Minerva Surgical v. Hologic

The Court kept assignor estoppel (a rule that can prevent a patent seller from later challenging that patent) but narrowed it. It blocks an invalidity defense only when the challenge conflicts with representations made when the patent was transferred.

Justice Kagan wrote the 5–4 opinion, joined by Chief Justice Roberts and Justices Breyer, Sotomayor, and Kavanaugh; Justices Alito, Barrett, Thomas, and Gorsuch dissented.

Majority

Kagan

Roberts

Breyer

Sotomayor

Kavanaugh

Dissent

Alito

Barrett

Thomas

Gorsuch

The decision affects inventors and businesses that sell patent rights and later face infringement suits. For example, a founder’s new company may sometimes challenge a transferred patent, depending on what the founder represented in the sale.

The Court has finished this case. Patent infringement disputes involving former patent owners must apply the Court’s narrower approach.

The Court kept assignor estoppel but limited it. The rule applies only when an invalidity defense contradicts representations made during the patent transfer.

It affects inventors, patent buyers, and companies founded by former patent owners. Their ability to raise invalidity defenses depends on the earlier transfer representations.

The Supreme Court has finished the case. Lower courts must use the narrower assignor-estoppel rule in relevant patent infringement disputes.

Yes. The Court kept the doctrine, while limiting it to challenges that conflict with an assignor’s representations when transferring the patent.