Fifth Circuit Freezes HSR Premerger Reform Until 2026

On May 26, 2026, a three-judge panel of the U.S. Court of Appeals for the Fifth Circuit granted an unopposed motion to hold the appeal challenging the Federal Trade Commission's 2024 Hart-Scott-Rodino Final Rule in abeyance through December 31, 2026. The order, entered eight days after the FTC and the Department of Justice jointly asked the court to pause proceedings, means the pre-February 2025 HSR form will remain the operative filing instrument for at least another six months. For the antitrust bar, the docket entry was a date to circle, not a decision to parse.

The motion itself, filed May 18, was notable less for its legal argument than for what it signaled about the agencies' posture. Rather than defend the 2024 Final Rule on the merits before the Fifth Circuit, the FTC and DOJ chose to buy time. The reason, outlined in a joint public inquiry launched March 25, 2026, is that the agencies are reconsidering which expanded filing requirements they actually need and which ones a reviewing court will permit. The abeyance is a tactical retreat dressed as an administrative reassessment.

The procedural history that delivered the government to this position is compact but consequential. In October 2024, the FTC promulgated a Final Rule that dramatically expanded the information and documentary requirements for HSR premerger notification filings. The new form demanded, among other things, detailed narratives about competitive overlaps, transaction rationales, and organizational charts reaching deeper into corporate structures than the decades-old prior version. The U.S. Chamber of Commerce and other business plaintiffs sued in the Eastern District of Texas, arguing the rule exceeded the FTC's statutory authority and imposed compliance costs that the agency had failed to adequately justify under the Administrative Procedure Act.

On February 12, 2026, Judge Amos L. Mazzant III of the Eastern District of Texas agreed with the plaintiffs and vacated the Final Rule in its entirety, staying his order for seven days to allow the FTC to seek emergency relief from the Fifth Circuit. The National Law Review, reporting on the decision, noted that the district court found the agency had not adequately considered the compliance burden the new form would impose on filing parties. The Fifth Circuit initially granted a temporary administrative stay on February 19, keeping the new form alive while it considered the FTC's motion for a stay pending appeal. That reprieve lasted exactly one month. On March 19, the Fifth Circuit denied the stay motion, lifted the administrative stay, and the pre-February 2025 form snapped back into effect immediately.

What the 2024 Final Rule had attempted to achieve was not modest. For nearly five decades, the HSR form had been a relatively streamlined document, requiring parties to identify themselves, describe the transaction, submit certain financial statements, and produce a limited set of deal-related documents, typically the transaction agreement and any competition analyses prepared by or for officers and directors. The 2024 rule added requirements for a narrative description of the transaction's rationale, identification of all products and services that compete horizontally between the merging parties, disclosure of supply relationships, submission of drafts of transaction-related documents (not just finals), and a broader set of organizational documents including those from entities the buyer controlled or that controlled the buyer.

The compliance burden was substantial. Dealmakers who filed under the new rules between February 2025 and the February 2026 vacatur described the process as requiring weeks of additional preparation, more extensive engagement with outside counsel, and, critically, more substantive early-stage disclosures that could shape an agency's theory of the deal before the parties had even begun to advocate their position. The old form could often be completed in a matter of days; the new form was measured in weeks.

What the agencies asked for, and what the court said

The Fifth Circuit's March 19 order denying the stay was a per curiam ruling that did not reach the merits of the APA challenge. Instead, the panel found that the FTC had failed to demonstrate a likelihood of success on appeal sufficient to warrant the extraordinary remedy of a stay pending appeal, and that the balance of equities favored the plaintiffs given the ongoing compliance costs the new rule imposed. The order did not dismiss the government's appeal, however. It simply refused to keep the vacated rule in effect while the appeal was briefed and argued.

That distinction is what enabled the May 18 abeyance motion. Because the appeal remains live, the government can choose when and how to prosecute it. By asking the court to hold the case in abeyance, the FTC and DOJ effectively acknowledged that their immediate interest is not in defending the 2024 rule as written but in replacing it with a revised rule that might survive judicial scrutiny. The motion was unopposed by the Chamber of Commerce plaintiffs, as Saul Ewing LLP noted in a client alert, which signals that the business community sees the status quo ante, the pre-2025 form, as a victory worth preserving while the agencies retool.

The parallel track: a public inquiry into what comes next

While the litigation sits on ice, the agencies have opened a second front. On March 25, 2026, the FTC and DOJ issued a joint Request for Public Comment seeking input on how to improve the HSR premerger notification process. The request, published in the Federal Register, asks a series of questions about what information is genuinely useful to agency review, what imposes disproportionate burden, and whether different categories of transactions warrant different filing requirements. The comment period closed in late May, and the agencies are now digesting the submissions.

One of the most closely watched submissions came from the American Hospital Association, which, as Dave Muoio reported for Fierce Healthcare on May 28, again asked the FTC and DOJ to exempt hospital mergers from expanded premerger notification requirements. The AHA argued that the expanded HSR form requirements that were in place for roughly a year before the court-ordered vacatur are overly burdensome and, in the hospital association's words, "do not bear on issues that typically arise in hospital mergers or even use language that makes sense in the hospital context." The AHA's letter framed the existing, pre-2025 process as adequate for the agencies to evaluate hospital transactions, and warned that expanded requirements would impose costs that ultimately flow through to patients.

The hospital lobby's intervention matters because it highlights a structural tension in any attempt to expand HSR requirements uniformly. The HSR form is a one-size-fits-all instrument. A requirement that makes sense for a horizontal merger between two pharmaceutical companies with overlapping pipeline products may be incoherent when applied to a hospital system acquiring a physician practice. The 2024 Final Rule did not include industry-specific carve-outs, a decision that the agencies may revisit in any revised proposal.

The FTC has indicated, according to DLA Piper's analysis of the agencies' statements, that it will propose a set of revised HSR premerger notification rules by the end of 2026. That timeline aligns with the December 31 abeyance deadline set by the Fifth Circuit. The implication is clear: the agencies intend to use the public inquiry to craft a narrower rule that they believe will survive APA review, then withdraw the appeal of the 2024 rule and publish a new proposed rule under notice-and-comment procedures.

What a revised rule might look like is the subject of intense speculation among the antitrust bar. The agencies are likely to retain some of the expanded information requirements, particularly around transaction rationale and competitive overlap narratives, while scaling back the most burdensome documentary demands, such as the requirement to submit drafts. They may also consider tiered requirements that vary by transaction size or industry, an approach that would address the AHA's criticism without requiring a blanket exemption. Any such tiering would itself be a significant departure from the HSR regime's long-standing uniformity principle.

For dealmakers, the practical consequence of the abeyance is straightforward: through at least December 31, 2026, HSR filings will be prepared using the pre-February 2025 form. The waiting period, 30 days for most transactions and 15 days for cash tender offers and bankruptcy acquisitions, will run from the date the agencies receive a complete filing under the old requirements. Early termination of the waiting period, a routine feature of the pre-2025 regime for transactions that raise no competitive issues, remains available. The agencies have not suggested any change to early termination policy during the abeyance period.

The calendar is the variable that antitrust practitioners are watching most closely. If the agencies publish a proposed rule in late 2026, the notice-and-comment period will extend into early 2027, with a final rule unlikely before mid-2027 at the earliest. If that rule is challenged, as it almost certainly will be, the litigation timeline could extend well into 2028. During that entire period, the pre-2025 form would remain in effect unless and until a new rule survives judicial review. The net result is that the FTC's attempt to modernize the HSR form, which began with an advance notice of proposed rulemaking in 2021, may not result in a durable set of requirements until the end of the decade.

The FTC has indicated it will propose a set of revised Hart-Scott-Rodino premerger notification rules by the end of 2026. In the meantime, the pre-February 2025 rules are in effect., DLA Piper client alert, May 26, 2026

The agencies may also face pressure from Capitol Hill. The HSR Act is a statute, and Congress retains the authority to amend it. While major HSR reform has not been a legislative priority in recent sessions, the spectacle of a vacated rule, a stalled appeal, and a multi-year rulemaking process could prompt oversight hearings or even targeted amendments. Some antitrust practitioners have pointed out that the most durable solution to the current impasse would be for Congress to specify with greater precision what information the agencies may require in an HSR filing, rather than leaving the question to agency rulemaking and the APA litigation that follows.

For now, the HSR calendar is frozen. The agencies are reading comment letters. The Fifth Circuit docket is quiet. And dealmakers are filing on a form their predecessors would recognize from decades past. The next milestone on the calendar is December 31, 2026. What happens after that date depends on whether the agencies have produced a new rule narrow enough to satisfy the judiciary's APA standards, and whether the business community finds that new rule worth challenging all over again.