What is Patent Marking?
Why marking determines when damages start, how to mark a product or a website, the licensee problem, and what false marking exposure looks like after the America Invents Act.
Definition
Patent marking is the practice of labeling a patented product, its packaging, or a linked web page with the word "patent" and the applicable patent numbers, as provided in 35 U.S.C. § 287. Marking gives the public constructive notice of the patent; without it, a patent owner can recover damages for a product patent only from the date the infringer received actual notice.
Key Facts
- Statute: 35 U.S.C. § 287(a) for marking and notice; § 292 for false marking
- Effect: Damages for an unmarked patented product run only from actual notice, usually the demand letter or complaint; marking makes them run from the start of infringement, subject to the 6-year limit
- Applies to: Patents with apparatus or product claims; method-only patents cannot be marked and do not need to be
- Virtual marking: Since 2011, marking "Patent" or "Pat." plus a freely accessible web address that lists the patents covering the product satisfies the statute
- Licensees must mark too: A patentee who licenses others to sell the patented product must make reasonable efforts to ensure they mark, or lose the benefit
- Consistency: Marking must be substantially consistent and continuous; sporadic marking does not count
- False marking: Marking with an expired or inapplicable patent with intent to deceive; since the America Invents Act, only the government or a party with competitive injury can sue
Why It Matters for Damages
An infringer of a marked product is liable from the first infringing sale. An infringer of an unmarked product is liable only from the day the patentee gave actual notice, which requires an affirmative communication charging infringement of a specific patent. For a product that has been on the market for years before a competitor is discovered, the difference is most of the damages. Marking is therefore one of the cheapest ways to protect the value of a patent portfolio, and one of the most often neglected.
How to Mark
- Physical marking: "Patent" or "Pat." followed by the patent numbers, on the product, or on the packaging if marking the product is impractical
- Virtual marking: "Pat." plus a URL, with a web page that associates each product with the patents that cover it, kept current as patents issue and expire
- Pending applications: "Patent pending" or "patent applied for" is permitted while an application is pending, gives no legal notice, and is false marking if no application is actually pending
Virtual marking is now the default for companies with more than a handful of products, because a web page can be updated when a continuation issues or a patent expires, and a mold or a printed label cannot.
Keeping the Marking Page Right
The marking page must list each product against the patents that actually cover it. Listing a patent that does not cover the product, or one that has expired or lapsed for non-payment of maintenance fees, is a false marking risk; omitting a patent forfeits its constructive notice. That makes the page a portfolio-management artifact: it needs the same claim-to-product mapping used for pruning and licensing, refreshed whenever legal status changes. ArcPrime's portfolio management keeps that mapping current so the marking page can be generated from it rather than maintained by hand.
Frequently Asked Questions
Don't see the answer you're looking for?
Feel free to reach out to us for more info.
What happens if you do not mark a patented product?
You cannot recover damages for infringement that occurred before the infringer received actual notice. Actual notice means an affirmative communication, such as a demand letter, identifying the patent and charging infringement, or the filing of a lawsuit. Damages for the earlier period are lost.
What is virtual patent marking?
Marking a product with "Patent" or "Pat." and a web address, where a freely accessible page lists the patents that cover each product. Permitted since the America Invents Act in 2011, it satisfies the marking statute and lets the patent list be updated without changing the product or its packaging.
Do you need to mark products covered only by method claims?
No. The marking requirement applies to patented articles. A patent with only method claims cannot be marked, so damages for infringing a method-only patent are not limited by § 287. If a patent has both product and method claims and the product is sold unmarked, the limitation generally applies.
Do licensees have to mark?
Yes, for the patentee to keep the benefit. A patent owner who licenses others to make or sell the patented product must make reasonable efforts to ensure the licensees mark, typically through a marking clause in the license and periodic checks. Unmarked licensee products can cut off the patentee's pre-notice damages.
What is false marking?
Marking a product with a patent that has expired, does not cover it, or does not exist, or using "patent pending" with no pending application, with intent to deceive the public. Since 2011 only the United States can sue for the statutory penalty, and private parties can sue only for actual competitive injury.
Power Every Patent Decision
With One Platform
See how ArcPrime connects your portfolio, workflows, and business context to help your team make better decisions across the patent lifecycle.