Too Late to Invent an Inventor: Forfeiture and 256 in IPR Proceedings

"Section 256 of the Patent Act is a remarkable statutory provision. It declares that a patent "shall not be invalidated" on the grounds of incorrect inventorship so long as the error "can be corrected." 35 U.S.C. § 256(a). Unlike its neighboring provisions for correcting other types of patent errors, Section 256 operates retroactively, reaching back to the patent's original filing date."

"In Implicit, LLC v. Sonos, Inc., No. 2020-1173 (Fed. Cir. Mar. 9, 2026), however, the Federal Circuit held that the absence of a statutory deadline does not immunize a patentee from the consequences of delay. Forfeiture principles, the court ruled, can prevent a patent owner from relying on a Section 256 correction to mount a new argument in an inter partes review that it failed to raise during the original proceeding."

Section 256 of the Patent Act provides that patents cannot be invalidated due to incorrect inventorship if the error can be corrected, operating retroactively to the original filing date without express statutory deadlines. In Implicit, LLC v. Sonos, Inc., the Federal Circuit determined that despite the statute's silence on timing, forfeiture principles prevent patentees from using delayed Section 256 corrections to introduce new arguments in inter partes review proceedings that were not raised originally. The case involved Implicit patents initially naming Edward Balassanian and Scott Bradley as co-inventors, though engineer Guy Carpenter had written the source code and authored the provisional application document without being named as an inventor.

Read at Patently-O