eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006)
eBay v. MercExchange is a landmark Supreme Court decision that reshaped the remedial landscape of patent law.
After a finding that a valid patent is infringed, must a court automatically grant a permanent injunction, or must it apply the traditional four-factor test for equitable relief under 35 U.S.C. § 283?
Under 35 U.S.C. § 283, courts "may grant injunctions in accordance with the principles of equity" to prevent patent infringement. A plaintiff seeking a permanent injunction must demonstrate: (1) that it has suffered an irreparable injury; (2) that remedies available at law, such as monetary damages, are inadequate to compensate for that injury; (3) that, considering the balance of hardships between the plaintiff and defendant, a remedy in equity is warranted; and (4) that the public interest would not be disserved by a permanent injunction. Courts may not adopt categorical rules either requiring injunctions after infringement is found or denying them based on a patentee's licensing posture or industry status; instead, they must exercise equitable discretion and evaluate the facts of each case.
The Supreme Court vacated the Federal Circuit's judgment and remanded. Permanent injunctions in patent cases are not automatic upon a finding of infringement and validity; courts must apply the traditional four-factor test and exercise equitable discretion without categorical presumptions for or against injunctive relief.
eBay reshaped patent remedies by eliminating any presumption of injunctive relief and insisting on proof-based, factor-driven equitable analysis. Practically, it reduced the automatic leverage patentees—especially non-practicing entities—once enjoyed, and it encouraged alternatives such as ongoing royalties when injunctions are denied. The decision also spilled over into other IP domains: appellate courts have invoked eBay to require proof of irreparable harm in copyright and trademark cases, rejecting categorical presumptions. For students, eBay is a canonical example of statutory interpretation reinforcing equitable tradition, the Supreme Court's supervisory role over specialized courts, and how remedial frameworks shape litigation strategy, settlement dynamics, and innovation policy. On remand in this case, no permanent injunction issued; courts have since routinely scrutinized evidence of irreparable harm, balance of hardships, and public interest rather than defaulting to injunctive relief.