Patent applications may be filed by an individual inventor(s) or the assignee of an inventor(s) patent rights. Even under the latter scenario, the application must still include the name of each and every inventor. The Federal Circuit Court of Appeal’s April 2, 2026 decision in Fortress Iron LP V. Digger Specialties, Inc. is reminder that patent applicants should ensure that the application names all of the inventors behind the invention for which patent protection is being sought. Failure to do so could make any resulting patent subject to invalidation.
Under 35 U.S.C. § 100, inventor is defined as the individual or, if a joint invention, the individuals collectively who invented or discovered the subject matter of the invention. This generally requires that the named inventor(s) contributed conceptually to the invention whether a new product, method, system, etc. The named inventor need not have personally reduced the concept to practice to be the legal inventor. By way of example, technicians who work on an inventive concept conceived by another person are generally not considered inventors unless they contributed conceptually to the invention.
Fortress Iron, LP (“Fortress”) is company that designs railing and fencing products used in the construction of outdoor living spaces. Its products are manufactured by two Chinese companies. In 2013 Fortress’s owner had an idea for a particular type of railing. He and a Fortress employee worked with one of Fortress’s suppliers to convert the idea into an actual product. Two employees of the supplier, a Mr. Lin and a Mr. Huang, contributed suggestions which were incorporated into the product’s final design. Fortress then filed a patent application as the assignee naming its owner and the employee as the inventors.
In 2021, Fortress sued Digger Specialties, Inc. (“Digger”) for patent infringement. During discovery, Digger learned that Lin and Huang had contributed conceptually to the invention, and Fortress acknowledged that the two men were indeed inventors. Fortress was faced with the prospect of patent invalidation under the patent statute since all inventors had not been named in the application. Statute 35 U.S.C. § 256(a) – (b) states:
(a) Correction. Whenever through error a person is named in an issued patent as the inventor, or through error an inventor is not named in an issued patent, the Director may, on application of all the parties and assignees, with proof of the facts and such other requirements as may be imposed, issue a certificate correcting such error.
(b)The error of omitting inventors or naming persons who are not inventors shall not invalidate the patent in which such error occurred if it can be corrected as provided in this section. The court before which such matter is called in question may order correction of the patent on notice and hearing of all parties concerned and the Director shall issue a certificate accordingly.
At the district court level, Fortress was able to successfully add Lin as a co-inventor following the procedure outlined in § 256(a). Unfortunately for Fortress, Huang had departed the employment from the Chinese manufacturer in 2016 and could not be located.
Fortress then moved the district court to add Huang as a coinventor pursuant to 35 U.S.C. § 256(b). The district court denied the motion and instead granted summary judgement to Digger. Fortress then appealed to the Federal Circuit Court of Appeals (“CAFC”), arguing that Huang was not a “party concerned” under § 256(b) since he could not be located. The CAFC disagreed by noting that the inventor “occupies the central role in the patent process” and it is irrelevant if they have an economic stake in the outcome. Being named an inventor on a patent “carries legal, financial, and ownership consequences that an inventor as a right to contest.” As such, Huang was entitled to receive the notice called for under § 256(b). Absent this notice, the requirements of § 256(b) could not be satisfied and inventorship could not be fixed. The Court affirmed the district court finding that the patent was invalid under § 101 because the patent incorrectly lists its inventors and cannot be corrected according to the law.
The CAFC’s decision may seem draconian, but it is consistent with the statute. Accordingly, all patent applicants should ensure that the application names all inventors. Failure to name all inventors (or naming people who are not inventors) could have serious implications not only in the event of an infringement lawsuit as the Fortress case demonstrates, but also in business transactions involving the acquisition of patents.
The following Take Home Points provide tips for ensuring that patent inventorship issues do not show up down the road.
Take Home Points
1. Companies filing patents resulting from the inventive efforts of its employees or independent contractors who have an assignment obligation to the company should ensure that all “assigning” individuals are named in the application. Copies of the executed assignment agreements should be retained with all patent-related documentation. The assignments should delineate the nature of the inventive concept contributed by the Inventor.
2. Individuals/companies engaged in a joint venture should ensure that each party’s respective proprietary rights in any invention resulting from the joint venture are carefully defined in an executed joint venture agreement. For example, will both parties be the owners of any resulting patent rights? Either way, as the Fortress case demonstrates, all actual inventors should be named in any resulting patent application.
3. Funders/investors of research and development conducted by others are not inventors unless they themselves are inventors under patent law’s definition of inventor. This issue came up recently for the undersigned and the funder was not named as an inventor on the application. As § 256(b) states, patent invalidation may arise when inventors are omitted or non-inventors are named as inventors.
4. Written documentation is an essential requirement of the inventive process. In the old days, laboratory notebooks were the norm for documenting experimentation and development activities for potential inventions. The pages had to signed, dated, and witnessed. Today electronic notebooks are the norm. Such documentation is essential should there ever be a patent contest and for demonstrating the “true” inventor’s inventive efforts should inventorship ever become an issue.
5. Due diligence activities involving the acquisition of patent applications and/or patents as an IP asset should include verifying that all inventors are/were included in the applications and that no non-inventor was included. Such steps are important for eliminating a potential cause of patent invalidation in the event the patent acquiring party should ever sue for patent infringement. If inventorship errors are found, the parties to the transaction should take steps to correct the inventorship under 35 U.S.C. § 256(a) if feasible.
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Susan Dierenfeldt-Troy
