Penetrating the Fortress Iron with a Missing Inventor

While the statute, 35 U.S.C. §256, provides a mechanism to correct inventorship after a patent has issued, a recent Federal Circuit decision, Fortress Iron, LP v. Digger Specialties, Inc.,¹ serves as a stark reminder that this safety net has limits. Specifically, if you cannot find the person you left off, you might not be able to save the patent.

The Statutory Framework: 35 U.S.C. §256

Section 256 is the statutory landing spot for correcting inventorship issues. It allows the factfinder to correct a patent if an inventor was omitted or a non-inventor was incorrectly included through error. Subsection (b) contains a critical procedural hurdle: “The court before which such matter is called in question may order correction of the patent on **notice and hearing of all parties concerned… “

“The court before which such matter is called in question may order correction of the patent on notice and hearing of all parties concerned…”

35 U.S.C. §256

The definition of a “party concerned” is at-issue. If a co-inventor is missing, is that co-inventor merely a bystander, or does he have a fundamental right to be heard before their name is added to (or removed from) a federal property right?

The dispute in Fortress Iron centered on patents for pre-assembled vertical cable railing panels. During development, Fortress collaborated with overseas manufacturers. Two employees from a partner company proposed technical solutions to prevent cable rotation – a contribution that ultimately made it into the final patent claims.

When Fortress sued Digger Specialties for infringement, the inventorship error came to light. Fortress attempted to fix the record under Section 256. They found one contributor, but the second, a Mr. Huang, had left his employer and could not be located.

Fortress argued that adding Mr. Huang shouldn’t require his presence because it was non-prejudicial—after all, adding an inventor usually strengthens a patent’s validity, and they argued his rights would have been assigned anyway. The Federal Circuit panel disagreed.

The “Concerned Party” and the Chou Precedent

The court’s analysis pivoted on the ruling that an omitted co-inventor is a “party concerned” under Section 256. To support this, the court leaned on the precedent case, Chou v. Univ. of Chicago.² In Chou, the Federal Circuit established that an inventor has a concrete interest in being correctly named on a patent, even if they have already assigned their financial interest to an employer. The “reputational” and “prestige” benefits of being a named inventor are legally cognizable interests.

Why the Co-Inventor Must Interject

By citing Chou, Fortress Iron reinforced that standing is personal, and that an inventor’s right to be recognized is independent of ownership. Further, Section 256 requires “notice and hearing.” Because Mr. Huang could not be found, he could not be given proper notice. Third, even if the correction seems beneficial to the patent holder, the court cannot strip or grant inventorship status without the individual having the opportunity to “interject himself” into the proceedings.

“Section 256(b) saves patents from invalidity for the ‘error of omitting inventors.’ Fortress’s position would mean that omission of an inventor, as long as one inventor is named, would not be an error at all. But ‘we must ‘give effect, if possible, to every clause and word of a statute’ and should avoid rendering any of the statutory text meaningless or as mere surplusage.” (citations omitted).

Lourie, C.J., from the slip opinion

As a result, because the omitted inventor was a “concerned party” who could not be notified, the Section 256 correction failed. Without a valid correction, the patents were held invalid.

Takeaways

The Fortress Iron decision highlights a terrifying dead zone in patent law: an uncorrectable error. It is necessary for patent owners to audit their portfolio for inventorship gaps, identify departed or deceased employees who may have contributed to the inventive process, and ensure proper post-employment contact information is valid and has not gone stale.

This blog posting is for informational purposes only and does not constitute legal advice.

Contact Yonaxis I.P. Law Group for guidance specific to your business.

Footnotes

1. ___4th____, Case No. 2024-2313 (Fed. Cir. April 2, 2026). ↩

2. 254 F.3d 1347 (Fed. Cir. 2001). ↩