Intellectual Property Report

Patent Invalidity Due to Incorrect Inventorship

Brian Hausman

Inventorship is an often overlooked detail in patent law that is a statutory condition tied to validity, ownership, standing, and enforceability. The Federal Circuit’s recent decision in Fortress Iron, LP v. Digger Specialties, Inc., 171 F.4th 1310 (Fed. Cir. 2026), makes that point sharply: where a patent omits a true inventor and the error cannot be corrected under 35 U.S.C. § 256, the patent is invalid.

In Fortress, the patents initially named only Fortress’s owner and an employee as inventors. Fortress later acknowledged that two vendor-side employees, Alfonso Lin and Hua-Ping Huang, were coinventors. Although Fortress added Lin through the PTO process, it could not locate Huang and sought court-ordered correction under Section 256(b). The Federal Circuit affirmed summary judgment of invalidity because Huang was an omitted coinventor and Fortress could not satisfy Section 256(b)’s notice-and-hearing requirement.