Inventorship Mistakes That Kill Patents

Getting inventorship wrong can do more than complicate a patent, it can destroy it. In this episode, we unpack a recent Federal Circuit decision that invalidated two patents after a co-inventor was omitted and couldn’t be added later. Using Fortress Iron v. Digger Specialties as a case study, we explore why inventorship errors arise in collaborative development environments, why some mistakes can’t be fixed after issuance, and what companies can do early in development to protect the enforceability of their patents.

Read the Full Article

• Inventorship Errors Can Undermine Patent Value: Practical Steps to Reduce Risk

 About the Authors

• Karthika Perumal, Ph.D.
• Michael R. Samardzija, Ph.D.
• Jeffrey S. Whittle

Transcript

Welcome to Womble Perspectives, where we explore a wide range of topics, from the latest legal updates to industry trends to the business of law. Our team of lawyers, professionals and occasional outside guests will take you through the most pressing issues facing businesses today and provide practical and actionable advice to help you navigate the ever changing legal landscape.

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Host 1:
Today we’re talking about a deceptively simple issue that can completely derail patent enforcement: inventorship. If a patent gets inventorship wrong, it’s often more than just a technical fix. A recent Federal Circuit decision shows just how high the stakes can be when an inventor is left off a patent.

Host 2:
That case is Fortress Iron v. Digger Specialties, decided in April 2026. The court invalidated two patents because a co-inventor was omitted and couldn’t be added later under the statute that allows inventorship correction. What makes this case especially important is that the omission was discovered during litigation, when correction options were already limited.

Host 1:
At a high level, patent law requires that every individual who contributed to the conception of the claimed invention be named as an inventor. If someone who contributed is omitted, the patent can be invalid. And as this case shows, sometimes that error can’t be fixed after the fact.

Host 2:
That’s exactly what happened here. Fortress Iron’s patents covered pre-assembled vertical cable railing panels. While the company began with an internal concept, development moved forward with foreign manufacturing and quality-control partners. Two engineers from one of those partners proposed specific technical changes to address cable rotation during tensioning.

Host 1:
Those changes were incorporated into the final design and ended up in the asserted patent claims. Even so, when the patents issued, neither of those third-party engineers was listed as an inventor.

Host 2:
And that omission didn’t come to light until infringement litigation was underway. Fortress was able to locate and add one of the contributors, but the other had left his employer and could not be found. Fortress then tried to rely on Section 256 to correct inventorship.

Host 1:
Their argument was straightforward: adding the missing inventor wouldn’t prejudice anyone because his rights had already been assigned. But the courts rejected that approach.

Host 2:
The Federal Circuit emphasized that Section 256 requires notice to all “parties concerned,” regardless of who owns the patent or whether correction seems fair. Because the omitted inventor couldn’t be located, notice was impossible. And that meant statutory correction was off the table.

Host 1:
So the takeaway is stark. If you can’t locate an omitted inventor after a patent issues, you may be stuck with an uncorrectable error that renders the patent invalid. The court also made clear that changes under the America Invents Act didn’t eliminate this risk.

Host 2:
Inventorship remains a statutory requirement, and if an error can’t be corrected, it can still destroy enforceability. The timing matters too—by the time litigation begins, options are narrower and practical problems like tracking down former collaborators become much harder.

Host 1:
This risk is especially acute for companies that rely on collaborative development. That includes overseas manufacturers, suppliers, consultants, and third-party engineers who propose real technical solutions along the way.

Host 2:
Inventorship isn’t limited to employees, and it doesn’t depend on job title or project role. It turns on whether someone contributed to the conception of subject matter that appears in at least one claim. That’s why contemporaneous documentation is so important.

Host 1:
The article highlights several practical takeaways. First, assignment agreements handle ownership, but they don’t fix inventorship errors by themselves. Second, when an omitted inventor can’t be located, a reissue application may provide a path forward under certain conditions.

Host 2:
In some circumstances, a substitute statement can stand in for an inventor’s declaration, and in limited cases the assignee may sign instead. But those remedies aren’t always available, and they’re far from guaranteed once enforcement is on the horizon.

Host 1:
That leads to the broader lesson: inventorship should be managed as a disciplined process, not a last-minute filing exercise. Early identification, clear documentation, and periodic checkpoints are far more effective than trying to fix problems later.

Host 2:
The inventorship checklist found in the article in the show notes reinforces that point. Fortress Iron is a reminder that when inventorship errors can’t be corrected, the cost may be the complete loss of patent protection.

Thank you for listening to Womble Perspectives. If you want to learn more about the topics discussed in this episode, please visit The Show Notes, where you can find links to related resources mentioned today. The Show Notes also have more information about our attorneys who provided today's insights, including ways to reach out to them.

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