Patent marking isn’t just a legal technicality—it’s a critical step that directly affects your ability to claim damages in a U.S. patent infringement case. Without proper marking, you may forfeit the right to recover retroactive compensation, even if infringement clearly occurred. This post explains how patent marking works, why virtual marking is the most practical solution, and the key risks of non-compliance for both patent holders and licensees. If you're not marking your products—or not updating your list—you may be leaving money on the table.
Congratulations, your published U.S. patent is granted - congratulations! You’re now officially protected when it comes to infringement, right?
Not quite.
If someone is infringing your IP, you want as much compensation for damages as possible. You might assume that this would be enough to be able to undertake action against infringers and receive full compensation for damages; but this is wrong.
If your patent is infringed, and you want to recover damages, you need more than just a granted patent. You must also show that the infringer was actually aware of your patent – which under U.S. law, often means you must mark your products appropriately.
Let’s break down what patent marking means, how to do it right, and what happens if you don’t.
Patent marking is the process of giving notice to the public that a product is protected by one of more patents. It is intended to put potential infringers on alert and establish your eligibility to claim damages in a legal dispute. There are two ways to comply with U.S. patent marking laws: traditional marking and virtual marking.
It is important maintain patent markings/websites with up-to-date information by adding new patents and removing outdated ones (because they are abandoned or expired for example), otherwise this creates liability for false marking.
It is important to note that these marking requirements do not apply to patents the include only method claims that are not tied to a specific product.
Marking your products correctly isn’t just good practice—it’s legally necessary if you want to recover the full range of damages available in an infringement lawsuit.
Under U.S. law, a patent owner can seek damages for up to six years of infringement prior to the date of the lawsuit…but there’s a catch. If a patent owner has not yet marked its products and the patent has been infringed, the owner will not be able to recover damages unless the infringer was notified and continued to infringe (and even then, the patent owner is only entitled to recover damages from the point the infringer was formally notified).
In most cases, the damages are available because the patent holder marked the product (known as ‘constructive notice’), rather than actual knowledge by an infringer.
Many patent holders assume that if they are marking their products, they’re covered. But, the obligation to mark patents also falls upon licensees.
In Rembrandt Wireless v. Samsung Elecs., the court ruled that Samsung infringed two of Rembrandt’s patents, and Rembrandt was awarded $15.7 million in damages. However, Samsung appealed and argued that Rembrandt licensed one of the patents to a third party - Zhone Technologies - but did not require the licensee to mark its products. The Federal Circuit agreed with Samsung and stated that damages awarded should be reduced to only include the damages suffered after the notice.
Even though Rembrandt did argue that they filed a statutory disclaimer (a statement in which a patent owner relinquishes legal rights to one or more claims of a patent), the Court found this didn’t excuse the lack of marking.
The takeaway? Patent holders must include explicit marking clauses in license agreements and actively verify compliance.
While legal damages are the primary motivator, proper marking also serves broader strategic purposes. It deters unintentional infringement by clarifying what’s protected. It signals credibility and seriousness to investors, partners, and competitors. And it helps ensure transparency in crowded markets where overlapping technologies are common.
Put simply, marking your patents is about more than litigation—it’s about good business.
If you're not already doing so, now is the time to implement a patent marking strategy:
If you’re unsure how to set up a compliant marking system—or want a second set of eyes on your IP strategy—we’re here to help. Stratford’s IP experts can guide you through best practices, licensing risk mitigation, and virtual marking implementation.
Reach out to us to start the conversation.
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A registered trademark agent in Canada, Kim Capiau is an IP Specialist with a unique combination of skills, education, and assets with a drive for success and a passion for Intellectual Property. Working with growing organizations for many years she’s honed her ability to be both creative and strategic with IP solutions and strategy implementation plans. She specializes in IP analytics and Trademark Strategy and Prosecution. Before becoming an IP specialist at Stratford, she practiced law in Belgium for 5 years. Kim holds an LLB and LLM in law from Belgium and followed trademark studies at McGill University. |