Employee Invention Assignment in Missouri

Can a Missouri employer require assignment of every invention?

The statutory silence is verifiable. A review of the Revised Statutes of Missouri surfaces no employee-invention-assignment provision. The only invention statutes on the books sit in Chapter 417 and regulate something else entirely: the invention-developer services law (RSMo §§ 417.400–417.436) is a consumer-protection regime for firms that sell invention-promotion services to the public, and the Missouri Uniform Trade Secrets Act (RSMo §§ 417.450–417.467) governs misappropriation. Neither says anything about what an employment assignment clause may reach — so a Missouri employer starts from contract law, not a § 2870-style statutory ceiling, and the state's one invention statute protects consumers, not employees.

The substantive default that Missouri contract law operates against is the federal patent premise restated in Stanford v. Roche: absent an effective assignment, rights in an invention belong to the person who conceived it A.1.

“Since 1790, the patent law has operated on the premise that rights in an invention belong to the inventor.”

Missouri's appellate courts apply the same framework. In Corrigan v. Armstrong, Teasdale, Schlafly, Davis & Dicus, the Missouri Court of Appeals, adopting United States v. Dubilier Condenser Corp., explained that an employer who has not taken an assignment cannot demand ownership of an invention that is the employee's own conception A.2. Quoting Dubilier, the court said the employer

“has no equity to demand a conveyance of the invention, which is the original conception of the employee alone, in which the employer had no part.”

The practical consequence is that a Missouri employer can, in principle, contract for assignment more broadly than a California or Washington employer, because no statute carves out own-time inventions from the reach of the clause. But that breadth is not unlimited: an assignment clause is still an ordinary contract term, subject to general contract-law defenses and, where it operates as a restraint on the employee, to Missouri's reasonableness limits on restraints arising from employment. There is simply no statutory own-time safe harbor for the employee to invoke and no statutory ceiling for the drafter to code around.

Must a Missouri employer notify the employee?

There is nothing to give notice of. A notice requirement exists in California and Washington precisely to alert the employee to a statutory own-time carve-out that limits the assignment; Missouri has enacted no such carve-out, so there is no statutory line for a notice to mark. This is why the entry is marked not applicable rather than a bare no: the question presupposes a statutory carve-out that Missouri does not have.

One Missouri statute does mandate a cover-sheet notice in the invention space — RSMo § 417.409, part of the invention-developer services law — but that provision protects consumers who hire invention-promotion firms. It is not employment law and imposes nothing on employers. A statute search that surfaces Chapter 417 can create the false impression of an employment notice rule; there is none.

Where Missouri courts police the boundary between employer and employee claims to an invention, they do it through fact-intensive common-law analysis rather than statutory formalities. In Dewey v. American Stair Glide Corp., the Missouri Court of Appeals weighed exactly how much company time, material, and equipment the employee had used and concluded the employer acquired no rights at all B.1.

“The use of the small amount of company materials and equipment is not sufficient to establish a shop right.”

For a multistate employer the takeaway is the inverse of the notice states: a Missouri employer neither has to give a § 2872-style notice nor can rely on one to cure an overbroad clause. The enforceability of the assignment turns entirely on the contract language and the general limits on restraints, not on any statutory notice or disclosure formality.

Who owns an invention by default in Missouri?

Stanford v. Roche anchors the default. The Supreme Court held that even the Bayh-Dole Act did not displace the long-standing rule that an invention belongs to its inventor, treating that premise as the baseline against which any assignment is measured C.1.

“Since 1790, the patent law has operated on the premise that rights in an invention belong to the inventor.”

The leading Missouri application is Dewey v. American Stair Glide Corp. A welder who was not employed to do engineering or design work conceived a safety device for the company's stair lifts, built a mock-up during his lunch hour from scrap parts, and fully developed the drawing at home. The trial court gave judgment to the employer, but the Missouri Court of Appeals reversed: no shop right arose on those facts, and the employee recovered $30,000 for the employer's unjust enrichment in appropriating the idea C.3.

“In this case the facts simply do not show Dewey developed his idea on company time using company materials or the time of fellow employees. The evidence unmistakably shows the idea was originated and fully developed by Dewey at home, and the work performed at the plant in developing the idea was during his lunch hour.”

Even where a shop right does arise, it conveys no title. In Corrigan v. Armstrong, Teasdale, Schlafly, Davis & Dicus, the Missouri Court of Appeals restated the doctrine in its modern form: the employer's shop right is a bare non-exclusive, royalty-free license to replicate the invention, not a transferable ownership interest C.2.

“Thus, the ‘right’ the employer acquires is more accurately described as a non-exclusive license or privilege to replicate the invention or trade secret, without payment for that license or privilege.”

The narrow exception is the employee hired to invent. Under United States v. Dubilier Condenser Corp., an employee engaged to make a particular invention who succeeds during the term of service must assign the resulting patent to the employer C.4. No Missouri appellate decision found in our review rests squarely on the hired-to-invent doctrine, so in Missouri it operates as background federal doctrine rather than a developed state-law rule — Dewey itself turned in part on the fact that the welder was not employed to design or invent.

“One employed to make an invention, who succeeds, during his term of service, in accomplishing that task, is bound to assign to his employer any patent obtained.”

Because ownership starts with the inventor and Missouri has no statute filling the gap, the dependable path for an employer is a written present-assignment (hereby assigns) clause that transfers legal title automatically on conception, rather than a future promise to assign that leaves the employer with a mere equitable claim — or, worse, no claim at all, as in Dewey.

Are trailing-assignment (holdover) clauses enforceable in Missouri?

Two gaps define the Missouri picture. First, there is no statute: nothing caps the duration of a post-employment trailing assignment or otherwise limits what such a clause may reach. Second, our review found no Missouri decision testing an invention-holdover clause on the merits. The closest encounter is Bunting v. McDonnell Aircraft Corp., 522 S.W.2d 161 (Mo. banc 1975), where the record reproduced a company patent plan whose assignment obligation extended to inventions made within six months after employment ended — but the court decided only compensation questions under the plan and never adjudicated the trailing clause, so the decision supplies no holding on enforceability either way.

What Missouri does supply is a firm public-policy boundary on what an employer may capture from a departed employee. In National Rejectors, Inc. v. Trieman — a trade-secret suit against former employees who had signed no restrictive covenant, not a covenant-enforcement case — the Missouri Supreme Court en banc stated the limiting principle D.1.

“We follow the rule that an employee may leave his employment and establish a new enterprise in competition with the former employer, absent a valid restrictive covenant therefor, or breach of a confidential relationship, and in connection therewith utilize his knowledge, memory, skill and experience gained in the former employment.”

The legislature has since written reasonableness into adjacent covenant law: RSMo § 431.202 declares certain employee- and customer-non-solicitation covenants presumptively reasonable when limited to one year, and the Missouri Uniform Trade Secrets Act (RSMo §§ 417.450–417.467) supplies the trade-secret backstop that a well-drafted holdover clause protects. Neither statute reaches invention assignments, but together they mark the doctrinal neighborhood a trailing clause lives in — restraints tied to a protectable interest, judged for reasonableness.

Extending that framework to holdover assignments is a prediction, not a holding. Because no Missouri court has spoken, a reader could fairly describe the question as open; the reasonableness answer rests on analogy to Missouri's general restraint doctrine, not on invention-specific authority. A Missouri court asked to enforce a clause sweeping in inventions an ex-employee conceives after leaving would most likely ask whether the restriction is reasonable — no broader than needed to protect the employer's trade secrets and confidential information — because a clause that captures inventions built from the former employee's general knowledge, skill, and experience collides directly with the mobility rule National Rejectors states. Out-of-state decisions voiding open-ended holdover assignments apply other states' law and are at most nonbinding guidance; they are not Missouri law.