Permanent Injunctions in Patent Litigation After eBay: An Empirical Study

70 Pages Posted: 20 Jul 2015 Last revised: 28 Jul 2016

See all articles by Christopher B. Seaman

Christopher B. Seaman

Washington and Lee University School of Law

Date Written: August 17, 2015


The Supreme Court’s 2006 decision in eBay v. MercExchange is widely regarded as one of the most important patent law rulings of the past decade. Historically, patent holders who won on the merits in litigation nearly always obtained a permanent injunction against infringers. In eBay, the Court unanimously rejected this “general rule” that a prevailing patentee is entitled to an injunction, instead holding that lower courts must apply a four-factor test before granting such relief. Almost ten years later, however, significant questions remain regarding how this four-factor test is being applied, as there has there has been little rigorous empirical examination of eBay’s actual impact in patent litigation.

This Article helps fill this gap in the literature by reporting the results of an original empirical study of contested permanent injunction decisions in district courts for a 7½ year period following eBay. It finds that eBay has effectively created a bifurcated regime for patent remedies, where operating companies who compete against an infringer still obtain permanent injunctions in the vast majority of cases that are successfully litigated to judgment. In contrast, non-practicing entities almost always are denied injunctive relief. These findings are robust even after controlling for the field of patented technology and the particular court that decided the injunction request. It also finds that permanent injunction rates vary significantly based on patented technology and forum. Finally, this Article considers some implications of these findings for both participants in the patent system and policy makers.

Keywords: patent, injunction, eBay, patent troll, NPE, PAE, innovation, remedies, pharmaceuticals, drugs, biotechnology, medical devices, software

JEL Classification: K00, K19, O34

Suggested Citation

Seaman, Christopher B., Permanent Injunctions in Patent Litigation After eBay: An Empirical Study (August 17, 2015). 101 Iowa Law Review 1949 (2016), Washington & Lee Legal Studies Paper No. 2015, Available at SSRN: or

Christopher B. Seaman (Contact Author)

Washington and Lee University School of Law ( email )

Lexington, VA 24450
United States
540-458-8520 (Phone)

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