Does a Defendant’s Knowledge of a Related Patent Application Establish Willful Patent Infringement?

Willful Patent Infringement and the Pre-Suit Knowledge Requirement

In U.S. patent litigation, the question of whether a defendant had pre-suit knowledge of the asserted patent often determines whether claims for willful infringement and indirect infringement, including inducement and contributory infringement, can survive at the pleading stage. In recent years, a recurring issue has emerged: plaintiffs are sometimes unable to show that a defendant had actual knowledge of an issued patent and instead rely on allegations that the defendant was aware of a related patent application. Whether such allegations are sufficient has become an important and contested question.

A recent decision from the U.S. District Court for the Eastern District of Texas provides useful guidance on this issue. In Advanced Integrated Circuit Process LLC v. Taiwan Semiconductor Mfg. Co. Ltd., No. 2:25-cv-00324-JRG, Dkt. No. 104 (E.D. Tex. Mar. 10, 2026), the court clarified the boundaries of when knowledge of a patent application may, or may not, support claims of willful and indirect infringement. The decision underscores a fundamental principle: liability for these forms of infringement requires that the defendant knew of the asserted patent itself.

This requirement reflects longstanding precedent. Willful infringement demands a showing that the defendant’s conduct was intentional or knowing, and inducement similarly requires that the defendant knew of the patent and that the induced acts constituted infringement. These doctrines impose a subjective component, making the defendant’s knowledge a central element of the claim.

Can Knowledge of a Patent Application Support an Infringement Claim?

Against this backdrop, mere awareness of a pending patent application is generally insufficient. Patent applications are inherently uncertain. There is no guarantee that an application will issue as a patent, and even if it does, the scope of the claims may change significantly during prosecution. As a result, knowledge of an application does not necessarily translate into knowledge of a legally enforceable patent right.

At the same time, the court’s decision makes clear that this principle is not absolute. The sufficiency of allegations regarding knowledge of a patent application depends on the specific factual context.

Issued Patents vs. Pending Applications

Where an application has progressed to an advanced stage, particularly where the U.S. Patent and Trademark Office has issued a Notice of Allowance, the analysis shifts. At that point, issuance is largely assured, and the claims are typically settled. If a plaintiff can plausibly allege that the defendant was aware of such an application and that the claims remained materially unchanged through issuance, it may be reasonable to infer that the defendant effectively knew of the resulting patent.

Similarly, where a defendant encounters materials that directly correspond to an issued patent, such as a published application or prosecution document that maps closely onto the patent as issued, a court may find it plausible to infer knowledge. This is especially true where the patent had already issued at the time of the defendant’s exposure to those materials. In such circumstances, the connection between the information known to the defendant and the asserted patent is sufficiently direct to support an inference of knowledge at the pleading stage.

When a Related Patent Application Is Not Enough

By contrast, the court rejected attempts to rely on more attenuated relationships. In the case before it, the plaintiff alleged that the defendant had been exposed to a publication related to, but not directly corresponding to, one of the asserted patents. That patent was a divisional of the application underlying the cited publication. The court held that this was insufficient. Knowledge of a related application or publication within the same patent family does not, without more, establish knowledge of a specific issued patent. The gap between the two is too significant to bridge through inference alone.

The decision thus highlights the importance of the relationship between the information allegedly known to the defendant and the asserted patent. The closer and more direct the correspondence, the more likely a court will find that the knowledge requirement has been plausibly alleged. Conversely, where the connection is indirect or speculative, the claim is unlikely to survive a motion to dismiss.

Key Pleading Lessons for Patent Plaintiffs and Defendants

From a practical perspective, this framework has important implications for both plaintiffs and defendants. Plaintiffs must carefully construct their allegations of pre-suit knowledge, ensuring that they are grounded in facts that tie the defendant’s awareness to the issued patent itself. This may involve tracing prosecution histories, identifying specific references cited during examination, or pointing to communications or materials that directly reference the patent. General allegations that a defendant was aware of related technology or patent filings are unlikely to suffice.

Defendants, in turn, should closely scrutinize the basis of any alleged knowledge. Where a complaint relies on awareness of applications, publications, or loosely related patent family members, there may be a strong basis to challenge the sufficiency of the pleadings. The distinction between knowledge of a patent and knowledge of a broader technological landscape can be outcome-determinative at the early stages of litigation.

Ultimately, the court’s analysis reflects a careful balancing of competing concerns. On the one hand, it prevents plaintiffs from advancing willful and indirect infringement claims based on speculative or attenuated allegations of knowledge. On the other hand, it preserves the ability of plaintiffs to proceed where the facts plausibly suggest that the defendant was, in substance, aware of the asserted patent before the lawsuit was filed. The key inquiry remains whether the alleged facts support a reasonable inference that the defendant knew of the patent itself, not merely of a related application.

(Disclaimer: The information published herein is for reference only and should not be regarded as legal authority or advice on any subject. All rights reserved. Reproduction requires permission from Allbelief Law Firm.)

Bill Deng

bdeng@allbelief.com

Managing Partner, U.S. Attorney and Registered Patent Attorney with the United States Patent and Trademark Office (USPTO)

Mr. Deng focuses his practice on U.S. intellectual property dispute resolution, with particular emphasis on patent, trademark, and copyright matters, as well as Section 337 investigations before the U.S. International Trade Commission and intellectual property litigation and defense involving cross-border e-commerce. His professional admissions cover multiple key institutions and procedures involved in U.S. intellectual property disputes, including the District of Columbia, the U.S. Court of Appeals for the Federal Circuit, the U.S. District Court for the District of Columbia, the U.S. District Court for the Northern District of Illinois, the U.S. Court of International Trade, the U.S. International Trade Commission, and the United States Patent and Trademark Office.

As a USPTO-registered patent attorney and a practitioner admitted before the U.S. International Trade Commission and multiple federal courts, Mr. Deng is well positioned to provide clients with comprehensive, strategically coordinated legal support across patent validity proceedings, Section 337 investigations, and federal litigation.

For brand owners, rights holders, and Chinese sellers alike, whether in enforcement litigation, infringement defense, or settlement negotiations, Mr. Deng communicates directly with both sides in Mandarin and English. In the complex, high-pressure, and fast-moving environment of cross-border e-commerce intellectual property disputes, he assists clients in identifying risks more efficiently, formulating effective strategies, and advancing implementation.

Allbelief Law Firm

Based in Washington, D.C., Serving at the Frontline of Cross-Border Intellectual Property Disputes

Allbelief Law Firm focuses on U.S. intellectual property and cross-border dispute resolution, with particular emphasis on patents, trademarks, copyrights, Section 337 investigations before the U.S. International Trade Commission, cross-border e-commerce infringement litigation, anti-counterfeiting enforcement, and related dispute matters. The firm is located in Washington, D.C., the capital of the United States, in close proximity to the U.S. Congress, the U.S. District Court for the District of Columbia, and USPTO. This geographic advantage enables the firm to engage more efficiently with federal judicial and administrative institutions.