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Federal Circuit says Fortress Iron patents stay invalid over missing co-inventor

Published
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11

Why it matters

The Federal Circuit affirmed that two Fortress Iron patents are invalid due to incomplete inventorship and rejected the company's attempt to cure the defect under 35 U.S.C. § 256. The court held that an omitted co-inventor qualifies as a "party concerned" entitled to notice and a hearing before inventorship can be corrected. Fortress Iron had successfully added one omitted co-inventor, Lin, but could not locate a second omitted inventor, Huang, to complete the correction. The patents at issue—U.S. Patent Nos. 9,790,707 and 10,883,290—cover pre-assembled vertical cable railing panels. The Northern District of Indiana had granted summary judgment for invalidity, and the Federal Circuit affirmed that ruling on April 2, 2026.

The decision does not address whether Fortress Iron made reasonable efforts to locate Huang or what standard courts will apply to such efforts going forward. The opinion also does not clarify whether partial correction under § 256—adding some but not all omitted inventors—creates any intermediate legal status for the patent.

Patent owners should treat inventorship accuracy as a threshold compliance matter. The Federal Circuit's strict approach means that discovering omitted inventors late in a patent's life, or being unable to contact them, creates genuine invalidation risk that § 256 may not cure. Counsel should audit inventorship records early and maintain contact information for all contributors to patented technology. For litigators, this decision signals that defendants will continue pressing inventorship defects as a straightforward path to invalidity when records are incomplete.

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