Key Takeaways

  • The patent marking statute (35 U.S.C. § 287) allows patent owners to notify the public of patent protection by marking products with patent numbers or virtual notices.
  • Proper marking is essential for maximizing damages in infringement suits and demonstrating compliance with the law.
  • Virtual marking, introduced in the America Invents Act, provides flexibility by allowing web-based notices instead of physical product markings.
  • Not all patents require notice—method-only claims are exempt—but products combining method and product claims usually do.
  • False marking, including marking unpatented items or failing to update expired patents, can create liability risks.
  • Strategic marking programs help businesses enhance enforcement leverage, deter infringement, and maintain compliance.

When Is Patent Notice Used?

35 U.S.C. § 287 provides that after being granted a patent, a patent owner can inform the public of its existence by including the patent number and words such as "U.S. Patent No." or "patented" on products and articles sold in association with the patent.

Why Are Patent Notices Used?

Patent notices are important in infringement cases as they help to show that the defendant was aware of the patent. If the notice was absent, the patentee would have to prove that the defendant knew of the patent before they can claim damages.

Benefits of Complying With the Patent Marking Statute

Complying with the patent marking statute offers several benefits beyond simply meeting legal requirements. Marked products put competitors on notice, discouraging infringement by signaling that enforcement actions may follow. They also preserve the patent owner’s right to recover damages dating back six years before filing suit, as long as consistent marking is demonstrated. In addition, companies with a disciplined marking program can strengthen their market reputation and enhance the perceived value of their intellectual property portfolio

How Are Patent Applications Maintained?

The United States Patent and Trademark Office keeps patent applications secret until the issuance of Letters Patent to the patentee.

How Are Actual Notices Achieved?

Actual notices are established by:

  • Sending a Cease and Desist Letter directly to the patent infringer notifying them of the patents they are infringing.
  • By filing an infringement lawsuit and sending the infringer notice of the suit.

The patentee is entitled to damages that accrue after the actual notice date if the infringer does not desist from infringement of the patent.

How Are Constructive Notices Achieved?

In the past, the only way to achieve constructive notices was by adding the word "patent" or the abbreviation "pat" and the patent number to patented products. New patent laws now allow virtual markings which are achieved by writing the word "patent" or abbreviated form "pat," and then adding a publicly accessible internet address that shows the link between the patent number and the patented item. The virtual marking makes it easier for many patent owners to maintain and update patent information online rather than updating on the physical product.

Virtual Marking and Its Advantages

The America Invents Act modernized the patent marking statute by allowing virtual marking. Instead of etching or printing every patent number on a product, companies can display the word “Patent” or “Pat.” followed by a publicly accessible URL that lists associated patents.This approach provides multiple advantages:

  • Cost savings: No need to redesign molds or packaging every time a new patent issues or expires.
  • Accuracy: A centralized online list reduces errors and simplifies updates.
  • Transparency: Customers, competitors, and courts can access the most up-to-date patent information.

Virtual marking has become the preferred option for many technology and consumer product companies, especially those with frequently updated patent portfolios

When Can Patent Owners Collect Damages?

Where the patent owner provides constructive notice, it can claim damages without actual notice. A patent owner that complies with the marking statute is entitled to claim damages six years before the date of filing the suit because the statute of limitations for infringement cases is six years.

Risks of Failing To Mark Properly

Failing to comply with the patent marking statute can significantly limit a patentee’s recovery. If products are sold without appropriate marking, the patent owner may only recover damages from the date the infringer received actual notice. This limitation can reduce potential damages by years and weaken negotiating leverage in litigation. Courts have also held that patent owners must demonstrate substantial compliance with marking requirements, meaning occasional lapses may jeopardize damages claims

How Are Patents Marked?

Under 35 U.S.C. § 287, patented products are to carry a marking, and if the nature of the product makes this impossible, then the marking must be affixed to the package of the patented product. Where possible, the marking should be affixed to the product itself, as courts frown at affixing it to the package because of expediency.

Who Should Comply With Marking the Products With Patents?

The patent owner producing or selling patented products is expected to mark the product with all the patent numbers associated with the item. Reasonable steps must be taken by the patent owner to make sure products are marked by all the licensees of the patent. The standing of the courts on the matter is that patent owners must show substantial compliance with the marking statute. It's important for patent owners to make sure their licensees comply with the marking statute consistently.

Best Practices for a Patent Marking Program

Developing a structured patent marking program is critical for businesses that manufacture or license patented products. Best practices include:

  • Regular portfolio audits: Ensure all active patents are reflected in product markings or on virtual marking websites.
  • Licensee oversight: Require licensees to comply with marking obligations through contractual provisions.
  • Clear responsibility: Assign internal teams or counsel to monitor compliance.
  • Documentation: Keep records of marking practices to demonstrate diligence in potential litigation.

These practices reduce the risk of missed markings, strengthen legal protection, and help companies maintain credibility with courts

What Are the Patents That Do Not Require Notice?

Patents with method claims, i.e., in which there are no products to affix the marking are exempt from notices. If a patent owner files an infringement suit over method claims, the court will not determine the compliance of the patent owner with the marking statute. In such circumstances, the patent owner can claim damages for six years before filing the suit, even if the defendant didn't receive a notice.

What Are the Patents That Require Notice?

Notice is required if a patent owner produces some part of or a complete item using a patented method which includes product and method claims. For example, a software with a computer program product claim which is delivered via a physical product such as a flash drive requires compliance with the marking statute in infringement cases.

False Marking

False marking occurs when a patent number is affixed to a product by adding the word "patent" or its abbreviation "pat" and other patent notifications when the product is not actually associated with any patent application or covered by a patent.

Avoiding Liability Under the Patent Marking Statute

False marking claims can arise when products are labeled with incorrect or outdated patent information. While current law no longer allows qui tam suits by the general public, competitors who suffer a competitive injury may bring actions for damages. To avoid liability, businesses should:

  • Promptly update markings when patents expire.
  • Avoid using placeholder terms such as “patent pending” without an active application.
  • Ensure accuracy in both physical and virtual markings.

Even unintentional false marking may expose companies to reputational harm and legal costs, making accuracy a key compliance priority

Who Can File a Civil Action Against False Marking?

A party who loses competitive advantage through false marking may file a civil action against the false marker to collect damages for their losses.

Are False Markings Applicable to Expired Patents?

The existing patent law does not penalize marking a product with an expired patent.

Frequently Asked Questions

1. What is the patent marking statute?

The patent marking statute, 35 U.S.C. § 287, requires patentees to mark products with patent numbers or virtual notices to notify the public and preserve damages claims.

2. Is virtual patent marking legally valid?

Yes. The America Invents Act authorizes virtual marking, allowing a URL to list applicable patents instead of physical markings on products.

3. Do method-only patents require marking?

No. If a patent contains only method claims, no marking is required, and damages can still be recovered for up to six years before filing suit.

4. What happens if a product is mismarked with an expired patent?

Expired patents no longer trigger false marking liability under current law, but patentees should still update markings to avoid confusion.

5. Why should businesses create a marking program?

A structured marking program ensures compliance, preserves damages, deters infringement, and reduces the risk of false marking claims.

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