Indirect Patent Infringement Claim Checklist: A Practical Checklist

Summary. This checklist breaks an indirect patent infringement claim into the facts each side must find, prove, or attack, in the order the work happens. It starts by mapping every claim element to the actor who performs it, choosing among inducement, contributory infringement, divided infringement, and the export and import theories, and testing the predicate act of direct infringement. Separate phases cover knowledge of the patent, specific intent and good-faith belief, active steps and causation, the staple-article and substantial noninfringing use inquiry, direction or control under Akamai, cross-border liability under sections 271(f) and 271(g), and pharmaceutical label cases. Later phases address notice letters and declaratory judgment risk, pleading and motions to dismiss, discovery and expert proof, damages and willfulness, and jury instructions and judgment as a matter of law. Each item is tagged for the patentee, the accused infringer, or both, and the checklist closes with a defense audit, red flags, an FAQ, and practical takeaways.

Indirect infringement cases are usually lost on a fact somebody could have pinned down in the first month: the day an engineering director first opened the patent, the share of customers who ever switched on the accused setting, or the onboarding page that said "must" where the drafter meant "may." This checklist is the list of those facts, in the order you will need them, for the lawyer bringing the claim and the lawyer defending it.

The short answer

An indirect claim, meaning a claim against someone who did not itself perform the whole patented invention, has four load-bearing facts: who directly infringed, when the defendant learned of the patent, what the defendant told people to do, and, for contributory claims, whether the accused feature has real uses that do not infringe. Everything below is a way of finding, proving, or attacking one of those four facts.

• Patentees should chart every claim step by actor, prove actual use rather than capability, build a dated knowledge record before suit, plead quoted instructions instead of statutory labels, and keep fallback theories alive until the evidence is in.
• Accused infringers should attack the predicate direct infringement first, fix the first-knowledge date, form and document a good-faith noninfringement position, measure noninfringing uses with data, and preserve every judgment-as-a-matter-of-law argument.

For the doctrine behind each item, read Indirect and Divided Patent Infringement: Inducement, Contributory Liability, and the Akamai Problem. For the step-by-step litigation sequence, see Pleading and Proving Induced and Contributory Patent Infringement: A Practical Guide. The letters, logs, charts, and memo outlines referred to below are collected in the Indirect Infringement Toolkit: Knowledge Evidence, Direction or Control Proof, and Substantial Noninfringing Use Analyses.

How to use this checklist

Every item carries a tag. [P] items are for the patentee, [D] items are for the accused infringer, and [Both] items should be done by whichever side you represent, because the same fact helps one side and hurts the other. Indented notes explain why the item matters and cite the controlling authority. Phases 1 and 2 come first in every case; after that, work the phases that match your theories. Keep one copy of the checklist per asserted patent, because knowledge dates, marking, and claim types differ from patent to patent even within one family.

The examples use the facts from the article's worked example: Juniper Labs, a software-as-a-service (SaaS) analytics vendor, and Stillwater Data LLC, which owns a method claim (receive a formatted dataset, score it on a server, display the score on the client device) and a parallel system claim.

Theory selector

All of these theories live in one statute, 35 U.S.C. § 271, and every one except § 271(f), § 271(g), and the § 271(e)(2) filing (which is itself the act of infringement) needs a completed act of direct infringement in the United States.

Phase 1: Map the claims, the actors, and the theories

• [Both] Chart every element of every asserted claim against the actor who performs or provides it: vendor, customer, end user, physician, patient, contract manufacturer, distributor, foreign affiliate. Note: the chart decides which theories exist. A method claim whose steps are split between actors raises the divided-infringement question; a system claim whose parts sit on both sides of a network raises the question of who "uses" the system. The toolkit's claim-by-actor chart is built for this.
• [Both] Classify each claim as method, system or apparatus, composition, or computer-readable medium, and note the consequences. Note: marking under 35 U.S.C. § 287(a) limits pre-notice damages for apparatus claims when unmarked products exist, but not when only method claims are asserted, Crown Packaging Technology, Inc. v. Rexam Beverage Can Co., 559 F.3d 1308 (Fed. Cir. 2009). Section 271(f) does not reach method claims, Cardiac Pacemakers, Inc. v. St. Jude Medical, Inc., 576 F.3d 1348 (Fed. Cir. 2009) (en banc in relevant part).
• [Both] Name, for each claim, the single actor who would be the direct infringer if the patentee is right. Note: there is no inducement unless one actor performed, or is legally responsible for, every step. Limelight Networks, Inc. v. Akamai Technologies, Inc., 572 U.S. 915 (2014).
• [Both] Flag claim words that quietly assign a step to someone ("user," "client device," "physician," "a human in need thereof") and send them to the claim construction team. Note: one construction of "displaying on the client device" can turn Stillwater's single-actor claim into a divided one. Population and purpose limitations also bind the direct infringer; where a claim required administering a vitamin "to a human in need thereof," a supplement seller was not liable without evidence that customers took it for the claimed purpose, Jansen v. Rexall Sundown, Inc., 342 F.3d 1329 (Fed. Cir. 2003). See the Claim Construction Checklist: A Practical Checklist.
• [Both] Confirm that the defendant's own acts are not already direct infringement before building an indirect theory. Note: selling equipment capable of performing a claimed process is not itself direct infringement of the process, Joy Technologies, Inc. v. Flakt, Inc., 6 F.3d 770 (Fed. Cir. 1993); Moba, B.V. v. Diamond Automation, Inc., 325 F.3d 1306 (Fed. Cir. 2003). A vendor that makes or sells a complete claimed apparatus, on the other hand, infringes directly and needs no indirect theory.
• [P] Plead and preserve every theory the facts support until discovery shows which ones work. Note: in CloudofChange, LLC v. NCR Corp., 123 F.4th 1333 (Fed. Cir. 2024), the patentee abandoned its inducement and contributory theories and tried a point-of-sale system claim against a SaaS vendor solely as direct "use." The Federal Circuit held that the merchants, not NCR, put the system into service, and that a contract term requiring merchants to supply their own Internet access was not direction or control of their use of the system. A $13.2 million verdict was reversed.
• [Both] Write down, per patent and per theory, the earliest date from which damages could run. Note: inducement and contributory liability begin with knowledge of the patent, Aro Manufacturing Co. v. Convertible Top Replacement Co., 377 U.S. 476 (1964) (Aro II); direct and divided infringement can reach back six years under 35 U.S.C. § 286, subject to marking. The difference often decides which theory the patentee leads with.

Phase 2: Prove or test the predicate direct infringement

• [Both] Identify the direct infringers, by class (customers, physicians, distributors, end users) and by name where possible. Note: a complaint need not name a specific direct infringer, In re Bill of Lading Transmission & Processing System Patent Litigation, 681 F.3d 1323 (Fed. Cir. 2012), but liability must relate to the instances or category of direct infringement actually proved; a hypothetical infringing configuration is not enough, Dynacore Holdings Corp. v. U.S. Philips Corp., 363 F.3d 1263 (Fed. Cir. 2004).
• [P] Collect evidence of actual use, not capability: usage logs, telemetry, default settings, mandatory workflows, support tickets, training attendance, and customer testimony. Note: an expert's own use of a product is not evidence that customers used it the same way, ACCO Brands, Inc. v. ABA Locks Manufacturer Co., 501 F.3d 1307 (Fed. Cir. 2007), and manual excerpts alone do not prove direct infringement for a product that can be used without infringing, Mirror Worlds, LLC v. Apple Inc., 692 F.3d 1351 (Fed. Cir. 2012).
• [P] Where direct proof is thin, pair sales volume with instructions that teach the claimed use. Note: extensive sales plus a widely distributed instruction sheet supported an inference of customer infringement in Moleculon Research Corp. v. CBS, Inc., 793 F.2d 1261 (Fed. Cir. 1986), and the inference held for a feature in mass-market software in Lucent Technologies, Inc. v. Gateway, Inc., 580 F.3d 1301 (Fed. Cir. 2009).
• [Both] If a technical standard is part of the proof, determine whether it makes the claimed feature mandatory or optional. Note: compliance with a standard proves infringement only when every compliant device must practice the claim; for optional features the patentee must show actual use, Fujitsu Ltd. v. Netgear Inc., 620 F.3d 1321 (Fed. Cir. 2010).
• [Both] Analyze the product in its normal, intended configuration, not in configurations that appear only under unusual conditions. Note: a device that does not infringe as intended does not become infringing because it could be altered, High Tech Medical Instrumentation, Inc. v. New Image Industries, Inc., 49 F.3d 1551 (Fed. Cir. 1995). The same rule cuts the other way: tests showing a noninfringing mode only under unusual conditions do not defeat infringement by a device reasonably capable of infringing in normal use, Hilgraeve Corp. v. Symantec Corp., 265 F.3d 1336 (Fed. Cir. 2001).
• [P] Subpoena two or three cooperative customers for usage records or a short declaration. Note: third-party proof under Fed. R. Civ. P. 45 is often the cleanest evidence of direct infringement in the case; a declaration under 28 U.S.C. § 1746 avoids a deposition when the facts are simple. See the Nonparty Discovery Toolkit: Subpoenas, Third-Party Records, and Privilege.
• [D] Check whether the customers' acts were authorized, which leaves no infringement to induce. Note: an authorized sale exhausts the patent in the article sold, including method claims it substantially embodies, Quanta Computer, Inc. v. LG Electronics, Inc., 553 U.S. 617 (2008); a supplier of compatible consumables cannot induce use of an exhausted machine, Keurig, Inc. v. Sturm Foods, Inc., 732 F.3d 1370 (Fed. Cir. 2013).
• [Both] Confirm that the direct infringement occurred in the United States. Note: inducing conduct may happen abroad, but the induced infringement must happen here, Enplas Display Device Corp. v. Seoul Semiconductor Co., 909 F.3d 398 (Fed. Cir. 2018). For conduct that never reaches the United States, look at § 271(f) in Phase 8.

Phase 3: Knowledge of the patent

• [Both] Build a dated knowledge timeline for each defendant and each patent: notice letters, earlier suits or licensing talks, citations of the patent in the defendant's own prosecution, marked products, competitor-monitoring reports, and hires from the patentee. Note: knowledge of the patent is an element of both inducement and contributory infringement, Global-Tech Appliances, Inc. v. SEB S.A., 563 U.S. 754 (2011), and it is usually proved circumstantially. Possession of the patentee's datasheets and of products marked with parent patents, efforts to imitate those products, and admitted patent monitoring supported actual pre-suit knowledge in SynQor, Inc. v. Artesyn Technologies, Inc., 709 F.3d 1365 (Fed. Cir. 2013). Hiring two of the patentee's former employees who knew the patent helped plead knowledge in Lifetime Industries, Inc. v. Trim-Lok, Inc., 869 F.3d 1372 (Fed. Cir. 2017).
• [Both] Separate knowledge of an application, a "patent pending" legend, or a parent patent from knowledge of the asserted patent. Note: a "patent pending" notice gives no knowledge of what will issue, State Industries, Inc. v. A.O. Smith Corp., 751 F.2d 1226 (Fed. Cir. 1985). Knowledge of a related patent is circumstantial evidence, not proof, of knowledge of the one in suit.
• [P] Find the assigned judge's position on knowledge supplied only by the complaint before you rely on it. Note: some courts dismiss indirect claims whose only alleged knowledge comes from the complaint itself, a rule stated most prominently in ZapFraud, Inc. v. Barracuda Networks, Inc., 528 F. Supp. 3d 247 (D. Del. 2021), while others allow post-filing claims. The Federal Circuit has not resolved the split; 6 Robert A. Matthews, Jr., Annotated Patent Digest §§ 39:7.25 and 39:7.50 collects the decisions.
• [Both] Test for willful blindness: a subjective belief that a patent very probably covers the product, plus deliberate steps to avoid confirming it. Note: willful blindness substitutes for actual knowledge; recklessness and negligence do not, Global-Tech. Copying a competitor's product and withholding that fact from the lawyer writing the clearance opinion was enough there. A no-read policy standing alone is weaker evidence than a no-read policy plus copying.
• [D] Record when the company first learned of the patent, who learned it, and what happened next. Note: where it was undisputed that the defendant first learned of the patents from a notice letter, the Federal Circuit refused to let a willfulness finding reach back earlier, and it treated evidence that the defendant designed and instructed an infringing use as proof of infringement and inducement, not of willfulness, SRI International, Inc. v. Cisco Systems, Inc., 930 F.3d 1295 (Fed. Cir. 2019). A later decision in the same case, 14 F.4th 1323 (Fed. Cir. 2021), clarified that willfulness requires deliberate or intentional infringement rather than a heightened showing of wanton conduct.

Phase 4: Specific intent and good-faith belief (inducement)

• [Both] Confirm that the intent alleged is intent to cause infringement, not merely intent to cause the acts. Note: the inducer must intend to cause infringement, not merely the acts that happen to infringe, DSU Medical Corp. v. JMS Co., 471 F.3d 1293 (Fed. Cir. 2006) (en banc in relevant part), and after Global-Tech it must know, or be willfully blind to the fact, that the induced acts infringe. Knowledge of the acts alone is not enough, Manville Sales Corp. v. Paramount Systems, Inc., 917 F.2d 544 (Fed. Cir. 1990).
• [P] Assemble circumstantial intent evidence: instructions, marketing that names the accused feature, design choices, technical support, and internal emails about the patent or the patentee. Note: direct evidence of intent is not required, Water Technologies Corp. v. Calco, Ltd., 850 F.2d 660 (Fed. Cir. 1988). In i4i Ltd. Partnership v. Microsoft Corp., 598 F.3d 831 (Fed. Cir. 2010), attendance at the patentee's product presentation and emails predicting that the accused feature would make the patentee's product obsolete carried the knowledge and intent findings.
• [D] Document any good-faith belief in noninfringement: when it was formed, by whom, on what facts, and whether the company acted on it. Note: a reasonable, good-faith belief that the induced acts do not infringe can negate intent; a belief that the patent is invalid cannot, Commil USA, LLC v. Cisco Systems, Inc., 575 U.S. 632 (2015). The jury's no-inducement verdict in DSU rested on noninfringement opinions the defendant actually believed.
• [D] Test the opinion's quality before relying on it: did counsel have the accused product, the prosecution history, and the claims as the court is likely to construe them? Note: in Golden Blount, Inc. v. Robert H. Peterson Co., 438 F.3d 1354 (Fed. Cir. 2006), the trial court permissibly gave little weight to oral opinions rendered without the prosecution history or the accused device, and rejected the defendant's claim of good faith. An opinion built on incomplete facts can look like willful blindness.
• [D] Decide early, with trial counsel, whether to rely on an opinion of counsel, and map the waiver. Note: reliance waives privilege over communications on the same subject, In re EchoStar Communications Corp., 448 F.3d 1294 (Fed. Cir. 2006), though ordinarily not over trial counsel, In re Seagate Technology, LLC, 497 F.3d 1360 (Fed. Cir. 2007) (en banc). Ask for an order under Fed. R. Evid. 502 to contain the waiver.
• [P] Do not argue that the defendant's failure to obtain or present an opinion proves intent. Note: 35 U.S.C. § 298 forbids that use in actions commenced on or after January 14, 2013. Older cases allowing the inference, such as Broadcom Corp. v. Qualcomm Inc., 543 F.3d 683 (Fed. Cir. 2008), no longer govern.
• [Both] Read any indemnity or supply agreement for what it says about intent. Note: an indemnity generally does not show intent to induce, but intent may be inferred when its primary purpose is to overcome the deterrent effect of the patent laws, Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464 (Fed. Cir. 1990).

Phase 5: Active steps and causation (inducement)

• [Both] Inventory every communication that tells anyone how to use the accused feature: manuals, every archived version of the help center, onboarding guides, API references, training courses, sales decks, demo scripts, labels, and press releases. Note: preserve and date each version; the help-center page from the month after the notice letter matters more than today's. The Litigation Hold and Evidence Preservation Checklist: A Practical Checklist covers the mechanics.
• [Both] Code each instruction as describing the infringing use, recommending it, or requiring it. Note: instructions that teach a noninfringing technique do not show intent, even if some users ignore them, Vita-Mix Corp. v. Basic Holding, Inc., 581 F.3d 1317 (Fed. Cir. 2009); instructions that tell users a step is necessary can carry inducement even where the product has noninfringing uses, Toshiba Corp. v. Imation Corp., 681 F.3d 1358 (Fed. Cir. 2012).
• [Both] Record defaults and design choices: whether the infringing mode is on out of the box, whether it can be turned off, and who decided. Note: design decisions and knowledge raised a triable intent question in Ricoh Co. v. Quanta Computer Inc., 550 F.3d 1325 (Fed. Cir. 2008). Selling a product that merely can be used to infringe, without active steps, is not inducement, Dynacore.
• [P] Tie the inducing conduct to the infringing acts. Note: inducement requires successful inducement; an instruction telling the jury that the infringement "need not have been actually caused" by the defendant's encouragement cost the patentee its verdict in Power Integrations, Inc. v. Fairchild Semiconductor International, Inc., 843 F.3d 1315 (Fed. Cir. 2016).
• [P] If a physical product ships with instructions, prove that the instructions went out with each unit. Note: instructions packaged with each device that teach the infringing configuration supported both direct infringement and inducement, even though the device could be rearranged into a noninfringing configuration, Golden Blount.
• [Both] Identify the individuals who directed the inducing conduct. Note: officers who actively assist their company's infringement can be personally liable for inducement, Orthokinetics, Inc. v. Safety Travel Chairs, Inc., 806 F.2d 1565 (Fed. Cir. 1986), subject to the same knowledge and intent requirements; Manville reversed liability for officers who acted on a good-faith, counseled belief of noninfringement.

Phase 6: Contributory infringement under section 271(c)

• [Both] Define the "component" at the level the cases use: the separable feature, firmware module, chip, or material actually sold, not the box it ships in. Note: a seller cannot escape by embedding a component with no noninfringing use inside a larger product that has other uses, Ricoh; i4i. The inquiry looks at the material actually sold and how purchasers use it, not the theoretical uses of one of its ingredients, Hodosh v. Block Drug Co., 833 F.2d 1575 (Fed. Cir. 1987).
• [Both] Confirm a sale, offer to sell, or importation of that component in the United States. Note: a hosted service that sells nothing fits § 271(c) awkwardly, which is why Stillwater's contributory theory against Juniper is weak. Components made, delivered, and paid for abroad were not sold here in Halo Electronics, Inc. v. Pulse Electronics, Inc., 831 F.3d 1369 (Fed. Cir. 2016).
• [Both] Assess whether the component is a material part of the invention and especially made or adapted for the infringing use. Note: a nonstaple chemical with no use except in the patented method is the paradigm, Dawson Chemical Co. v. Rohm & Haas Co., 448 U.S. 176 (1980). Knowledge that the combination is both patented and infringing is required, Aro II.
• [P] Make a prima facie case that the component has no substantial noninfringing use, then make the defendant answer it. Note: the patentee bears the burden of persuasion, but instructions that teach only the infringing configuration shift the burden of production to the defendant to show actual noninfringing use, Golden Blount. General assertions that a noninfringing mounting method was "common" did not rebut the showing in Spansion, Inc. v. International Trade Commission, 629 F.3d 1331 (Fed. Cir. 2010).
• [D] Prove noninfringing uses with data: telemetry, configuration surveys, sales by configuration, and customer testimony. Note: a use is substantial unless it is "unusual, far-fetched, illusory, impractical, occasional, aberrant, or experimental," Vita-Mix. A reasonable jury could find substantial noninfringing use of a catheter in a procedure that did not practice the claimed method in C.R. Bard, Inc. v. Advanced Cardiovascular Systems, Inc., 911 F.2d 670 (Fed. Cir. 1990), and the court reminded the parties that argument by counsel about percentages is not evidence.
• [P] Do not plead yourself out of the claim. Note: complaints that described the products' noninfringing uses defeated the contributory counts in Bill of Lading, even as the inducement counts survived.

Phase 7: Divided infringement and direction or control

• [Both] For every method claim split between actors, list who performs each step and what the defendant requires of the other actor. Note: one entity is responsible for another's performance of method steps where it directs or controls that performance (agency, contract, or conditioning plus manner or timing) or where the actors form a joint enterprise, Akamai Technologies, Inc. v. Limelight Networks, Inc., 797 F.3d 1020 (Fed. Cir. 2015) (en banc). Whether the test is met is a question of fact.
• [Both] Ask whether the other actor must perform the step to participate in an activity or receive a benefit, and whether the defendant sets the manner or timing of that performance. Note: Limelight's standard contract made customers tag content to use the network, and its welcome letter and engineers told them how. The benefit can be intangible and the condition need not be a legal obligation, Travel Sentry, Inc. v. Tropp, 877 F.3d 1370 (Fed. Cir. 2017), but "mere guidance or instruction" is not enough. Physicians who condition treatment on a patient's pretreatment and prescribe its dose and schedule direct or control the patient's step, Eli Lilly & Co. v. Teva Parenteral Medicines, Inc., 845 F.3d 1357 (Fed. Cir. 2017).
• [D] Show that the other actor's step is optional, chosen by the customer for its own reasons, or performed at arm's length. Note: no conditioning was shown where use of a remote-monitoring system did not depend on patients performing the claimed steps, Medgraph, Inc. v. Medtronic, Inc., 843 F.3d 942 (Fed. Cir. 2016), and an arm's-length collaboration between two companies was not enough in Golden Hour Data Systems, Inc. v. emsCharts, Inc., 614 F.3d 1367 (Fed. Cir. 2010). Controlling access to a system and explaining how to use it was not control under the older standard of Muniauction, Inc. v. Thomson Corp., 532 F.3d 1318 (Fed. Cir. 2008); check whether Akamai's conditioning test changes the answer on your facts.
• [Both] Test a joint-enterprise theory against all four elements: agreement, common purpose, community of pecuniary interest, and an equal right to a voice in direction. Note: the elements come from Restatement (Second) of Torts § 491, as adopted in Akamai. Independent commercial parties rarely share an equal right of control.
• [Both] For system claims, ask who puts the whole system into service and benefits from it, and only then whether that use can be attributed to the defendant. Note: the customer who runs reports from a vendor's back-office system "uses" the system, Centillion Data Systems, LLC v. Qwest Communications International, Inc., 631 F.3d 1279 (Fed. Cir. 2011); see also Intellectual Ventures I LLC v. Motorola Mobility LLC, 870 F.3d 1320 (Fed. Cir. 2017). CloudofChange holds that directing a customer to supply one element is not the test for attributing use of a system claim.
• [P] Plead the conditioning and manner-or-timing facts, not the phrase "direction or control." Note: a complaint that alleged direction or control without facts was dismissed in Lyda v. CBS Corp., 838 F.3d 1331 (Fed. Cir. 2016); allegations that the defendants themselves ran pilot and full-scale tests of the claimed method survived in Nalco Co. v. Chem-Mod, LLC, 883 F.3d 1337 (Fed. Cir. 2018).

Phase 8: Exports, imports, and foreign defendants

• [Both] Map where each act occurs: manufacture, negotiation, contracting, delivery, payment, importation, assembly, and use. Note: where a contract was negotiated and signed can make the place of sale a fact question, Carnegie Mellon University v. Marvell Technology Group, Ltd., 807 F.3d 1283 (Fed. Cir. 2015); Halo (2016) found no domestic sale despite U.S. price negotiations.
• [P] Build a foreign supplier's inducement on U.S.-directed conduct: reference designs, U.S. standards compliance, demonstration boards shipped here, and support for U.S. design teams. Note: that pattern sent inducement to the jury in the 2016 Power Integrations decision and in MEMC Electronic Materials, Inc. v. Mitsubishi Materials Silicon Corp., 420 F.3d 1369 (Fed. Cir. 2005).
• [Both] Choose the right part of § 271(f), and test the "component" and "supplied" elements. Note: a single component can never be a "substantial portion" under (f)(1), Life Technologies Corp. v. Promega Corp., 580 U.S. 140 (2017); software copies made abroad from a master disk are not supplied from the United States, Microsoft Corp. v. AT&T Corp., 550 U.S. 437 (2007); and (f)(2) requires intent that the combination occur abroad, not proof that it did, Waymark Corp. v. Porta Systems Corp., 245 F.3d 1364 (Fed. Cir. 2001).
• [Both] Limit or defend the royalty base by geography. Note: an inducement award must be confined to products that entered the United States, Enplas; worldwide sales were rejected in Power Integrations, Inc. v. Fairchild Semiconductor International, Inc., 711 F.3d 1348 (Fed. Cir. 2013). Foreign lost profits are recoverable for (f)(2) infringement, WesternGeco LLC v. ION Geophysical Corp., 585 U.S. 407 (2018), and the Federal Circuit applies that framework to other extraterritorial damages questions, Brumfield v. IBG LLC, 97 F.4th 854 (Fed. Cir. 2024).
• [P] Consider the International Trade Commission for imported products whose infringement is induced after importation. Note: the Commission may exclude such articles under 19 U.S.C. § 1337, Suprema, Inc. v. International Trade Commission, 796 F.3d 1338 (Fed. Cir. 2015) (en banc). See the ITC Section 337 Checklist: A Practical Checklist.

Phase 9: Drug labels and skinny labels

• [Both] Read the label as a whole and decide whether it recommends or encourages the claimed use or merely permits it. Note: a label that permits but does not encourage the claimed step does not induce, HZNP Medicines LLC v. Actavis Laboratories UT, Inc., 940 F.3d 680 (Fed. Cir. 2019); a broad indication ("severe chronic pain") did not specifically encourage the narrower claimed use in Grünenthal GmbH v. Alkem Laboratories Ltd., 919 F.3d 1333 (Fed. Cir. 2019); and circumstantial evidence could not overcome a label that, taken in its entirety, did not recommend the claimed use, Bayer Schering Pharma AG v. Lupin, Ltd., 676 F.3d 1316 (Fed. Cir. 2012).
• [Both] Audit everything outside the label: press releases, "generic version of" statements, therapeutic-category listings, sales figures quoted for the carved-out use, and sales-force materials. Note: those facts carried inducement past a skinny label in GlaxoSmithKline LLC v. Teva Pharmaceuticals USA, Inc., 7 F.4th 1320 (Fed. Cir. 2021), and past a motion to dismiss in Amarin Pharma, Inc. v. Hikma Pharmaceuticals USA Inc., 104 F.4th 1370 (Fed. Cir. 2024); a patentee relying on an FDA-required label alone lost in H. Lundbeck A/S v. Lupin Ltd., 87 F.4th 1361 (Fed. Cir. 2023). This area moves quickly; check subsequent history before relying on any of them.
• [D] Do not rely on noninfringing indications to defeat inducement. Note: substantial noninfringing uses are a defense to contributory infringement only, Sanofi v. Watson Laboratories Inc., 875 F.3d 636 (Fed. Cir. 2017). The Hatch-Waxman sequence is in the Paragraph IV and ANDA Litigation Checklist: A Practical Checklist.

Phase 10: Notice letters and the first response

• [P] Identify the patent number, the specific accused product, and the infringing activity, and send the letter from the patentee or its agent. Note: actual notice under § 287(a) requires an affirmative communication of a specific charge of infringement by a specific accused product, Amsted Industries Inc. v. Buckeye Steel Castings Co., 24 F.3d 178 (Fed. Cir. 1994), from the patentee, Lans v. Digital Equipment Corp., 252 F.3d 1320 (Fed. Cir. 2001). The same letter supplies knowledge for § 271(b) and (c).
• [P] Set the letter's intensity knowing that it may hand the recipient a declaratory judgment action in its home forum. Note: the test is whether all the circumstances show a substantial, immediate controversy, MedImmune, Inc. v. Genentech, Inc., 549 U.S. 118 (2007). A letter saying the recipient was "likely selling other infringing products," coupled with references to pending suits against competitors and a refusal to license, created jurisdiction even over products the patentee had never accused, Asia Vital Components Co. v. Asetek Danmark A/S, 837 F.3d 1249 (Fed. Cir. 2016); short letters with tight deadlines were enough in Hewlett-Packard Co. v. Acceleron LLC, 587 F.3d 1358 (Fed. Cir. 2009). Sufficiently numerous and pointed communications can also subject the patentee to personal jurisdiction in the recipient's home forum, Trimble Inc. v. PerDiemCo LLC, 997 F.3d 1147 (Fed. Cir. 2021).
• [P] Expect letters to customers to draw the supplier into court. Note: a supplier has declaratory judgment standing if it must indemnify the customers or if the charges implicitly accuse it of inducement, Arris Group, Inc. v. British Telecommunications PLC, 639 F.3d 1368 (Fed. Cir. 2011); claim charts built on the supplier's own manuals did that in Microsoft Corp. v. DataTern, Inc., 755 F.3d 899 (Fed. Cir. 2014). Letters to eleven banks in one state supported jurisdiction over the patentee in a supplier's suit, Jack Henry & Associates, Inc. v. Plano Encryption Technologies LLC, 910 F.3d 1199 (Fed. Cir. 2018).
• [D] On receipt, calendar the letter, issue a litigation hold, route every reply through counsel, and stop engineers from writing about the patent. Note: a party that fails to preserve electronically stored information faces measures under Fed. R. Civ. P. 37(e). The letter is now the first entry on the knowledge timeline.
• [D] Choose and sequence the responses: claim charts requested, opinion of counsel, design change, license discussion, inter partes review, declaratory judgment. Note: filing a civil action challenging validity before petitioning bars the petition, and the petition must be filed within one year of service of an infringement complaint, 35 U.S.C. § 315(a)(1) and (b). See the Declaratory Judgment Checklist: A Practical Checklist.
• [D] Decide what happens to the instructions after notice, and write the decision down. Note: continuing to publish a walkthrough of the accused configuration after notice is the most common source of post-notice inducement exposure; a documented change is also evidence of remedial action for enhancement purposes, Read Corp. v. Portec, Inc., 970 F.2d 816 (Fed. Cir. 1992).
• [D] Answer customer indemnity tenders on a schedule, and consider a common-interest agreement before sharing analysis. Note: an indemnity does not by itself show intent to induce, Hewlett-Packard v. Bausch & Lomb. For the contract side, see Indemnification and Limitation of Liability: The Risk Allocation Engine of Every Contract.

Phase 11: The complaint and the motion to dismiss

• [P] Plead facts for every element: direct infringers by class and what they do, quoted or screenshotted instructions, knowledge facts that do not depend on the complaint, the component and why it lacks substantial noninfringing use, and any conditioning facts. Note: plausibility governs, Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007); Ashcroft v. Iqbal, 556 U.S. 662 (2009). Quotations from the defendants' own websites and advertising carried the inducement counts in Bill of Lading; an inducement count without knowledge or intent facts was dismissed in Superior Industries, LLC v. Thor Global Enterprises Ltd., 700 F.3d 1287 (Fed. Cir. 2012). The detail required rises with the complexity of the technology, Bot M8 LLC v. Sony Corp. of America, 4 F.4th 1342 (Fed. Cir. 2021).
• [D] Target the weak counts under Fed. R. Civ. P. 12(b)(6): knowledge alleged only through the complaint (in courts that follow ZapFraud), contributory counts that plead noninfringing uses, and divided-infringement counts without control facts. Note: do not ask the court to resolve a claim construction dispute on the pleadings, Nalco. See Motions to Dismiss Under Rule 12: A Practical Guide for Plaintiffs and Defendants.
• [P] Calendar an amendment under Fed. R. Civ. P. 15 once discovery shows pre-suit knowledge. Note: some courts dismiss pre-suit indirect claims without prejudice and allow repleading after fact discovery opens.
• [D] Plead the defenses that fit indirect claims in the answer: no direct infringement, exhaustion and license, the § 271(e)(1) safe harbor, government use under 28 U.S.C. § 1498, marking, and invalidity counterclaims. Note: the Answer and Affirmative Defenses Checklist: A Practical Checklist covers form and timing.

Phase 12: Discovery, experts, and summary judgment

• [Both] Serve requests under Fed. R. Civ. P. 34 for manuals and archived help pages, onboarding and training materials, sales decks and demo scripts, support tickets, default-setting histories, usage telemetry, product requirement documents, and every document mentioning the patent or the patentee. Note: proportionality under Fed. R. Civ. P. 26(b)(1) bounds all of it; ask for telemetry in native, aggregated form rather than raw logs. See the Discovery Toolkit: A Roadmap and Resource Guide for Federal Discovery.
• [Both] Notice or prepare a corporate witness under Fed. R. Civ. P. 30(b)(6) on first knowledge of the patent, design decisions about the accused feature, the content and distribution of instructions, known customer usage, and the response to the notice letter. Note: a witness who cannot say when the company learned of the patent turns the knowledge date into a jury argument. See Preparing and Defending a Rule 30(b)(6) Deposition.
• [Both] Use interrogatories under Fed. R. Civ. P. 33 to fix the earliest-knowledge date and the factual basis for any good-faith belief or noninfringing use, and requests for admission under Fed. R. Civ. P. 36 to establish the dates and authenticity of archived web pages. Note: archived pages need a foundation under Fed. R. Evid. 901; usage data usually comes in as business records under Fed. R. Evid. 803(6), and large data sets through summaries under Fed. R. Evid. 1006.
• [Both] Assign experts by burden: a technical expert to prove or rebut actual use, and a data or survey expert to measure noninfringing uses. Note: each opinion must rest on sufficient facts and a reliable application of method under Fed. R. Evid. 702 as amended in 2023. Courts routinely bar experts from telling the jury what the defendant intended, and experts may not argue claim construction to the jury, Warsaw Orthopedic, Inc. v. NuVasive, Inc., 824 F.3d 1344 (Fed. Cir. 2016). See the Expert Disclosure and Daubert Challenge Checklist: A Practical Checklist and the Expert Deposition Preparation Checklist: A Practical Checklist.
• [D] Move for summary judgment under Fed. R. Civ. P. 56 on the elements that are usually decided as a matter of law: no proof of actual direct infringement, proven substantial noninfringing uses, and no evidence of conditioning. Note: intent itself rarely goes away on summary judgment (Ricoh, Toshiba, MEMC); the predicate often does (ACCO, Mirror Worlds, Fujitsu, Medgraph).

Phase 13: Damages, marking, and willfulness

• [Both] Compute the damages window per patent and per theory: the knowledge date for § 271(b) and (c), six years under § 286, and the marking date under § 287(a) for apparatus claims. Note: once the accused infringer identifies unmarked products, the patentee must prove marking compliance, Arctic Cat Inc. v. Bombardier Recreational Products Inc., 876 F.3d 1350 (Fed. Cir. 2017), and marking applies where apparatus and method claims are asserted together and there is a product to mark, American Medical Systems, Inc. v. Medical Engineering Corp., 6 F.3d 1523 (Fed. Cir. 1993). The Patent Marking Compliance: A Practical Checklist has the audit steps.
• [Both] Tie the royalty base to the induced or contributed-to infringement, not to all sales. Note: a lump sum untethered to the value of a small infringing feature was vacated in Lucent; damages under 35 U.S.C. § 284 must track the identified direct infringement, Dynacore. See the Patent Damages Checklist: A Practical Checklist.
• [Both] Account for recoveries from direct infringers and customer settlements. Note: a patentee fully compensated by the direct infringer cannot collect again from the contributory infringer for the same units, Aro II. Draft releases in customer settlements with the supplier's exposure in mind.
• [Both] Evaluate willfulness separately from inducement, even though the evidence overlaps. Note: enhancement is discretionary and reserved for egregious cases, Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016); the jury question is whether infringement was deliberate or intentional, Eko Brands, LLC v. Adrian Rivera Maynez Enterprises, Inc., 946 F.3d 1367 (Fed. Cir. 2020); knowledge plus infringement is not enough, Bayer HealthCare LLC v. Baxalta Inc., 989 F.3d 964 (Fed. Cir. 2021); and an invalidity defense assembled for trial does not insulate pre-suit conduct, WBIP, LLC v. Kohler Co., 829 F.3d 1317 (Fed. Cir. 2016).
• [P] Frame any injunction around the inducing conduct: instructions, labels, onboarding requirements, and marketing. Note: the four-factor test of eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006) applies under 35 U.S.C. § 283.

Phase 14: Jury instructions, the verdict form, and judgment as a matter of law

• [Both] Start from the Federal Circuit Bar Association's model instructions on induced and contributory infringement and justify every departure. Note: the causation error in the 2016 Power Integrations decision came from a plaintiff's custom instruction.
• [D] Insist that the knowledge instruction require actual knowledge or willful blindness, not "reason to be aware." Note: an instruction that a defendant cannot induce if it had "no reason to be aware" of the patent was described as potentially erroneous in isolation and survived only because the trial as a whole required actual knowledge, SynQor.
• [Both] Object on the record before the jury retires, as Fed. R. Civ. P. 51 requires.
• [Both] Request a special verdict or interrogatories under Fed. R. Civ. P. 49 that separate direct, induced, and contributory infringement and the pre-notice and post-notice periods. Note: a general verdict that blends theories makes every later damages error harder to isolate and cure.
• [D] Move under Fed. R. Civ. P. 50(a) on each element before the case goes to the jury, and renew under Rule 50(b). Note: after winning on intent in the Supreme Court, the patentee in Commil lost on remand because the evidence did not show that the accused devices performed a claimed step, Commil USA, LLC v. Cisco Systems, Inc., 813 F.3d 994 (Fed. Cir. 2015). The Post-Trial Motion Checklist: A Practical Checklist covers the renewed motion.

Defense audit

Use this table to confirm that every available defense has been considered, pleaded where required, and assigned a witness or document.

Invalidity work belongs in the Prior Art Qualification Checklist: A Practical Checklist; a belief in invalidity, however sincere, is not an intent defense.

Red flags

Frequently asked questions

Does the patentee have to name the customers who infringed? Not in the complaint, under Bill of Lading. At trial it must prove that real customers, as a class or individually, actually performed the claim, and its damages must track what it proves.

Does the complaint itself give the defendant knowledge of the patent? For conduct after filing, many courts say yes; for conduct before filing, no; and some courts dismiss indirect claims whose only knowledge allegation is the complaint. Plead independent pre-suit facts whenever they exist.

If we change our instructions after the notice letter, does that look like an admission? It does not erase liability for the past, and the patentee may argue that it shows awareness. Continuing to walk customers through the accused configuration is worse, and remedial action counts in the defendant's favor when enhancement is considered under Read.

Can a SaaS vendor be liable when customers perform one of the steps? Yes, in two ways: directly, if the vendor conditions use of its service on the customer's step and controls how or when it happens (Akamai), or as an inducer of customers who perform every step. For system claims, Centillion and CloudofChange make direct "use" by the vendor hard to prove, so inducement is usually the realistic theory.

Is an opinion of counsel required? No, and its absence cannot be used to prove intent or willfulness under § 298. A competent, timely noninfringement opinion is still the strongest affirmative evidence of good faith.

Can contributory infringement apply to a software feature? Yes, when the feature is a separable component with no substantial noninfringing use, as in i4i, Lucent, and Ricoh. It fits poorly when the defendant sells nothing and only hosts a service.

Practical takeaways

• Map claim steps to actors before choosing theories, and keep fallback theories alive until the evidence is in.
• Prove, or attack, actual direct infringement first; capability is not use.
• The first-knowledge date sets the inducement and contributory damages window. Build or test the timeline early.
• Instructions are the battlefield: describing an option is different from requiring it.
• For § 271(c), define the component as the separable feature and measure noninfringing uses with data.
• Use model instructions, a special verdict form, and timely Rule 50 motions; most reversals in this area come from the predicate or the instructions, not from intent.

This document is general information, not legal advice for any particular situation; the law changes, and the facts matter.

Related Documents

Related Articles

• Indirect and Divided Patent Infringement: Inducement, Contributory Liability, and the Akamai Problem: the doctrine behind every item in this checklist.
• What Constitutes Patent Infringement: Claims and Defenses: A Practical Guide: the direct-infringement elements that indirect claims borrow.
• Patent Damages: Reasonable Royalties, Lost Profits, Apportionment, and Enhancement: the damages framework for Phase 13.
• Declaratory Judgment Actions: Jurisdiction, Discretion, and the Race to the Courthouse: what a notice letter can set in motion.

Related Guides

• Pleading and Proving Induced and Contributory Patent Infringement: A Practical Guide: the litigation sequence, step by step.
• Motions to Dismiss Under Rule 12: A Practical Guide for Plaintiffs and Defendants: testing the indirect counts at the pleading stage.
• Preparing and Defending a Rule 30(b)(6) Deposition: the corporate deposition that fixes knowledge and instruction facts.

Related Checklists

• Claim Construction Checklist: A Practical Checklist: the constructions that decide who performs each step.
• Patent Damages Checklist: A Practical Checklist: royalty base, apportionment, and the damages window.
• Patent Marking Compliance: A Practical Checklist: the pre-notice damages question for apparatus claims.
• Declaratory Judgment Checklist: A Practical Checklist: the accused infringer's offensive option after a letter.
• Paragraph IV and ANDA Litigation Checklist: A Practical Checklist: label-based inducement in Hatch-Waxman cases.
• ITC Section 337 Checklist: A Practical Checklist: exclusion orders for induced post-importation infringement.
• Answer and Affirmative Defenses Checklist: A Practical Checklist: pleading the defenses in the defense audit.
• Prior Art Qualification Checklist: A Practical Checklist: building the invalidity case that intent cannot supply.
• Post-Trial Motion Checklist: A Practical Checklist: renewed motions on intent and the predicate.
• Expert Deposition Preparation Checklist: A Practical Checklist: preparing the use and noninfringing-use experts.

Related Toolkits

• Indirect Infringement Toolkit: Knowledge Evidence, Direction or Control Proof, and Substantial Noninfringing Use Analyses: templates for the timelines, letters, charts, and analyses this checklist calls for.
• Patent Litigation Toolkit: A Roadmap and Research Guide: the broader patent case workflow.
• Patent Damages Toolkit: Royalty Models, Expert Reports, and Daubert Motions: models for the royalty base and apportionment.
• Nonparty Discovery Toolkit: Subpoenas, Third-Party Records, and Privilege: subpoenas to customers who hold the direct-infringement evidence.