A patent injunction is a court order telling an adjudicated infringer to stop. Since eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006), winning a patent case does not win an injunction. The patentee must separately prove the four traditional factors of equity, and a meaningful share of winners now walk out with money instead of an order.
The statute has always said so. 35 U.S.C. § 283 authorizes courts to grant injunctions “in accordance with the principles of equity,” on “such terms as the court deems reasonable.” The word is may, not shall. What changed in 2006 was that the Supreme Court made the Federal Circuit read it.
To get a permanent injunction, a patentee must demonstrate:
The patentee bears the burden on all four. Failing one is enough to lose the injunction while keeping the damages verdict.
MercExchange held a business-method patent on the electronic-market technology behind eBay’s “Buy It Now” feature. It did not practice the patent; it licensed. A jury found infringement, and the district court denied an injunction, partly reasoning that a non-practicing patentee that had shown willingness to license could not show irreparable harm. The Federal Circuit reversed under its long-standing general rule that courts issue permanent injunctions against patent infringement absent exceptional circumstances.
The Supreme Court, unanimously and through Justice Thomas, vacated the Federal Circuit’s judgment and remanded. Neither categorical rule survived: the Court faulted the district court for adopting broad classifications, and vacated the Federal Circuit’s judgment for presuming injunctions follow validity and infringement. The right of exclusion in 35 U.S.C. § 154 does not decide the remedy, because the Patent Act expressly subjects remedies to equitable principles.
Two concurrences did most of the practical work. Chief Justice Roberts, joined by Scalia and Ginsburg, observed that injunctions had issued in the vast majority of patent cases for centuries and that this history should inform discretion: “a page of history is worth a volume of logic.” Justice Kennedy, joined by Stevens, Souter, and Breyer, pointed the other way, naming the firms that “use patents not as a basis for producing and selling goods but, instead, primarily for obtaining licensing fees,” and adding that the “potential vagueness and suspect validity” of many business-method patents “may affect the calculus under the four-factor test.” Where the invention is “but a small component of the product the companies seek to produce and the threat of an injunction is employed simply for undue leverage in negotiations,” he wrote, “legal damages may well be sufficient.”
Lower courts followed Kennedy. The concurrence, not the opinion, became the operative doctrine.
The pattern since 2006 is stable and easy to state. Direct competitors still win injunctions; licensing entities usually do not.
If the infringer takes sales from you in a market you actually serve, irreparable harm is provable and money is genuinely inadequate, because you cannot buy back a lost customer relationship or an eroded price. If your business model is collecting royalties, you have already told the court what your injury is worth: a royalty. A damages award is the same thing, delivered by a judgment rather than a contract.
Two Federal Circuit refinements matter. Robert Bosch LLC v. Pylon Manufacturing Corp., 659 F.3d 1142 (Fed. Cir. 2011), confirmed that eBay eliminated the presumption of irreparable harm, but held that district courts may not swing to the opposite extreme of treating the patentee’s practice or non-practice as dispositive. And in the long-running smartphone litigation, the court developed the causal nexus requirement: a patentee must show that the infringing feature, not the product generally, drives the harm. In Apple Inc. v. Samsung Electronics Co., 809 F.3d 633 (Fed. Cir. 2015), the court held that “some connection” between the patented features and consumer demand suffices, reversing a denial of an injunction. That is a real burden in cases where the patent covers one feature among thousands.
Everything above concerns permanent injunctions, granted after a merits judgment. A preliminary injunction is relief before trial, and its factors come from Winter v. Natural Resources Defense Council, Inc., 555 U.S. 7 (2008): likelihood of success on the merits, likelihood of irreparable harm absent relief, a balance of equities favoring the movant, and the public interest.
The difference is the first factor. At the preliminary stage the patentee has not yet won anything, so it must show it is likely to prove infringement and likely to withstand the validity attack that will certainly come. A substantial question of invalidity raised by the accused infringer defeats the motion, even if the challenge would ultimately fail. Preliminary injunctions in patent cases are correspondingly rare, and delay in filing suit undercuts the irreparable-harm showing: a patentee who waited two years is telling the court it can wait through trial.
Denial of an injunction leaves a live problem. The infringer keeps infringing, the patent stays valid, and the jury’s verdict only covers past conduct. Courts filled that gap with the ongoing royalty, approved in Paice LLC v. Toyota Motor Corp., 504 F.3d 1293 (Fed. Cir. 2007), which held that a district court may impose a forward-looking royalty on continued infringement as an alternative to injunctive relief.
The economics of the post-verdict rate differ from the jury’s. The pre-verdict hypothetical negotiation assumes a patent of uncertain validity and uncertain infringement. After judgment, both uncertainties are gone, and the infringer’s continued sales are knowing. Courts routinely set ongoing rates above the jury’s number for that reason. In effect, the United States has developed a compulsory-license mechanism through remedies doctrine, without Congress ever legislating one.
One forum sits outside all of this. The U.S. International Trade Commission, acting under 19 U.S.C. § 1337, issues exclusion orders barring infringing imports rather than injunctions, and the Federal Circuit held in Spansion, Inc. v. ITC, 629 F.3d 1331 (2010), that eBay does not govern the ITC’s statutory public-interest analysis. That is why patentees who expect to lose the eBay analysis in district court often file at the ITC instead: the exclusion order is functionally the injunction eBay would deny.
What are the eBay factors for a patent injunction? A patentee seeking a permanent injunction must show four things: that it has suffered an irreparable injury; that remedies available at law, such as money damages, are inadequate to compensate for that injury; that considering the balance of hardships between the plaintiff and defendant, a remedy in equity is warranted; and that the public interest would not be disserved by a permanent injunction. The Supreme Court set out that test in eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006).
Did eBay v. MercExchange abolish patent injunctions? No. It abolished the presumption that a valid, infringed patent automatically earns one. Before 2006 the Federal Circuit issued permanent injunctions as a matter of course absent exceptional circumstances. eBay held that 35 U.S.C. § 283 requires district courts to apply the traditional four-factor equitable test, case by case, with no categorical rule either for or against patent owners. Competitors who compete head to head with an infringer still win injunctions regularly.
Why do patent trolls rarely get injunctions after eBay? Because a licensing entity that does not practice its patent usually cannot show irreparable injury or that money damages are inadequate. Its whole business is accepting money for use of the invention, which is what a damages award provides. Justice Kennedy’s concurrence flagged exactly this: for firms that use patents primarily to obtain licensing fees, an injunction can serve as leverage to charge exorbitant fees rather than to protect a market position.
What happens if a patent owner is denied an injunction? Infringement usually continues, and courts commonly impose an ongoing royalty for future use rather than leaving the patentee uncompensated. The Federal Circuit approved that remedy in Paice LLC v. Toyota Motor Corp., 504 F.3d 1293 (Fed. Cir. 2007). The ongoing rate is often set higher than the jury’s past-damages rate, because the infringer is now adjudicated, and willful, rather than merely accused.
Going further: Patent Enforcement and Monetization, in practice .
This page is general legal information, not legal advice, and it does not create an attorney-client relationship.
The Federal Circuit vacated the one-click preliminary injunction because Barnes & Noble raised a substantial question of validity Amazon could not rebut.
The Supreme Court held in 1908 that a patentee who does not use its invention may still enjoin infringement, because the patent right is the right to exclude.
The Federal Circuit revived Apple's bid for a permanent injunction against Samsung, holding that a patented feature need only have some connection to consumer demand, not exclusively drive it, to support irreparable harm.
The Federal Circuit affirms a preliminary injunction barring a competing cancer-recurrence assay, sharpening how courts trace irreparable harm to the patented method through the causal-nexus requirement.
The Federal Circuit finally confirmed that eBay abolished the presumption of irreparable harm, yet reversed a district court that had used categorical reasoning to deny a competitor's permanent injunction.
The Federal Circuit affirmed a permanent injunction against a feature of Microsoft Word, showing how a small patentee can satisfy all four eBay factors against a dominant competitor when the injunction is carefully scoped.
The Supreme Court refused to treat injunctive relief as an automatic consequence of patent infringement, restoring the traditional four-factor equity test and reshaping patent litigation for a generation.
