November/December 2025
IP Litigator

Under Article III of the Constitution, a plaintiff must have standing in order to bring a suit in federal court. To establish standing, the plaintiff must have “(1) suffered an injury in fact, (2) that is fairly traceable to the challenged conduct of the defendant, and (3) that is likely to be redressed by a favorable judicial decision.”[1]Constitutional standing is a jurisdictional requirement, a defect in which can be challenged at any time, even on appeal.[2]In patent cases, the Federal Circuit has held that, “the touchstone of constitutional standing in a patent infringement suit is whether a party can establish that it has an exclusionary right in a patent.”[3]As long as the plaintiff can show that it “holds at least one exclusionary right,” it will have standing.[4]
The precise meaning and application of the exclusionary-right requirement remain subjects of ongoing debate. Many district courts have applied it in their constitutional standing analysis,[5] but not consistently. This article traces the development of the requirement and reviews how courts have applied it in recent cases. This review seeks to provide parties and practitioners guidance on establishing or challenging a plaintiff’s possession of “exclusionary right” required to show standing.
The concept of “exclusionary right” standing originated in pre-Lexmark[6]case law. Federal Circuit cases in that era often discussed standing as a broader threshold that encompass both (1) constitutional standing and (2) standing that derives from the statutory requirement (35 U.S.C. § 281) that only a “patentee” can sue for patent infringement. One of the pre-Lexmark cases first introducing the exclusionary-right requirement is Morrow,[7]a case from 2007. Morrow remains an often-cited source for “exclusionary right” and has been credited as the closest the Federal Circuit has come to defining it.[8]
Morrow addressed whether a liquidating trust that shared certain rights to a patent upon the original patentee’s liquidation had standing to sue for infringement. The court reviewed the allocation of patent rights between different trusts under the liquidation plan and what rights the plaintiff trust obtained. In that context, the court explained, because “the patent statutes give rise to the right to sue others for patent infringement, they also define the nature and source of the infringement claim and determine the party that is entitled to judicial relief.”[9]The court then turned to what rights are granted under the patent statute.
“A patent grant,” the court continued, “bestows the legal right to exclude others from making, using, selling, or offering to sell the patented invention in the United States, or importing the invention,” namely, the “right to exclude.”[10]So according to the court, a “[c]onstitutional injury in fact occurs when a party performs at least one prohibited action with respect to the patented invention that violates these exclusionary rights.”[11]In WiAV, the court reiterated that “the legally protected interests in a patent are the exclusionary rights created by the Patent Act.”[12]
Seemingly straightforward, the contours of “exclusionary rights” remain to be defined. Case law has not established a complete list of “exclusionary rights.”[13]In practice, courts’ exclusionary-right analyses examine relevant provisions of the rightallocating agreement(s) at issue.[14]They then look to prior cases addressing similar contractual arrangements or restrictions. Consequently, the exclusionary right inquiry has become a factintensive exercise involving contract interpretation and an evolving body of case law.
The Federal Circuit has repeatedly warned against conflating the “exclusionary right” required for constitutional standing and “substantial rights” for the “patentee” requirement under 35 U.S.C. § 281. Under § 281, only a “patentee” can sue for patent infringement, who can be the patent owner, or a party that obtained all “substantial rights” to the patent.[15]This requirement is also referred to as statutory standing, or the statutory cause of action.
The separation between the two inquiries is significant, because the Supreme Court’s Lexmark[16]decision mandated that a plaintiff’s statutory cause of action, unlike constitutional standing, is not a jurisdictional requirement. Following that guidance, in Lone Star, the Federal Circuit held that “whether a party possesses all substantial rights in a patent does not implicate standing or subject-matter jurisdiction.”[17]A defect in statutory standing can be cured after the suit commences, but a defect in constitutional standing cannot.[18]Lone Star, however, does not address whether “exclusionary right” remains the requirement for constitutional standing.[19]Recent decisions from the court have continued to apply the exclusionary-right requirement for constitutional standing, so it remains the law.
Pre-Lexmark standing decisions, however, continue to operate in both the “exclusionary rights” and “substantial rights” analysis, and not consistently. In Fujifilm, for instance, the Federal Circuit addressed the § 281 “patentee” requirement and cited Mann,[20]a pre-Lexmark decision addressing whether a licensor transferred all substantial rights to the licensee and thereby rendered the licensee the patent owner.[21]The court reiterated Mann’s discussion of several rights that should be examined in the “substantial rights” inquiry. The same Mann decision was later cited by the Federal Circuit in Zebra to support the conclusion that others’ shared ability to license did not divest the patent owner “of all exclusionary rights” for constitutional standing purposes.[22]In Uniloc I, the patent owner also relied on Mann and another pre-Lexmark case to argue (unsuccessfully) that it retained constitutional standing despite granting a license and a right to sublicense.[23]The patent owner appealed, but the Federal Circuit resolved the case on collateral estoppel grounds.[24]
The inconsistency similarly exists in district court cases. In a recent case, Recor Medical, the Norther District of California noted courts’ different views on whether the Federal Circuit’s Mann decision was relevant or instructive for the exclusionary-right inquiry.[25] The court ultimately concluded that, in its view, the Mann analysis was more instructive for the substantial-rights analysis and rejected patent owner’s reliance on Mann to show constitutional standing. In contrast, in CEMCO, the Western District of Washington addressed challenges as to both “substantial rights” under § 281 and “exclusionary rights” for constitutional standing.[26]Relying on primarily pre-Lexmark law, including Mann, the court reviewed the rights transferred under the license at issue and found the plaintiff retained “substantial rights.”[27]That analysis was then incorporated into the court’s constitutional standing inquiry, to support the conclusion that the plaintiff retained “exclusionary rights.”[28]Similarly, in Ingenus, the Northern District of Illinois applied primarily pre-Lexmark law in its “exclusionary rights” and “sufficient rights” analysis and found Mann instructive for both.[29]
Fundamentally, the concept of an “exclusionary right” derives from the rights granted under the patent statute. So does any right encompassed by the “substantial rights” in a patent. The statutory basis is the same, and the scope of the two are at least overlapping. Nonetheless, pending further clarification from the Federal Circuit, parties should remain mindful of post-Lexmark cases directed to one as opposed to the other. That applies particularly to cases decided by district courts that have explicitly held that certain case law pertains to one and not the other.
The exclusionary-right inquiry differs from the traditional threeelement constitutional standing analysis. Some recent decisions focus only on the exclusionary-right inquiry, without separately discussing the three traditional elements.[30]Courts appear satisfied that owning an exclusionary right means that infringement would cause an injury, and that this injury can be redressed by judicial relief, so all three elements are met.
The Federal Circuit’s early discussions of exclusionary rights, however, pertained specifically to the injury-in-fact analysis. In Morrow, the court stated that constitutional injury-in-fact occurred when one party’s action violated another party’s exclusionary rights.[31]The court noted that it only discussed injuryinfact without reaching the other two elements (causation and redressability), because injury alone was dispositive in that case.[32]In Lone Star, the court found the plaintiff sufficiently alleged possession of exclusionary rights, infringement of which resulted in injury.[33]For the other two elements, the court simply stated that “it is clear that a court could redress an injury caused by that infringement.”[34]
Confusion as to the connection between exclusionary rights and the traditional constitutional injury-in-fact persists. For instance, although monetary harm “readily qualif[ies] as concrete injury under Article III,”[35]how monetary harm factors into the exclusionary-right analysis remains to be clarified. In In re Cirba, the appellant disputed whether an exclusionary right was necessary for a “concrete injury,” and whether a monetary-harm-based “competitive” injury would suffice.[36]That question came to the Federal Circuit in a writ of mandamus petition, and the court denied it under the high mandamus standard without resolving the question. A similar issue arose in Vericool, and the district court found the harm to the plaintiff’s monetary interest plainly satisfied the injury requirement.[37]Other cases, in contrast, have focused only on the exclusionary-right analysis without considering monetary harm as a basis for Article III injury.[38]
Given the ongoing debate, parties may find it beneficial to discuss all three elements in conjunction with the exclusionary-right requirement. In CEMCO, for instance, the court found that the plaintiff suffered an injury based on its retained exclusionary rights in the asserted patents.[39]In addition to the injury element, the defendant also disputed whether the injury was speculative and whether it was redressable. The court, in turn, addressed each in its analysis.
Courts have cautioned that constitutional standing does not depend on whether a plaintiff is designated as a patentee, licensee, or otherwise.[40]But the types of plaintiffs do matter, as courts’ exclusionary-right inquiries differ depending on whether the plaintiff is a patent owner/licensor, or a licensee or transferee of certain rights in a patent. We divide our discussion below accordingly.
According to the Federal Circuit, a patent owner has “exclusionary rights as a baseline matter unless it has transferred all exclusionary rights away.”[41]In Zebra, the court held that a patent owner did not lose all exclusionary rights because another entity shared the ability to license.[42]In Lowe, the court reiterated the same and held that the assignee had “an exclusionary right sufficient to establish Article III standing even if [it granted another party a non-exclusive license with] an unrestricted right to sublicense.”[43]
In these cases, the Federal Circuit’s reasoning focused on the rights that were transferred away, and whether those rights amounted to all exclusionary rights and left the patent owner with none. Several recent district court cases, in contrast, examined each right the patent owner allegedly retained to determine whether any of them was an exclusionary right. For instance, in Recor Medical[44]and Deere,[45]the district courts analyzed each right the patent owner/licensor alleged to have retained but found none to be an exclusionary right.
The right to sue for infringement continues to be an important factor, but courts’ views vary. In Deere, for instance, the Southern District of Iowa interpreted the Federal Circuit’s Morrow decision as establishing that “the right to initiate a patent enforcement action is not an exclusionary right supportive of constitutional standing.”[46]The court then found the plaintiffs’ asserted enforcement rights insufficient to support constitutional standing.
The Northern District of California followed similar reasoning in Recor Medical.[47]Under the licensing agreement in that case, the patent owner had a right to sue for infringement if the licensee declined to or failed to do so within a reasonable time. The court found this “secondary right to sue” depended on the licensee’s exclusionary rights and was not itself an exclusionary right.[48]The court also rejected the patent owner’s reliance on Mann and found Mann “more instructive for a statutory standing analysis.”[49]
Other courts took a different view. In Ingenus, the Northern District of Illinois acknowledged that Mann concerned the transfer of substantial rights for statutory standing purposes, but it found Mann’s right-to-sue analysis nonetheless instructive.[50]Comparing to Mann, the court concluded that under the licensing agreement at issue, the licensor’s “right to sue [was] stronger,” and the licensee’s “right to sublicense [was] just as fettered.”[51]The court noted that, among other things, the licensor was the only entity that could initiate a patent infringement action, and that the licensee was required to pay the licensor a portion of sublicensing profits. The court concluded that the licensor retained the “exclusionary right to sue for infringement” and thus had constitutional standing.[52]Similarly, the District of Massachusetts in Chr. Hansen found that the licensor had constitutional standing because it “retained the right to sue, which [was] an exclusionary right.”[53]
In addition to the right to sue, the court in Recor Medical, like the court in Deere, also considered other rights that the licensors retained but found none of them to be an exclusionary right. In Recor Medical, the court also discussed the patent owner’s retained rights to veto sublicense, to limit licensee’s transfer of its rights, and to terminate the agreement in case of a material breach.[54]It found none of them to be an exclusionary right sufficient for constitutional standing. In Deere, similarly, the court also discussed other rights the patent owner allegedly retained, including: the rights to maintain patent registrations, the right to examine the quality of products practicing the asserted patents, the licensee’s grant-back of a non-exclusive license and the right to sublicense, and the alleged reversionary interests upon termination.[55]The court found none of these rights to be an exclusionary right supportive of constitutional standing. The infringement claims in both cases were therefore dismissed.
It seems that the conflicting views again come down to the lack of a clear definition of “exclusionary right” and the inconsistent interpretations of pre-Lexmark case law. Several cases noted here are currently on appeal. As those appeals progress, the Federal Circuit may have an opportunity to provide further guidance and to address the divide among district courts.
The Federal Circuit has long recognized exclusive licensees as one category of plaintiffs having constitutional standing to sue. In WiAV, the court explained that, because exclusive licensees hold one or more exclusionary rights created under the patent statute, they suffer an injury when others violate those rights.[56]
Having exclusionary rights, however, does not require an exclusive licensee to have the sole right to practice the patent. A licensor, for instance, may reserve the right to practice the patent. In Lone Star, the Federal Circuit held that licensee/transferee Lone Star had constitutional standing even though the transferor (and its affiliates) retained the right to practice the patents-at-issue and the right to “indulge” infringing activities by other entities.[57]Similarly, in Flow, the Northern District of California rejected the defendant’s argument that the plaintiff-licensee lacked standing because the licensor reserved the right to practice the patent.[58]The court explained that although such a reservation was relevant to the “patentee” requirement, “a plaintiff need not have a perfectly exclusive license to proceed as a party.”[59]
An exclusive licensee also does not need to “be the only party with the ability to license the patent.”[60]The fact that other entities share the right to grant future licenses does not necessarily defeat the exclusive licensee’s constitutional standing. In WiAV, for instance, WiAV held an exclusive license to practice the asserted patents in the field of wireless handsets, subject to earlier licenses and third-parties’ right to grant future licenses. The court found that WiAV did not lack constitutional standing “merely because its license [was] subject not only to rights in existence at the time of the license but also to future licenses that may be granted only to parties other than the accused.”[61]
Importantly, as the court stressed, an exclusive licensee’s constitutional standing is defendant-specific and depends on the scope of its exclusivity as prescribed in the license. To establish standing, the licensee must show that the relevant contractual arrangement gives it the right to exclude the defendant from entering its exclusive domain.[62]If the defendant does not have and cannot obtain a license to practice the patent within the exclusive licensee’s exclusive domain, the exclusive licensee would suffer an injury by the defendant’s infringement.[63]So the exclusive licensee would have standing to sue that defendant.
In Puma, for instance, the Delaware District Court dismissed an exclusive-licensee’s suit because it lacked standing to pursue infringement outside of its exclusivity pertaining to certain compounds.[64]There, the exclusive licensee, Puma, held exclusive rights to practice the asserted patents with respect to certain compounds, but not with respect to the accused infringing compound, osimertinib. As such, in the court’s view, Puma lacked exclusionary rights with respect to the alleged infringement based on the defendant’s osimertinib product. The court thus dismissed Puma as a plaintiff.
Case law also has established that certain rights, by themselves, were insufficient to support the right holder’s standing. First, a mere right to practice a patent, a socalled “bare license,” is not an exclusionary right supportive of standing.[65]Second, courts have also frowned upon premising standing on the grant of a mere right to sue infringers that is separate from any accompanying proprietary interest in the patent.[66] But as discussed above, what more is required is subject to debate.
An exclusionary-right analysis may require tracing the chain of transfer and mapping out all parties with a stake in the patent. For plaintiffs, it is best to do the homework preemptively rather than risking dismissal. In Western Digital, five plaintiffs filed the suit as a group, asserting that the group together owned all substantial rights in the asserted patents.[67]Facing a motion to dismiss, plaintiffs claimed that at least one company among the five entities owns the rights to each patent. The court dismissed the complaint, finding plaintiffs’ pleading to be insufficient and muddled as to whether any of them had standing to sue.
For a defendant, potential standing defects present a unique defense against infringement allegations, one that can be raised at any time.[68]It is important to examine allegations and evidence relating to each named plaintiff’s purported rights and interests in the asserted patent, and whether each has the required exclusionary right necessary for constitutional standing.
In Midwest Energy, the court dismissed, post-trial, a co-plaintiff because it lacked exclusionary rights in the asserted patents, and the court removed it from the previously entered judgments of infringement.[69]The court rejected the co-plaintiff’s “one-plaintiff rule” argument that so long as one plaintiff has constitutional standing, then the other plaintiff’s standing need not be considered. In the court’s view, the application of the “one-plaintiff” rule is discretionary, and it is not warranted in a case between two private parties concerning patent infringement claims for monetary damages.
Further, developing a potential standing challenge may involve reviewing previous transfers of rights and analyzing how they may have affected the rights later transferred to the named plaintiff(s). In Applications in Internet Time, for instance, the defendant moved to dismiss based, in part, on a lack of constitutional standing because the assignment of patent rights to the plaintiff was void.[70]Reviewing previous agreements, the court determined that the assignor had already sold the asserted patents to another party, so its later assignment to the plaintiff was null and void. Therefore, the court concluded, the plaintiff obtained no exclusionary rights and lacked constitutional standing.
Notably, although constitutional standing defects can be challenged at any time, the applicable standard of proof changes depending on the stage of the suit. At the pleading stage, a plaintiff may only need to plausibly plead its possession of exclusionary rights to survive a dismissal. If the suit proceeds to later stages such as summary judgment or trial, the plaintiff must adduce sufficient evidence to establish standing under the respective evidentiary standards applicable at those later stages.
The allocation and transfer of the rights and interests in a patent can take myriad forms. The exclusionary-right inquiry often involves interpreting intricate contractual arrangements and finding supporting cases that address rights with a similar scope or restrictions. As case law continues to evolve, parties should stay informed of new guidance from the Federal Circuit and be mindful of differing approaches taken by district courts.
Originally printed in the November/December 2025 edition of the IP Litigator. This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. This article is only the opinion of the authors and is not attributable to Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, or the firm’s clients.
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