Case: 22-1884    Document: 54     Page: 1   Filed: 08/28/2024




   United States Court of Appeals
       for the Federal Circuit
                  ______________________

  WISCONSIN ALUMNI RESEARCH FOUNDATION,
               Plaintiff-Appellant

                             v.

                      APPLE INC.,
                    Defendant-Appellee
                  ______________________

                   2022-1884, 2022-1886
                  ______________________

     Appeals from the United States District Court for the
 Western District of Wisconsin in Nos. 3:14-cv-00062-wmc,
 3:15-cv-00621-wmc, Judge William M. Conley.
                  ______________________

                 Decided: August 28, 2024
                  ______________________

    MORGAN CHU, Irell & Manella LLP, Los Angeles, CA,
 argued for plaintiff-appellant. Also represented by ALAN J.
 HEINRICH, AMY E. PROCTOR.

     WILLIAM F. LEE, Wilmer Cutler Pickering Hale and
 Dorr LLP, Boston, MA, argued for defendant-appellee.
 Also represented by ANDREW J. DANFORD, LAUREN B.
 FLETCHER; STEVEN JARED HORN, Washington, DC.
                 ______________________

    Before PROST, TARANTO, and CHEN, Circuit Judges.
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 2     WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 PROST, Circuit Judge.
     Wisconsin Alumni Research Foundation (“WARF”) ap-
 peals two final judgments of the U.S. District Court for the
 Western District of Wisconsin in Case Nos. 14-cv-062
 (“WARF I”) and 15-cv-621 (“WARF II”). Wis. Alumni Rsch.
 Found. v. Apple, Inc., No. 14-cv-062, No. 15-cv-621, 

 (W.D. Wis. May 10, 2022), J.A. 1‒13. With
 respect to WARF I, the district court denied WARF’s re-
 quest to pursue an abandoned doctrine-of-equivalents the-
 ory and entered judgment in favor of Apple Inc. (“Apple”)
 of noninfringement of 

 (“the ’752
 patent”). The district court also entered a final judgment
 in favor of Apple in WARF II, which accused similar, next-
 generation Apple products of infringing the same ’752 pa-
 tent, finding that action barred by WARF I. For the rea-
 sons below, we affirm the district court’s judgment in both
 WARF I and WARF II.
                         BACKGROUND
     This case began more than ten years ago and involves
 a patent that has long since expired. The lengthy litigation
 history is scattered with strategic decisions that gave rise
 to the current appeal. We therefore begin with a mostly
 chronological retelling of the major events that have led to
 the matter before us.
      In short, before us are the appeals from two district
 court cases with the same parties, the same patent, and
 multiple generations of the accused product. WARF ac-
 cused Apple’s A7 and A8 processors of infringing the ’752
 patent in WARF I. In WARF II, separately filed on the eve
 of trial in WARF I, WARF accused Apple’s A9 and A10 pro-
 cessors of infringing the ’752 patent. In WARF I, the jury
 found Apple’s A7 and A8 literally infringed the ’752 patent.
 Apple appealed, arguing no reasonable jury could find Ap-
 ple literally infringed under the plain and ordinary mean-
 ing of “particular” as used in the asserted claims. We
 agreed and reversed the prior judgment. On remand,
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.           3



 WARF attempted to reassert infringement against A7 and
 A8 under the doctrine of equivalents. The district court
 denied that request based on WARF’s prior affirmative
 abandonment of that theory. WARF II was stayed during
 the pendency of the previous appeal because the claim con-
 struction dispute was also relevant to the A9 and A10 pro-
 cessors accused in WARF II. Following the remand in
 WARF I, WARF attempted to continue WARF II against A9
 and A10 under the doctrine of equivalents. But the district
 court found that WARF I precluded WARF from proceeding
 in WARF II. The context of these events is explained in
 more detail below.
                               I
        The ’752 patent was filed on December 26, 1996, and
 issued on July 14, 1998. The patent is titled “Table Based
 Data Speculation Circuit for Parallel Processing Com-
 puter” and is directed to “[a] predictor circuit [that] permits
 advanced execution of instructions.” ’752 patent Abstract.
 “In an electronic computer with a single processing unit
 . . . . [t]he order in which the instructions are executed is
 determined by the value of a program counter within the
 processing unit.” 

 at col. 1 ll. 22‒32. “One method of
 increasing the speed of electronic computers involves using
 multiple processing and/or functional units to execute mul-
 tiple instructions at the same time or in an ‘execution or-
 der’ differing from the program order.” 

 at col. 1 ll.
 50‒53. “An instruction level parallel (‘ILP processing unit’)
 is one where individual instructions of a single program are
 separated to be run on different processing units . . . .” 

 at col. 1 ll. 55‒57. But “as the ILP processing unit prepares
 to execute an instruction, it cannot always determine if the
 instruction will in fact be dependent on earlier instructions
 that have not yet completed their execution.” 

 at col. 2
 ll. 18‒22. In some circumstances, “the ILP processing unit
 is forced to assume dependencies exist,” while in other cir-
 cumstances, “an ambiguous dependency is resolved as no
 dependency.” 

 at col. 2 ll. 24‒27.
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 4       WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




      “[S]ome ILP processors may provide for ‘speculation’,
 that is, execution of an instruction that has ambiguous de-
 pendency as if it had no dependency at all.” 

 at col. 2
 ll. 28‒30. Yet “in the course of execution of instructions,
 [an ILP processing unit] may execute some dependent in-
 structions before the instructions on which they are de-
 pendent,” referred to as a mis-speculation. 

 at col. 2
 ll. 45‒47; see also Appellant’s Br. 6. “A cumbersome or in-
 accurate speculation system may hurt overall system per-
 formance . . . .” ’752 patent col. 3 ll. 18‒19; see also
 Appellant’s Br. 6 (“[A] ‘mis-speculation’ . . . caus[es] an er-
 ror and harm[s] performance.”). To overcome these prob-
 lems, the ’752 patent claims a processor with a “data
 speculation circuit for detecting data dependence between
 instructions and detecting a mis-speculation.” ’752 patent
 claims 1, 9.
                               II
                               A
     On January 31, 2014, WARF filed a complaint against
 Apple, thus beginning WARF I. The complaint accused the
 Load-Store Dependency Predictor (“LSD Predictor”) in Ap-
 ple’s A7 processor of infringing the ’752 patent. See
 J.A. 1001‒06. WARF later served its supplemental in-
 fringement contentions, accusing Apple’s A7, A8, A9, and
 A10 processors of infringing claims 1‒3, 5‒6, and 9 of the
 ’752 patent. 1 In October 2014, WARF moved to compel dis-
 covery related to A9 and A10. Apple objected to the pro-
 duction of discovery on A9 and A10 because they were still
 under development and subject to design changes. Apple
 submitted a declaration with its opposition to WARF’s



     1   For simplicity, we refer to the A8 and A8X proces-
 sors collectively as A8; the A9 and A9X processors collec-
 tively as A9; and the A10 and A10X processors collectively
 as A10.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         5



 motion, stating: “A9 is still in development. . . . [M]ajor
 changes will occur at A9’s stage of design. One change be-
 ing considered for A9 involves the LSD Predictor”; and “sig-
 nificant design changes are being considered for at least
 one model of the A10 design, including at least one signifi-
 cant change involving the LSD Predictor.” Appellant’s
 Br. 9 (cleaned up). Based at least in part on (1) the release
 dates for A9 and A10, which would not occur until the fall
 of 2015 for A9 (when trial was already scheduled) and 2016
 for A10, (2) the need for experts to review materials prior
 to the deadline for expert reports in January 2015, and
 (3) the deadline for summary-judgment motions in March
 2015, the district court concluded “[w]e can’t just keep add-
 ing additional products that are still being worked on.”
 J.A. 15129. The court reasoned that “the fairest line to
 draw right now is with all of the currently released prod-
 ucts,” J.A. 15129, and it denied WARF’s motion to compel
 discovery related to A9 and A10. J.A. 15135.
     In September 2015, less than two weeks before the
 scheduled WARF I trial, WARF filed a second lawsuit,
 WARF II, accusing the LSD Predictor in A9 of infringing
 the ’752 patent. J.A. 1008‒14. In March 2016, WARF
 moved to amend its complaint, adding A10 to the list of ac-
 cused products. J.A. 8006‒14.
                              B
     WARF originally pursued both a literal and doctrine-
 of-equivalents theory of infringement in WARF I. Wis.
 Alumni Rsch. Found., 

, at *1.
     About a month before the WARF I trial, WARF filed a
 motion in limine to exclude evidence and argument regard-
 ing Apple’s U.S. Patent Application No. 13/464,647 (“the
 ’647 application”), which later issued as 

. Apple opposed the motion because it in-
 tended to use the ’647 application to rebut WARF’s doc-
 trine-of-equivalents theory and WARF’s arguments that
 the ’752 patent is not invalid. J.A. 6810‒16. During
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 6     WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 briefing, however, WARF “agreed to ‘drop doctrine of equiv-
 alen[ts] and make no doctrine of equivalents arguments
 whatsoever at trial’” in exchange for Apple’s agreement not
 to offer the ’647 application at trial. J.A. 15290. The court
 thereafter denied WARF’s motion in limine but ordered,
 based on the parties’ agreement, that “neither side may in-
 troduce evidence or argument regarding the ’647 applica-
 tion . . . during the liability phase of trial.” J.A. 15294.
     In October 2015, the jury returned a verdict of literal
 infringement in WARF I.
                              III
                              A
     During the WARF I trial, Apple moved for judgment as
 a matter of law under Federal Rule of Civil Procedure 50(a)
 on WARF’s abandoned noninfringement claims. Shortly
 after trial, the district court denied the motion but noted
 that “any attempt by WARF to resurrect abandoned claims
 would be futile in light of preclusion rules.” J.A. 15322.
      After the WARF I trial, Apple moved for renewed judg-
 ment as a matter of law under Federal Rule of Civil Proce-
 dure 50(b) on literal infringement, arguing that no
 reasonable jury could find that Apple’s accused products
 literally infringe because, among other reasons, Apple’s
 LSD Predictor did not “produce a prediction associated
 with the particular [load] instruction.” ’752 patent claim 1
 (emphasis added); see also J.A. 15333‒34. Instead, “Apple
 explained that the plain and ordinary meaning of ‘particu-
 lar’ meant that the claimed ‘prediction’ must be associated
 with a single load instruction (i.e., one and only one load
 instruction), rather than with a group of load instructions.”
 Wis. Alumni Rsch. Found. v. Apple Inc., 

 (Fed. Cir. 2018) (“2018 Decision”) (emphases in origi-
 nal). WARF’s infringement theory, Apple argued, rendered
 the term “particular” meaningless.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.          7



     Apple raised this argument as a noninfringement de-
 fense as early as March 2015 in its expert report. But the
 dispute over the meaning of “particular” was resurrected
 during trial when WARF moved to exclude Apple’s nonin-
 fringement defense as inconsistent with the plain and or-
 dinary meaning of “particular.” The district court denied
 WARF’s motion “because Apple’s non-infringement argu-
 ment . . . was consistent with the plain meaning of ‘partic-
 ular’ as contemplating association with a single load
 instruction.”    Wis. Alumni Rsch. Found., 

, at *2. Apple then asked the court to enter a jury
 instruction regarding the meaning of “particular,” but the
 court denied this request because the parties had failed to
 seek a claim construction for the term. 

     Ultimately, the district court denied Apple’s renewed
 motion for judgment as a matter of law and entered a final
 judgment of infringement against Apple. J.A. 15328;
 J.A. 15372‒73. Apple appealed, and we reversed, explain-
 ing that “the plain meaning of ‘particular,’ as understood
 by a person of ordinary skill in the art after reading the
 ’752 patent, requires the prediction to be associated with a
 single load instruction. A prediction that is associated with
 more than one load instruction does not meet this limita-
 tion.” 2018 Decision, 

 (emphasis in origi-
 nal).    Then, we determined that even “drawing all
 reasonable inferences in favor of WARF, there is insuffi-
 cient evidence to support the jury’s finding that Apple’s
 products literally satisfy the ‘particular’ limitation.” 2 

.




     2   We also noted at that time that “WARF abandoned
 its theory of infringement under the doctrine of equivalents
 before trial, and has proceeded only on a theory of literal
 infringement.” 2018 Decision, 

 n.5.
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 8       WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




                              B
     WARF also filed post-trial motions after the WARF I
 trial in 2015—for example, regarding the similarity be-
 tween the A7 and A8 processors accused in WARF I and the
 A9 processor accused in WARF II. 3 In a motion for equita-
 ble relief, WARF argued that A9 uses “the same infringing
 LSD Predictor design” as A7 and A8. Appellee’s Br. 8;
 J.A. 7005‒06, 7008. In response, Apple confirmed that the
 “LSD Predictor in its recently released [A9] products is not
 more than colorably different from the LSD Predictor in the
 [A7 and A8] products addressed at trial.” J.A. 7127. And
 Apple did not oppose WARF’s request to include A9 in the
 calculation of damages from WARF I. WARF also filed a
 motion for an accounting, supplemental damages, and in-
 terest, the briefing of which again confirmed the similari-
 ties between A7, A8, and A9. For example, in response to
 WARF’s motion, Apple agreed that “any award of supple-
 mental damages should include not only Apple products
 containing the [A7 and A8 processors] but also Apple prod-
 ucts containing the [A9 processors]” because “Apple does
 not dispute that the LSD Predictor contained in the [A9]
 products is not more than colorably different, with respect
 to the asserted claims of the ’752 patent, from the LSD Pre-
 dictor in the [A7 and A8] products that were addressed at
 trial.” J.A. 7045‒46. Apple explained that the inclusion of
 A9 in the damages award would “eliminate[] the need to
 pursue [WARF II] further.” J.A. 7046.
     In June 2017, the district court, in response to WARF’s
 motion for an accounting and supplemental damages, or-
 dered the parties to brief their positions on consolidating
 WARF II with WARF I and awarding damages for




     3 A10 was not yet asserted as an accused product in
 WARF II at the time of this post-trial briefing in 2015.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.          9



 infringement of A9 and A10. 4 J.A. 15362‒63. WARF
 stated that, although “[t]he parties appear to agree with
 the [c]ourt’s proposal in substance,” it believed that “the
 most efficient path forward would be to enter final judg-
 ment regarding the [A7 and A8] chips now and to defer,
 until after Apple’s appeal is complete, the more extensive
 discovery that will be required for the [A9 and A10] chips.” 5
 J.A. 7129. WARF also stated that “Apple represented that
 it would not dispute that the [A9] and A10 chips are not
 more than colorably different from the [A7 and A8] chips
 with respect to the accused feature,” and “[t]he parties are
 now working together to formulate a stipulation to this ef-
 fect.” J.A. 7129–30; see also Appellant’s Reply Br. 29‒30;
 Appellee’s Br. 8. WARF explained that “[s]hould WARF
 prevail on appeal, then the task of calculating the numbers
 of infringing units of [the A9 and A10] processors can re-
 sume in [WARF II] once the stay is lifted. Conversely,
 should Apple prevail on appeal, there may be no need for
 such calculations.” J.A. 7130; see also Appellee’s Br. 19,
 57–58; Appellant’s Reply Br. 29. Apple, in response, did
 not oppose WARF’s proposal to keep the two cases uncon-
 solidated but again confirmed that the damages award for
 A9 and A10 should be awarded at the same rates as A7 and
 A8 because the LSD Predictor in each generation of chips
 was “not more than colorably different.” J.A. 7148–50.



     4 By this time, WARF had amended its complaint in
 WARF II to add A10 as an accused product.
     5    The only additional discovery that WARF asserted
 may be necessary for A9 and A10 was related to damages—
 e.g., information on the number of unit sales, the effect of
 the ’752 patent’s expiration in 2016 on a damages award,
 and the number of products containing infringing proces-
 sors that were imported into the United States.
 J.A. 7129‒39.
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 10       WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




     As a result of WARF’s desire to keep the cases separate,
 and Apple not opposing that request, the district court
 stayed WARF II pending the outcome of the appeal in
 WARF I. J.A. 15457. 6
                              IV
     After this court’s 2018 Decision, which effectively re-
 versed the jury verdict finding Apple’s A7 and A8 proces-
 sors literally infringe the ’752 patent, a briefing schedule
 was set in both WARF I and WARF II to determine next
 steps in both proceedings.
                               A
      With respect to WARF I, WARF requested a new trial
 on infringement under the doctrine of equivalents. Apple
 opposed this request, and the district court denied WARF’s
 request for two reasons. First, it concluded that WARF
 “abandoned its doctrine of equivalents theory in response
 to Apple’s agreement not to introduce its newly-acquired
 patent on a LSD Predictor despite the patent-in-suit to
 demonstrate that the accused technology was separately
 patentable and therefore, not equivalent.” Wis. Alumni
 Rsch. Found., 

, at *3 (emphasis omitted).
 Second, the district court held that WARF’s argument un-
 der the doctrine of equivalents is precluded as a matter of
 law because the plain and ordinary meaning of “particular”
 as determined by this court—“to be associated with a single
 load instruction”—foreclosed an equivalent where the pre-
 diction could be associated with a group of load instruc-
 tions. Id. at *4 (emphases added). In other words, WARF’s
 doctrine-of-equivalents theory would, according to the dis-
 trict court, vitiate the claim limitation by rendering


      6  The district court had also previously stayed
 WARF II in part, recognizing that “a final judgment in
 WARF I will likely have preclusive effect” in WARF II.
 J.A. 8003.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         11



 “particular” meaningless. The district court therefore con-
 cluded that “WARF I leaves no room for WARF to revisit
 the doctrine of equivalen[ts] claim it voluntarily aban-
 doned,” and it denied WARF’s request to pursue a doctrine-
 of-equivalents theory in WARF I. Id. at *4–5.
                               B
     With respect to WARF II, WARF sought to continue the
 case under a doctrine-of-equivalents theory of infringe-
 ment against Apple’s A9 and A10 processors. Apple op-
 posed, arguing that our decision in WARF I precluded a
 finding that A9 and A10 infringe the ’752 patent under
 multiple preclusion doctrines, including claim preclusion,
 issue preclusion, the Kessler doctrine, and judicial estoppel.
     The district court agreed and, relying on Nystrom v.
 Trex Co., 

 (Fed. Cir. 2009) (“Nystrom II”),
 held that the claims in WARF II were barred by the judg-
 ment in WARF I. The court reasoned that “the procedural
 posture of this case is the same as that presented in the
 Nystrom [II] case, and the Federal Circuit had no trouble
 concluding . . . that the plaintiff in that case was barred
 from revisiting a doctrine of equivalents theory of infringe-
 ment based on waiver of that doctrine in past litigation
 over materially similar, earlier generation of the same
 products despite later generations being produced during
 and after the course of the first litigation.” Wis. Alumni
 Rsch. Found., 

, at *5 (emphasis in origi-
 nal).
     Final judgments were thus entered in both WARF I and
 WARF II. WARF timely appealed both, and we consoli-
 dated the appeals. We have jurisdiction under 

(a)(1).
                         DISCUSSION
     WARF appeals the final judgments in both WARF I and
 WARF II. With respect to WARF I, WARF argues that it
 did not waive its doctrine-of-equivalents theory generally
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 12       WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 with respect to A7 and A8. With respect to WARF II,
 WARF argues that issue preclusion does not apply. Apple
 disagrees with each of WARF’s arguments and further ar-
 gues that, even if issue preclusion does not apply, the Kess-
 ler doctrine bars WARF II.
      We affirm the district court’s conclusion that WARF
 waived its doctrine-of-equivalents theory in WARF I and
 thus its denial of WARF’s motion for a new trial. We also
 affirm, under both issue preclusion and the Kessler doc-
 trine, the district court’s ruling that WARF I bars WARF
 II.
                               I
     We begin with WARF I and whether WARF waived its
 doctrine-of-equivalents theory. 7 “We apply our law to sub-
 stantive and procedural issues unique to and intimately in-
 volved in federal patent law, and we apply regional circuit
 law to other substantive and procedural issues.” Verinata
 Health, Inc. v. Ariosa Diagnostics, Inc., 

 (Fed. Cir. 2016). “Waiver is a procedural issue,” but we
 have held that Federal Circuit law controls where “the un-
 derlying substance of the arguments is intimately related
 with the substance of enforcement of a patent right.” Har-
 ris Corp. v. Ericsson Inc., 

, 1250‒51 (Fed. Cir.



      7   “Waiver is different from forfeiture. Whereas for-
 feiture is the failure to make the timely assertion of a right,
 waiver is the intentional relinquishment or abandonment
 of a known right.” United States v. Olano, 

 (1993) (cleaned up); see also In re Google Tech. Hold-
 ings LLC, 

, 862–63 (Fed. Cir. 2020). Although
 some aspects of WARF’s actions (or inactions) in WARF I
 sound more in forfeiture and others more in waiver, for
 simplicity—and because any distinction between the two is
 immaterial to our disposition—we use the term “waiver” in
 our discussion.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         13



 2005) (cleaned up). We “review[] the trial court’s decision
 on the waiver issue for an abuse of discretion.” United
 States v. Ziegler Bolt & Parts Co., 

 (Fed.
 Cir. 1997). “An abuse of discretion occurs when a court
 misunderstands or misapplies the relevant law or makes a
 clearly erroneous finding of fact.” Nat’l Westminster Bank,
 PLC v. United States, 

 (Fed. Cir. 2008).
      WARF argues that it “did not and could not have
 waived” its doctrine-of-equivalents theory in WARF I. Ap-
 pellant’s Br. 36. WARF argues that it “believed Apple lit-
 erally infringed” under the plain and ordinary meaning of
 “particular,” and such claim construction “did not require”
 a doctrine-of-equivalents theory. 

 Instead, WARF ar-
 gues that it was Apple who waived a claim construction for
 the term “particular” in WARF I, that WARF relied on this
 alleged waiver of a narrower claim construction for the
 term “particular” in deciding that “it could present only lit-
 eral infringement at the 2015 trial,” that the narrower con-
 struction of “particular” “became relevant only after
 appeal,” and that the narrower construction “foreclosed lit-
 eral infringement.” 

 at 36‒37 (emphasis omitted).
 WARF further argues it did not take any actions to waive
 its doctrine-of-equivalents theory generally, “did not stipu-
 late to any adverse inferences or judgments against it,” and
 successfully opposed Apple’s motion for judgment as a mat-
 ter of law on the doctrine of equivalents on the basis that it
 was never actually litigated. Id. at 38. Where there has
 been a change in claim construction as a result of an ap-
 peal, WARF believes that Exxon Chemical Patents, Inc. v.
 Lubrizol Corp. controls. 

 (Fed. Cir. 1998)
 (“Exxon II”).
     Apple presents a different narrative of events—i.e.,
 “WARF made the strategic choice to abandon its [doctrine-
 of-equivalents] theory in order to prevent Apple from intro-
 ducing evidence of Apple’s own patent during the trial’s li-
 ability phase.” Appellee’s Br. 22. Apple relies on this
 court’s 2018 Decision for support, arguing (1) we expressly
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 14    WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 acknowledged that “WARF abandoned its theory of in-
 fringement under the doctrine of equivalents before trial,”
 and (2) we reversed without remand for further proceed-
 ings, such that the district court must follow that mandate.
 

 at 22‒24 (quoting 2018 Decision, 

 n.5).
 Apple further asserts that this court “did not adopt a new
 claim construction” and thus argues that Exxon II does not
 apply. 

 at 24‒29.
      For the reasons below, we agree with the district court
 that WARF waived its doctrine-of-equivalents theory in
 WARF I. In particular, we conclude that (1) no change in
 the claim construction excused WARF’s failure to present
 its doctrine-of-equivalents theory to the jury in WARF I;
 (2) in fact, WARF affirmatively abandoned that theory for
 strategic purposes unrelated to claim construction; and
 (3) for each of these reasons, our holding in Exxon II does
 not help WARF.
                              A
     We begin with WARF’s argument that our 2018 Deci-
 sion adopted a claim construction for the term “particular”
 that was different from what had previously been advanced
 or understood as the proper construction in the WARF I
 trial. Whether our 2018 Decision changed the claim con-
 struction is not the correct inquiry. The correct inquiry is
 whether the claim construction changed in a way that
 would excuse WARF’s failure to raise, at the previous trial,
 the doctrine-of-equivalents theory that it now attempts to
 reassert in WARF I. We find under the facts here that it
 did not.
     Our 2018 Decision clarified the plain and ordinary
 meaning of “particular,” the meaning of which was wholly
 consistent with Apple’s understanding of the plain and or-
 dinary meaning of the term before and during trial. 2018
 Decision, 

 (“Giving a term its plain and
 ordinary meaning does not leave the term devoid of any
 meaning whatsoever.”). For example, by at least March
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.        15



 2015 (six months before trial), Apple set forth a nonin-
 fringement defense in its expert report that argued, even
 under the plain and ordinary meaning of “particular,” a
 “‘prediction’ must be associated with a single load instruc-
 tion (i.e., one and only one load instruction), rather than
 with a group of load instructions.” 

 (emphases
 in original). And during trial, when WARF moved to ex-
 clude Apple’s noninfringement defense as inconsistent
 with the plain and ordinary meaning of “particular,” the
 district court disagreed and denied WARF’s motion “be-
 cause Apple’s non-infringement argument . . . was con-
 sistent with the plain meaning of ‘particular’ as
 contemplating association with a single load instruction.”
 Wis. Alumni Rsch. Found., 

, at *2. These
 examples demonstrate Apple’s consistent understanding of
 the plain and ordinary meaning of “particular”—an under-
 standing that persisted through Apple’s trial presentation
 in WARF I and that is substantively equivalent to the 2018
 Decision’s articulation of the plain and ordinary meaning
 of “particular.”
      Moreover, WARF was not foreclosed from raising the
 doctrine of equivalents at trial as an alternative to literal
 infringement given Apple’s noninfringement position. Ra-
 ther, WARF subjectively “believed [that] Apple literally in-
 fringed” such that it “did not require” a doctrine-of-
 equivalents theory. Appellant’s Br. 36. That confidence in
 the strength of its literal infringement theory does not ex-
 cuse WARF from failing to litigate the doctrine of equiva-
 lents. Similarly, WARF’s argument that our 2018 Decision
 foreclosed WARF only from pursuing a theory of literal in-
 fringement is unavailing because it is irrelevant to whether
 WARF waived its right to assert a doctrine-of-equivalents
 theory. 

 at 36–37. Indeed, WARF asserts that “[i]f Ap-
 ple had timely requested and received the narrower ‘one
 and only one’ construction that it later sought and obtained
 for the first time on appeal . . . then WARF would have cer-
 tainly pursued an infringement claim under the [doctrine
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 16    WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 of equivalents] at trial.” Id. at 36. But Apple had asserted
 its understanding of the plain and ordinary meaning of
 “particular” (as one and only one) since well before trial in
 its expert reports, such that WARF could have raised, and
 had ample incentive to raise, the doctrine of equivalents at
 trial under the same theory it attempts to resurrect now.
                              B
     We also conclude that WARF separately, and for rea-
 sons unrelated to claim construction, waived its doctrine-
 of-equivalents theory.
      “Waiver is the intentional relinquishment or abandon-
 ment of a known right.” Olano, 

 (cleaned
 up). “[F]ail[ing] to present substantive arguments to the
 district court concerning infringement under the doctrine
 of equivalents” constitutes a waiver of the issue. Boss Con-
 trol, Inc. v. Bombardier Inc., 

, 1380 (Fed. Cir.
 2005); see also United States v. Hible, 

 (7th Cir. 2012) (finding waiver when a party “for strategic
 reasons elects to pursue one argument while foregoing an-
 other” (cleaned up)).
     While WARF attempts to recharacterize its reasons for
 not pursing the doctrine of equivalents in WARF I, the rec-
 ord speaks for itself: before the WARF I trial, WARF inten-
 tionally relinquished and abandoned its doctrine-of-
 equivalents theory in exchange for Apple’s agreement not
 to present its own patent at trial. J.A. 15290 (explaining
 that WARF had “agreed to ‘drop doctrine of equivalen[ts]
 and make no doctrine of equivalents arguments whatsoever
 at trial’” (emphasis added)). This was a relinquishment of
 a known right. As a result of the parties’ bargained-for ex-
 change, the district court ordered that “neither side may
 introduce evidence or argument regarding [Apple’s pa-
 tent] . . . during the liability phase of trial.” J.A. 15294.
 Moreover, when WARF struck this bargain and dropped its
 doctrine-of-equivalents theory, and indeed throughout the
 district court proceedings, both WARF and Apple retained
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.        17



 their ability to argue their positions on what the plain and
 ordinary meaning required or allowed. The incentive for
 preserving a doctrine-of-equivalents theory persisted
 through trial, and WARF dropped that theory for reasons
 independent of that incentive.
      WARF essentially asks this court to allow WARF to re-
 litigate WARF I under a doctrine-of-equivalents theory
 that would have been available and realistically useful to
 it in WARF I in essentially the same form as it is today. We
 find that WARF’s abandonment of the doctrine of equiva-
 lents forecloses this result.
                              C
     Finally, we disagree that Exxon II applies to the cir-
 cumstances here. WARF argues that this case stands for
 the proposition that “when the doctrine of equivalents be-
 comes a critical issue only after a new claim construction is
 adopted on appeal, a plaintiff’s prior choice to not present
 that theory at trial does not constitute abandonment.” Ap-
 pellant’s Br. 38. WARF’s understanding of the holding of
 Exxon II is too broad.
      There, Exxon sued Lubrizol for patent infringement.
 The parties disputed how to interpret the claims. Under
 Exxon’s read, the patent claims were like a “recipe” of in-
 gredients that extended to any product made by using the
 claimed ingredients; Lubrizol, on the other hand, argued
 that the claims were directed to the composition of the final
 product. Exxon Chem. Pats., Inc. v. Lubrizol Corp., 

 (Fed. Cir. 1995) (“Exxon I”). The district court
 did not decide which claim construction was correct “until
 all the evidence was in, just before the case was submitted
 to the jury.” 

. Thus, during trial, Exxon “had
 the choice of simply proving infringement under its view of
 the claims, or in addition proving infringement under
 Lubrizol’s view as well. Exxon chose to do both.” 

 (emphasis omitted). After the evidence was pre-
 sented, the judge charged the jury under Exxon’s view of
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 18    WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 the claims as a “recipe.” 

. Exxon then chose to
 stop pursuing its doctrine-of-equivalents theory. See Exxon
 II, 

. “To find infringement as charged, all
 the jury had to find is that Lubrizol used Exxon’s claimed
 starting ingredients in the amount claimed, an essentially
 uncontested fact.” Exxon I, 

 n.5. In other
 words, “[o]nce the district judge construed the claim lan-
 guage in Exxon’s favor, the doctrine-of-equivalents issue in
 the case became moot.” Exxon II, 

. The
 jury found Lubrizol infringed Exxon’s patents.
     On a first appeal, we concluded that the correct claim
 construction was a third option—one that, while partially
 based on Lubrizol’s construction, was neither party’s pro-
 posed construction in full. Exxon I, 

;
 Exxon II, 

. We then “held that under the
 correct claim interpretation no reasonable jury could have
 found that Lubrizol’s products literally infringed Exxon’s
 patent,” and we reversed the judgment of the district court.
 Exxon II, 

. Back at the district court,
 Exxon moved for a new trial on the doctrine of equivalents,
 but the district court denied the motion, stating it had “no
 authority to grant a new trial.” 

      Exxon filed a second appeal, “arguing that although
 our reversal of the jury verdict foreclosed any further pro-
 ceedings relating to literal infringement, our mandate did
 not preclude the district court from entertaining a motion
 for a new trial on the issue of infringement under the doc-
 trine of equivalents.” 

 at 1477‒78. We agreed, explain-
 ing that “in determining that Lubrizol did not literally
 infringe Exxon’s patent [in Exxon I], this court did not dis-
 pose of Exxon’s doctrine-of-equivalents infringement
 claim.” 

. The question in Exxon II was “what
 the appellate court’s mandate left for the district court to
 do.” 

. We decided that the district court could
 consider a motion for a new trial, and “we le[ft] to the dis-
 trict court the questions whether Exxon is entitled to a new
 trial on th[e] [doctrine-of-equivalents] theory and whether
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         19



 there is any procedural flaw in Exxon’s motion that would
 prevent the district court from considering the motion on
 its merits.” 

.
     At a bird’s eye view, there are similarities between
 Exxon I and II and the facts before us, but there are critical
 differences. First, while the district court’s claim construc-
 tion charge to the jury rendered Exxon’s doctrine-of-equiv-
 alents theory moot, here there was no such mootness. 

. In other words, while there was no reason for the
 jury to consider Exxon’s doctrine-of-equivalents theory un-
 der the uncontested facts, here, in contrast, there were rea-
 sons for WARF to pursue its doctrine-of-equivalents
 theory—namely, the parties were actively disputing the
 scope of the plain and ordinary meaning of “particular” be-
 fore, during, and after trial. And the district court had in-
 formed WARF that Apple’s noninfringement defense
 (under what WARF calls a narrower construction of the
 plain and ordinary meaning) “was consistent with the plain
 meaning of ‘particular.’” Wis. Alumni Rsch. Found., 

, at *2. Therefore, the dispute on this term
 was not moot. And while we explained in Exxon II that
 Exxon “could not realistically be expected to request alter-
 native jury instructions asking for an advisory verdict on
 whether the patent would be infringed under the doctrine
 of equivalents on Lubrizol’s proposed claim construction,”
 Exxon II, 

, the same is not true here. Pro-
 ceeding on the doctrine of equivalents in WARF I would not
 have resulted in a mere “advisory verdict.”
      Second, unlike Exxon I and II, WARF affirmatively
 abandoned its doctrine-of-equivalents theory. In Exxon II,
 we explained that, because the doctrine-of-equivalents the-
 ory became moot, Exxon had not “abandoned [that] theory
 of liability by not submitting it to the jury or raising it on
 the previous appeal.” 

 at 1478–79. Here, WARF aban-
 doned its doctrine-of-equivalents theory in a quid-pro-quo
 exchange where Apple agreed not to present evidence of its
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 20       WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 patent at trial—not in reliance on a particular claim con-
 struction that mooted any doctrine-of-equivalents theory.
      Third, Exxon II “simply [held] that our prior mandate
 did not deprive the district court of the authority to enter-
 tain the motion [for a new trial].” 

. Exxon II did
 not grant a per se right to a new trial on the doctrine of
 equivalents as WARF appears to suggest. Here, the dis-
 trict court considered WARF’s motion for a new trial on the
 doctrine of equivalents but disagreed that WARF’s motion
 should be granted. Indeed, the district court agreed
 that Exxon II “allow[ed] an opening for a claim of infringe-
 ment under the doctrine of equivalents” but “did not dictate
 th[at] result.” Wis. Alumni Rsch. Found., 

, at *3 (emphasis in original). Upon consideration
 of the facts here, the district court determined WARF was
 not entitled to a new trial because it had abandoned its doc-
 trine-of-equivalents theory. Id. at *4. 8 The district court’s
 consideration of the motion, and its denial of that motion
 due to the “procedural flaw” of WARF’s previous waiver,
 was not inconsistent with Exxon II. See 

.
     For the reasons above, the district court did not err in
 finding that WARF waived its doctrine-of-equivalents the-
 ory in WARF I. We therefore affirm its denial of WARF’s
 motion for a new trial.




      8   The district court also determined that our prior
 appellate ruling as to the plain and ordinary meaning of
 “particular” “precludes as a matter of law” WARF’s doc-
 trine-of-equivalents theory of infringement. Wis. Alumni
 Rsch. Found., 

, at *4. Due to the sua
 sponte nature of this claim vitiation determination, which
 the parties had no opportunity to brief, we do not rely on
 this analysis.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         21



                               II
     We next turn to WARF II and the question of whether
 WARF I precludes WARF from pursuing a doctrine-of-
 equivalents theory in WARF II. We conclude that it does.
 As stated above, we affirm the district court’s judgment as
 to WARF II based on issue preclusion and the Kessler doc-
 trine. We address each in turn below.
                               A
      “We apply the law of the regional circuit to the general
 procedural question of whether issue preclusion applies.”
 Soverain Software LLC v. Victoria’s Secret Direct Brand
 Mgmt., LLC, 

 (Fed. Cir. 2015). “We
 apply this court’s precedent to questions involving substan-
 tive issues of patent law, issues of issue preclusion that im-
 plicate substantive patent law issues, or issues of issue
 preclusion that implicate the scope of our own previous de-
 cisions.” 

 Whether issue preclusion applies is a legal
 question reviewed de novo. Bernstein v. Bankert, 

 (7th Cir. 2013). Underlying factual findings are
 reviewed “under the highly deferential clear error stand-
 ard.” Goodpaster v. City of Indianapolis, 

 (7th Cir. 2013). Clear error exists when “the trial
 judge’s interpretation of the facts is implausible, illogical,
 internally inconsistent or contradicted by documentary or
 other extrinsic evidence.” 

 (cleaned up).
     Issue preclusion, sometimes called collateral estoppel,
 requires that “(1) the issue sought to be precluded is the
 same as that involved in a prior action; (2) the issue was
 actually litigated; (3) the determination of the issue was es-
 sential to the final judgment; and (4) the party against
 whom estoppel is invoked was represented in the prior ac-
 tion.” Adair v. Sherman, 

 (7th Cir. 2000);
 see also Soverain Software, 

.
    The dispute between the parties here relates only to el-
 ements (1) and (2), which requires an answer to the
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 22     WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 threshold question—what is the “issue”? WARF defines
 the issue in WARF I as “whether Apple’s A7 and A8 proces-
 sors literally infringe the ’752 patent” and the issue in
 WARF II as “whether Apple’s A9 and A10 processors in-
 fringe the ’752 patent under the [doctrine of equivalents].”
 Appellant’s Br. 28. Apple defines the issue as the same in
 both cases—“whether Apple’s accused products infringe
 the ’752 patent.” Appellee’s Br. 41. The differences be-
 tween these two characterizations of “the issue” require us
 to determine whether, for the purposes of issue preclusion,
 the A7/A8 and A9/A10 processors are “essentially the
 same” and whether literal infringement and the doctrine of
 equivalents are part of the same overall issue of infringe-
 ment.
                                1
     Issue preclusion may apply and bar a second litigation,
 even where the products are different from the first litiga-
 tion, under “limited circumstances where it is shown that
 a close identity exists between the relevant features of the
 accused device and the device previously determined to be
 non-infringing such that they are essentially the same.”
 ArcelorMittal Atlantique et Lorraine v. AK Steel Corp., 

 (Fed. Cir. 2018) (cleaned up). “Accused de-
 vices are essentially the same where the differences be-
 tween them are merely colorable or unrelated to the
 limitations in the claim of the patent.” 

 (cleaned up).
       We find no clear error in the district court’s finding that
 the LSD Predictors in the A7/A8 and the A9/A10 processors
 are essentially the same. See Wis. Alumni Rsch. Found.,
 

, at *3 (“There is no dispute that the LSD
 Predictor technology at issue in this second lawsuit, WARF
 II, is the same as that at issue in WARF I, at least as ma-
 terial to plaintiff’s renewed infringement claims under the
 ’752 patent.”). While framed as an issue not in dispute by
 the district court, WARF argues that “the district court
 . . . erred in apparently concluding that the A9 and A10
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.            23



 processors were essentially the same as the A7 and A8 pro-
 cessors at issue in WARF I.” Appellant’s Br. 27.
      Yet WARF waffles on whether it disputes that the
 A7/A8 and A9/A10 processors are essentially the same. For
 example, in WARF’s opening brief, WARF does not appear
 to dispute that A7/A8 and A9/A10 are essentially the same
 for the purposes of issue preclusion (instead, it focuses on
 whether literal infringement and the doctrine of equiva-
 lents are the same issue). See 

 at 28–36. Likewise, in
 reply, WARF again relies on the distinction between literal
 infringement and the doctrine of equivalents even in rebut-
 ting Apple’s argument that the products are essentially the
 same. See Appellant’s Reply Br. 11 n.2 (“Apple suggests
 issue preclusion turns on whether the accused products in
 the later case are ‘essentially the same’ as those in the ear-
 lier case. . . . But that only holds if all of the other require-
 ments of issue preclusion are also met, including that the
 identical issue was actually litigated.” (emphasis in origi-
 nal)). Similarly, WARF quotes its June 2017 briefing on
 the potential consolidation of WARF I and II, saying “Apple
 represented that it would not dispute that the [A9] and A10
 chips are not more than colorably different” and adding
 that this is “not inconsistent with WARF’s positions.” 

 at 29–30 (emphasis omitted). Yet, when asked at oral ar-
 gument whether WARF was still disputing whether A7/A8
 and A9/A10 are essentially the same, WARF indicated it
 was. Oral Arg. at 1:06‒9:24; see also 

 at 18:40–21:00. 9
     At any rate, a generous read of WARF’s briefing reveals
 just two possible arguments for why the A7/A8 and A9/A10
 processors may not be essentially the same: (1) “Apple pro-
 vided no discovery on the A9 and A10 processors,”




     9   Nos. 22-1884, -1866, https://oralarguments.cafc.us
     courts.gov/default.aspx?fl=22-1884_06032024.mp3.
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 24        WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 Appellant’s Br. 27 (citing J.A. 15106); 10 and (2) there was a
 potential “significant change involving the [LSD] Predic-
 tor” in the later A9 and A10 processors from the earlier A7
 and A8 processors. Id. at 9 (emphasis omitted). Neither
 argument is persuasive. Apple was initially able to resist
 discovery on A9 and A10 as part of WARF I, resulting ulti-
 mately in the filing of WARF II. J.A. 15129. At that time,
 in October 2014, before the development of A9 and A10 was
 complete, Apple indeed represented certain design changes
 were being contemplated for the LSD Predictor in A9 and
 A10. Appellant’s Br. 9. But this was not the end of the
 story. A year later in late 2015, after WARF had won a
 jury verdict on infringement, WARF moved for equitable
 relief, repeatedly stating that A9 used “the same infringing
 LSD Predictor design” as A7 and A8. See J.A. 7005–06,
 7008. Apple also admitted in post-trial briefing that “the
 LSD Predictor contained in the A9 and A9X products is not
 more than colorably different . . . from the LSD Predictor
 in the A7, A8, and A8X products that were addressed at
 trial” and agreed to produce financial information on A9 for
 the calculation of damages in WARF I. J.A. 7046; see also
 J.A. 7127 (same). In 2017 (by which time A10 had been
 accused in WARF II), WARF and Apple again agreed that
 the A9 and A10 processors were not more than colorably
 different. J.A. 7129–30 (“The parties are now working to-
 gether to formulate a stipulation to this effect . . . .”).
     WARF contends, however, that it did not want WARF
 I and II consolidated after trial in WARF I because more
 discovery was necessary for A9 and A10. Appellant’s Reply
 Br. 6. But the only discovery WARF still needed was



      10 Apple disputes the merits of this argument, ex-
 plaining that source code for A9 was produced, WARF’s ex-
 pert reviewed that source code, and a declaration and other
 documents about A9 and A10 were produced. Oral Arg. at
 41:43–43:29.
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         25



 damages-related discovery—not technical discovery for the
 purposes of determining the products were essentially the
 same. See J.A. 7129–39 (never once mentioning the need
 for additional technical discovery). Indeed, WARF ex-
 plained its preference to keep WARF I and II separated as
 follows:
     The second case [WARF II], which concerns Apple’s
     A9, A9X, A10, A10X and later processors, should
     not be consolidated and should remain stayed
     pending resolution of Apple’s appeal in [WARF I].
     Should WARF prevail on appeal, then the task of
     calculating the numbers of infringing units of these
     processors can resume in [WARF II] once the stay
     is lifted. Conversely, should Apple prevail on ap-
     peal, there may be no need for such calculations.
 J.A. 7130 (emphasis added); see also J.A. 7149 (Apple
 again agreeing damages may be awarded at the same rates
 for the A9/A10 as the A7/A8 LSD Predictors because they
 are not more than colorably different); see also
 J.A. 7187–7208 (same). Further still, in 2019, Apple con-
 firmed with source code and an Apple engineer’s declara-
 tion supporting the conclusion that “all of the chips at issue
 in these two cases contain the same accused feature—the
 LSD Predictor using hashed load tags.” Appellee’s Br. 34
 (quoting Wis. Alumni Rsch. Found., 

, at
 *3).
     From 2015 until the filing of this appeal, WARF has
 not disputed that the A7/A8 and A9/A10 LSD Predictors
 are essentially the same. It is simply not credible to rely
 on statements made while the products were still under de-
 velopment in 2014 and ignore all of the parties’ statements
 and evidence after the products were developed from 2015
 to today. We therefore conclude that the district court did
 not err in finding that the A7/A8 and A9/A10 processors are
 essentially the same.
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 26    WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




                               2
      Having settled that WARF I and II raise infringement
 allegations against essentially the same products, the only
 other difference between WARF’s and Apple’s articulation
 of “the issue” is whether the issue is infringement or the
 separate theories of infringement.
     WARF correctly states that the issue “actually liti-
 gated” in the first action must be “identical” to the issue in
 the second action for issue preclusion to apply. Appellant’s
 Br. 28. WARF quotes B & B Hardware, Inc. v. Hargis In-
 dustries, Inc. for the proposition that “[i]ssues are not iden-
 tical if the second action involves application of a different
 legal standard, even though the factual setting of both suits
 may be the same.” 

, 154 (2015) (quoting 18 C.
 Wright, A. Miller, & E. Cooper, Federal Practice & Proce-
 dure § 4417, p. 449 (2d ed. 2002)). WARF then concludes
 that because literal infringement and the doctrine of equiv-
 alents have different tests, they must be different issues.
 But WARF reads this statement in B & B Hardware too
 broadly.
     In B & B Hardware, the dispute was about whether a
 Trademark Trial and Appeal Board (“TTAB”) decision
 could have preclusive effect on a district court proceeding.
 In trademark law, a party may seek to register a trade-
 mark with the Patent and Trademark Office (“PTO”). If
 another entity believes the to-be-registered trademark
 would be too similar to its own trademark, it may oppose
 the registration before the TTAB in an administrative pro-
 ceeding. Separately, that entity may also file a trademark
 infringement suit in district court. Both proceedings, au-
 thorized by two different statutes, look to whether there
 would be a “likelihood of confusion” between the two trade-
 marks. Compare 

(d) (PTO registration
 permissibility), with § 1114(1) (district court trademark in-
 fringement liability). The Supreme Court held that TTAB
 proceedings did have preclusive effect on district-court
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.          27



 trademark-infringement suits and concluded that “the
 same likelihood-of-confusion standard applies to both reg-
 istration and infringement” even though they arise from
 different statutory authority and apply different factors to
 assess “likelihood of confusion.” B & B Hardware, 575 U.S.
 at 154. The Court explained that “minor variations in the
 application of what is in essence the same legal standard
 do not defeat preclusion.” Id. (cleaned up).
     Critical here, B & B Hardware does not hold that the
 factors or tests must be identical for issues to be identical.
 Indeed, the “likelihood of confusion” factors at the TTAB
 were different from (albeit similar to) those in district-court
 proceedings. Id. For this reason, WARF reads B & B Hard-
 ware too broadly, and WARF’s mere observation that the
 tests for literal infringement and the doctrine of equiva-
 lents are different is insufficient to demonstrate that the
 issues are different. See Appellant’s Br. 29–30.
     Instead, the Court concluded that the legal standards
 were the same in B & B Hardware, giving reasons for that
 conclusion that are relevant here: (1) “the operative lan-
 guage [of the two statutes] is essentially the same”; (2) “the
 likelihood-of-confusion language . . . has been central to
 trademark registration since at least 1881”; and (3) the Re-
 statement (Second) of Judgments supported the conclusion
 that the issues were the same. B & B Hardware, 575 U.S.
 at 148, 154–55, 157. In other words, the Court looked to
 the statutes, the history, and the Restatement (Second) of
 Judgments. Id. at 148, 153, 157. We take the same ap-
 proach.
     Here there is only one statute governing patent in-
 fringement. See 

. Section 271(a) provides
 that “whoever without authority makes, uses, offers to sell,
 or sells any patented invention, within the United States
 or imports into the United States any patented invention
 during the term of the patent therefor, infringes the
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 28        WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 patent.” 11 This is the statutory basis for direct infringe-
 ment, which covers both literal infringement and the doc-
 trine of equivalents. Thus, unlike B & B Hardware, we are
 not dealing with two statutes, just one describing liability
 for all direct infringement.
     As to history, the statute and the derivation of the doc-
 trine of equivalents demonstrate that the doctrine of equiv-
 alents is a long-established theory of infringement.
 Liability for patent infringement was first enacted in the
 Patent Act of 1790. By 1853, the Supreme Court recog-
 nized a patentee may prevail on a theory of infringement
 where the accused device “substantially . . . embod[ies] the
 patentee’s mode of operation, and thereby attain[s] the
 same kind of result as was reached by his invention”—
 thereby laying the foundation for what today is the doc-
 trine of equivalents. Winans v. Denmead, 

 (1853); see also Graver Tank & Mfg. Co. v. Linde Air Prods.
 Co., 

 (1950) (articulating the now familiar
 test for the doctrine of equivalents). 12 Both Graver Tank
 and Winans treated infringement, either literal or doctrine
 of equivalents, as a single issue. See Graver Tank, 

 (considering the “issue” under both the doctrine of
 equivalents and literal infringement and noting that “the
 single issue before us is whether the trial court’s holding
 that the . . . claims have been infringed will be sustained”
 (emphasis added)); Winans, 

 (“How is a




      11 Other sections of § 271 provide the basis for other
 types of infringement not at issue here, such as induced
 and contributory infringement. See 

(b)–(c).
      12 “A patentee may invoke this doctrine to proceed
 against the producer of a device if it performs substantially
 the same function in substantially the same way to obtain
 the same result.” Graver Tank, 

 (cleaned
 up).
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         29



 question of infringement of this patent to be tried?” (empha-
 sis added)). 13
     The Restatement (Second) of Judgments § 27 also pro-
 vides guidance on the scope of the “issue” here as it did in
 B & B Hardware. Indeed, the Restatement (Second) of
 Judgments contemplates the difficulties in defining the “is-
 sue” for purposes of issue preclusion:
     When there is a lack of total identity between the
     particular matter presented in the second action
     and that presented in the first, there are several
     factors that should be considered in deciding
     whether for purposes of the rule of this Section the
     “issue” in the two proceedings is the same, for ex-
     ample: Is there a substantial overlap between the


     13  Underscoring this is the Supreme Court’s recogni-
 tion that the doctrine of equivalents is limited to covering
 products or processes that are at most insubstantially dif-
 ferent from what would literally infringe a patent claim.
 See Graver Tank, 

 (noting that allowing re-
 covery only under strict literal infringement “would leave
 room for—indeed encourage—the unscrupulous copyist to
 make unimportant and insubstantial changes and substi-
 tutions in the patent which, though adding nothing, would
 be enough to take the copied matter outside the claim, and
 hence outside the reach of law” (emphasis added)). In
 B & B Hardware, a trademark case, the Court explained
 that “trivial variations between the usages set out in an
 application [for registration] and the use of a mark in the
 marketplace do not create different ‘issues,’ just as trivial
 variations do not create different ‘marks.’” 575 U.S. at 157.
 A same-issue conclusion is likewise warranted for an asser-
 tion of patent infringement under the doctrine of equiva-
 lents, which is necessarily an assertion that the accused
 product or process is at most insubstantially different from
 what the patent claim at issue literally sets out.
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 30     WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




      evidence or argument to be advanced in the second
      proceeding and that advanced in the first? Does
      the new evidence or argument involve application
      of the same rule of law as that involved in the prior
      proceeding? Could pretrial preparation and discov-
      ery relating to the matter presented in the first ac-
      tion reasonably be expected to have embraced the
      matter sought to be presented in the second? How
      closely related are the claims involved in the two
      proceedings?
 Restatement (Second) of Judgments § 27 cmt. c (AM. L.
 INST. 1982). Here, the evidence would be substantially the
 same between literal infringement and the doctrine of
 equivalents; it will always boil down to the patent claim,
 the accused product (or method), and a comparison of the
 two. Indeed, the evidence must necessarily be substan-
 tially the same because the doctrine of equivalents is in-
 tended to cover “unimportant and insubstantial changes
 and substitutions in the patent which, though adding noth-
 ing, would be enough to take the copied matter outside the
 claim.” Graver Tank, 

 (emphases added).
 Further, and for essentially the same reason, it is hardly
 disputable that pretrial preparation and discovery in a pa-
 tent suit could be “reasonably expected” to embrace both
 literal infringement and the doctrine of equivalents.
      Finally, we note that treating literal infringement and
 the doctrine of equivalents as the same issue is consistent
 with our precedent. For example, in Nystrom II, Nystrom
 filed a first lawsuit, alleging Trex’s first-generation “Trex
 boards” infringed Nystrom’s patent. After claim construc-
 tion, Nystrom stipulated to noninfringement, and the dis-
 trict court entered judgment accordingly. We affirmed this
 judgment but remanded for further proceedings on valid-
 ity. “On remand, Nystrom attempted to pursue his in-
 fringement claim under the doctrine of equivalents.”
 Nystrom II, 

. The district court deter-
 mined the doctrine of equivalents had been waived. 

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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         31



 Thereafter, Nystrom filed a second lawsuit, accusing sec-
 ond-generation products (that were essentially the same as
 the first-generation products) of infringing the same patent
 under the doctrine of equivalents. We held this second suit
 barred by the first. 

. And we clarified, in Aspex
 Eyewear, Inc. v. Marchon Eyewear, Inc., that Nystrom II
 applied issue preclusion to reach this result. 14 

 (Fed. Cir. 2012); cf. ArcelorMittal, 

 (explaining that even though a first lawsuit found
 noninfringement under the doctrine of equivalents, a sec-
 ond lawsuit on infringement would be barred if the prod-
 ucts in both suits were “materially” the same). 15
      For the foregoing reasons, we are convinced that literal
 infringement and the doctrine of equivalents are the same
 issue for issue-preclusion purposes. To conclude otherwise
 would allow a patentee to proceed through the entirety of
 litigation only on a theory of literal infringement and, after
 losing its case, allow that same party to accuse the same
 entity of infringing the same patent, accusing the same or
 essentially the same products, as long as those products
 were sold after judgment of the first suit. See Galderma



     14  At oral argument, WARF agreed that the stipula-
 tion to noninfringement in Nystrom II “necessarily em-
 braced” both literal infringement and the doctrine of
 equivalents. See Oral Arg. at 30:11–32:03. Such an admis-
 sion implicitly concedes that the issue of infringement nec-
 essarily embraces both underlying theories.
     15  At oral argument, WARF also argued that Exxon I
 and II demonstrate that literal infringement and the doc-
 trine of equivalents are different issues. Oral Arg. at
 25:11–26:35, 29:00–30:11, 32:03–32:32.         We disagree.
 Exxon I and II involved a single case, meaning there was
 no possibility that a final judgment in one case could pre-
 clude an issue in another. In contrast, the appeal before us
 involves multiple, repetitious lawsuits.
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 32    WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 Labs., L.P. v. Amneal Pharms., LLC, 337 F. Supp. 3d. 371,
 411 (D. Del. 2018) (Stark, J.) (treating literal and doctrine-
 of-equivalents infringement as a single issue because not
 doing so would “upend[] the finality of judgements that col-
 lateral estoppel aims to preserve and would require parties
 to relitigate infringement of the same products covered by
 the same patents when the issue of infringement has al-
 ready been decided – a decidedly wasteful use of judicial
 resources.”), rev’d in part on other grounds, 806 F. App’x.
 1007 (Fed. Cir. 2020). Such a repetitious litigation strategy
 is untenable.
     Therefore, like Nystrom II, when the district court en-
 tered a judgment of noninfringement in WARF I, issue pre-
 clusion barred WARF II which accuses essentially the same
 products of infringement.
                               B
     Additionally, WARF II is barred by the Kessler doc-
 trine. See Kessler v. Eldred, 

 (1907).
      Kessler is a patent-specific preclusion doctrine that
 “fills the gap between [claim and issue] preclusion doc-
 trines . . . allowing an adjudged non-infringer to avoid re-
 peated harassment for continuing its business as usual
 post-final judgment.” Brain Life, LLC v. Elekta Inc., 

 (Fed. Cir. 2014) (emphasis omitted). In
 Kessler, Eldred filed a patent infringement suit against
 Kessler. The district court and the court of appeals deter-
 mined that Kessler did not infringe. Eldred then filed a
 second patent suit against Kessler’s customer for infringe-
 ment of the same patent. The Supreme Court deemed the
 second suit barred, explaining that the first action “settled
 finally and everywhere . . . that Kessler had the right to
 manufacture, use, and sell the [accused product].” Kessler,
 

; see also Rubber Tire Wheel Co. v. Goodyear
 Tire & Rubber Co., 

 (1914) (under Kessler,
 a prevailing non-infringer obtains “the right to have that
 which it lawfully produces freely bought and sold without
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         33



 restraint or interference”). The Supreme Court explained
 that the right “attaches to its product—to a particular
 thing—as an article of lawful commerce.” Rubber Tire
 Wheel, 

. Likewise, we too have held that
 Kessler operates to grant a product a noninfringing status.
     The principle that, when an alleged infringer pre-
     vails in demonstrating noninfringement, the spe-
     cific accused device(s) acquires the “status” of a
     noninfringing device vis-à-vis the asserted patent
     claims is an essential fact of a patent infringement
     claim. The status of an infringer is derived from
     the status imposed on the thing that is embraced
     by the asserted patent claims. And, when the de-
     vices in the first and second suits are “essentially
     the same,” the “new” product(s) also acquires the
     status of a noninfringing device vis-à-vis the same
     accusing party or its privies.
 Brain Life, 

 (cleaned up).
     We have applied the Kessler doctrine in limited circum-
 stances. 16 For example, in Brain Life we deemed a second
 suit asserting method claims barred where the patent
 owner had proceeded to trial solely on apparatus claims in



     16   We have previously questioned “whether the Kess-
 ler doctrine was created as an exception to the mutuality of
 estoppel rule that existed at the time or as a matter of sub-
 stantive patent law.” SpeedTrack Inc. v. Off. Depot, Inc.,
 

 (Fed. Cir. 2015); see also MGA, Inc. v.
 Gen. Motors Corp., 

, 733–34 (Fed. Cir. 1987);
 Brain Life, 

. “But, the Kessler Doctrine
 exists, and we are bound by it . . . .” Brain Life, 

. “[W]e must follow Kessler unless and until the Su-
 preme Court overrules it . . . .” SpeedTrack, 

. Until then, “[w]e may only apply the law as it con-
 tinues to exist.” Brain Life, 

.
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 34     WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 a first lawsuit. 

. We explained that “[w]hile [the
 original plaintiff] ultimately abandoned the method claims
 prior to trial, it could have continued to assert those claims.
 Thus, once the accused devices . . . were adjudged to be
 noninfringing with respect to the asserted claims and judg-
 ment was entered as to all claims, [the defendant] was free
 to continue engaging in the accused commercial activity as
 a non-infringer.” 

. We determined this applied
 even where the second lawsuit was directed to allegations
 of infringement for subsequent versions of the originally
 accused products because there were “no material differ-
 ences between the currently accused products and the pre-
 viously adjudicated non-infringing products.” 

 (cleaned
 up).
     As a second example, in SpeedTrack, the plaintiff orig-
 inally asserted only literal infringement in its contentions.
 See SpeedTrack, 

. When the defendant
 moved for summary judgment of noninfringement, Speed-
 Track simultaneously moved to amend its infringement
 contentions to assert the doctrine of equivalents. 

 SpeedTrack’s motion for leave to amend was denied be-
 cause “SpeedTrack had actually been on notice of defend-
 ants’ non-infringement argument” for nearly six months.
 

 The district court entered a judgment of noninfringe-
 ment in the first suit, but SpeedTrack filed a second law-
 suit, alleging infringement of the same product under the
 doctrine of equivalents. 

 at 1320–21. The district court
 deemed the second lawsuit barred by the Kessler doctrine,
 and we affirmed. 

. We explained:
      [T]he Kessler doctrine is a necessary supplement to
      issue and claim preclusion: without it, a patent
      owner could sue a manufacturer for literal infringe-
      ment and, if unsuccessful, file suit against the
      manufacturer’s customers under the doctrine of
      equivalents. Or, a patent owner could file suit
      against the manufacturer’s customers under any
      claim or theory not actually litigated against the
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 WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.         35



     manufacturer as long as it challenged only those
     acts of infringement that post-dated the judgment
     in the first action. That result would authorize the
     type of harassment the Supreme Court sought to
     prevent in Kessler . . . .
 

. WARF II presents exactly this type of litigation
 harassment, applied to a second suit against the very same
 defendant, the manufacturer itself. 17
      There is little relevant difference between SpeedTrack
 and the facts here except that SpeedTrack’s second suit ac-
 cused the same software as the first suit, 

,
 whereas here WARF has accused subsequent versions of
 the originally accused products. But this difference is im-
 material. As explained above, Brain Life concluded that
 the “non-infringing status” applies to subsequent versions
 of the originally accused products if there are “no material
 differences” between the accused products in each suit.
 Brain Life, 

. Therefore, like in Speed-
 Track, the Kessler doctrine bars WARF’s second lawsuit
 against essentially the same products.
     WARF does not respond to SpeedTrack and argues only
 that Kessler does not apply because we have “relied on the
 Kessler doctrine only to bar assertion of the claims at issue
 against essentially the same products made or sold after
 the judgment of noninfringement in the earlier case.” Ap-
 pellant’s Reply Br. 13 (emphases omitted) (quoting Sim-
 pleAir, Inc. v. Google LLC, 

 (Fed. Cir.




     17 As we explained in SpeedTrack, had the product
 manufacturer been a party to the second action, there
 would be “no doubt” that “the facts here would fall squarely
 within Kessler.” SpeedTrack, 

.
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 36        WISCONSIN ALUMNI RESEARCH FOUNDATION v. APPLE INC.




 2018)). 18 WARF is mistaken, as was the quoted dicta in
 SimpleAir. For example, in SpeedTrack, the first suit was
 filed in November 2006 and ended in a jury verdict in 2012.
 The second suit was filed in July 2007 (i.e., well before
 there was a first judgment). And there, we stated “that the
 Kessler doctrine precludes SpeedTrack’s infringement
 claims in full.” SpeedTrack, 

 (emphasis
 added). In other words, this court has indeed relied on the
 Kessler doctrine to bar assertion of claims against essen-
 tially the same products made or sold before the judgment
 of noninfringement in the earlier case. Therefore, WARF’s
 argument—that Kessler does not apply because A9 and
 A10 were sold before any final judgment of noninfringe-
 ment—fails.
                          CONCLUSION
     We have considered WARF’s remaining arguments and
 find them unpersuasive. For the foregoing reasons, we af-
 firm the district court’s denial of WARF’s motion for a new
 trial in WARF I and affirm the district court’s conclusion
 that WARF I precludes WARF II.
                          AFFIRMED




      18  WARF also cites Brain Life for the same proposi-
 tion, stating the “Kessler doctrine is ‘temporally limited to
 acts occurring after final judgment was entered in the first
 suit.’” Appellant’s Reply Br. 14 (quoting Brain Life, 

). This quote is about claim preclusion—not
 the Kessler doctrine.