U.S. Patent Marking Guide

By Austen Zuege

What follows is the ultimate guide to patent marking in the United States.  Marking is optional but can provide significant benefits to the patent owner in the event there is infringement.  Not only are there practical burdens associated with marking patent products, there can also be questions about the legal requirements for proper patent marking notices.  This patent marking guide aims to address both legal requirements and practical considerations for patentees. A shorter overview is available here.


Table of Contents


Basic U.S. Marking Requirements

Patent marking can be important for obtaining full recovery of infringement damages.  When enforcing a patent against an infringer in the United States, damages for infringement of a patented article can usually be recovered only from the date the infringer had actual or constructive notice of the patent(s), whichever comes first.[1] 

The statutory marking requirement comes from § 287(a) of the patent laws, which provides:

“Patentees, and persons making, offering for sale, or selling within the United States any patented article for or under them, or importing any patented article into the United States, may give notice to the public that the same is patented, either by fixing thereon the word ‘patent’ or the abbreviation ‘pat.’, together with the number of the patent, or by fixing thereon the word ‘patent’ or the abbreviation ‘pat.’ together with an address of a posting on the Internet, accessible to the public without charge for accessing the address, that associates the patented article with the number of the patent, or when, from the character of the article, this can not be done, by fixing to it, or to the package wherein one or more of them is contained, a label containing a like notice. In the event of failure so to mark, no damages shall be recovered by the patentee in any action for infringement, except on proof that the infringer was notified of the infringement and continued to infringe thereafter, in which event damages may be recovered only for infringement occurring after such notice. Filing of an action for infringement shall constitute such notice.”

35 U.S.C. § 287(a)

These statutory marking requirements apply to all types of U.S. patents: utility, design, and plant.

Explanations of what constitutes actual notice and how to properly mark patented articles to provide constructive notice are provided below. 

Policy Behind the Marking Requirement

The marking requirement is meant to protect the public’s ability to exploit an unmarked product’s features without liability for damages until a patentee provides either constructive notice through marking or actual notice.[2]  More specifically, marking requirements serve three related purposes: 1) helping to avoid innocent infringement; 2) encouraging patentees to give notice to the public that the article is patented; and 3) aiding the public to identify whether an article is patented.[3]

Actual Notice: An Alternative to Marking

Actual notice requires the affirmative communication of a specific charge of infringement, such as in a demand or cease-and-desist letter.[4]  In this sense, actual notice (pre-suit) requires proactive communication by the patentee to the accused infringer to enable “proof that the infringer was notified of the infringement and continued to infringe thereafter.”[5]  The marking statute also explicitly provides that “[f]iling of an action for infringement shall constitute such [actual] notice.”[6]  So, at a minimum, the commencement of an infringement lawsuit will cause damages to accrue going forward. 

Constructive Notice Established Through Patent Marking

Marking patented articles provides constructive notice to the public that an article is patented.  This is called “constructive” notice because it does not matter whether or not an infringer actually saw the patent marking notice, only that the patentee marked patented articles appropriately.  To be sufficient to establish constructive notice, the patentee must be able to establish that substantially all of the patented articles being distributed were marked, and, once marking began, that the marking was substantially consistent and continuous.[7]  If marking is defective at first, curing those defects going forward is possible.  But full compliance with marking requirements sufficient to provide constructive notice to infringers is not achieved until the time the patentee “consistently marked substantially all” of the patented products, and if marking was deficient for a time then constructive notice will not be provided unless and until proper marking occurs with subsequent sales.[8] 

Possible Exceptions to Marking Requirements

The most important exception to the marking requirement is where the patentee has not sold any patented articles. When there are no products to mark, there is no failure to mark and therefore no bar to recovery of pre-suit damages.[9] A patentee who has not sold anything under a patent can still recover back damages despite having not literally marked any products.

Additionally, because the marking statute refers only to a “patented article”, patents with method or process claims are treated differently.  Courts have said that neither marking (constructive notice) nor actual notice is required to obtain back damages for infringement of asserted patents having only method or process claims.[10]  For patents having both apparatus and method claims, marking may still be required to establish constructive notice depending on which claims are asserted in an infringement lawsuit.[11]  In light of that standard, it is recommended to mark products whenever a relevant patent contains an apparatus claim.

Whether a website or other cloud-based/networked computer-implemented invention (that runs on at least some user-supplied rather than patentee-supplied hardware) or downloadable software that exists only electronically counts as an “article” that a patentee must mark has not yet been definitively settled. But some courts have said that a patentee must mark a website either where the website is somehow intrinsic to the patented device or where the customer downloads patented software from the website. It is recommended to treat downloadable and online system inventions as articles that require marking whenever the patentee provides something important to operation of the invention and the relevant patent’s claims are not exclusively method claims.

Lastly, there is a “rule of reason” exception of sorts that may apply to a failure of a licensee or other authorized third party to substantially consistently and continuously mark despite reasonable efforts by the patentee, as discussed below.

Licensee(s) and Other Authorized Parties Must Mark Too

Marking requirements apply not only to the patentee but anyone making, selling, or offering for sale the patented article “for or under” the patentee or importing it into the U.S.[12]—essentially all the types of things that can constitute direct infringement under 35 U.S.C. § 271(a) except for mere “use”.  Where a patent is licensed to another, expressly or impliedly, or there is a covenant not to sue or the like, the other entity is required to mark as well.[13]  Authorized activities by an outsourced manufacturer or authorized seller, or even an explicitly or impliedly licensed customer, are treated as if they are by the patentee in terms of marking requirements in this respect.  Failure of a licensee to consistently mark substantially all licensed products will frustrate efforts to establish constructive notice.  However, because third parties are implicated, this requirement is subject to a rule of reason.[14]  A court can excuse some instances of omitted marking by others and still find constructive notice satisfied if the patentee made reasonable efforts to ensure compliance with marking requirements.[15] 

Care should be taken whenever there are other entities involved with making, selling, offering for sale, or importing into the U.S. a patented article intended to be marked.  It is recommended that any license for a U.S. patent, or a covenant not to sue under the patent, obligate the licensee or other party to comply with marking requirements, and/or that a part sold so that a downstream purchaser or user will specifically combine it with other parts to assemble a patented article carry a “for use under” marking notice.[16] 

How to Implement Patent Marking: Two Possibilities

There are two ways to mark patented articles in accordance with U.S. law: physical or virtual marking.

Physical Marking

Physical (or conventional or traditional) patent marking involves fixing notices on the patented articles themselves in a way that associates the patented article with the number of the patent.[17]  Such a notice must include the word “patent” or the abbreviation “pat.”, together with the number of the patent(s).[18] 

If the nature of the patented article means such a notice cannot be fixed to the patented article itself, such as due to size constraints or where the article is a fluid, the notice can alternatively be placed on a label fixed either to the patented article or to a package containing one or more of the patented articles—a notice included only in an accompanying manual or instructions may or may not be sufficient.[19]  This is an alternate form of physical marking. But if marking on packaging or a label used, the patentee should be prepared to articulate a reason why marking on the article itself was not practical.

It does not appear that courts have specifically interpreted what constitutes a “label” as opposed to affixing a marking notice “thereon” a patented article. But, in context, it seems fair to say that such a “label” refers to something like a removable hang tag that is only temporarily connected to the article, just as a package is normally separated from an article it initially contains after purchase. In other words, the important point would seem to be the permanence of the the patenting marking notice in terms of the patent marking notice remaining affixed to the article during its useful life. It does not appear that the statute narrowly requires etching, embossing, inscribing, molding, or otherwise integrally and monolithically forming the marking on the patented article. Rather, a plate or badge that is permanently attached to the article, such as a marked metal plate riveted, welded, or permanently adhered to the article, would seem to qualify as being affixed “thereon” rather than being a “label” as an alternative to the primary form of physical marking. In contrast, a marking sticker temporarily secured with pressure-sensitive adhesive to a patented article in a location in which it would interfere with the use or enjoyment of that article if left in place and having a protruding tab to facilitate and encourage removal upon purchase would seem to instead be a “label”.

If patent marking is provided on packaging, use caution with respect to what is included within the marked package. A package containing both patented and unpatented articles should not be marked in a way that deceives the public about which of those article(s) are patented. This is a question of false marking, which is discussed below.

An example of a proper physical patent marking notice (for the fictitious U.S. Pat. No. 00,000,000) is the following fixed directly on an article covered by the claims of the indicated patent:

Pat. 00,000,000

If multiple patents apply to the same patented article, they can be listed together.  It is not necessary to repeat the word “patent” or abbreviation “pat.” before each patent number in such a list.  Court decisions are often unconcerned with the word “patent” being pluralized in the notice, as well as with the addition of a word or abbreviation, such a saying “patent number 00,000,000” or “pat. nos. XX,XXX,XXX and YY,YYY,YYY” in a marking notice.  After all, the point is to provide public notice not simply the unthinking repetition of certain words and numbers in isolation.  The use of “U.S. patent” or “U.S. pat.” is acceptable, and might be worthwhile for products sold or shipped internationally. Though the text of the notice should be in English, because the statute explicitly uses English words and does not explicitly permit translations.

Virtual Marking

The Basics of Virtual Patent Marking

Virtual patent marking is an acceptable alternative to physical marking.  It can be useful in situations where all the patent information required to provide constructive notice cannot easily fit on the patented article or even its label, such as where there are multiple patents that apply to a given article or the article itself is very small.  As the number of digits in patent numbers increase, this sort of difficulty increases.  Virtual marking can also be helpful in situations where different patents are associated with different products but having product-specific badges, labels, or packages is burdensome—a single badge, label, or package might be used listing a URL for a web page with patent association information for multiple products.  Virtual marking can also separate some aspects of marking from the product manufacturing process, such as by minimizing the need to replace or modify expensive molds used to create a patent marking notice directly on molded articles as new patents issue.

Implementing virtual patent marking involves fixing notices on the patented articles themselves in a way that (indirectly) associates the patented article with the number of the patent via a web page identified on the notice.[20]  Such a virtual marking notice must use the word “patent” or the abbreviation “pat.” together with an address of a posting on the Internet (that is, a web page URL), accessible to the public without charge for accessing the address.[21]  If the nature of the patented article makes means such a notice cannot be fixed to the patented article itself, the virtual marking notice (indicating “patent” or “pat.” together with a URL) can instead be placed on a label fixed either to the patented article or to a package containing one or more of the patented articles—just as with traditional physical marking as explained above.[22]

An example of a proper virtual patent marking notice fixed to a patented article or its label is the following:

Pat. example.com/patents

Further, the following is a photo of a reusable bottle cap product with a virtual patent marking notice etched into the metal of the product itself. It says “PAT” followed by a URL to a web page, although only a portion of the URL is visible in the photo due to the shape of the product. This type of virtual marking notice fixed to a patented product is acceptable under U.S. law.

photo of reusable bottle cap product with "PAT WWW.KLEAN..." virtual patent marking notice etched into metal of the product
Photo of product with virtual marking notice etched directly onto it

The main feature of virtual marking—the part that makes it “virtual”—is that the information associating the patented article with the number(s) of the patent(s) that cover it appears on a freely-accessible web page rather than directly on the article or its label or package.  There is still a requirement for a notice on the patented product or its label or package.  A marking web page, alone, is insufficient unless there is also a proper notice on the patented product or its label or package to direct people to that web page’s address.[23] Moreover, a virtual marking notice on a product or its package is insufficient without an acceptable posting accessible from the identified Internet address.

The difference between physical and virtual marking really involves the manner of conveying the required association between the patent number(s) and the patented article.  With traditional physical patent marking, the association is implicit in terms of which patent numbers are including in or omitted from a notice fixed to a particular product or its label or package.  In virtual marking, the notice fixed to the product or its label or package merely directs the public to a web page but the web page must further provide an association between given patent(s) and the specific product(s) that practice those patent(s). 

Courts have said that virtual patent marking does not allow a patentee to avoid the traditional burden of determining which patent(s) apply to specific products and indicating that patent-to-product association.[24]  The patentee cannot shift that burden to the public.[25]  Any web page that fails to create the required “association” between specific patent(s) and patented article(s) means that such attempted virtual marking is ineffective and fails to provide constructive notice—unless and until the virtual marking web page is revised to cure the lack of patent-to-product association defect(s). 

Minimum Requirements for Virtual Marking Web Pages

Virtual marking is relatively new compared to physical marking.  Only a few courts have addressed questions about what does or does not constitute sufficient virtual marking, and those few decisions are not necessarily definitive.  But what courts have said to date is that a virtual patent marking web page must make an association between specific product(s) and specific patent(s) in order to be effective.  The virtual marking web page must be as specific and detailed as was always required with physical marking.[26] 

Courts have repeatedly emphasized that a virtual marking web page cannot create a “research project” for the public that requires visitors to investigate and determine on their own which patent(s) are associated with which patented article(s).[27]  Merely listing all patents that could possibly apply to a product or all patents owned by the patentee (without further identifying specific patent-to-product associations) is insufficient, even if that list involves only a relatively small number of patents, as is a general statement that “one or more” patents in a list of patents applies to given product(s).[28]  Also, associating patent(s) with broad categories of products rather than specific patented products has been found insufficient.[29]  One court has even said that a web page linking to documents about legal proceedings that visitors would have to read and interpret to determine which patent(s) cover which product(s) is still an impermissible “research project”.[30]  In reaching these decisions, courts have noted prohibitions on false patent marking,[31] which is discussed below

Courts have not yet interpreted whether “an address of a posting on the Internet, accessible to the public without charge for accessing the address, that associates the patented article with the number of the patent” requires a URL that directs to a specific web page with virtual patent marking information or whether a URL for a general home page of a web site is sufficient, where visitors must search for a different page on that site containing virtual marking information. But the plain language of the statute suggests that the marking notice on the article must indicate the relevant “posting” and not merely a collection of postings that are not all relevant or some intermediate posting where the address of the real posting of virtual marking information is findable. Cases that prohibit a “research project” also support the notion that requiring visitors to search out the relevant information on a different web page than the one at the URL indicated on the patented article impermissibly shifts the patentee’s burden to the public. It is recommended that the notice list the URL for the specific web page with virtual marking information—considerations regarding redirects and menus are taken up below.

A virtual marking web page needs to be technologically functional. One court found that virtual marking was substantially continuous despite unavailability of the web page over a three-month period during a web site update.[32]  But the fact that the court had to rule on that issue at all means that patentees should minimize the length of downtime due to maintenance, cosmetic redesigns, and the like.

Some Practical Considerations for Virtual Marking

Virtual marking implicitly requires that reliable records be kept and retained to prove that relevant information actually appeared on the Internet at particular times—in addition to evidence that the patented articles bore a notice.  If a patent is enforced and the patentee wishes to rely on constructive notice provided by virtual marking, there will be a need to provide evidence that the Internet address (URL) in the notice fixed to the patented article or its label was substantially continuously “accessible to the public without charge for accessing the address” and that the content of that web page “associate[d] the patented article with the number of the patent”.  That evidence must be correlated with provable date(s) of constructive notice from which infringement damages run. 

One way to provide such evidence is testimony from information technology (IT) staff and/or a webmaster knowledgeable about the creation of the virtual marking web page and any modifications or changes to it over time.  But depending on how a web site is set up and managed, logs or other records of changes might not be automatically kept, and IT staff and webmasters might not recall the history of any given page.  These concerns are significant when the page appears on a large and complex web site, where there is a large team of IT/webmaster personnel with diffuse responsibilities, or when there is significant personnel turnover over the enforcement period of a patent (potentially more than 20 years). 

Another—and more consistently reliable—way to provide evidence to support virtual patent marking is to create a verifiable record (i.e., archive) of the virtual marking web page.  If such records are kept in the ordinary course of business, they may fall in an exception to hearsay and be self-authenticating under federal evidentiary rules applied by courts,[33] which may avoid the need to produce a witness to authenticate them.  Similarly, archived copies of the virtual patent marking web page can be periodically created.  There are third-party digital evidence authentication services that could be used for this purpose.  The Internet Archive’s “Wayback Machine” (web.archive.org) is a free, open-access archive service that can be used to create a verifiable archive.  But the ability of some tools to archive a given web page will depend on web site settings and permissions allowing “bots” to crawl the site.  In any event, under this approach, the virtual marking web page should be affirmatively submitted to a desired archive provider when first created and following each and every substantive modification. 

Make sure that the patent marking web page URL remains static and unchanged (i.e., link permanence is maintained and link rot avoided), that the web page at that URL remains substantially continuously available and functional (i.e., a hosting web server is operational and the web page code is reasonably free of bugs or browser compatibility problems), and that the notice accurately lists the web page URL (i.e., patented articles carry an accurate virtual marking notice).  Typos in the URL carried on the patented article or its label are potentially problematic here.  Also, notices that list a dead URL will not satisfy marking requirements.  This could arise, for instance, from prolonged web server malfunctions or the like.  It could also arise if the URL for the actual web page is changed but labels on patented products that have already been distributed cannot be altered.  Loss of rights to the domain name that forms part of the URL in virtual marking notice in previously-distributed products could be a problem, such as if the link involves a domain name registration that is cancelled or transferred due to cybersquatting.  Mergers and acquisitions or the sale of a patent might also make it difficult to maintain a static URL for virtual marking purposes.  So, before implementing virtual marking, it is recommended to confirm that the relevant URL used in a marking notice can remain static for the enforceable life of the relevant patents (which is up to six years after the expiration of the last of those patent(s)).  In corporate mergers and acquisitions (M&A) and patent acquisition scenarios, and corresponding due diligence activities, it may be desirable to secure access to existing virtual marking URLs, or at least to provide for a redirect from that URL. 

It is not necessary for the URL of the virtual marking web page to include any particular domain name. It is not necessary that the domain in the URL reference the patentee’s name or trademark, for instance. It is acceptable for the URL to direct to a page at a third-party provider’s web site. Moreover, the URL listed in a marking notice could even utilize a publicly-accessible server Internet Protocol (IP) address instead of a domain name as such (for instance, “http://000.000.0.0/patents.html”).

However, consider whether the URL of the virtual marking web page as affixed to articles is for a domain that may not be readily recognized as an Internet address, such as an IP address without a domain name or using an uncommon top-level domain.  If the public is unlikely to recognize such an address as an Internet address in a shortened form, make sure that a full address including “http://” and/or “www.” is included.  Though for URLs at familiar top-level domains like “.com”, it seems adequate to list a shortened address so long as typical web browsers will direct visitors to the site by typing only the shortened address. 

While a machine-scannable QR code or the like may seem helpful for virtual marking, use of such a scannable but not human-readable code on the patented article or its label may not alone satisfy the “address of a posting on the Internet” requirement for virtual marking.  Courts have not yet addressed this question. If used at all, any QR code or the like should appear in addition to an Internet address (URL) in alphanumeric characters. 

It is recommended to keep the virtual marking page as simple as possible. Use of complex user interfaces may present problems.  If the complexity of a web page, such as requiring the use of highly uncommon or unreliable web browser plug-ins, raises questions about whether it is really “accessible to the public”, then it may not provide constructive notice.  Use of menus on a virtual marking landing page and/or redirects (such as URL mapping from a “clean” or “friendly” URL) may or may not satisfy the constructive notice requirements.  The sufficiency may depend on the specific circumstances and context.  On the one hand, the statue refers to “an address of a posting on the Internet . . .”, which does not explicitly prohibit interactive features or redirects. After all, the Internet Domain Name System (DNS) relies on a variety of pointers to relevant servers all the time, as do commonplace site mirroring practices. An effective browser redirect or simple menu to select a particular product would seem to reasonably provide public notice without any meaningful restriction, and therefore seems acceptable for providing constructive notice.  On the other hand, redirects or complex menus that mean the “posting on the Internet” is not actually at the “address” provided in the notice fixed to the patented article or its label might not satisfy constructive notice requirements under a strictly literal reading.  And complicated or non-intuitive menus may create an impermissible “research project” for the public. Courts have not definitively resolved such issues. Though effective redirects seem unlikely to raise concern, though the use of menus might depending on context. It generally recommended to use a relatively simple implementation, and possibly the least complex technical implementation that is feasible.  Consider separate virtual patent marking web pages for different products or categories of products rather than a single page, if doing so will avoid the need for potentially problematic complexity. 

Also consider the accessibility of the format in which virtual marking information is displayed or rendered on a web page from a disability access perspective.  For instance, displaying a graphical image without alt text information, conveying information based solely on color-coding, or complex “flyout” displays tied to precise cursor hovering actions may not be able to be conveyed by a braille or audio reader for a visually-impaired site visitor.  It is a best practice to follow common accessible design standards for the formatting and presentation of virtual patent marking information.  Such considerations also extend to any menus that must be navigated to access specific patent-to-product association information. Accessibility requirements from other areas of federal law, or from state or foreign jurisdictions, may or may not apply to any given virtual patent marking web page. However, the patent laws do not directly impose any minimum accessibility requirements for differently-abled visitors.

Product photos or drawings could be utilized on a virtual marking web page to aid in the association of particular patents and particular products. However, such photos or drawings should ideally be used only in addition to textual product identifiers. A photo or drawing alone might still be considered to present an impermissible research project if visitors need to decipher which product(s) it depicts. It is also recommended to include alt text metadata with any product photos or drawings used on the virtual marking page.

Use of visitor tracking features on virtual patent marking web pages presents a few issues that suggest caution.  Patent owners might wish to verify whether the page has been visited, and who visited, through tracking mechanisms (“cookies”, “free” login requirements, etc.).  The thought may be that this could provide evidence that an infringer visited the page.  However, constructive notice for the accrual of damages does not require that the infringer actually saw a patent marking notice or actually knew about the asserted patent(s).  So that sort of evidence is not necessary to establish constructive notice, nor is it sufficient to establish actual notice—although it might be usable to establish willful infringement.  The U.S. marking statute says that the virtual marking web page must be “accessible to the public without charge for accessing the address.” Whether or not visitor tracking (with or without a predetermined “conversion value”) effectively constitutes a non-monetary access “charge” has not yet been addressed or settled by courts. Websites that require affirmative visitor consent to tracking or to obtain login credential in order to view a virtual marking page or might especially raise such concerns and therefore are not recommended.

Additionally, the retention of visitor data for online tracking ( via “cookies”, etc.) is subject to increasing scrutiny and regulation.  These are privacy concerns. Use of visitor tracking functionality and associated data retention may require analysis for legality under applicable laws other than the U.S. patent laws—state law(s) or even possibly foreign law(s) like GDPR in Europe and PIPEDA in Canada.

Pre-Grant Marking

“Patent Pending”

The statutory patent marking requirements discussed above apply only to granted/issued patents.  There is no requirement to mark products as “patent pending” or in any other way while a patent application is pending.  However, it is permitted and recommended to mark products as “Patent Pending” or “Pat. Pending” when a patent application has been filed but not patent granted yet. This serves as a “copy at your own risk” warning.

Sometimes there will be one or more granted patents plus one or more pending patent applications that apply to a given product. It is possible to list all patents granted to date in a marking notice and further indicate “other patents pending” or the like. Sometimes notices of this sort may indicate that foreign patents exist or are pending as well. This sort of information is extraneous to U.S. patent marking requirements but might be helpful, so long as it is accurate.

There is no consequence to having sold products with no marking or only “patent pending” marking before a patent is granted. It is not necessary to recall or modify markings on products that were sold before an applicable patent issued. But there may be difficult decisions to be made if a considerable inventory of articles is being held at the time an applicable patent issues, given that the subsequent sale of those unmarked products from inventory will generally trigger the limit on damages for selling unmarked products. Marking notices would need to be added to inventoried products or their packages in such a scenario in order to satisfy marking requirements.

Publication Number Marking

Marking a pre-grant patent publication number could possibly help support later damages recovery for infringement, in theory.  One anomaly of U.S. patent infringement damages law is that under certain circumstances reasonable royalty damages can accrue before a patent is granted.[34]  These are referred to as “provisional rights”.[35]  They are available only if the invention as claimed in the granted patent is “substantially identical” to the invention as claimed in a published version of the underlying patent application and suit is brought within six years of grant of the patent.[36]  An infringer who “had actual notice of the published patent application” can be liable for pre-grant “provisional rights” reasonable royalty damages in addition to traditional infringement damages.[37]

Provisional rights for pre-grant reasonable royalty damages are not subject to any marking requirement.  There is no statutory requirement that an article later patented be marked as “patent pending” or the like before a patent is granted in order to obtain reasonable royalty provisional rights damages—provided all other requirements are satisfied.  Courts have interpreted “actual notice of the published patent application” for pre-grant provisional rights to be based only on the infringer’s actual knowledge (i.e., state of mind), without requiring affirmative action by the applicant or eventual patentee.[38] 

However, because “actual knowledge” of a published patent application may give rise to provisional rights damages, marking the patent application publication number on articles subject to a pending patent application could potentially support a claim of such knowledge by the infringer—provided there is evidence that the infringer actually saw that notice. At the least, marking a publication number could support an inference of actual knowledge if there is evidence that the infringer saw a marked product.  This may be an incentive to mark a published patent application number on relevant goods, beyond merely a generic “patent pending” notice. 

But provisional rights are rarely available in typical real-world scenarios.  Opportunities to assert them rarely materialize.  So this sort of enhanced pre-grant publication number marking may be of marginal practical value.  The burden of doing this may outweigh the potential benefit.  Certainly, this approach will be less effective than affirmatively communicating with a potential infringer to provide knowledge of a published patent application via a letter or the like, when possible. 

False Patent Marking Prohibited

An important related concept is false patent marking.  Under § 292 of the U.S. patent laws, false marking generally involves marking products as patented when they are not, or marking products as “patent pending” when no patent application has been filed, with an intent to deceive.  Use of words like “patent” or “patentee” to advertise unpatented articles with intent to deceive the public is also prohibited. False marking also applies to certain acts of intentional counterfeiting.  Penalties apply in the U.S. to false marking with requisite intent, which are applied on a per article basis.[39]  However, the U.S. patent laws now expressly exclude from the scope of false marking the indication of an expired patent that once applied to the marked product (historically this did constitute false marking but no longer).[40]   Also, there is no liability for honest mistakes about whether or not a patent applies.[41]  A reasonable belief that the articles were properly marked (i.e., covered by the indicated patent) avoids false marking liability.[42]

Currently, either the U.S. Government or “a person who has suffered a competitive injury as a result of a violation” can sue for false marking.[43] Government action fines are “not more than $500 per offense[.]”[44] Private actions are “for recovery of damages adequate to compensate for the injury[,]” meaning there is no fixed limit on potential damages for a competitive injury suit by a competitor or certain potential competitors.[45]

False marking is prohibited for a number of reasons.  It misleads the public into believing that a patentee controls the article in question (as well as like articles), externalizes the risk of error in that determination (shifting it to the public from the manufacturer or seller of the article), and increases the cost to the public of ascertaining whether a patentee in fact controls the intellectual property embodied in an article.[46] 

It is important to only use patent marking where there is a reasonable basis to believe that the product is covered by the indicated patent(s) (or by a pending patent application if “patent pending” is marked).  Patents that do not apply to a given product must not be marked on it.  In the virtual marking context, patent-to-product associations must be specific enough to avoid false marking.  Imprecise, blanket statements on virtual marking web pages implicating multiple patents and multiple products might give rise to false marking if done for purposes of deceiving the public about which patents, if any, apply to particular products.

Conditional marking, such as marking products with “may be covered by” patent notices or indicating that “one or more” listed patents apply, may constitute false marking.[47] Some courts have said that the mere fact that one applicable patent is listed among others that are inapplicable is insufficient to dismiss a claim of false marking.[48] Often, these evaluations are ultimately less about such language being categorically permissible or impermissible in terms of truth or falsity (in relevant part) but instead turn on whether the patentee had intent to deceive the public by using conditional language.[49]. Courts have not been entirely clear or consistent about what could plausibly constitute intent to deceive. Yet acting recklessly rather than innocently or negligently, taking a self-serving (if not outright bad-faith) position that the public would allegedly never be deceived by conditional language, or consciously choosing to place profitability concerns above compliance with false marking prohibitions should all qualify as an intent to deceive. As a best practice, it is recommended to avoid conditional marking language.

Falsely listing an irrelevant patent number on an unpatented product is not the only possible ground for false marking liability. Falsely marking or otherwise advertising something is “patented” without giving a patent number,[50] or potentially even indicating alphanumeric characters that look like a patent number without the word “patent” or “pat.”, are prohibited as well, if done with an intent to deceive. Notices such as “patented internationally” or “patented worldwide” may or may not constitute false marking, depending on the context and the intent to deceive when providing such a notice. For one, setting aside foreign patents that are regionally enforceable only outside the USA, there is no such thing as an “international” or “worldwide” patent. But, also, the lack of an applicable U.S. patent may be especially important for false marking liability if “worldwide”, “international”, or similar terms are used with deceptive intent.[51]

It is recommended to avoid marking products with any “patented” language that is confusing, geographically vague, or potentially misleading with respect to that product’s patent status in the USA. Moreover, for products that are sold internationally, patent markings and advertisements should delineate the specific jurisdiction(s) where they are patented or the products, their labels or packages, and their advertisements should be modified by jurisdiction

In the following example photo, a commercial product has “Patent product” marked on its package. Because no U.S. patent number is listed, such a notice is insufficient to provide constructive notice under U.S. patent laws to accrue damages, as discussed above. But a notice like this could potentially still give rise to false patent marking liability if used in connection with a product sold or imported into the U.S. that is unpatented in the U.S. with intent to deceive the public.

Photo of product package marked with "Patent product, all rights reserved by..."
Photo of example product package marking notice insufficient for constructive notice but still subject to false marking prohibitions

Courts have not definitively ruled on the effect, for false marking analyses, of continuing to mark products with a patent that has been completely invalidated or cancelled, or how opportunities to appeal such an adverse ruling may alter the analysis.[52] Suffice it to say, the § 292(c) exception for expired patents does not apply. In such situations, it may be possible to explicitly indicate the adverse ruling next to the patent number (something easiest with virtual marking). Though courts have not explicitly ruled on the sufficiency of such a disclaimer-like indication, and considerations like those for conditional marking may arise. Of course, ceasing to mark the invalidated or cancelled patent number would completely avoid allegations of false marking. In situations involving partial invalidation or cancellation, more nuanced review is appropriate. Bear in mind that partial invalidity or cancellation may affect some but not all patent-to-product associations and therefore may require very context-specific virtual patent marking web page updates.

To Mark or Not to Mark?

There is no affirmative requirement for patentees to mark patented articles.  It is optional.  A failure to mark only limits one of two ways to recover pre-suit damages.  In the end, there is no right or wrong answer to the question of whether a patentee should mark or not. 

In fact, many patentees consciously make the decision not to mark.  This may simply be because the burdens are considered too high.  For instance, it may be too burdensome to mark a product sold internationally but only in limited quantities in the U.S. Or the patentee may feel that the likelihood of a contentious infringement lawsuit where constructive notice matters is too remote.  In some industries, competitors may be generally aware of the patents they each hold, and that may satisfy patentees.  And for “paper” patents that are not being actively practiced, marking is a moot point.

But in many situations, infringement might begin well before the patentee becomes aware of it.  Thus, a significant amount of infringement may occur before a letter can be sent to communicate a charge of infringement or a lawsuit initiated.  In those situations, the potential damages that arise before the patentee can affirmatively act may be significant.  That is perhaps the best reason to mark.  Patent marking is a way to preserve the ability to recover all or nearly all damages from infringement in the face of imperfect knowledge of competitor activities. 

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.


Endnotes:

[1] Am. Med. Sys., Inc. v. Med. Eng’g Corp., 6 F.3d 1523, 1536 (Fed. Cir. 1993). Additionally, back damages are only available for the period six years prior to commencing a lawsuit or raising a counterclaim. 35 U.S.C. § 286.

[2] Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141, 162 (1989).

[3] Nike, Inc. v. Wal-Mart Stores, Inc., 138 F.3d 1437, 1443 (Fed. Cir. 1998); cf. Lans v. Digital Equip. Corp., 252 F.3d 1320, 1327 (Fed. Cir. 2001) (“knowledge of the patentee” through notice requirements “facilitates avoidance of infringement with design changes, negotiations for licenses, and even early resolution of rights”).

[4] Amsted Indus. Inc. v. Buckeye Steel Castings Co., 24 F.3d 178, 187 (Fed. Cir. 1994).

[5] 35 U.S.C. § 287(a).

[6] Id.

[7] Nike, 138 F.3d at 1446; see also, e.g., Funai Elec. Co v. Daewoo Elecs. Corp., 616 F.3d 1357, 1374-75 (Fed. Cir. 2010) (evidence that 88-91% of patented products were marked supported verdict that such marking was substantially consistent and continuous).

[8] Am. Med. Sys., 6 F.3d at 1538; Arctic Cat, Inc. v. Bombardier Recreational Prods., Inc., 950 F.3d 860, 861,864-66 (Fed. Cir. 2020) (merely ceasing sales of unmarked products does not cure a failure to mark and back damages are precluded until sales resume with proper marking or actual notice is provided).

[9] Tex. Digital Sys., Inc. v. Telegenix, Inc., 308 F.3d 1193, 1219-20 (Fed. Cir. 2002) (“The recovery of damages is not limited where there is no failure to mark, i.e., where the proper patent notice appears on products or where there are no products to mark.”) (citing Wine Ry. Appliance Co. v. Enterprise Ry. Equipment Co., 297 U.S. 387, 398 (1936)).

[10] Bandag, Inc. v. Gerrard Tire Co., 704 F.2d 1578, 1581 (Fed. Cir. 1983)(citing Wine, 297 U.S. at 395).

[11] Crown Packaging Tech., Inc. v. Rexam Beverage Can Co., 559 F.3d 1308, 1316-17 (Fed. Cir. 2009) (while assertion of both method and apparatus claims triggers the obligation to mark under 35 U.S.C. § 287(a), the assertion of only the method claims of a patent containing both method and apparatus claims does not) (citing Am. Med. Sys., 6 F.3d at 1538-39 and Hanson v. Alpine Valley Ski Area, Inc., 718 F.2d 1075, (Fed. Cir. 1983)).

[12] 35 U.S.C. § 287(a).

[13] Amsted Indus., 24 F.3d at 185 (“A licensee who makes or sells a patented article does so ‘for or under’ the patentee, thereby limiting the patentee’s damage recovery when the patented article is not marked.”) (citing Devices for Med., Inc. v. Boehl, 822 F.2d 1062, 1066 (Fed. Cir. 1987)); In re Yarn Processing Patent Validity Litigation, 602 F. Supp. 159, 169 (W.D. N. Car. 1984) (the marking requirement “applies to authorizations by patentee of other persons to make and sell patented articles regardless of the particular form these authorizations may take and regardless of whether the authorizations are ‘settlement agreements,’ ‘covenants not to sue’ or ‘licenses.’ ” (citation omitted)). This includes impliedly authorizing customers to make, use, and sell the patented article, such as selling a part specifically for use in the patented combination while providing customers with installation drawings which instruct how to assemble the part, along with other components, according to the teachings of the patent. Amsted Indus., 24 F.3d at 185. In that situation, the Federal Circuit suggested that a marking such as “for use under U.S. X,XXX,XXX” would suffice. Id. Without explanation, that Federal Circuit-recommended notice did not include the word “patent” or the abbreviation “pat.” as mandated by the marking statute, so preferably such a notice should instead say something like “for use under U.S. pat. X,XXX,XXX” or “for use under pat. X,XXX,XXX”.

[14] Maxwell v. J. Baker, Inc., 86 F.3d 1098, 1111-12 (Fed. Cir. 1996) (“with third parties unrelated to the patentee, it is often more difficult for a patentee to ensure compliance with the marking provisions. A ‘rule of reason’ approach is justified in such a case and substantial compliance may be found to satisfy the statute.”  “When the failure to mark is caused by someone other than the patentee, the court may consider whether the patentee made reasonable efforts to ensure compliance with the marking requirements.”).

[15] Id.

[16] See Amsted Indus., 24 F.3d at 185; Arctic Cat, 950 F.3d at 861,864-65; In re Yarn Processing Patent Validity Litigation, 602 F. Supp. at 169; see also Frolow v. Wilson Sporting Goods Co., 710 F.3d 1303, 1309 (Fed. Cir. 2013) (“The practice of marking a product with a patent number is a form of extrajudicial admission that the product falls within the patent claims” that is “not ‘binding,’ and ‘may be controverted or explained by the party’ that made the statement.” (citation omitted)).

[17] 35 U.S.C. § 287(a).

[18] Id.

[19] Id.; see also Sessions v. Romadka, 145 U.S. 29, 50 (1892) (“in a doubtful case, something must be left to the judgment of the patentee, who appears in this case to have complied with the alternative provision of the act, in affixing a label to the packages”); Rutherford v. Trim-Tex, Inc., 803 F. Supp. 158, 161-62 (N.D. Ill. 1992) (noting patentee discretion to alternatively mark package rather than product and that courts generally do not severely scrutinize the character of the patented articles to determine whether the article was capable of being marked); Ethicon Endo-Surgery, Inc. v. Hologic, Inc., 689 F. Supp. 2d 929, 945-46 (S.D. Ohio 2010); but see Creative Pioneer Products Corp. v. K Mart Corp., 5 U.S.P.Q.2d 1841, 1848 (S.D. Tex. 1987) (when patented tool had lettering and calibrations embossed on it “the character of the product was such that a marking on the product would have been a relatively simple matter. Therefore, marking the packaging . . . is insufficient to commence the period for the recovery of damages.”); John L. Rie, Inc. v. Shelly Bros., Inc., 366 F. Supp. 84, 90-91 (E.D. Pa. 1973) (when products had been marked “PAT PEND.” and had other inscriptions, marking the patent number only on packaging carton found insufficient). Some courts have found that patent marking in literature describing the patented article constitutes constructive notice when that literature is distributed with the product or placed in the box the product is contained. E.g., Acantha LLC v. Depuy Orthopaedics Inc., No. 15–C–1257, 2018 WL 1951231 (E.D. Wis. Apr. 25, 2018) (some patent numbers marked on product and additional ones listed in accompanying installation instructions found to meet marking requirements) (citations omitted); LifeNet Health v. LifeCell Corp., 93 F. Supp. 3d 477, 508 (E.D. Va. 2015) (marking patent number only on instructions for use always included in product packages found sufficient to provide constructive notice); cf. In re Ultraflight Inc., 221 USPQ 903, 906 (TTAB 1984) (in administrative trademark registration case, affixing trademark to instruction manual included in self-assembly glider kit held to constitute use of the mark on the goods because “the instruction manual is as much a part of applicant’s goods as are the various parts that are used to build the gliders. Application of the mark to the manual of assembly instructions, then, must be considered affixation to the goods.”). However, other courts have rejected or narrowed that approach, finding that the marking statute only provides for marking the product itself or its package/label but not accompanying manuals. E.g., Metrologic Instruments, Inc. v. PSC, Inc., No. 99-cv-04876, 2004 WL 285195 (D.N.J. Dec. 13, 2004) (granting summary judgment of no constructive notice when the only marking on product or package was a label that said, “See User’s Guide for Patent Coverage.”). In many situations, use of virtual marking should be considered instead of marking only an accompanying manual or similar document.

[20] 35 U.S.C. § 287(a).

[21] Id.

[22] Id.

[23] Engera, Inc. v. Cisco Sys., Inc., 547 F. Supp. 3d 112, 126-27 (D. Mass. 2021).

[24] Mfg. Res. Int’l, Inc. v. Civiq Smartscapes, LLC, 397 F. Supp. 3d 560, 577 (D. Del. 2019); accord Engera, 547 F. Supp. 3d at 128; VLSI Tech. LLC v. Intel Corp., No. 1:19-CV-00977 (W.D. Tex. April 12, 2021).

[25] Id.; see also Clontech Labs., Inc. v. Invitrogen Corp., 406 F.3d 1347, 1356-57 (Fed. Cir. 2005).

[26] Mfg. Res. Int’l, 397 F. Supp. 3d at 577; Engera, 547 F. Supp. 3d at 128; VLSI Tech., No. 1:19-CV-00977 (W.D. Tex. April 12, 2021).

[27] Id.

[28] Mfg. Res. Int’l, 397 F. Supp. 3d at 576-77 [screenshots of the insufficient virtual patent marking web pages are available in Exhibit EEEE to the patentee’s brief]; Engera, 547 F. Supp. 3d at 128 (“that a smaller number of patents entails a less time-consuming research project does not alter the fact that the webpage does not provide the statutorily required association between a patented product and the applicable patents.”).

[29] Mfg. Res. Int’l, 397 F. Supp. 3d at 576-77.

[30] VLSI Tech., No. 1:19-CV-00977 (W.D. Tex. April 12, 2021).

[31] Id.; Mfg. Res. Int’l, 397 F. Supp. 3d at 576-77; Engera, 547 F. Supp. 3d at 128; cf. Clontech Labs., 406 F.3d at 1356-57 (discussing problems raised by false marking).

[32] Engera, 547 F. Supp. 3d at 126 and n. 15.

[33] Fed. R. Evid. 803(6)-(7) and 902(11)-(14)

[34] 35 U.S.C. § 154(d)

[35] Id.

[36] 35 U.S.C. § 154(d)(2).  Additionally, provisional rights damages are only available in infringement suits brought within six years of the issuance of the patent.  35 U.S.C. § 154(d)(3).

[37] 35 U.S.C. § 154(d)(1).

[38] Rosebud LMS Inc. v. Adobe Sys. Inc., 812 F.3d 1070, 1073-75 (Fed. Cir. 2016).

[39] 35 U.S.C. § 292; Pequignot v. Solo Cup Co., 608 F.3d 1356, 1361-63 (Fed. Cir. 2010) (“mere knowledge that a marking is false is insufficient to prove intent if [the patentee] can prove that it did not consciously desire the result that the public be deceived.” “the combination of a false statement and knowledge that the statement was false creates a rebuttable presumption of intent to deceive the public” but finding that, in context, this particular use of “may be covered” patent marking was not done with intent to deceive and thus the presumption rebutted) abrogated in part on other grounds by statute; The Forest Group, Inc. v. Bon Tool Co., 590 F.3d 1295, 1304 (Fed. Cir. 2009) (“§ 292 requires courts to impose penalties for false marking on a per article basis”) abrogated in part on other grounds by statute as recognized by Sukumar v. Nautilus, Inc., 785 F.3d 1396, 1399-1402 (Fed. Cir. 2015) (AIA amendment to § 292 replaced qui tam standing with “competitive injury” standing requirement for private false marking claims). False marking does have a scienter (intent) requirement but Pequignot‘s assertion that a presumption of intent can be rebutted if it is shown there was no conscious desire for deception to result borders on unconvincing sophistry that would render the false marking statute a dead letter unless taken as a fact-specific inquiry that is satisfied by recklessness and that allows for reasonable inferences of desires that are likely to be concealed or denied in court in a self-serving manner. In other contexts, reckless disregard (or knowing or having reason to know) has been found sufficient to establish a willful intent. See Halo Elecs., Inc. v. Pulse Elecs., Inc., 979 U.S. 93, ___, 136 S. Ct. 1923, 1933 (2016) (ordinary or subjective recklessness at the time of the conduct in question is sufficient for enhanced patent infringement damages, overturning Federal Circuit “objective recklessness” case law that precluded enhancement if an objectively reasonable rationalization/defense was offered after-the-fact); cf. Merck & Co., Inc. v. Reynolds, 559 U.S. 633, 648-49 (2010) (under securities law, an “intent to deceive” means “not merely innocently or negligently”); Tellabs, Inc. v. Makor Issues & Rights, Ltd., 551 U.S. 308, 319 n.3 (2007).

[40] 35 U.S.C. § 292(c); see also Fasteners for Retail, Inc. v. Anderson, No. 11-cv-02164 (N.D. Ill. Oct. 28, 2011) (noting that the AIA eliminated liability for marking a patent number that had already expired and dismissing false marking claim); Hall v. Bed Bath & Beyond, Inc., 705 F.3d 1357, 1373 (Fed. Cir. 2013) (marking “patent pending” on articles after the patent has issued is not false marking).

[41] Clontech Labs., 406 F.3d at 1352-53; cf. Boyd v. Schildkraut Giftware Corp., 936 F. 2d 76 (2d cir. 1991) (mismarking due to temporary failure of non-English-speaking employees of a foreign outsourced manufacturer to follow instructions to replace labels with new ones that omitted a patent number was “entirely accidental and unintentional” and “for a brief period” and therefore did not provide a basis for marking estoppel).

[42] Id.

[43] 35 U.S.C. §§ 292(a) and (b).

[44] 35 U.S.C. § 292(a).

[45] 35 U.S.C. § 292(b); see also Sukumar, 785 F.3d at 1402 (standing to sue for a “competitive injury” is present only if the alleged injury “results from competition, and a potential competitor is engaged in competition if it has attempted to enter the market, which includes intent to enter the market and action to enter the market. And, for the sake of completeness, an entity has standing under § 292(b) if it can demonstrate competitive injury that was caused by the alleged false marking.”)

[46] Clontech Labs., 406 F.3d at 1256-57.

[47] Pequignot, 608 F.3d at 1361-62; Clontech Labs., 406 F.3d at 1352 (“When the statute refers to an ‘unpatented article’ the statute means that the article in question is not covered by at least one claim of each patent with which the article is marked.” (emphasis added)); Brinkmeier v. Graco Children’s Products Inc., 767 F. Supp. 2d 488, 494-99 (D. Del. 2011) abrogated in part by statute (refusing to dismiss false marking claim based on use of the conditional language “[t]his product is protected by one or more of the following patents”); Hollander v. Etymotic Research, Inc., 726 F. Supp. 2d 543, 557 (E.D. Pa. 2010) abrogated in part by statute.

[48] E.g., Brinkmeier, 767 F. Supp. 2d at 495 (rejecting the proposition that conditional marking language constitutes a per se bar to a claim for false marking) accord Brinkmeier v. Graco Children’s Prods., Inc., 684 F. Supp. 2d 548, 552 (D. Del. 2010).

[49] E.g., Pequignot, 608 F.3d at 1361-65; Arcadia Mach. & Tool Inc. v. Sturm, Ruger & Co., 786 F.2d 1124, 1125 (Fed. Cir. 1986); Brinkmeier, 767 F. Supp. 2d at 494-99; Lutron Elecs. Co., Inc. v. Crestron Elecs., Inc., No. 2:09-cv-707 (D. Utah Aug. 6, 2012).

[50] Johnston v. Textron, Inc., 579 F. Supp. 783, 794-96 (D. R.I. 1984) (finding intent to deceive the public by failing to cease using the word “patented” in a radio advertisement for an unpatented item following notification by the patentee of the falsity of such use), aff’d, 758 F.2d 666 (Fed. Cir. 1984).

[51] Cf. Blenheim Group, LLC v. Int’l Innovation Co. USA, Inc., No. 12-cv-05669, 2011 U.S. Dist. LEXIS 78074 (E.D. Pa. July 18, 2011) (European press release announcing that “[e]ach and every one of our products is patented worldwide, and we protect the patents vigorously” insufficient to establish intent to deceive by continuing to mark expired U.S. patent number) abrogated in part by statute.

[52] Cf. Cal. Med. Prods., Inc. v. Tecnol Med. Prods., Inc., 921 F. Supp. 1219, 1260-61 (D. Del. 1995) (reinstatement of patent lapsed for failure to pay maintenance fee did not constitute false marking of expired patent) abrogated in part by statute.

Have an invention you would like to patent? Have a brand you would like to register as a trademark? Concerned about infringing someone else’s intellectual property? Is someone else infringing your IP? Need representation in an IP dispute? Austen is a patent attorney / trademark attorney who can help. These and other IP issues are his area of expertise. Contact Austen today to discuss.