In Keranos, LLC v. Silicon Storage Technology, Inc., Nos. 14-1360, -1500 (Fed. Cir. August 13, 2015), the Federal Circuit held that the test for whether an exclusive licensee has standing to sue by itself for infringement is the same for both expired and unexpired patents—specifically whether the exclusive licensee has obtained “all substantial rights” in the expired patent.

The Court considered whether Keranos, an exclusive licensee who was assigned its rights after the asserted patents expired, should be subject to the same standing threshold as a licensee of an unexpired patent. The Court determined that “the same legal analysis applies to both expired and unexpired patents” and stated that “the most important factor” for determining if all substantial rights were transferred was whether the patent owner retained any right to sue accused infringers. After examining the license agreement, the Court determined that the patent owner transferred all rights, including the right to sue infringers, to Keranos and had not retained any other rights for itself. The Court also explained that the “absence of some rights” resulting from a patent’s expiration, such as the right to exclude others from practicing the invention, does not affect the standing of a licensee that received all substantial rights.