Beware the Cost of Incorrect Inventorship By: Mike Turner and Alex Dominguez April 16, 2026
On April 2, 2026, the Federal Circuit Court of Appeals issued a decision in Fortress Iron, LP v. Digger Specialties, Inc. (appeal docket No. 2024-2313) that serves as a stinging reminder of the cost of incorrect inventorship. Fortress Iron designs and sells railing and fencing products for outside living spaces. In 2021, it sued a competitor, asserting two related patents covering a design for a pre-assembled cable railing panel. The product idea came from Fortress’s owner, who was named as an inventor on the patents along with an employee who drew up the design and developed an initial prototype. However, discovery determined that two other employees combined to solve a problem with the design that led to the version ultimately patented and sold. These two employees were not named as inventors on the patent. Worse yet, one employee had left the company, and Fortress was unable to locate him.
CLIENT ALERT
Though there is a “savings provision” in the Patent Act allowing a person to be added or removed as an inventor after a patent is granted, this may only be done “on notice and hearing of all parties concerned.” 35 U.S.C. §256(b). The Appellate Court took a strict approach to the interpretation of this language, finding the missing inventor to be a “party concerned” despite Fortress’s argument that he would only benefit by being added as a patentee. Because the missing inventor could not be reached to collect his input, he could not be added as an inventor to the patent. Thus, there was incorrect inventorship that rendered the two patents invalid. Fortress lost its five-year-old lawsuit on summary judgment not because it failed to prove infringement or because its patents lacked merit, but rather because Fortress failed to simply name and obtain oaths from the proper inventors when it applied for patent applications. This decision underscores the importance of getting inventorship correct and maintaining proper documentation. Because inventorship is wrong if an extra person is named or if a necessary inventor is not, it is important to know what it means to be an inventor. An inventor is someone who meaningfully contributed to the conception of an invention set forth in at least one claim of the patent. Because claims are different with each application and can change during prosecution of an application, the inventorship decision should be assessed independently with every application filing and ideally again before a patent grants in the event the claims have significantly changed. A person is not an inventor simply because they participated in the project that resulted in the invention, managed that project, or owned the company. Contractors or even third parties may qualify as inventors and should also be considered. We strongly encourage clients to have inventors review applications before filing, and to execute declarations of inventorship and assignments either then or shortly after filing. Declarations must be filed before the patent grants, or at the time a patentee needs to be added later, such as in the case above. The longer an applicant waits to obtain and file inventor declarations and assignments, the more difficult it may become to obtain them. Though we recommend that clients obtain fresh assignments for each invention, clients also should have employees sign agreements upon starting their employment under which the employee’s inventions made during their employment or while using company resources will automatically be the property of the client. Likewise, contractor agreements should have work-for-hire clauses that expressly identify the
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