand the roadmap. Legal must stitch all of it together into a filing that is accurate, consistent, and defensible.

One common experience is that the earliest version of a deal story is often too simple. Someone says, “There is no overlap.” Then, after a few conversations, it becomes, “There is no meaningful overlap, except in one product line, in two customer segments, in three states, if you define the market narrowly.” That does not mean the deal is anticompetitive. It means the filing team needs enough time to understand the nuance before regulators ask the same question in a less friendly tone.

Another practical lesson is that document collection can be surprisingly emotional. Executives may not remember every deck created during early discussions, bankers may have multiple versions of materials, and business teams may use colorful language that sounded harmless in a brainstorming session but looks dramatic in a regulatory review. Nobody wants a routine filing derailed by a forgotten slide titled “Project Domination.” The best practice is to identify responsive documents early, review them carefully, and make sure the filing narrative matches the company’s actual records.

More extensive filings also change the relationship between business speed and regulatory discipline. Dealmakers naturally want momentum. Antitrust counsel naturally wants precision. The two can coexist, but only when the filing process is treated as part of the deal strategy rather than a paperwork detour. The fastest filings are usually not the ones rushed at the end. They are the ones prepared steadily from the beginning.

Companies that handle HSR filings well tend to have three habits. First, they involve antitrust counsel early, before signing pressure becomes intense. Second, they keep clean records explaining legitimate business reasons for the transaction, such as efficiency, innovation, customer expansion, or complementary capabilities. Third, they avoid casual exaggeration in documents. Regulators understand business ambition, but they do not love dramatic language that makes a lawful acquisition look like a villain monologue.

The broader experience is clear: if premerger filings become more extensive, the winners will not simply be the companies with the biggest legal budgets. The winners will be the companies with organized information, disciplined communication, realistic timelines, and a calm understanding of how antitrust review works. In M&A, confidence is good. Prepared confidence is better. Prepared confidence with indexed documents, consistent narratives, and a clean filing strategy is the antitrust version of showing up to the exam with sharpened pencils and a full night’s sleep.

Conclusion: More Detail May Be the New Direction, Even If the Route Is Unclear

Premerger filings may become more extensive because the agencies believe modern deals require more context than the traditional HSR form provided. Although the expanded 2025 form has been vacated and the older form is currently back in use, the FTC and DOJ are still studying possible changes. That means companies should not assume the filing process will remain static.

The smartest approach is practical preparation. Treat HSR analysis as an early-stage deal issue. Keep transaction documents disciplined. Map overlaps honestly. Coordinate messaging. Build timelines that respect regulatory review. And remember: the filing is not just a form. It is the opening chapter of the government’s understanding of your deal.

In other words, premerger filings may become more extensive, but they do not have to become more chaotic. With the right planning, companies can survive the process with their transaction, their timeline, and perhaps even their sense of humor intact.