How Long Does a Company Have to Sue for Trade Secret Misappropriation in California?

Last updated: November 2026. Reviewed by Pavel Kolmogorov, California business litigation attorney (State Bar No. 321018).

Three years. An action for misappropriation under California's Uniform Trade Secrets Act must be brought within three years after the misappropriation is discovered or, with reasonable diligence, should have been discovered. A continuing misappropriation is a single claim, so later uses of the same secret by the same defendant do not restart the clock. (Civ. Code, § 3426.6.) The federal Defend Trade Secrets Act sets the same period. (18 U.S.C. § 1836(d).) Kolmogorov Law, P.C. represents companies that bring these claims and companies that defend them.

Call (909) 235-6116 or contact us online to discuss a deadline before it decides the case.

When the three years begin

The period starts at discovery, actual or constructive, and discovery does not mean proof. Under California's general discovery rule, a plaintiff has reason to discover a claim when it has reason at least to suspect a factual basis for its elements. The Court of Appeal applied that rule to a trade secret claim against a customer of the original taker. It held that the period began when the plaintiff had any reason to suspect that the customer knew, or should have known, the information was a trade secret. The focus was on the plaintiff's suspicions, not on the customer's actual state of mind. (Cypress Semiconductor Corp. v. Superior Court (2008) 163 Cal.App.4th 575.)

The starting date is likely to sit in the company's own files. It may be a customer's tip, a look-alike product at a trade show, an exit interview, a forensic report, or a letter the company itself sent. The date the company would prefer is not the test. The earliest date on which a reasonable company would have suspected wrongdoing generally is.

Why continued use does not restart the clock

The California Supreme Court has separated a misappropriation from a claim. A misappropriation occurs with the first wrongful acquisition and again with each misuse or disclosure. A claim against a given defendant arises only once, when the secret is first misappropriated, subject to the discovery rule. Each later use adds to that one claim. (Cadence Design Systems, Inc. v. Avant! Corp. (2002) 29 Cal.4th 215.)

So a company that learned of a taking cannot wait and then sue on a use that came four years later. The damages may grow with each use, but the deadline does not move.

Each defendant has its own clock

The single-claim rule works defendant by defendant. The Supreme Court noted in the same decision that a continuing misappropriation can produce separate claims against different defendants, with different accrual dates.

The Court of Appeal decision described above is the example. The claim against the customer had its own accrual date, separate from the claim against the original taker. On the record in that case, that date was a question for a jury. (Cypress Semiconductor, supra, 163 Cal.App.4th at p. 588.)

Two consequences follow. A claim against the first taker can expire while a claim against a later recipient is still alive. And discovering the first taking does not by itself start the clock against a company that had not yet touched the secret.

Other claims on the same facts keep their own deadlines

A trade secret complaint may carry other claims, each with its own period.

• Breach of a written nondisclosure agreement has four years. (Code Civ. Proc., § 337, subd. (a).) Our page on breach of an NDA covers that claim.
• The federal claim has three years on the same discovery rule, and it also treats a continuing misappropriation as one claim. (18 U.S.C. § 1836(d).) Our comparison of the federal and California statutes covers the rest.
• Tort claims that only restate the misappropriation may be displaced altogether, as our page on CUTSA preemption explains.

The parties can also agree to pause the clock while they talk. Our page on tolling agreements explains how, and our overview of California limitations periods lists the periods for related claims.

A company that found out two years ago

Take a company that learned two years ago that a former vendor copied its process. On those facts about one year remains, and possibly less.

The first question is whether two years ago was really the first warning. An earlier customer complaint, or an internal email voicing the same suspicion, can move the start date back.

The second question is who the defendants are. The vendor's clock has been running since the first reason to suspect it. The clock against a company that began using the process only recently may have started later.

Waiting has another cost. A long delay can undercut a request for urgent relief such as a preliminary injunction.

The practical steps are short. Preserve the documents that show when and how the company found out. Decide whom to sue. Then file, or get a signed tolling agreement, well before the earliest plausible date.

If your company is the defendant

Limitations is a defense worth developing from the first day. The evidence is in the plaintiff's hands: when it first complained, what its employees wrote to each other, when it hired an investigator, and whether it sent a demand letter. A demand letter dated more than three years before the complaint can show when the plaintiff first had reason to suspect.

Ask for those documents in the first round of discovery. In the appellate case above, the trial court had excluded evidence of the limitations defense, and the Court of Appeal ordered that the defense go to the jury.

What to bring to the first meeting

• A dated timeline of how the company learned of the taking, starting with the first suspicion.
• The emails, reports, or customer messages behind each date on it.
• Any demand letter sent or received, and any reply.
• The agreements with the people or companies involved.
• A list of everyone believed to have received or used the information, and since when.

Frequently asked questions

We found out two years ago that a former vendor copied our process. Is it too late to sue?

Probably not yet, but time is short. California gives three years from the date the misappropriation was discovered, or should have been discovered with reasonable diligence, under Civil Code section 3426.6. If two years ago was the first reason to suspect the vendor, about one year remains. An earlier warning sign would shorten that.

What is the statute of limitations for trade secret misappropriation in California?

Three years. Civil Code section 3426.6 requires an action for misappropriation to be brought within three years after the misappropriation is discovered or, by the exercise of reasonable diligence, should have been discovered. A continuing misappropriation counts as a single claim for this purpose. The federal statute has the same three-year rule.

Does each new use of a trade secret restart the statute of limitations?

No. The California Supreme Court has held that a claim against a given defendant arises once, when the secret is first misappropriated, and that each later use or disclosure adds to that single claim. Continued use can increase the damages, but it does not give the owner a new three-year period against the same defendant.

We knew years ago that a former partner took our formula. Can we still sue the manufacturer that started using it last year?

Possibly. California courts treat each defendant separately. A claim against a later recipient accrues when the owner has reason to suspect that this recipient knew, or had reason to know, it was using another's trade secret. The claim against the original taker may be barred while the claim against the newer user remains timely.

Is the federal trade secret deadline different?

No. Under 18 U.S.C. § 1836(d), a civil action under the Defend Trade Secrets Act may not be commenced later than three years after the misappropriation is discovered or should have been discovered with reasonable diligence. Like California's statute, it treats a continuing misappropriation as a single claim. A California company may plead both claims in one complaint.

Talk to a California trade secret attorney

If a trade secret deadline is approaching, or a claim against your company looks stale, call (909) 235-6116 or contact us online. Kolmogorov Law, P.C. is located in Irvine, California. See also our trade secret attorney page.

This page provides general information about California and federal law and is not legal advice. Outcomes depend on the dates, the evidence of discovery, and the court.