IP Law Daily, TRADE SECRETS—6th Cir.: Maybe not convincing, but clear enough: standard for preliminary injunction is clarified, (May 21, 2026)

By Matthew Hersh, J.D.

The proponent of a preliminary injunction in a trade secrets case was not required to prove its case by clear and convincing evidence.

A district court in Ohio erred when it rejected a preliminary injunction in a trade secrets case after requiring that the company seeking the injunction prove its case by a heightened “clear and convincing” standard, the U.S. Court of Appeals for the Sixth Circuit has held. But the court, in reversing and remanding the trial court’s ruling due to this error of law, remained mum on the merits of the highly contested factual dispute (PCC Airfoils, LLC v. Daugherty, No. 25-3794 (6th Cir. May 19, 2026)).

The lawsuit arises out of a dispute between a company and its former employee. Justin Daugherty worked for 26 years as an engineer at PCC Airfoils, a company that manufactures certain specialized heat-resistant components for turbine engines. In 2025, Daugherty left his job at PCC Airfoils and went to work for a competitor, Consolidated Precision Products Corp. PCC, believing that Daugherty had made off with precious trade secrets, sued its former employee—along with his new employer—for trade secrets violations. The company also moved for a preliminary injunction to prevent the former employee from disclosing the trade secrets or working on products similar to the ones he worked on while at PCC.

The district court, applying a clear and convincing standard to all four prongs of the preliminary injunction standard, rejected the preliminary injunction. Central to the company’s claim, the trial court noted, was the fact that the former employee queued up for printing several documents containing trade secrets on his last two days of employment. But the company did not prove by clear and convincing evidence that the former employee had made off with trade secrets, the trial court found, because there was no proof that the cued-up documents had actually been printed (and moreover, the court noted, there was also evidence that the former employee had a legitimate job-related reason for printing those documents during that time period). The district court also found that the company failed to present clear and convincing evidence that it met the other three prongs of the preliminary injunction test.

The company appealed, leading to this decision.

Clear and convincing standard. The court of appeals, reversing the district court, found that it had erred in applying the “clear and convincing” standard. In considering a motion for a preliminary injunction, the court of appeals noted, a district court must consider four factors: (1) the plaintiff’s likelihood of success on the merits; (2) the risk of irreparable harm to the plaintiff in the absence of an injunction; (3) the risk that an injunction will harm others; and (4) the broader public interest. Generally speaking, the court of appeals noted, courts should engage with all four factors “in a sliding-scale inquiry” rather than demanding a stringent level of proof for each factor independently. “Measured by these requirements,” the court of appeals noted, “the district court erred in requiring PCC to establish ‘clear and convincing evidence’ with respect to each of the four factors in order to be eligible for preliminary relief. No such checklist of quantum-of-proof elements exists.”

The district court was led astray, the court of appeals found, but its misreading of Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7 (2008). In that case, the court noted, the Supreme Court held that a district court may issue a preliminary injunction only if a plaintiff makes “a clear showing that [it] is entitled to such relief.” But the district court’s reliance on that wording “overreads the phrase ‘clear showing’ and misplaces its import,” the court of appeals noted. “Requiring a ‘clear showing’ to obtain a preliminary injunction—because it is an extraordinary form of relief—is not the same thing as requiring ‘clear and convincing evidence’ to establish each of the four factors to establish eligibility for this relief.” Moreover, the court noted, the Supreme Court only a year ago cautioned, in E.M.D. Sales, Inc. v. Carrera, 604 U.S. 45 (2025), that the clear and convincing evidence standard “applies in only a few rare circumstances” and that “a court may not require every plaintiff to meet a heightened standard of proof for every preliminary injunction factor to qualify for injunctive relief.” No such circumstances presented here, the court of appeals emphasized.

Nor was the district court’s reasoning supported by any other caselaw, the court of appeals found. PCC pointed to an unpublished decision of the Sixth Circuit, Honeywell, Inc. v. Brewer-Garrett Co., 1998 WL 152951 (6th Cir. Mar. 23, 1998), which did indeed hold that a plaintiff must “establish its case by clear and convincing evidence” to qualify for a preliminary injunction. But that case was unpublished, the court noted, and in any event it “lost whatever persuasive value it had after the Supreme Court’s decision in E.M.D. Sales.” And to the extent that Ohio state law cases also imposed a “clear and convincing” standard, the court noted, federal rules and their interpreting caselaw trumped.

Although the court of appeals remanded to the district court to reconsider the motion under the proper test, that far from ensured PCC a victory on remand. “Because we are a court of review, not of first view,” the court noted, “we leave it to the district court to apply this test to PCC’s request in the first instance. In doing so, we do not mean to cast doubt on the district court’s factual findings or any other legal conclusions.”

The Case is No. 25-3794.

Judge: Sutton, J.

Attorneys: Russell Beck (Beck Reed Riden) for PCC Airfoils, LLC. James Michael Drozdowski (Kaufman, Drozdowski & Grendell) for Justin Daugherty. Phillip G. Eckenrode (Benesch, Friedlander, Coplan & Aronoff) for Consolidated Precision Products Corp.

Companies: PCC Airfoils, LLC; Consolidated Precision Products Corp.

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