Checklist · Intellectual Property

Patent Marking and Constructive Notice: A Practical Checklist

Type
Checklist
Jurisdiction
National
Date
2025-12-19
Topic
Intellectual Property

Patent marking under 35 U.S.C. § 287 is the cheapest compliance step in patent law and the one whose neglect most often destroys value—a missing patent number can wipe out years of pre-suit damages even against a deliberate copyist. Because SCA Hygiene abolished laches as a damages defense inside the six-year window of § 286, marking is now the principal doctrine fixing how far back a patentee can reach. This checklist walks a patentee from deciding whether the duty attaches at all, through earning constructive notice by consistent and durable marking, using the AIA virtual-marking website option, policing licensees under the Arctic Cat burden-shifting framework, and sending an actual-notice letter that starts the damages clock without handing the recipient a declaratory-judgment forum. It closes with false-marking exposure under § 292 and an auditable compliance program built to carry the patentee's burden of proof. Every deadline, fee, and marking specification should be confirmed against current statutes and the patents actually in suit.

Patent Marking and Constructive Notice: A Practical Checklist

Intellectual Property > Patent | Published 19 December 2025 - Updated 8 May 2026 | UpLaw - uplaw.us

A patent can cost half a million dollars to obtain and a fraction of a cent per unit to mark. Skip the mark, and a court may forbid you from recovering a single dollar for years of infringement—even against a competitor who copied on purpose. This checklist turns 35 U.S.C. § 287 into an operating discipline: who owes the duty, how to earn constructive notice, how to police licensees, and how to give actual notice without surrendering the courthouse.

Keywords: patent marking, 35 U.S.C. § 287, constructive notice, actual notice, virtual marking, America Invents Act, false marking under § 292, Arctic Cat burden-shifting, licensee marking, pre-suit damages, method claims, § 286 damages window, SCA Hygiene, declaratory-judgment risk.

The cheap step that decides an expensive case

Picture a mid-size manufacturer that spent four years and a small fortune prosecuting a patent on a clever fluid coupling. It sells the coupling by the container-load. A competitor reverse-engineers the design and floods the market. Five years later our manufacturer sues, wins on liability, proves willfulness, and then loses almost everything at the damages phase—not because the patent was weak, but because nobody at the company ever stamped the patent number on the part. The court holds that damages run only from the date the complaint was served. Four and a half years of infringement evaporate. The cure would have cost less than a rounding error in the tooling budget.

That result is not a glitch. It is the design of the patent marking statute, 35 U.S.C. § 287(a), doing exactly what Congress built it to do. Marking is not a validity requirement and not an element of infringement. An unmarked patentee can still sue, still win, still get an injunction. What marking governs is timing—specifically, how far back in time a patentee may reach to collect money damages. The entire doctrine is a machinery for delivering notice to the public that an article is patented, and the statute rewards patentees who deliver that notice by the cheapest possible means: printing it on the product.

The stakes rose sharply in 2017. In SCA Hygiene Products Aktiebolag v. First Quality Baby Products, LLC, 580 U.S. 328 (2017), the Supreme Court held that laches is not a defense to a claim for patent damages brought within the six-year window of 35 U.S.C. § 286. Before SCA Hygiene, an accused infringer who had been sitting on a slow-moving patentee could sometimes shave years off a damages award by invoking equity. That escape hatch is gone. As a result, § 287 is now the single most important limit on the reach of a damages claim, and the equitable-defenses conversation has migrated almost entirely to trademark, where laches still bites—a divergence explored in the guide to laches, acquiescence, waiver, and equitable estoppel. If you want to reach back six years, marking is how you earn the right.

This checklist is the operational companion to the deeper narrative treatment in Patent Marking Requirements: A Practical Guide for Practitioners and Entrepreneurs, and it dovetails with the cross-regime analysis in Patent, Trade Dress, and Copyright Marking Requirements, which shows how to fold patent marking into one unified notice program alongside your trademark and copyright notices.

The statute in one breath

Section 287(a) says that a patentee who makes, offers to sell, sells, or imports a patented article—or whose licensees do so—may give notice to the public that the article is patented in one of two ways:

  1. Constructive notice, by marking the article (or, where that is impracticable, its packaging) with the word "patent" or the abbreviation "pat." together with either the patent number or an internet address that lists the patent number; or
  2. Actual notice, by affirmatively informing a specific infringer that a specific product infringes a specific patent.

If a patentee does neither, "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." That final clause is the guillotine. It converts a marking lapse directly into forfeited damages, and it places the burden of proving notice squarely on the patentee.

Two features deserve emphasis at the outset. First, constructive notice is objective and impersonal: once you mark consistently, you are entitled to damages across the whole six-year window regardless of whether any particular infringer ever saw the mark or knew the patent existed. Second, actual notice is subjective and personal: it counts only against the infringer you actually told, and only from the day you told them forward. Constructive notice is a floodlight; actual notice is a flashlight pointed at one defendant. The whole strategic game is to get the floodlight on before you ever need the flashlight.

How to use this checklist

Work the phases in order. Phase 1 asks whether the marking duty even attaches—for a surprising number of patents, it does not. Phases 2 and 3 are about earning constructive notice, physically and virtually. Phase 4 addresses the failure mode that quietly destroys more constructive-notice defenses than any other: an unmarked licensee. Phases 5 and 6 are the fallback and its hazards—giving actual notice without handing the recipient a declaratory-judgment forum. Phase 7 covers the mirror-image risk of marking too much, and Phase 8 turns the whole thing into a program you can defend with dated evidence.

Phase 1 — Decide whether the marking duty attaches at all

Before you spend a dime on tooling or web pages, determine whether § 287 even applies to your situation. It frequently does not, and the analysis is claim-type and business-model specific.

  • [ ] Identify a tangible "patented article." Section 287 attaches to physical things that are made, offered for sale, sold, or imported. If there is no article—only a service, a process performed in-house, or a licensing operation with no products—there may be nothing to mark and no duty.
  • [ ] Check whether the asserted claims are method/process claims only. A pure method patent covers no physical product, so there is nothing on which to stamp a number, and the marking requirement generally does not apply. See Am. Med. Sys., Inc. v. Med. Eng'g Corp., 6 F.3d 1523 (Fed. Cir. 1993); Crown Packaging Tech., Inc. v. Rexam Beverage Can Co., 559 F.3d 1308 (Fed. Cir. 2009).
  • [ ] Watch the mixed-claim trap. When a single patent contains both apparatus and method claims, marking is required if the patentee asserts the apparatus claims and there is a tangible article that practices them. A patentee cannot dodge marking merely by pointing to a method claim if it is also selling and asserting a covered device. Crown Packaging, 559 F.3d at 1316–17; Am. Med. Sys., 6 F.3d at 1538–39.
  • [ ] Confirm your status as producer or non-producer. A non-producing patentee who neither makes nor authorizes anyone to make a covered article may recover damages for the full § 286 period without ever marking. Wine Ry. Appliance Co. v. Enter. Ry. Equip. Co., 297 U.S. 387 (1936). But the duty snaps into place the instant you—or a licensee—begin selling a covered product.
  • [ ] Map every patent that reads on the product. A single SKU may be covered by several patents. Plan to mark all of them; virtual marking (Phase 3) makes multi-patent marking manageable without re-tooling.
  • [ ] Remember marking is assessed patent-by-patent. Compliance is measured for each patent separately; marking one patent does not earn constructive notice for a different, unmarked patent that also reads on the same article. Cf. Rembrandt Wireless Techs., LP v. Samsung Elecs. Co., 853 F.3d 1370 (Fed. Cir. 2017).

Why this phase matters. The method-claim carve-out is the most consequential and most misunderstood rule in this area. It is genuinely favorable to method patentees: a company practicing a patented process to make an unmarked product, and asserting only the method claims, is not penalized by § 287 at all and may reach back the full six years. But the carve-out is narrow and treacherous. If the same patent has apparatus claims, or if the patentee also sells a device embodiment, the safe harbor collapses. Counsel litigating a mixed patent should think hard about which claims to assert precisely because that choice can determine whether marking was ever required.

Worked example — the two faces of one patent. Cobalt Cycles owns a patent with claims 1–8 directed to a "regenerative braking assembly" (apparatus) and claims 9–14 directed to "a method of recovering kinetic energy" (process). Cobalt sells e-bikes with the braking assembly built in, and never marks them. If Cobalt sues a copyist and asserts the apparatus claims, § 287 required marking, and Cobalt's failure to mark caps damages at the date of actual notice. If Cobalt instead asserts only the method claims—say, because the infringer performs the energy-recovery method during use—marking was never required, and Cobalt may claim the full six years. The doctrinal difference is worth millions, and it turns entirely on litigation-strategy choices about claim selection that should be modeled long before filing. For the underlying infringement analysis that drives those choices, see What Counts as Patent Infringement: An Anatomy of the Section 271 Analysis.

Phase 2 — Earn constructive notice by marking correctly

Constructive notice is the prize. Once you have it, damages decouple from the infringer's knowledge entirely, and you may recover across the whole § 286 window without any showing that the defendant ever heard of the patent. The mechanics are specific, and courts enforce them literally.

  • [ ] Use the word "patent" or "pat." plus the number. A bare "Patented," "Patent Pending," or a company slogan will not do. The statute requires the word or its abbreviation together with the number of the patent. "Patent Pending" is not marking at all—there is no issued patent to give notice of.
  • [ ] Mark the article itself whenever practicable. Marking the packaging is permitted only "when, from the character of the article, this cannot be done"—for example, an item too small to bear legible text, or one that marking would deface or impair. If the article can be marked, mark the article.
  • [ ] Make the mark visible and durable. A mark that rubs off, hides inside a sealed housing, or is illegible does not give notice. Arcadia Mach. & Tool, Inc. v. Sturm, Ruger & Co., 786 F.2d 1124 (Fed. Cir. 1986).
  • [ ] Mark substantially consistently and continuously. This is the rule that undoes careful companies. Once marking begins, it must be "substantially consistent and continuous"; sporadic or interrupted marking forfeits constructive notice for the unmarked runs. Am. Med. Sys., 6 F.3d at 1537; Nike, Inc. v. Wal-Mart Stores, Inc., 138 F.3d 1437 (Fed. Cir. 1998).
  • [ ] Start at first sale. If the mark is present from the very first commercial unit, constructive notice is in place before any infringement can occur, and the actual-notice inquiry never arises. This is the cleanest possible posture.
  • [ ] Build the proof file now. The patentee bears the burden of proving compliance by a preponderance of the evidence. Maxwell v. J. Baker, Inc., 86 F.3d 1098 (Fed. Cir. 1996). Dated photographs, label specifications, and production records are what carry that burden years later.

Consistency is the whole ballgame. The "substantially consistent and continuous" requirement means marking is not a one-time act but a standing state. A company that marks 100% of units for three years, drops the mark for a product refresh, and resumes six months later has, during that six-month gap, no constructive notice—and if an infringer's sales spiked in exactly that window, the damages consequences can be severe. The word "substantially" gives some grace: a stray unmarked unit or a small good-faith error will not necessarily blow the defense. But systematic gaps do. Treat the mark like a safety label: not optional, not intermittent, and not something to be dropped for a marketing redesign without a compliance sign-off.

Worked example — the refresh that cost three years. Meridian Instruments marks its patented surgical stapler correctly from launch. Two years in, marketing commissions a sleeker housing and, in the changeover, the mold that embossed "Pat. 9,xxx,xxx" is retired and not replaced. Marketing did not know the emboss was legally load-bearing. For eleven months, Meridian ships unmarked staplers. A competitor's infringing sales climb during that exact period. When Meridian later sues, the court holds that constructive notice lapsed for the eleven-month gap, and Meridian must prove actual notice to reach any of that period. The engineering change order never crossed counsel's desk—which is precisely the failure Phase 8's audit program is designed to catch.

Note the burden allocation carefully. The patentee must affirmatively prove marking; the accused infringer does not have to prove the absence of marking as an element of a defense. In practice this means the patentee who cannot reconstruct what its product looked like three years ago is in trouble regardless of what actually happened on the factory floor. Contemporaneous documentation is not housekeeping; it is the evidence that wins the damages phase. The broader picture of how damages are computed once the marking gate is cleared—reasonable royalties, lost profits, the Georgia-Pacific factors, and enhancement—appears in What an IP Case Is Worth: A Guide to Intellectual Property Damages.

Phase 3 — Use the AIA virtual-marking option

The Leahy-Smith America Invents Act, Pub. L. No. 112-29 (2011), amended § 287(a) to permit virtual marking: instead of printing the patent number on the article, a patentee may mark it with "patent" or "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." The reform solved a real problem—re-tooling molds and reprinting labels every time a patent issued or expired—and for portfolio owners it is now the default best practice.

  • [ ] Mark the article with "patent"/"pat." plus a stable URL. For example: Patented. See www.example.com/patents. The mark on the product points to the page; the page carries the numbers.
  • [ ] Maintain a page that associates each article with its patent number(s). The statutory phrase is exact: the page must associate the patented article with the number of the patent. A generic list of "our patents" that does not tie specific patents to specific products may not satisfy the statute.
  • [ ] Keep the URL stable and the page free. No login, no paywall, no broken links. "Accessible to the public without charge" is a statutory condition, not a suggestion.
  • [ ] Keep the page current. Add patents as they issue; remove them (and record the date) as they expire. A stale page under-notices new patents and over-marks expired ones—the latter raising false-marking questions under Phase 7.
  • [ ] Archive every version of the page. Because damages turn on what the page said on specific historical dates, you must be able to prove the page's contents on any given day. Automated version snapshots or a dated content-management log are the cleanest proof.

Why virtual marking is worth the discipline. Physical marking freezes your notice at the moment the mold is cut. If a continuation issues two years into a product's life, the physical mark cannot be updated without re-tooling, and the new patent goes unmarked—no constructive notice for it. A well-run virtual-marking page fixes this: the moment the continuation issues, you add it to the page, and constructive notice attaches to the new patent for that product going forward. The tradeoff is that the page becomes a piece of legal infrastructure. It must be owned, versioned, and audited like any other compliance artifact. A neglected virtual-marking page is arguably worse than no page at all, because it invites disputes about whether the "association" was adequate and whether the page was truly accessible on the dates that matter.

Worked example — the continuation that finally got marked. Larkspur Labs sells a water-testing probe embossed only with Patented. See larkspur.com/ip. At launch the page lists one patent. Eighteen months later a continuation issues with broader claims that also read on the probe. Larkspur's IP paralegal adds the continuation to the page the day it issues and logs the change. When Larkspur later sues an importer of knock-off probes, it can prove constructive notice for the original patent from day one and for the continuation from the documented date it hit the page. No mold was ever recut. That is the entire value proposition of virtual marking: the web page does the work the product surface used to do, and it can be updated at the speed of a git commit.

A practical caution: virtual marking shifts the compliance burden from the factory to the web team, and web teams reorganize sites, migrate domains, and let certificates lapse. Build the marking URL into your change-management process so that a routine site redesign cannot silently break the legal function of the page.

Phase 4 — Police your licensees

This is the phase that quietly kills more constructive-notice defenses than any physical-marking mistake, because it depends on people you do not control. Section 287 applies to "persons making, offering for sale, or selling within the United States any patented article for or under [the patentee]." A licensee's unmarked sales can defeat your constructive notice, even if every unit you personally shipped was marked flawlessly.

  • [ ] Put a marking obligation in every license. Any license that authorizes a licensee to make, use, or sell covered articles should require the licensee to mark, specify the form of the mark (or the virtual-marking URL), and give you audit rights. Structure this alongside the rest of the deal using Building a Patent License Term Sheet: A Practical Checklist.
  • [ ] Monitor and enforce compliance under a rule of reason. A patentee need not achieve perfection across every licensee, but must make reasonable efforts to ensure licensees mark. Maxwell, 86 F.3d at 1111–12; Nike, 138 F.3d at 1446. Passive licensing with no follow-up is not reasonable effort.
  • [ ] Understand the Arctic Cat burden-shifting framework. An accused infringer who challenges marking bears an initial burden of production—a low bar—to identify products it believes are unmarked "patented articles." Once it does, the burden shifts to the patentee to prove those products were properly marked or did not practice the patent. Arctic Cat Inc. v. Bombardier Recreational Prods., Inc., 876 F.3d 1350, 1368 (Fed. Cir. 2017) (Arctic Cat I).
  • [ ] Keep records that span the entire licensee population. Because the patentee ultimately must prove marking or non-coverage for every product an infringer identifies, you need certifications, samples, and audit results from each licensee—not just your own line.
  • [ ] Know that cessation does not cure a past failure. If unmarked licensed products were sold, later stopping those sales does not restore constructive notice; damages remain barred until marking resumes or actual notice is given. Arctic Cat Inc. v. Bombardier Recreational Prods., Inc., 950 F.3d 860 (Fed. Cir. 2020) (Arctic Cat II).

The Arctic Cat framework, unpacked. The two Arctic Cat decisions are the most important modern authority on marking, and together they set a demanding trap. Arctic Cat I establishes that the accused infringer's opening move is cheap: it need only point to products it contends were unmarked and covered. It does not have to prove those products actually practiced the patent. That production burden satisfied, the entire persuasion burden lands on the patentee, who must then prove, product by product, either that the item was marked or that it did not embody the claimed invention. For a patentee with a sprawling licensee network and thin records, that is a burden it may simply be unable to carry.

Arctic Cat II closes the escape route. A patentee facing a marking problem might hope to argue: "Yes, unmarked covered products were sold, but sales stopped before the damages period, so by the time of the infringement at issue there were no unmarked products in the channel." The Federal Circuit rejected that. Once a patentee (or its licensee) has sold unmarked covered articles, it cannot recover damages for any later period until it either resumes marking or provides actual notice. Stopping sales of the unmarked product does not reset the clock. The lesson is blunt: an unmarked sale is a stain that only marking-going-forward or an actual-notice letter can remove.

Worked example — the one licensee that sank the fleet. Northwind Manufacturing licenses its patented valve to three companies. Two mark flawlessly. The third, a small OEM, ships 4,000 unmarked units before anyone notices. Years later Northwind sues an unrelated infringer. The infringer's counsel, invoking Arctic Cat I, simply identifies the third licensee's unmarked valves and demands that Northwind prove they were marked or non-covering. Northwind cannot—the units were unmarked and plainly covered. Under Arctic Cat II, the fact that the OEM stopped selling them two years ago does not help. Northwind's constructive notice is gone for the whole pre-notice period, and its recovery is capped at the date it served the complaint. One neglected licensee, 4,000 units, and a multimillion-dollar damages window collapses. The fix cost pennies per valve and a contract clause nobody enforced.

The licensee problem is why marking cannot live inside the legal department alone. It requires contractual hooks, real audit rights, and someone whose job is to exercise them. The economics of when licensee marking is worth policing—and how marking interacts with royalty structure and grant scope—are developed in Monetizing a Patent Through Licensing: From Valuation to Term Sheet.

Phase 5 — When you did not mark, give effective actual notice

If constructive notice failed—no marking, gappy marking, or an unmarked licensee—your only path to pre-complaint damages is actual notice. The requirements are strict, and the doctrine is unforgiving of vague or friendly letters that talk around the point.

The counterintuitive core of actual notice. The most surprising feature of § 287 actual notice is that the infringer's own knowledge is legally irrelevant. An infringer might have the patent framed on its wall, might have studied it, might have been quoted the number by a mutual customer—none of that starts the damages clock. Only an affirmative communication from the patentee charging this product with infringing this patent does. The statute cares about the patentee's conduct because § 287 is fundamentally about incentivizing patentees to speak up, not about penalizing infringers for what they happened to know. Hanson makes the point starkly: even where the accused infringer clearly knew of the patent, absent an affirmative charge from the patentee, there was no actual notice.

This is also why the content of the letter is dispositive. A letter that says "we own U.S. Patent 9,xxx,xxx and would welcome a licensing discussion" is not actual notice, because it charges no specific product with infringement. The friendly, deal-making tone that lawyers reach for to avoid provoking litigation is exactly the tone that fails § 287. To start the clock, the letter must accuse. That tension—between a letter aggressive enough to be actual notice and one restrained enough to avoid a declaratory-judgment suit—is the subject of Phase 6.

Worked example — the friendly letter that started no clock. Vantage Optics never marked its patented lens coating. It sends a prospective infringer a warm letter: "We hold several patents in this space, including U.S. Patent 10,xxx,xxx, and think there may be opportunities to collaborate." Eighteen months later, talks having gone nowhere, Vantage sues. It argues the letter was actual notice. The court disagrees: the letter named a patent but charged no specific product with infringement and made no accusation. Under Amsted and SRI, that is not actual notice. Vantage's damages start the day it served the complaint, and eighteen months of infringement are gone. Had the letter said "your Model X eyewear, which uses the coating claimed in claim 1 of U.S. Patent 10,xxx,xxx, infringes that patent," the clock would have started on receipt.

For the general anatomy of a firm, credible, legally safe demand—including the settlement-privilege and delivery-proof mechanics that apply to any pre-suit letter—see Drafting an Effective Demand Letter: The Basics. And because the accused infringer's counsel will be running its own analysis of coverage and validity the moment your letter lands, the mirror-image workflow appears in Clearing a Product for Launch: How to Conduct a Freedom-to-Operate Analysis.

Phase 6 — Manage the notice-letter / declaratory-judgment tension

A letter specific enough to be actual notice is, by definition, a letter that tells a competitor you intend to enforce a patent against a named product. That is precisely the fact pattern that can hand the recipient a declaratory-judgment action in a forum of its choosing. Phase 6 is about walking that line with eyes open.

Why marking early is a litigation-posture decision, not just compliance. The strategic beauty of consistent marking is that it dissolves the Phase 6 dilemma entirely. If you have constructive notice, you do not need to send a specific charge letter to preserve pre-suit damages—those damages are already secured by the mark. You can then choose whether to send a letter at all, and if you do, you can calibrate its tone freely, because it is no longer load-bearing for damages. The patentee who never marked, by contrast, is cornered: to capture pre-complaint damages it must send an accusatory letter, and that very letter may launch the recipient into a distant courthouse. Marking converts a forced move into a free one.

The MedImmune totality-of-circumstances standard is deliberately fuzzy, and the Federal Circuit's application of it has trended toward finding jurisdiction where a patentee's conduct, viewed as a whole, communicates a genuine enforcement intent—SanDisk (setting out an infringement position while promising not to sue still created jurisdiction) and Hewlett-Packard v. Acceleron (a non-practicing entity's insistent letters with short deadlines) mark the boundaries. Trimble then confirmed that the same conduct that creates a controversy can, in the right circumstances, create personal jurisdiction over the patentee in the recipient's forum. The practical upshot: assume a specific charge letter can be sued upon, in the recipient's backyard, and decide in advance whether you are ready to litigate there. Parallel strategic considerations for the trademark side of the demand-letter equation—where the same MedImmune dynamic governs—appear throughout the UpLaw enforcement materials, and the same declaratory-judgment calculus recurs in Standard-Essential Patents and FRAND Licensing in the 5G and IoT Era, where notice, willingness-to-license conduct, and forum races are central.

Finally, do not overlook the willfulness dimension. A specific notice letter does more than start the § 287 damages clock; it plants knowledge of the patent, which is a predicate for enhanced damages under 35 U.S.C. § 284 and the Halo Elecs., Inc. v. Pulse Elecs., Inc., 579 U.S. 93 (2016), framework, and a predicate for induced and contributory infringement, which require knowledge of the patent. The letter that captures back-damages also arms your willfulness and indirect-infringement theories—another reason its content should be drafted with the full case in mind, as detailed in The Patent Infringement Lawsuit From Filing to Appeal: A Comprehensive Guide.

Phase 7 — Avoid false marking

Marking too much carries its own liability. Section 292 prohibits marking an unpatented article as patented with intent to deceive the public. Post-AIA the exposure is far narrower than it once was, but it has not vanished, and stale markings on expired patents are the most common trigger.

  • [ ] Do not mark an unpatented article as patented. Marking a product with a patent number when no patent covers it—or using "patent pending" with no pending application—violates § 292 if done with intent to deceive the public.
  • [ ] Remove or update markings promptly when patents expire or are invalidated. A leftover number for a lapsed patent is the classic false-marking scenario; keep the physical mark or the virtual-marking page current.
  • [ ] Know the AIA narrowed the cause of action. Congress eliminated the qui tam bounty regime. Now only "a person who has suffered a competitive injury as a result of a violation" may sue for damages adequate to compensate that injury; the United States may still sue for the statutory per-article penalty. 35 U.S.C. § 292(b).
  • [ ] Use the expired-patent safe harbor. Marking a product with a patent that "covered that product but has expired" is not a violation of § 292. 35 U.S.C. § 292(c). This is a meaningful cushion for products still bearing recently expired numbers—but it does not protect marks for patents that never covered the product.
  • [ ] Remember intent to deceive is required and can be presumed. False marking requires an intent to deceive the public; marking with an expired patent creates a rebuttable presumption of intent that a good-faith explanation can overcome. Pequignot v. Solo Cup Co., 608 F.3d 1356 (Fed. Cir. 2010).

How the false-marking landscape got here. For a brief, chaotic period, false marking was a cottage industry. In Forest Group, Inc. v. Bon Tool Co., 590 F.3d 1295 (Fed. Cir. 2009), the Federal Circuit held that the § 292 penalty accrues on a per-article basis—potentially a fine for every mismarked unit. Because the pre-AIA statute let any person sue as a qui tam relator and split the penalty with the government, Forest Group triggered a wave of opportunistic suits by plaintiffs who bought a mismarked product off a shelf and sued for astronomical per-article sums. Congress responded in the 2011 AIA by (1) abolishing qui tam standing for private relators, (2) limiting private damages actions to competitors who suffered a genuine competitive injury, and (3) adding the § 292(c) safe harbor for expired patents. The result is a much calmer regime: a competitor annoyed by your stale markings can still sue, but must prove actual competitive injury, and you can defend a recently expired number outright.

Worked example — the number that outlived the patent. Ridgeline Tools marks its patented level with Pat. 8,xxx,xxx. The patent expires. Ridgeline keeps selling the level with the same emboss for another three years, simply because nobody updated the mold. Under § 292(c), marking with the now-expired patent that did cover the product is not a violation—Ridgeline is protected. But suppose Ridgeline also slaps the same number on a new accessory the patent never covered, hoping to borrow the aura of "patented." That is a different story: the number never read on the accessory, the safe harbor does not apply, and a competitor who lost sales to the "patented" accessory could plausibly plead a § 292 competitive-injury claim, with intent-to-deceive inferred from the mismatch. The line is between keeping an honest-but-expired number and fabricating patent coverage that never existed.

The compliance takeaway is symmetrical with the rest of this checklist: the same audit that keeps your marks present on covered products (Phase 2) must keep them accurate, pruning numbers for patents that never covered a given SKU and refreshing pages as patents expire. Under-marking forfeits damages; over-marking invites § 292 liability; the audit prevents both.

Phase 8 — Build an auditable compliance program

Everything above collapses into one operational reality: marking is a standing state that must be maintained, documented, and proven. A compliance program is what turns scattered good intentions into evidence you can put in front of a jury.

  • [ ] Maintain a master product-to-patent matrix. Map every product and SKU to the patents that cover it, reviewed and updated by counsel. This matrix is the backbone of both physical and virtual marking and the reference for pruning stale marks.
  • [ ] Assign clear ownership. Name who updates the virtual-marking page, who audits physical marking on the line, who tracks licensee compliance, and who signs off on engineering change orders that touch a marked surface.
  • [ ] Calendar issuance and expiration dates. New patents must get added to marks and pages when they issue; numbers must come off (or move to the "expired but covered" logic of § 292(c)) when patents lapse. Tie this to your maintenance-fee docket.
  • [ ] Retain dated evidence. Product photographs, label and mold specifications, virtual-marking page archives, and signed licensee marking certifications are the proof that carries the patentee's Maxwell burden years later.
  • [ ] Re-audit on a schedule and on every trigger. Audit periodically and on every product change, new patent issuance, new license, and patent expiration or invalidation.
  • [ ] Wire marking into change management. The most common failure is not ignorance of the law but a redesign, re-tool, or website migration that silently drops the mark. Make marking a checklist item in every ECO and every site release.

Treat marking like a control, not a project. The companies that lose marking fights are rarely the ones that never heard of § 287; they are the ones that marked correctly for years and then let a routine business change—a housing refresh, a new contract manufacturer, a website redesign, a lightly supervised licensee—break the chain without anyone noticing. The defense is boring and effective: a named owner, a living matrix, a change-management hook, and a document trail. When an accused infringer later invokes Arctic Cat I and demands that you prove marking, the audit file is the difference between carrying that burden and watching six years of damages disappear. For companies running the full patent-litigation gauntlet, this program feeds directly into the pre-suit and damages workstreams mapped in Litigating Patent Infringement: A Roadmap and Research Guide and the small-business perspective in Federal Civil Litigation for Small Businesses: A Patent-Focused Field Guide.

Edge cases and hard questions

The eight phases cover the mainline. Several recurring situations deserve their own treatment because they arise constantly and are easy to get wrong.

Design patents. Section 287 applies to design patents just as it does to utility patents, and the damages consequences can be even more dramatic because design patents carry the total-profit remedy of 35 U.S.C. § 289. A design patentee who fails to mark can lose access to that potent remedy for the pre-notice period. The interaction of marking with § 289 total-profit damages is developed in Litigating Design Patents: From Claim Construction to Total-Profit Damages. If you are still deciding which form of protection to pursue, the design-versus-utility patent checklist frames the tradeoffs, several of which have downstream marking consequences.

Components and combinations. When a patent claims a combination but you sell an unpatented component that others assemble into the infringing combination, marking questions get subtle. The safest course is to mark whatever covered article you actually make and sell, and to rely on actual notice for downstream assemblers you cannot reach with a mark. Do not assume that marking a component earns constructive notice for a combination claim it does not itself embody.

Contract manufacturers and private label. If a third party manufactures your covered product, or you sell it under a customer's private label, marking responsibility must be pinned down by contract. An unmarked private-label run is functionally identical to the unmarked-licensee problem of Phase 4: it can defeat your constructive notice even though your own branded units are perfect. Build marking obligations and audit rights into manufacturing and supply agreements, not just licenses.

Software and articles without a surface. Section 287 is written for tangible articles, and applying it to pure software distributed by download is genuinely uncertain. Where software ships with any physical medium, documentation, or packaging, marking that medium is prudent. Where it does not, the virtual-marking option and a well-documented actual-notice practice become the primary tools. Companies whose patents read on downloadable software should treat the marking question as unsettled and hedge accordingly.

Foreign sales and imports. The marking duty reaches articles "imported" into the United States, and § 287(a)'s notice rules apply to the domestic damages claim. Products manufactured and sold entirely abroad raise different questions, but any covered article entering the U.S. market should be marked as if it were domestically produced.

Pre-issuance provisional rights. Marking's cousin lives in 35 U.S.C. § 154(d), which grants a patentee reasonable-royalty "provisional rights" for infringement occurring between publication of the application and issuance of the patent—but only if the infringer had actual notice of the published application and the claims that ultimately issued are substantially identical. It is a separate regime, but it rewards the same instinct: notice, given early and specifically, is what unlocks recovery.

Medical practitioners and process patents. Section 287(c) separately limits certain remedies against medical practitioners for performance of a "medical activity," a niche but important carve-out for method patents in the healthcare space. It is not a marking rule, but it lives in the same statute and can interact with the method-claim analysis of Phase 1 for medical-device and surgical-technique portfolios.

Common mistakes, restated

  • A word without a number. "Patented" or "Patent Pending" alone never satisfies § 287. The number—or a compliant virtual-marking URL—is mandatory.
  • Gappy marking. Sporadic or interrupted marking forfeits constructive notice for the unmarked stretches. For damages purposes, intermittent marking is close to no marking. Am. Med. Sys., 6 F.3d at 1537.
  • Ignoring licensees and contract manufacturers. A single unmarked covered product from anyone selling "for or under" you can defeat your constructive notice, and under Arctic Cat II, later stopping those sales does not cure it.
  • The friendly license letter. A letter that names a patent but accuses no specific product is not actual notice and starts no damages clock. Amsted, 24 F.3d at 187.
  • Stale marks on the wrong product. Keeping an expired number on the product it covered is protected by § 292(c); putting any patent number on a product it never covered is the false-marking trap.
  • No proof file. Because the patentee bears the burden of proving compliance, the company that cannot document what its product and web page looked like on historical dates loses the marking fight regardless of what actually happened. Maxwell, 86 F.3d at 1111.

A worked timeline: the same facts, two outcomes

To see how much marking is worth, run one set of facts twice.

Summit Fasteners obtains a utility patent on a self-locking bolt in January 2020 and begins selling the bolt that spring. A competitor, Apex Hardware, launches an infringing bolt in July 2020 and sells 500,000 units a year at a $2 profit each. Summit discovers the infringement in mid-2024, sends a specific charge letter in September 2024, and files suit in January 2026.

Scenario A — Summit marked from first sale. Constructive notice has been in place since spring 2020. Under § 286, Summit may reach back six years from the January 2026 complaint—to January 2020—and recover for all of Apex's infringing sales in that window. Four-plus years of infringement, roughly two million units, are on the table. Marking cost Summit a fraction of a cent per bolt.

Scenario B — Summit never marked. Constructive notice never attached. Actual notice was not given until the September 2024 letter (assume it was properly specific). Damages run only from September 2024 forward. Everything from July 2020 through August 2024—more than four years and the large majority of Apex's infringing sales—is unrecoverable, no matter how willful Apex was, and SCA Hygiene offers no equitable relief because the claim is already inside the § 286 window. The difference between the two scenarios is not the strength of the patent, the quality of the lawyering, or the culpability of the infringer. It is a patent number on a bolt.

That single comparison is the entire argument for treating marking as a first-day, standing discipline rather than a litigation afterthought. Everything else in this checklist is machinery for keeping Scenario A true across every product, every licensee, every redesign, and every year the patent lives.

Primary and secondary authority

Statutes. 35 U.S.C. § 287 (marking; constructive and actual notice; virtual marking; medical-practitioner and § 271(g) provisions); 35 U.S.C. § 286 (six-year damages limitation); 35 U.S.C. § 292 (false marking; post-AIA competitive-injury and expired-patent provisions); 35 U.S.C. § 284 (damages; enhancement); 35 U.S.C. § 154(d) (pre-issuance provisional rights); 35 U.S.C. §§ 315(a), 325(a) (AIA review bars); Leahy-Smith America Invents Act, Pub. L. No. 112-29 (2011).

Supreme Court. SCA Hygiene Prods. Aktiebolag v. First Quality Baby Prods., LLC, 580 U.S. 328 (2017); Halo Elecs., Inc. v. Pulse Elecs., Inc., 579 U.S. 93 (2016); MedImmune, Inc. v. Genentech, Inc., 549 U.S. 118 (2007); Wine Ry. Appliance Co. v. Enter. Ry. Equip. Co., 297 U.S. 387 (1936).

Federal Circuit. Arctic Cat Inc. v. Bombardier Recreational Prods., Inc., 876 F.3d 1350 (Fed. Cir. 2017), and 950 F.3d 860 (Fed. Cir. 2020); Rembrandt Wireless Techs., LP v. Samsung Elecs. Co., 853 F.3d 1370 (Fed. Cir. 2017); Trimble Inc. v. PerDiemCo LLC, 997 F.3d 1147 (Fed. Cir. 2021); Myco Indus., Inc. v. BlephEx, LLC, 955 F.3d 1 (Fed. Cir. 2020); Jack Henry & Assocs., Inc. v. Plano Encryption Techs. LLC, 910 F.3d 1199 (Fed. Cir. 2018); Asia Vital Components Co. v. Asetek Danmark A/S, 837 F.3d 1249 (Fed. Cir. 2016); Funai Elec. Co. v. Daewoo Elecs. Corp., 616 F.3d 1357 (Fed. Cir. 2010); Pequignot v. Solo Cup Co., 608 F.3d 1356 (Fed. Cir. 2010); Forest Group, Inc. v. Bon Tool Co., 590 F.3d 1295 (Fed. Cir. 2009); Crown Packaging Tech., Inc. v. Rexam Beverage Can Co., 559 F.3d 1308 (Fed. Cir. 2009); Hewlett-Packard Co. v. Acceleron LLC, 587 F.3d 1358 (Fed. Cir. 2009); SanDisk Corp. v. STMicroelectronics, Inc., 480 F.3d 1372 (Fed. Cir. 2007); SRI Int'l, Inc. v. Advanced Tech. Labs., Inc., 127 F.3d 1462 (Fed. Cir. 1997); Nike, Inc. v. Wal-Mart Stores, Inc., 138 F.3d 1437 (Fed. Cir. 1998); Maxwell v. J. Baker, Inc., 86 F.3d 1098 (Fed. Cir. 1996); Amsted Indus. Inc. v. Buckeye Steel Castings Co., 24 F.3d 178 (Fed. Cir. 1994); Am. Med. Sys., Inc. v. Med. Eng'g Corp., 6 F.3d 1523 (Fed. Cir. 1993); Arcadia Mach. & Tool, Inc. v. Sturm, Ruger & Co., 786 F.2d 1124 (Fed. Cir. 1986); Hanson v. Alpine Valley Ski Area, Inc., 718 F.2d 1075 (Fed. Cir. 1983).

State statutes (bad-faith patent assertion). E.g., Vt. Stat. Ann. tit. 9, §§ 4195–4199.

Agency resources. U.S. Patent and Trademark Office, patent resources, https://www.uspto.gov/patents (confirm current fees and procedures at the official site).

This checklist is general legal information, not legal advice, and does not create an attorney-client relationship. Marking specifications, damages exposure, and the availability of the method-claim and non-producing-patentee carve-outs depend on the specific patents, products, and licenses at issue. Consult qualified patent counsel before relying on any point above.

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