Medtronic, Inc. v. Mirowski Family Ventures, LLC.
The Supreme Court ruled that when a company holding a patent license sues to establish that its products don't infringe the patent, the patent owner still has to prove infringement — the burden doesn't shift just because the license-holder filed first.
The unanimous decision reverses a Federal Circuit rule that would have forced licensees to prove a negative, and keeps the usual rules of patent litigation the same regardless of which side goes to court first.
“when a licensee seeks a declaratory judgment against a patentee to establish that there is no infringement, the burden of proving infringement remains with the patentee”
The Court's core holding on who must prove infringement in this kind of lawsuit.
How it got here: A federal trial court ruled for Medtronic because Mirowski failed to prove infringement; the Federal Circuit reversed, holding Medtronic bore the burden instead.
The Case in Depth
What happened
Medtronic makes medical devices, including implantable heart stimulators. Mirowski Family Ventures owns patents covering related technology and licensed some of them to Medtronic for royalty payments. When Mirowski told Medtronic that several new products infringed its patents, Medtronic disagreed, kept paying disputed royalties into an escrow account, and sued for a court ruling that its products did not infringe.
The question before the Court
When a company sues its own patent licensor to prove its products don't infringe, who has to prove infringement — the company or the patent owner?
Why it matters
Companies that license patents can challenge a patent owner's infringement claims in court without taking on the harder job of proving they don't infringe. This preserves a predictable, well-established burden-of-proof rule in patent disputes and keeps licensees from facing a tougher legal fight than they would if the patent owner sued them directly.
What changes now
The case returns to the lower courts, where it will be reconsidered with Mirowski, not Medtronic, bearing the burden of proving infringement. This is a final ruling on the legal question of who carries that burden, though the underlying dispute over whether Medtronic's products actually infringe Mirowski's patents still needs to be resolved on remand.
What this does not decide
The Court did not decide whether Medtronic's products actually infringe Mirowski's patents — that factual question goes back to the lower courts. The ruling addresses only who bears the burden of proof, not the outcome of the infringement dispute itself.
How the Court got there
The legal reasoning, step by step
- The Court first confirmed it had authority to hear the case, reasoning that if Medtronic had simply stopped paying royalties instead of suing, Mirowski could have sued for patent infringement — a claim that arises under federal patent law — so this lawsuit, which heads off that scenario, also counts as arising under patent law.
- Turning to the burden-of-proof question, the Court relied on three settled rules: patent owners normally must prove infringement themselves; using a request for a declaratory judgment (a court statement of legal rights before any harm occurs) is just a procedural tool that doesn't change anyone's underlying legal rights; and the burden of proof itself counts as one of those underlying, substantive rights.
- Combining those three rules, the Court concluded that switching who has to prove infringement, just because the licensee sued first instead of waiting to be sued, would improperly change the substance of the patent owner's rights.
- The Court also weighed practical concerns: shifting the burden could leave the question of infringement unresolved if neither side had strong enough evidence, would force the licensee to prove a negative across a complex patent's many claims, and would recreate the very dilemma — abandon your rights or risk a lawsuit — that declaratory judgment suits are meant to avoid.
- The Court rejected counterarguments, including that ordinary lawsuits put the burden on whoever sues first, explaining that patent licensing disputes are an exception to that ordinary rule, and that fears of opening patent owners to unwanted litigation were outweighed by the lack of any strong reason to favor patent owners over licensees on this point.