What Do You Still Own After Signing an Invention Assignment?

What an Invention Assignment Actually Transfers

Patent rights start with the person who invents. The U.S. Supreme Court opened its decision in Board of Trustees of the Leland Stanford Junior University v. Roche Molecular Systems, Inc., 563 U.S. 776 (2011) with that rule: “Since 1790, the patent law has operated on the premise that rights in an invention belong to the inventor.” The Court added that “an employer does not have rights in an invention ‘which is the original conception of the employee alone’” unless there is an agreement to the contrary, and that “mere employment is sufficient to vest title” was an idea it had rejected.

That is why your employer asked you to sign. The invention assignment is the agreement that moves your rights to the company. Under 35 U.S.C. § 261, patent applications and patents “shall be assignable in law by an instrument in writing.”

Present Assignment Versus a Promise to Assign

The wording matters. Some agreements say you “hereby assign” future inventions; others say you “agree to assign” them. In the litigation behind Stanford v. Roche, the Federal Circuit treated a researcher’s “agree to assign” as, in the Supreme Court’s description, “a mere promise to assign rights in the future,” while a later agreement that said “do hereby assign” “itself assigned” his rights. The company holding the second document came out ahead. If your agreement uses present-tense language, assume ownership of covered inventions passed to the company automatically, without any further document.

The Shop Right When There Is No Assignment

Without an assignment, an employer may still hold a limited right. In United States v. Dubilier Condenser Corp., 289 U.S. 178 (1933), the Supreme Court described the “shop-right”: when an employee, “during his hours of employment, working with his master’s materials and appliances, conceives and perfects an invention for which he obtains a patent, he must accord his master a non-exclusive right to practice the invention.” The employee keeps ownership; the employer keeps the right to use the invention.

Minnesota’s Limit: Minn. Stat. § 181.78

Minnesota caps how far an assignment clause in an employment agreement can reach. Minn. Stat. § 181.78, subd. 1 provides that an assignment provision “shall not apply to an invention for which no equipment, supplies, facility or trade secret information of the employer was used and which was developed entirely on the employee’s own time, and (1) which does not relate (a) directly to the business of the employer or (b) to the employer’s actual or demonstrably anticipated research or development, or (2) which does not result from any work performed by the employee for the employer.” A provision that tries to reach such an invention is “to that extent void and unenforceable.”

In plain English, an invention you made is outside the clause when you can answer yes to every question in the left column and yes to at least one in the right:

Both must be true	And at least one must be true
You used none of the employer’s equipment, supplies, facilities, or trade secret information	The invention does not relate directly to the employer’s business or to its actual or demonstrably anticipated research or development
You developed it entirely on your own time	The invention does not result from any work you performed for the employer

Expect an employer to read these conditions narrowly. Your strongest position is an invention that meets all of them at once: built on your own time and equipment, outside the company’s line of business, and unconnected to your job. One use of a company laptop or one test run in the company lab can put an otherwise personal invention in dispute.

The statute adds two protections. Under subdivision 2, “No employer shall require a provision made void and unenforceable by subdivision 1 as a condition of employment or continuing employment.” Under subdivision 3, an employer whose agreement (entered into after August 1, 1977) requires you to assign inventions “must also, at the time the agreement is made, provide a written notification” to you describing the same exclusion. Look for that notice in your onboarding papers; it is often an exhibit to the agreement. Section 181.78 itself does not state a consequence for an employer that skipped the notice, so a missing notice is a fact to raise with an attorney, not an automatic release. The employer-side view of the same statute is in IP ownership for Minnesota employers.

What You Still Own

After signing a typical invention assignment, you generally still own:

• Inventions outside the clause’s own definition. Many clauses cover only inventions made during employment that relate to the business. Read the definition before assuming the worst.
• Inventions protected by section 181.78. Any part of the clause that reaches them is void.
• Inventions you listed as prior inventions. Most agreements include a schedule for inventions you brought with you.
• Your general skill and know-how. An invention assignment transfers inventions, not your experience. Confidentiality obligations still restrict what company information you may use.

When Aaron Hall analyzes a dispute over what an employee still owns, the question turns on two facts: when the idea was conceived, and what work the person was doing for the company at that time. Those facts are then compared with what the agreement’s definition of covered inventions and its term actually reach. That is why dated records of your own work matter more than any general reading of the agreement.

Starting a Business or Joining a Competitor

Leaving does not undo what the agreement already assigned. Before you build a product or accept an offer, take these steps:

1. Find every agreement you signed. The offer letter, the invention assignment, any confidentiality agreement, and any equity or bonus plan documents can each carry IP terms.
2. Read the definition of covered inventions and the time window. Some agreements reach inventions conceived during employment even if you finish them later, and some include a clause reaching inventions made for a period after you leave. Whether such a clause is enforceable is its own question; see post-employment IP assignment clauses and enforceability of assignment of invention clauses.
3. Check what you disclosed. Many agreements require you to report inventions while employed. See invention disclosure requirements.
4. Separate the new work cleanly. Use your own equipment and your own accounts, work on your own time, and keep dated records of when and how you developed the new idea. That record is what proves the section 181.78 conditions if a dispute arises.
5. Leave the employer’s materials behind. Taking files, code, or customer data invites claims against you; see litigation risk from former employer IP.

A noncompete is a separate question. Under Minn. Stat. § 181.988, subd. 2, “Any covenant not to compete contained in a contract or agreement is void and unenforceable,” and the enacting session law makes that section apply to agreements entered into on or after July 1, 2023. The same section excludes nondisclosure agreements and agreements “designed to protect trade secrets or confidential information” from its definition of a covenant not to compete, so your confidentiality obligations survive even where a noncompete does not. More on that in the Minnesota noncompete FAQ.

What If the Company Asks You to Sign Patent Papers?

Assigning ownership does not take away your status as inventor. Under 35 U.S.C. § 115(a), a patent application “shall include, or be amended to include, the name of the inventor for any invention claimed in the application,” so your name stays on the company’s application if you invented what it claims. The company will usually ask you to sign an inventor declaration and an assignment. Refusing the declaration does not stop the filing, because federal law lets the company file a substitute statement in its place; refusing the assignment can breach your agreement if it obligates you to assign. What each document says, what to check before signing, and what happens if you decline are covered in do you have to sign your employer’s patent declaration.

If You Were a Contractor, Not an Employee

Section 181.78 addresses a provision “in an employment agreement.” If you signed a consulting or independent contractor agreement, expect that agreement’s own wording to control which inventions it reaches, and read its IP section closely. The patent paperwork works the same way for contractors; see do you have to sign your employer’s patent declaration. For how ownership defaults differ between employees and contractors, see patents for Minnesota employers and the employment law practice area.