KKR Lawsuit: DOJ Allegations, $650M Penalty, and Defense

On January 14, 2025, the U.S. Department of Justice sued KKR & Co. Inc. in the Southern District of New York, alleging the private equity firm violated the Hart-Scott-Rodino Act across at least 16 transactions in 2021 and 2022 by altering, omitting, or entirely skipping required premerger filings. The KKR HSR Act lawsuit seeks civil penalties the government says could exceed $650 million, and it is now pending on KKR’s motion to dismiss.¹

The Hart-Scott-Rodino Act requires companies to notify the DOJ and Federal Trade Commission before closing large mergers, then wait 30 days so regulators can review competitive effects. A core piece of that filing is the set of “Item 4” documents: internal analyses prepared by or for officers and directors that discuss competitors, market shares, pricing, and post-merger plans. Those documents are often the most candid picture regulators get of what a deal means for competition. Violations of the HSR Act carry a maximum civil penalty of $53,088 per day per violation.²

What the DOJ Alleges

The complaint describes not isolated errors but a pattern across three types of conduct.

Altered Documents

In at least eight transactions, the DOJ says KKR physically deleted pages or sections from Item 4 documents before submitting them. In the ERM deal, the government alleges KKR cut 70 pages across four documents, including 40 out of 48 pages in one document and 25 out of 42 in another. The deleted material covered competitors, market shares, barriers to entry, pricing, and post-merger plans. In the OutSystems transaction, six pages were removed from one document and seven from another, covering competitive positioning, customer surveys, and market landscape. According to the DOJ, the same deletions appeared in the corrective filings that followed, which the government cites as evidence that the cuts were deliberate.³

The complaint quotes an internal KKR communication in which an employee wrote, “I’ve always been told less is more.” In another instance, a KKR partner allegedly directed a deal team to “revise for HSR purposes” an Investment Committee report, after which a section labeled “Competitive Behavior” was deleted.¹

Omitted Documents

In at least 10 transactions, the DOJ alleges KKR certified that its filings were complete when they were not, and only produced the missing Item 4 documents after the Antitrust Division prompted corrective action. In the Emsi deal, a roughly $350 million acquisition of a labor market analytics firm, KKR initially submitted two Item 4 documents. A corrective filing later added 32 more, 28 of which predated the original submission and contained analysis of head-to-head competition, product overlaps, customer interviews, and pricing. In the Lynx transaction, a roughly $425 million acquisition of a fixed-base aviation operator, KKR filed five documents but omitted 29 others covering pricing, market shares, and regional competitive overlaps.³

No Filing at All

For two transactions, the Applovin and Adjust acquisitions, the DOJ alleges KKR failed to submit any premerger notification, then filed corrective paperwork more than seven months after each deal had already closed. KKR admitted these failures to the FTC in December 2021.⁴ One of those transactions was valued at $6.9 billion; the other was valued between $376 million and $919 million.¹

Across all 16 transactions, the complaint alleges KKR certified under penalty of perjury that its filings were complete and compliant. HSR rules require filers who cannot provide all required information to submit a statement explaining why. The DOJ says KKR never submitted such a statement for any of the 16 deals.³

How the $650 Million Figure Was Built

The DOJ arrived at its penalty estimate by applying the daily statutory rate in effect at the time, $51,744, to more than ten thousand cumulative days of noncompliance across the 16 transactions. The government is also seeking structural and equitable relief, though public materials say little about the specifics.¹

Separately, the DOJ opened a criminal investigation in December 2024 into the accuracy of KKR’s HSR filings. Reporting indicates that investigation was ongoing in parallel with the civil case as of early 2025.⁵

How KKR Is Fighting the Case

On the same day the DOJ sued, KKR filed its own action in the U.S. District Court for the District of Columbia against the DOJ, the FTC, and Doha Mekki, then the Acting Assistant Attorney General for the Antitrust Division. KKR asked the court to declare it had not violated the HSR Act, that the agencies’ interpretations of the statute were “unconstitutionally vague,” and that the penalties sought were “excessive.”⁶ KKR voluntarily dismissed that D.C. action two days later, on January 16, 2025, and the case was terminated on February 11, 2025.⁷

KKR then refocused its defense in the Southern District of New York before Judge Jennifer H. Rearden. On April 18, 2025, it filed a motion to dismiss, describing the DOJ’s allegations as targeting “immaterial purported errors” and seeking “draconian, unconstitutional and unprecedented penalties.”⁸ Three arguments sit at the center of that motion:

Substantial compliance. KKR argued the case should be dismissed because the DOJ did not allege it lacked “substantial compliance” with the Act. The DOJ responded that the substantial compliance standard governs equitable relief, not civil penalties, which require only that a filer fail to comply.³
Document necessity. KKR argued the government must prove each omitted or altered document was individually “necessary” for antitrust review. The DOJ said the statute directs the agencies to define what categories of information filers must produce, and no document-by-document necessity test exists in the law.³
Ministerial mistakes. KKR framed its conduct as minor and inadvertent. The DOJ countered that this framing cannot be squared with allegations of physical page deletions, systematic omissions, and internal communications suggesting deliberate suppression.³

Judge Rearden granted KKR’s request to stay two counts revived from the earlier D.C. filing as counterclaims: the vagueness challenge to the agencies’ HSR interpretations and the excessive-fines challenge. Both are paused while the motion to dismiss is decided. The court also approved a joint stipulation dismissing a separate count that had sought a declaration KKR did not violate the Act.⁹

Industry Weighs In

On June 6, 2025, the American Investment Council, a private equity trade group, moved to file an amicus brief supporting KKR’s dismissal bid. The AIC argued the DOJ was advancing a “novel interpretation” of the HSR Act that departs from more than 45 years of practice, would effectively require “perfect” filings, and would chill procompetitive investment.¹⁰ The DOJ opposed the filing, and the court had not ruled on whether to accept the brief as of the available record.¹¹

Why This Case Is Bigger Than KKR

Federal antitrust enforcers had already been signaling closer scrutiny of private equity compliance with merger notification rules, especially for roll-up strategies in which a firm makes serial acquisitions within the same industry. KKR manages more than $500 billion in assets and was required to make over 100 HSR filings since 2021, which made it a visible test case.¹

The complaint highlights a roll-up pattern regulators find concerning. KKR’s Lynx acquisition, a fixed-base aviation operator, was followed by the Ross acquisition in the same sector. KKR also acquired Atlantic Aviation for $3.5 billion in 2021, another player in the same industry.⁴

Doha Mekki, who led the enforcement action while at the DOJ, said KKR’s conduct “threatened the integrity of the Division’s premerger reviews” and allowed the firm to obscure the “market impact of its deals and serial acquisitions.” Mekki has since left the DOJ.¹

A separate development in HSR rulemaking does not affect this case. The FTC finalized new HSR filing rules in October 2024, effective February 10, 2025, but a federal court in Texas vacated those rules in February 2026, and filers reverted to the earlier form.¹² The KKR case involves conduct under the old rules, so the vacatur has no direct bearing on the allegations.

Where the Case Stands

KKR’s motion to dismiss remains pending before Judge Rearden. The DOJ filed its opposition on May 15, 2025, arguing that the allegations of systematic document alteration and omission raise factual disputes that should not be resolved on a motion to dismiss.³ KKR’s constitutional challenges to HSR Act vagueness and to the size of the penalties are stayed until the motion is decided.⁹ The parallel criminal investigation into the accuracy of KKR’s filings is a separate, unresolved matter.

1
U.S. Department of Justice. Justice Department Sues KKR for Serial Violations of Federal Premerger Review Law
2
Pillsbury Winthrop Shaw Pittman LLP. FTC Hart-Scott-Rodino Act Threshold Filing Fee Increases for 2026 Transactions
3
U.S. Department of Justice. Plaintiff’s Opposition to Defendants’ Motion to Dismiss
4
Applied Antitrust. United States v. KKR, Complaint
5
Arnold & Porter. DOJ Sues Private Equity Firm
6
Willkie Farr & Gallagher. Antitrust Regulators Continue Focus on HSR Compliance and Private Equity
7
Justia. KKR & Co. GP LLC v. Doha Mekki
8
Law360. United States of America v. KKR & Co. Inc. et al.
9
MLex. KKR Request for Stay, Partial Dismissal of Claims Granted in Case Against US DOJ
10
Applied Antitrust. American Investment Council Amicus Motion
11
Law360. DOJ’s KKR Suit Turning M&A Into a Trap, PE Group Says
12
FTC. HSR Notification Forms, Instructions, and Guidance