An intellectual property lawsuit is a civil case, almost always in federal court, in which the owner of a patent, trademark, copyright, or trade secret asks a judge to stop someone from using that right without permission and to pay for the harm already done. How intellectual property cases work depends heavily on which of those four rights is at stake: the registration you need before filing, the court you file in, the deadline you’re racing, what you have to prove, and what you can collect all shift with the category. The stages themselves are consistent. Confirm your rights, file a complaint, serve the defendant, work through discovery, and try the case or settle it along the way.
The Four Types of IP Claims
Every IP case starts with identifying which right was infringed, because the statute controls everything that follows.
Patent infringement covers making, using, selling, or importing a patented invention without the patent holder’s permission.1Office of the Law Revision Counsel. 35 U.S. Code 271 – Infringement of Patent Patents reach utility inventions, ornamental designs, and plant varieties.
Trademark infringement protects branding: logos, slogans, product names, and trade dress. The Lanham Act lets an owner stop uses of a mark that are likely to confuse consumers about who made a product or provided a service.2United States Patent and Trademark Office. Likelihood of Confusion
Copyright infringement covers unauthorized reproduction, distribution, or public display of original works fixed in a tangible form, including books, music, film, software, and architectural designs.3Office of the Law Revision Counsel. 17 U.S. Code 102 – Subject Matter of Copyright In General Copyright attaches automatically at creation, but registration governs whether you can sue and what you can recover.
Trade secret misappropriation, under the federal Defend Trade Secrets Act, protects confidential business information that has economic value because it is kept secret, from formulas and manufacturing processes to customer lists and pricing strategies.4Office of the Law Revision Counsel. 18 U.S. Code 1836 – Civil Proceedings The owner must have taken reasonable steps to keep the information secret in the first place.5Office of the Law Revision Counsel. 18 U.S. Code 1839 – Definitions
What You Need Before You Can File
A common early mistake is filing the moment infringement is spotted. Whether that’s possible depends on the type of IP.
Copyright owners must register the work with the U.S. Copyright Office, or receive a refusal, before filing suit.6Office of the Law Revision Counsel. 17 U.S. Code 411 – Registration and Civil Infringement Actions The Supreme Court held in 2019 that submitting an application is not enough. The Office has to act. Registration timing also drives remedies: statutory damages and attorney fees are available only if the work was registered before the infringement began or within three months of first publication. Register late and you’re limited to actual losses, which are harder to prove and usually smaller.
Patent holders need an issued patent in hand. USPTO examination can run years, so if you’re relying on a pending application, you don’t yet have a claim to file.
Trademark owners can bring a federal Lanham Act claim with or without federal registration, but a registration certificate carries a strong evidentiary advantage in court.
Trade secret claims have no registration prerequisite. Registering a trade secret would defeat the point.
Which Court Hears the Case
Federal courts have exclusive jurisdiction over patent and copyright claims. No state court can hear them, no matter the amount in dispute.7Office of the Law Revision Counsel. 28 U.S. Code 1338 – Patents, Plant Variety Protection, Copyrights, Mask Works, Designs, Trademarks, and Unfair Competition Trademark and trade secret claims can go to either state or federal court depending on the specific legal theories.
Patent venue is unusually strict. A patent suit can be filed only in the district where the defendant is incorporated, or where the defendant has committed acts of infringement and has a regular, established place of business.8Office of the Law Revision Counsel. 28 U.S. Code 1400 – Patents and Copyrights, Mask Works, and Designs Filing in the wrong district can get the case transferred or dismissed before a judge ever looks at the merits.
Deadlines That Can End the Case
Copyright infringement claims must be filed within three years after the claim accrues.9Office of the Law Revision Counsel. 17 U.S. Code 507 – Limitations on Actions
Patent cases have no traditional statute of limitations, but damages are capped at infringement occurring within six years before the lawsuit is filed.10Office of the Law Revision Counsel. 35 U.S. Code 286 – Time Limitation on Damages Older infringement is unrecoverable even when proven.
Trade secret claims under the Defend Trade Secrets Act must be brought within three years after the misappropriation was discovered or reasonably should have been.4Office of the Law Revision Counsel. 18 U.S. Code 1836 – Civil Proceedings Because trade secret theft is often hidden, the clock runs from discovery, not from the underlying act.
Trademark law has no fixed statute of limitations. Courts instead use the doctrine of laches: an owner who knew about infringement and delayed unreasonably, prejudicing the defendant, can lose or limit recovery. Trademark infringement is treated as a continuing violation, so new infringing uses can reopen the door to prospective relief.
Filing, Serving, and Answering
Before filing, gather your registration certificates, evidence of the infringement (products, screenshots, marketing materials), and the correct legal name and address of the infringer. Many IP owners send a cease-and-desist letter first. It isn’t required, but it builds a record, and in trademark matters a pattern of non-enforcement can weaken the mark over time. A well-drafted letter sometimes resolves the dispute on its own.
Federal cases are filed electronically through CM/ECF, the courts’ Case Management/Electronic Case Files system.11United States Courts. Electronic Filing (CM/ECF) The complaint sets out jurisdiction, the facts of the infringement, and the relief sought. A Civil Cover Sheet (Form JS 44) goes with it.12United States Courts. Civil Cover Sheet The statutory filing fee is $350, and administrative fees set by the Judicial Conference bring the typical total to $405.13Office of the Law Revision Counsel. 28 U.S. Code 1914 – District Court Filing and Miscellaneous Fees
After filing, you have 90 days to serve the defendant with the summons and complaint. Miss that window and the court can dismiss without prejudice or order service completed by a set date; showing good cause can save you, but the burden is yours.14Legal Information Institute. Federal Rules of Civil Procedure Rule 4 – Summons The defendant then has 21 days after service to file an answer or a motion to dismiss.15Legal Information Institute. Federal Rules of Civil Procedure Rule 12
Proving the Claim
Every IP plaintiff has to prove two things: that they own a valid right, and that the defendant infringed it.
On ownership, a federal registration certificate does much of the work. A copyright registered within five years of first publication is presumed valid, and the registrant is presumed to own it.16Office of the Law Revision Counsel. 17 U.S. Code 410 – Registration of Claim and Issuance of Certificate Issued patents come with a statutory presumption of validity, and the challenger has to overcome it. Trademark registrations shift the burden to the defendant to show the mark is not protectable.
Proving infringement itself looks different in each category. Patent infringement is a technical comparison between the specific claims of the patent and the accused product or process, usually developed through expert testimony. Trademark infringement turns on likelihood of confusion, evaluated through factors like the strength of the mark, the similarity of the marks and the products, and evidence of actual consumer confusion.2United States Patent and Trademark Office. Likelihood of Confusion Copyright infringement requires substantial similarity to protected expression, not just a general resemblance, and courts apply both an objective comparison of specific expressive elements and a subjective test of overall concept and feel.17United States Courts for the Ninth Circuit. 17.19 Substantial Similarity – Extrinsic Test and Intrinsic Test
Defenses You Should Expect
Even a valid right can lose to a defense.
Fair use is the most common defense in copyright cases. Courts weigh four factors: the purpose and character of the use, including whether it’s commercial or educational; the nature of the copyrighted work; the amount used relative to the whole; and the effect on the market for the original.18Office of the Law Revision Counsel. 17 U.S. Code 107 – Limitations on Exclusive Rights Fair Use No single factor decides it.
Trademark fair use comes in two forms. Descriptive fair use lets you use another company’s mark in its ordinary descriptive sense to describe your own product. Nominative fair use lets you use a mark to refer to that company’s actual product, as long as you use only what’s necessary and don’t imply sponsorship. Comparison advertising is the standard example.19United States Courts for the Ninth Circuit. Defenses – Nominative Fair Use
Patent defendants often attack the patent itself, arguing it should never have been granted. Grounds include prior art showing the invention was already known or obvious, inadequate description, or problems with the patent term. The defendant carries the burden and must prove invalidity by clear and convincing evidence.
In trademark cases, laches gives defendants a way to punish delay, as described above.
What You Can Win
Copyright plaintiffs choose between actual damages (their losses plus the infringer’s attributable profits) and statutory damages. Statutory damages run from $750 to $30,000 per work, at the court’s discretion, rising to $150,000 per work for willful infringement and dropping to as low as $200 per work when the infringer had no reason to believe they were infringing.20Office of the Law Revision Counsel. 17 U.S. Code 504 – Remedies for Infringement Damages and Profits Statutory damages are unavailable if the copyright was registered late, per the timing rule above.
Patent damages must be at least a reasonable royalty for the defendant’s use, plus interest and costs. Willful infringement can support increased damages up to three times the amount found, though treble damages are discretionary and typically require proof the defendant knew about the patent and acted recklessly.21Office of the Law Revision Counsel. 35 U.S. Code 284 – Damages
Trademark owners can recover the defendant’s profits, their own actual damages, and costs. Courts can adjust awards upward, not exceeding three times actual damages, or modify a profits-based recovery if it’s inadequate or excessive. Attorney fees are reserved for exceptional cases. Counterfeit-mark cases carry mandatory treble damages absent extenuating circumstances.22Office of the Law Revision Counsel. 15 U.S. Code 1117 – Recovery for Violation of Rights
Money isn’t always the point. Plaintiffs often want the infringing activity stopped, through a preliminary injunction during the case or a permanent injunction after trial. The Supreme Court’s eBay v. MercExchange decision established that an injunction requires the plaintiff to show irreparable harm, that money damages are inadequate, that the balance of hardships favors an injunction, and that the public interest supports it. Proving infringement is no longer enough on its own.
Discovery, Trial, and Appeal
Once the defendant answers, the case enters discovery: document exchanges, depositions, and expert reports. IP cases are discovery-heavy. Patent cases usually need technical experts to compare products against claims and to model a reasonable royalty. Copyright cases may need experts in the relevant creative field to address substantial similarity. Discovery in a complex IP case routinely runs a year or more.
If the case doesn’t settle, it goes to trial, with a jury on request. Some patent issues, like claim construction, are decided by the judge rather than a jury. Patent appeals go exclusively to the U.S. Court of Appeals for the Federal Circuit. Copyright and trademark appeals go to the regional circuit.
What It Costs
IP litigation is expensive, and the cost surprises many first-time plaintiffs. According to surveys by the American Intellectual Property Law Association, the median cost of a patent infringement case through trial is roughly $700,000 when less than $1 million is at stake, and climbs past $4 million when more than $25 million is on the line. Copyright and trademark cases generally cost less than patent disputes, but a straightforward trademark case can still run into six figures if it reaches trial. Those numbers are why most IP cases settle. If you’re thinking about filing, get a written budget estimate from counsel early. If you’re on the receiving end of a suit, remember that defense cost alone creates settlement pressure independent of the merits.