Joint Authorship: What Copyright Co-Owners Can and Cannot Do Without Each Other
Last updated: November 2026. Reviewed by Pavel Kolmogorov, California business litigation attorney (State Bar No. 321018).
Joint authorship exists when two or more authors prepare a work intending their contributions to merge into one whole, and it makes each of them a co-owner of the copyright. (17 U.S.C. §§ 101, 201(a).) A true co-owner may use and license the work without permission but must share the profits. (Oddo v. Ries (9th Cir. 1984) 743 F.2d 630, 633.) Whether a collaborator qualifies is often the real fight. Kolmogorov Law, P.C. litigates these disputes in Orange County, Los Angeles, and across California.
Call (909) 235-6116 or contact us online to discuss a co-ownership claim over software, music, film, writing, or brand content.
What joint authorship requires
The statute defines a joint work as one prepared by two or more authors with the intention that their contributions be merged into inseparable or interdependent parts of a unitary whole. (17 U.S.C. § 101.) The authors of a joint work are co-owners of the copyright. (17 U.S.C. § 201(a).)
The Ninth Circuit reads that definition narrowly. Each claimed author must make an independently copyrightable contribution. (Aalmuhammed v. Lee (9th Cir. 2000) 202 F.3d 1227, 1231.) Ideas, direction, feedback, and funding generally do not count, however valuable they were.
Even a copyrightable contribution may not be enough. The court held that a creative contribution does not by itself make someone an author of the whole work. (Id. at p. 1233.) Absent a contract, it looks at three things: who exercised control over the work, whether the parties showed a shared intent to be co-authors, and whether the work's appeal depends on both contributions. Control is often the most important. (Id. at p. 1234.)
So the consultant who rewrote several scenes, or the engineer who contributed one module, is usually not a joint author of the film or the platform. Two founders who designed and wrote a product together, each with a say over the final result, usually are.
How co-ownership disputes arise in business
Two developers build an application before forming a company. One leaves. No assignment to the company was ever signed, and both now claim the code. Our page on co-founder disputes covers the equity side of that breakup.
A songwriter and a producer finish a recording with no split sheet. Years later one of them licenses the track for a commercial.
A brand and an outside creative studio develop a character together. The studio starts selling merchandise.
In each case the first question is ownership, and the paperwork often answers it before joint authorship doctrine applies. An employee's work within the scope of the job ordinarily belongs to the employer. A contractor's work usually does not, unless there is a signed assignment or a signed work-for-hire agreement covering one of the statutory categories. Our page on contractors and work made for hire explains those rules.
What a co-owner may do alone
Each co-owner has an independent right to use the work and to license its use. A co-owner cannot be liable to another co-owner for infringing the shared copyright. (Oddo, supra, 743 F.2d at pp. 632-633.) If your former collaborator really is a co-owner, he can license the software to others without asking you, and you cannot stop him with an infringement suit.
There are limits. As the Ninth Circuit has explained, a license from one owner cannot cut off the other owners' rights, so in practice it is nonexclusive as to them. An owner may transfer his own share, but he cannot sell or exclusively license yours. Apart from transfers by operation of law, a transfer of copyright ownership, including an exclusive license, must be in a writing signed by the owner of the rights conveyed or the owner's authorized agent. (17 U.S.C. §§ 101, 204(a).)
A company that wants exclusive rights to jointly owned software therefore needs a signed grant from every owner.
The duty to account for profits
The price of that freedom is money. A co-owner must account to the other co-owners for any profits earned from licensing or using the copyright. (Oddo, supra, 743 F.2d at p. 633.)
The duty does not come from the infringement provisions of the Copyright Act. It comes from equitable principles of unjust enrichment and the general law of co-ownership. (Ibid.) Two consequences follow. The claim is often pleaded under state law, sometimes in state court. And the remedy is a share of profits, not statutory damages.
How the profits divide depends first on any agreement. Without one, do not assume the split tracks who did more of the work. Our page on the accounting cause of action describes how these claims are pleaded and proved in California.
The three-year clock on ownership claims
A civil action under the Copyright Act must be commenced within three years after the claim accrued. (17 U.S.C. § 507(b).) For ownership, the clock works differently than it does for infringement.
A claim of joint authorship accrues once. It is barred three years after a plain and express repudiation of the claimant's authorship. (Aalmuhammed, supra, 202 F.3d at pp. 1230-1231.)
Repudiation in a business setting can be an email saying "you have no ownership in this" or a product release that credits someone else. The other side may argue that a copyright registration omitting your name was one too. If you received any of those, plan as if the three years began on the earliest date. Infringement claims follow a different rule, covered on our page on the copyright statute of limitations.
If you are the one claiming a share
Gather proof of what you personally created: commits, drafts, session files, dated designs. Then gather proof of control and intent, such as credits, emails describing the project as "ours," and decisions you made that the other side accepted. Ask for an accounting in writing before you sue.
If someone claims a share of your work
Do not ignore the claim, and do not answer it with a casual email that concedes authorship. Check the paperwork first: employment agreements, contractor agreements, assignments, and registrations. Consider whether a clear written repudiation is in your interest, since it starts the three-year clock.
When ownership under the Copyright Act is at issue, the case generally belongs in federal court. For a defendant based in Orange County or Los Angeles, that is usually the Central District of California, in Santa Ana or Los Angeles. Pure accounting disputes between acknowledged co-owners may belong in Superior Court.
What to bring to the first meeting
- Any agreement touching the work: partnership, employment, contractor, split sheet, or assignment.
- Version history, drafts, or project files showing who created what.
- Copyright registrations and applications.
- Emails or messages about credit, ownership, or payment.
- Licenses granted to others and any revenue records you have.
Frequently asked questions
Can a co-owner of a copyright license the work without permission?
Yes, on a nonexclusive basis. In California's federal courts, each co-owner has an independent right to use and license the work, and one co-owner cannot sue another for infringement. (Oddo v. Ries (9th Cir. 1984) 743 F.2d 630, 633.) The licensing owner must account to the others for the profits. A license that excludes the other owners needs their agreement.
A former collaborator claims he co-owns the software we built and is licensing it to others. Can he do that?
Only if he is a joint author or otherwise holds a share. In the Ninth Circuit that requires an independently copyrightable contribution plus factors such as control and shared intent. If he qualifies, he may license it nonexclusively but owes you a share of profits. If he does not, his licensing may be infringement. A California court will look first at any written agreements.
What is required for joint authorship?
A copyrightable work, two or more authors, and an intention that their contributions merge into inseparable or interdependent parts of a unitary whole. (17 U.S.C. § 101.) Federal courts in California also require that each author contribute independently copyrightable material and weigh control over the work, objective signs of shared intent, and whether the work's appeal turns on both contributions.
How long do I have to claim co-ownership of a copyright?
Three years from a plain and express repudiation of your authorship, under 17 U.S.C. § 507(b) as applied by the Ninth Circuit. The claim accrues once, unlike infringement claims. For California creators and businesses, a credit that leaves you out or a written denial of your ownership can start the period, and the other side may argue that a registration naming only itself did too.
My business partner and I wrote a training course together and never signed anything. Who owns it now that we split?
Probably both of you, if each wrote copyrightable material and you intended one combined course. As co-owners under federal law, each of you may use and license the course nonexclusively and must share profits from doing so. Neither can give a third party rights that shut the other out without the other's consent. If a California partnership or company owned the course, the entity's governing documents may change that answer.
Talk to a California copyright ownership attorney
If a collaborator is claiming your work, or using work you helped create, call (909) 235-6116 or contact us online. Kolmogorov Law, P.C. is located at 327 Magnet, Irvine, CA 92618, and represents businesses and creators in Orange County, Los Angeles, and throughout California. Other copyright and trademark work is described on our intellectual property page.
This page provides general information about federal copyright law and is not legal advice. Outcomes depend on the agreements, each person's contribution, the facts, and the court.