Invention Assignment Laws in Wisconsin: Who Owns What You Create

Federal law does not comprehensively regulate invention assignment rights between employers and employees. The Patent Act, 35 U.S.C. § 101, recognizes that inventors own their patents unless they assign them by contract, but federal law does not restrict what employers can claim through agreements. The Defend Trade Secrets Act (18 U.S.C. § 1836) protects trade secrets but does not address invention ownership.

Most federal protection comes through state law, which varies significantly. At the federal level, the USPTO (United States Patent and Trademark Office) administers patent law but does not intervene in employment disputes over ownership. Federal courts apply contract law principles to interpret invention assignment agreements, but have no federal baseline requirement that such agreements be reasonable or limited in scope. Employees working on federally funded research may have specific rights under the Patent Cooperation Treaty or Defense Department rules, but these are narrow exceptions.

Federal employment law (Title VII, the ADEA, the ADA) does not address invention ownership. Therefore, Wisconsin state law provides the primary legal framework governing what inventions your employer can claim.

Wisconsin Statute Chapter 134 provides detailed statutory protection for employee inventions, making Wisconsin one of the most employee-protective states on this issue. Wisconsin law is substantially stronger than federal baseline (which is essentially silent on the topic) and is comparable to California's protections, though slightly different in application.

Under Wisconsin Statute section 134.04, an employer can claim ownership of an employee's invention only if: (1) the invention is made on company time, on company premises, or using company resources; (2) the invention is related to the employer's business, existing or reasonably anticipated; or (3) the invention is created using trade secrets or confidential information of the employer. Critically, Wisconsin law applies only to inventions developed by the employee in the course of work, not to inventions developed entirely on personal time.

Wisconsin Statute section 134.03 requires that any invention assignment agreement be in writing and provided to the employee at the time of hire (or before, but certainly before the employee begins work that generates the invention). The statute imposes strict notice requirements: the agreement must be separate from the general employment agreement and must explicitly state what inventions are being assigned. Employers cannot bury invention assignment language in a general non-compete clause or other catch-all provision.

Section 134.05 further protects employees by stating that no employee shall be required to sign an invention assignment agreement that claims inventions developed entirely on the employee's own time, without use of the employer's equipment, facilities, or trade secrets, and that do not relate to the employer's business or a reasonably anticipated future business of the employer. This is a critical carve-out: Wisconsin law explicitly invalidates overly broad agreements. An employer cannot require an employee to assign all inventions ever created, or inventions wholly unrelated to the employer's business.

Coverage is broad: Wisconsin's protections apply to all employees working in Wisconsin, regardless of employer size or industry. There is no threshold based on number of employees or business revenue. This differs from some federal protections that only apply to employers with 15+ employees. State statute 134.04 applies equally to small startups and large corporations.

Unique to Wisconsin is the explicit statutory framework. Rather than relying on case law or broad non-compete principles (as some states do), Wisconsin has enacted clear statutory limits on what employers can claim. This gives employees stronger legal ground to challenge overbroad agreements. Wisconsin courts have consistently enforced these statutes to void invention assignment provisions that violate the statutory limits.

Remedies under Wisconsin law include voiding the illegal invention assignment clause, allowing the employee to retain ownership of the invention, and in some cases recovering damages if the employer wrongfully claimed ownership or filed a patent in the employer's name without authorization. Employees can bring suit in Wisconsin state court.

Wisconsin law does provide exceptions and defenses that favor employers in certain circumstances. First, if an employee is hired specifically to invent or develop in a particular field, the employer's claim is broader. An employee hired as a research scientist or inventor at a pharmaceutical company has a different presumption than an employee hired as an accountant who invents in their spare time. However, even hired inventors retain ownership of inventions developed outside the scope of their role.

Second, if an invention is developed using trade secrets or confidential information of the employer, the employer has a claim even if the invention was developed on personal time, provided the employee had access to those trade secrets during employment. The key distinction is whether the employee used proprietary information; merely knowing the field does not trigger this exception.

Third, an invention assignment agreement that has been signed in compliance with Wisconsin Statute section 134.03 (written agreement provided at hire) and complies with section 134.04 (limited to work-related inventions) will be enforced. The employee cannot later claim the invention is personal property if the agreement is valid on its face. However, the agreement must be specific and cannot be a blanket assignment of all future inventions.

Fourth, employers can protect trade secrets and confidential information through separate confidentiality agreements, which are valid under Wisconsin law and provide remedies beyond invention assignment. This is an important distinction: an employer does not need to claim ownership of an invention to prevent an employee from using a trade secret or disclosing confidential information.

Fifth, at-will employment status does not strengthen an employer's invention claims. Wisconsin is an at-will employment state, but at-will doctrine does not override the statutory limits in Chapter 134. An employer can fire an employee for any reason (subject to other legal limits), but cannot use that power to extract a broader invention assignment than the law permits.

Sixth, agreements signed under duress or coercion may be voidable. If an employer demands an employee sign a broad invention assignment agreement after employment has begun, or threatens termination if the employee will not sign an illegal agreement, Wisconsin courts may void the agreement as procured by duress.

Seventh, very broad non-compete agreements that attempt to claim all future work or ideas are disfavored in Wisconsin and may be unenforceable, particularly if they effectively prevent an employee from working in their field after leaving the employer. This is distinct from invention assignment but often litigated together.

Step 1 — Document Everything. As soon as you are hired or suspect your employer may claim ownership of an invention you are developing, begin detailed documentation. Keep personal notes on when you worked on the invention (dates, times, location—note if you worked at home or at the office), what resources you used (your own computer, company equipment, internet access, materials), and whether you used any company trade secrets or confidential information. Maintain copies of emails, chat messages, or memos that show when you disclosed the invention to the employer, how you developed it, and what you said about ownership at the time. Preserve the original invention assignment agreement you signed (or confirmation that you did not sign one, or that no written agreement was provided at hire). Save any documentation showing the invention is unrelated to the employer's business or current products. Take screenshots of your work portfolio, patents you filed personally, or copyright registrations. Store all documentation in a personal cloud account or external drive that is not accessible through the employer's network.

Step 2 — Review the Employment Agreement and Invention Assignment Clause. Carefully read your employment agreement, any separate invention assignment agreement, and any confidentiality or non-compete agreement you signed. Identify exactly what language claims ownership of your inventions. Check whether the agreement was provided in writing at the time of hire, as Wisconsin Statute section 134.03 requires. Note the specific definition of what inventions are claimed (e.g., "all inventions related to the business," "all inventions developed on company time," "all inventions ever created"). Compare the agreement to the statutory limits in Wisconsin Statute section 134.04. If the agreement claims ownership of inventions developed entirely on your own time, without company resources, and unrelated to the employer's business, it likely violates Wisconsin law. Consult the statute directly: Wisconsin Statute Chapter 134 is publicly available online and is written in plain language.

Step 3 — Send a Written Internal Complaint and Demand. Before filing with a government agency, send a written email or letter to your employer (typically to HR and your direct manager) clearly stating: (a) what invention you are claiming ownership of, (b) when and where it was developed, (c) what resources you used (personal, not company), (d) that it is unrelated to the employer's business (if applicable), and (e) that you are asserting personal ownership under Wisconsin Statute section 134.04. State that you are requesting written confirmation that the employer does not claim ownership. Request a response within 10 business days. Keep a copy of this communication. This step is important because it creates a record and may prompt the employer to back down. If the employer responds claiming ownership despite your assertion, that response becomes evidence that the employer is asserting an illegal claim (if the invention qualifies for employee protection under Wisconsin law).

Step 4 — File a Complaint with the Wisconsin Department of Safety and Professional Services or Consult Legal Counsel. Wisconsin does not have a dedicated employment agency for invention disputes comparable to the EEOC. Instead, you have two options: (1) Consult an employment attorney licensed in Wisconsin immediately. Do not wait. Invention disputes are complex, and an attorney can evaluate whether the agreement is illegal, whether you have a strong claim to ownership, and whether litigation or demand letters might resolve the dispute. Find an attorney through the State Bar of Wisconsin (wisbar.org, 608-257-3838). Specifically seek attorneys with experience in intellectual property or employment law. (2) If you believe the employer has committed a crime (such as theft or conversion of your property), you can file a police report with the Wisconsin Department of Justice, though this is rare and typically not the first step.

Step 5 — Prepare for Litigation or Settlement Negotiation. If internal complaint fails and an attorney confirms you have a strong claim, the attorney will likely send a demand letter to the employer stating that the invention assignment agreement is void under Wisconsin Statute section 134.04, that you own the invention, and that you are demanding the employer cease claiming ownership, cease using the invention, and potentially pay damages for any unauthorized use or patent filing. Many disputes settle at this stage. If settlement fails, your attorney will file suit in Wisconsin state court (Circuit Court in the county where you work or where the employer is located) seeking a declaratory judgment that the invention assignment agreement is void as to your invention, that you own the invention, and for damages including attorney's fees if the statute permits. Wisconsin Statute section 134.04 does not explicitly provide for attorney's fees, but Wisconsin courts may award them under breach of contract or conversion theories. Expect litigation to take 18-36 months from filing to resolution.