Untitled case

I'll research this case thoroughly before drafting the overview.

Let me dig into the specific appeal number and the underlying PTAB proceedings.

Case Overview and Background — Proxense, LLC v. Apple Inc. / [Microsoft Corp.](/litigations/by-plaintiff/Microsoft%20Corp.), No. 26-1283 (Fed. Cir.)

Parties. The appellant/patent owner is Proxense, LLC, an Oregon-based company founded in 2001 that, per its own complaint, "developed, inter alia, mobile payment technologies" and wireless biometric authentication from roughly 2004–2012 (Compl. ¶ 34, Proxense v. Microsoft, No. 6:23-cv-00319-ADA, W.D. Tex., available at ai-lab.exparte.com). It is now characterized in trade press as a non-practising entity and former operating company whose CEO, John Giobbi, is also the named inventor on the asserted patents (ip fray, "PTAB abused discretion by staying reexamination…," ipfray.com). Its enforcement campaign has produced settlements/licenses with Samsung (2023, on the eve of trial), Google (case dismissed with prejudice Jan. 13, 2025), LG, and Intel (settled March 2026); litigation against the remaining holdouts, Apple Inc. and Microsoft Corp. — the appellees here — has been stayed (ip fray, Jan. 2025 and March 2026 reports). Proxense's lead appellate counsel is David L. Hecht of Hecht Partners LLP (signature block of Patent Owner's Notice of Appeal, IPR2024-00573, Oct. 6, 2025); Apple's Federal Circuit team includes Erika H. Arner, Daniel C. Tucker, and Taylor Stark, and Microsoft's includes Lauren A. Degnan, W. Karl Renner, Christopher Dryer, and Alex Yu (docket entries 2 in Nos. 25-2168 and 25-2131). Note: the prior case summary's hypothesis that this is the "Microsoft-side appeal" is incorrect — the appellant is Proxense, appealing adverse PTAB decisions, with Apple and/or Microsoft as appellees.

Technology and patent. The accused technology is the defendants' passwordless/biometric authentication stacks. Against Microsoft, Proxense targets the "universal platform password-less architecture": Windows Hello, the Microsoft Authenticator app, and the Microsoft Identity Platform (the Entra ID/Azure AD successor), which uses FIDO2/WebAuthn and OpenID Connect and issues bearer tokens that Proxense characterizes as the claimed "access message," running on Windows 10/11 devices with TPM 2.0/VBS hardware requirements (Compl. ¶¶ 49–57, 6:23-cv-00319). Against Apple — in what ip fray described as the first patent suit ever filed over the Apple Vision Pro — Proxense asserted the same family (Case No. 6:24-cv-00143-ADA) (ip fray, March 23, 2024). The patent at issue, U.S. 8,886,954, "Biometric personal data key (PDK) authentication," claims an integrated device that (i) stores biometric data, a device ID code, and a secret decryption value in a persistent, tamper-proof format, (ii) validates a live biometric scan against that stored data, (iii) wirelessly sends the device ID for authentication by "a third party that operates a trusted authority," and (iv) receives an access message back permitting the user access to an application (claims 1, 12, 16, 22; claim text reproduced in Proxense's Fed. Cir. opening brief). It is in the same PDK family as U.S. 8,352,730 and U.S. 9,298,905.

Procedural posture and why it matters. This is not a district-court appeal: No. 26-1283 is a PTAB appeal under 35 U.S.C. §§ 141(c), 319, arising from the '954 inter partes reviews — IPR2024-00233/IPR2024-01334 (Google petition, Apple joined; Google terminated, Apple sole petitioner; FWD June 17, 2025 holding claims 1–7, 10, 12–19, 22–27 unpatentable) and IPR2024-00846 (Microsoft; instituted Nov. 18, 2024; FWD in 2025 holding claims 1, 2, 4, 5, 7–13, 15, 16, 18–24, 26–29 unpatentable — meaning claims 3, 6, 14, 17 and 25 survived). The underlying district cases sit in the W.D. Tex., Waco Division, before Judge Alan D. Albright (Proxense v. Microsoft, 6:23-cv-00319-ADA, filed May 2, 2023; Proxense v. Apple, 6:24-cv-00143-ADA) and are stayed pending the PTAB/reexam outcomes. Venue matters because Proxense fought off transfer motions in both cases on judicial-economy grounds arising from Judge Albright's earlier work in Proxense v. Samsung (6:21-cv-00210-ADA): the Federal Circuit denied Google's mandamus petition (In re Google LLC, No. 2024-117, 2024 WL 1460003 (Fed. Cir. Apr. 4, 2024)), and Judge Albright then denied Microsoft's transfer to the Western District of Washington (April 2024) (ip fray, Apr. 27, 2024). On the merits of the appeal, Proxense's April 3, 2026 opening brief (captioned Proxense v. Apple and Microsoft) argues an APA violation: the PTAB sua sponte stayed the parallel ex parte reexamination 90/015,052 (covering the nearly identical '730 claims) just as the Central Reexamination Unit was withdrawing the petitioners' prior art and proposing an examiner's amendment, then dismissed the CRU's contrary findings as "moot"; Proxense also presses a BRI-vs-Phillips claim-construction error on "a third party that operates a trusted authority," and a pre-AIA § 112 ¶ 6 dispute (ip fray, Apr. 2026; Proxense opening brief, ipfray.com). The stakes are substantial: Proxense previously requested adverse judgment in the '730 and '905 IPRs (entered Apr. 28, 2025), cancelling all original '730 claims and triggering 37 C.F.R. § 42.73(d)(3) estoppel, so reviving the '954 claims on appeal is the main remaining path to value against Apple and Microsoft; the case is also one of several parallel Proxense appeals raising the same APA intra-USPTO arguments (No. 25-2168, Proxense v. Apple, filed Sept. 30, 2025; Nos. 25-2130/25-2131, consolidated Proxense v. Microsoft, filed Sept. 22, 2025; No. 26-1025, Proxense v. Microsoft and Apple, filed Oct. 8, 2025, from the '042 IPRs).

Sourcing caveats. I could not retrieve a PACER/Justia docket sheet for No. 26-1283 itself, so the appellee lineup (Apple alone, Microsoft alone, or both) and whether 26-1283 is a lead or member of a consolidated appeal are unverified; the best-supported reading is that it is Proxense's appeal of the Microsoft '954 FWD (IPR2024-00846, PTAB docket showing termination Oct. 17, 2025), briefed together with the Apple '954 appeal under the Proxense v. Apple and Microsoft caption reflected in the April 3, 2026 opening brief. The patent number, court, case number, and appellant identity come from the supplied metadata; all PTAB facts above are grounded in the posted FWDs, institution decision, and notice of appeal, and all press characterizations are attributed to ip fray. I found no confirmation of further developments after April 2026 (e.g., appellee briefs or argument date).

I'll research this case systematically across the litigation and PTAB records.

Good initial leads. Let me dig into the Federal Circuit appeal and the PTAB proceedings.

Now let me pin down the district court chronology for each case.

Bottom line

Federal Circuit No. 26‑1283 is Proxense, LLC v. Apple Inc. and Microsoft Corp. — a consolidated appeal in which Proxense challenges two PTAB final written decisions that invalidated all 29 claims of U.S. Patent No. 8,886,954 ("Biometric Personal Data Key (PDK) Authentication"). The "litigation" proper consists of Proxense's W.D. Tex. enforcement campaign (Samsung, Microsoft, Google, Apple, LG), all of which were resolved by settlement or stay, plus the parallel PTAB/ex parte reexamination track that produced the decisions now on appeal. Proxense's opening brief is dated 2026‑04‑03. No district court case on the '954 patent ever reached trial or verdict.

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1. The patent and the parties

• U.S. 8,886,954 issued 2014‑11‑11, a continuation in the same family as U.S. 8,352,730 (issued 2013‑01‑08); both share the title "Biometric Personal Data Key (PDK) Authentication." 29 claims. Owner/enforcer: Proxense LLC (Bend, OR; NPE/former operating company; CEO John Giobbi).
• Accused products in the Microsoft case: Microsoft's "universal passwordless architecture" — Microsoft Authenticator, Windows Hello, Platform Credential for macOS, FIDO2 keys, Entra/Azure AD identity platform, with bearer tokens alleged to be the claimed "access message." (Complaint ¶¶ 48–53, 6:23‑cv‑00319.)
• Counsel of record: Proxense – Hecht Partners LLP (David L. Hecht, James A. Zak). Apple (IPR) – Duane Morris (Monte T. Squire, Philip W. Woo). Microsoft – Desmarais LLP (Betty Chen, Benjamin Elacqua, among others).

2. Chronology

A. First wave — Samsung (2021) and the two May 2023 complaints

B. Second wave — Apple (2024) and the stays

• 2024‑03‑18: Proxense v. Apple Inc., No. 6:24‑cv‑00143‑ADA (W.D. Tex., Judge Albright) filed, asserting the '730, '954, '989, '042 and '289 patents. In its responsive claim construction brief Proxense noted this was "the fourth time that this Court will construe claim terms for the Patents‑at‑Issue" (after Samsung, Google, Microsoft).
• 2024‑09‑26: Scheduling Order (Dkt. 38); 2024‑11‑27: Proxense's Responsive Claim Construction Brief (Dkt. 50), opposing Apple's proposed "tamper proof format" construction ("a format that prevents any changes to the stored data") and Apple's § 112 ¶ 6 argument on the "verification unit" limitation.
• 2025‑02‑07: Judge Albright denied Apple's motion to transfer to N.D. Cal., holding the case "would not be clearly more convenient to try in the Northern District of California." (Law360 case page.)
• 2026‑04‑03 (Fed. Cir. R. 47.4 statement): Proxense reports the Apple case as "Stayed" and the Microsoft case as "Stayed."

C. Microsoft's stay/PR-trial skirmishing (2025)

• 2025‑05‑06: Proxense files an amended complaint (Dkt. 93) that continues to assert the '730 patent.
• 2025‑05‑09: Microsoft motion to dismiss the '730 patent with prejudice for lack of subject‑matter jurisdiction (Dkt. 95), on the ground that the PTAB had cancelled all '730 claims (see §4 below), leaving nothing to assert. Proxense opposed on 2025‑05‑23; Microsoft replied 2025‑05‑30.
• 2025‑05‑16: Joint Notice of Case Narrowing; 2025‑05‑27: Microsoft notice of supplemental authority in support of its opposed motion to stay pending IPR (Dkt. 76).
• 2025‑06‑03: Microsoft Daubert motion to exclude the damages opinions of Dr. Cole and Dr. Vanderhart (Dkt. 106) — the last substantive activity reflected on the docket (latest entry 2025‑06‑04; RPX shows the case effectively frozen thereafter).

D. The Google case — the only '954 case that went to the brink of trial

• Google lost its transfer motion and sought mandamus at the Federal Circuit (an order from the Federal Circuit on the mandamus petition is on the IPR exhibit list as Ex. 2011).
• 2025‑01‑14/24: Proxense dropped/settled the Google case roughly a month before a February 2025 Waco jury trial ("Startup Drops Patent Case Against Google Ahead Of Trial," Law360, 2025‑01‑14; ip fray dates the Google settlement announcement 2025‑01‑24).

E. Other Proxense enforcement tracks

• LG Electronics proceedings (ip fray, 2025‑01‑14).
• Intel — settled 2026‑03‑24 (ip fray).
• 2025‑12‑03 — ip fray reports prior USPTO decisions upholding "core Proxense patents."

3. The Federal Circuit appeal — No. 26‑1283 (the case at issue)

Filing/initial pleadings. Proxense's appeals followed the PTAB decisions below: the Director Review denial in IPR2024‑00233 (2025‑08‑13) and the Microsoft IPR2024‑00846 final written decision (2025‑10‑17). The two appeals were consolidated, captioned Proxense, LLC v. Apple Inc. and Microsoft Corp. The Fed. Cir. R. 47.4 statement lists as related cases: Samsung (settled), Google (6:23‑cv‑00320), Microsoft (6:23‑cv‑00319, stayed), Apple (6:24‑cv‑00143, stayed), and reexams 90/015,052, 90/015,053 and 90/015,054.

Proxense's opening brief (2026‑04‑03). Available at ip fray: ipfray.com/wp-content/uploads/2026/04/26-04-03-Proxense-v.-Apple-Microsoft-appellate-opening-brief-1.pdf. Arguments:

1. APA / inconsistent results. The Board stayed ex parte reexam 90/015,052 just as the Central Reexamination Unit was about to allow claims the CRU found patentable over the same Ludtke art, then dismissed the examiner's withdrawal of the Ludtke rejection as "moot" and "of no relevance" (IPR2024‑00233 FWD at 44). Proxense invokes In re Vivint, 14 F.4th 1342 (Fed. Cir. 2021), and Vicor Corp. v. SynQor, 869 F.3d 1309 (Fed. Cir. 2017), and says the PTAB engaged in "outcome control" over the CRU.
2. Claim construction (reviewed de novo). The Board construed "a third party that operates a trusted authority" as an entity separate from undefined "parties to a transaction." Proxense argues the claims themselves define the transaction as the user gaining access to an application, so the user and the application are the principal parties — and that the Board's construction renders the final claim step meaningless (citing Power Integrations).
3. No remand needed. Proxense contends the CRU already determined the claims patentable over Ludtke/Burger (EPR 90/015,052 NIRC at 14), so vacatur — not remand — is the proper remedy.

Current posture. As of today (2026‑09‑27) the appeal is pending; I could not verify from the sources reviewed whether appellees' response briefs, oral argument, or a decision have issued. The addendum to Proxense's brief lists the FWDs appealed: IPR2024‑00233 Paper 35 (06/17/25); Director Review denial Paper 138 (08/13/25); IPR2024‑01334 Paper 10 (06/17/25); IPR2024‑00846 Paper 32 (10/17/25). Relatedly, Proxense filed a separate notice of appeal on 2025‑10‑06 from the IPR2024‑00573/01398 FWD on the '042 patent (2025‑08‑04).

4. Parallel PTAB and reexamination proceedings — and their effect

IPRs on the '954 patent (the appealed decisions)

Net PTAB effect: the union of the two FWDs invalidates claims 1–29 — every claim of the '954 patent. Both district court cases asserting the '954 patent (Microsoft and Apple) are stayed pending these outcomes.

IPRs on related patents

• '730 patent: Google's IPR2024‑00232 and Microsoft's IPR2024‑00775 — Proxense requested adverse judgment on 2025‑04‑15, and the PTAB on 2025‑04‑28 cancelled claims 1‑17 (and claims 1‑6, 8‑17 in the other), with § 42.73(d)(3) estoppel. Apple's IPR2024‑01333 was the duplicate. This mooted Proxense's '730 infringement claim — the basis for Microsoft's 2025‑05‑09 motion to dismiss that patent with prejudice.
• '905 patent: Google IPR2024‑00234 — terminated on Proxense's request for adverse judgment.
• '042 patent: Microsoft IPR2024‑00573 (and duplicate IPR2024‑01398) — FWD 2025‑08‑04 invalidating claims; Proxense's notice of appeal 2025‑10‑06 (separate Federal Circuit appeal).
• '960 patent: Microsoft IPR2024‑00405.
• Estoppel arithmetic mattered: Microsoft's 2025‑05‑27 supplemental notice argued a PTAB office action rejecting Proxense's amended '730 claims supported a stay.

Ex parte reexaminations (the APA core of the appeal)

The '052 reexam is the linchpin of the appeal: the CRU's positive patentability findings on claims "not patentably distinct" from the '954 claims are the "inconsistent Office results" Proxense says the APA forbids.

5. Final dispositions / present posture

• No trial, no verdict, no JMOL/new‑trial/fee rulings on the '954 patent. The only case that reached the eve of jury selection (Google) settled in January 2025; Samsung settled at jury selection.
• District court dispositions: Samsung (settled); Google (dismissed/settled Jan. 2025); Microsoft and Apple — stayed (per Proxense's own Fed. Cir. R. 47.4 statement, 2026‑04‑03).
• PTAB disposition: all '954 claims held unpatentable (FWDs 2025‑06‑17 and 2025‑10‑17); Director Review denied 2025‑08‑13.
• Appellate posture: active. Fed. Cir. Nos. 26‑1283 (this case) and the companion '042 appeal; Proxense's opening brief filed 2026‑04‑03; decision unknown as of 2026‑09‑27. A Proxense win would restore the claims and, as ip fray put it, "bolster the case … against Apple and Microsoft in stayed litigation."

6. Confidence and gaps

• Well sourced: the two '954 FWDs and their claim counts; the 2025‑06‑17 and 2025‑10‑17 dates; the adverse judgments on the '730; the reexam certificate dates and the 2025‑03‑27 stay; the W.D. Tex. docket events quoted above; the Apple transfer denial (2025‑02‑07); the Google January 2025 settlement; Proxense's 2026‑04‑03 opening brief and its arguments.
• Not verified / flagged: the exact case numbers and filing dates of the notices of appeal that became No. 26‑1283; whether appellees' briefs, oral argument, or a decision exist; the exact dates of the Microsoft and Apple stay orders (both confirmed "stayed" only through Proxense's 2026 Fed. Cir. statement); the disposition of Microsoft's IPR2024‑01327; whether Apple's 2025‑02‑07 transfer denial was followed by any mandamus relief; and the precise date of the Samsung settlement. The existing case summary's uncertainty about the appellee is now resolved: the consolidated appeal names both Apple Inc. and Microsoft Corp.

I'll research this case's counsel of record. Let me start with several targeted searches.

Let me dig into the specific Federal Circuit docket and the '954 appeals.

Let me pin down the Federal Circuit docket numbers and the brief caption.

Bottom line

I was able to verify Proxense's appellate counsel team for the ’954 patent appeals, but I could not retrieve a PACER docket sheet for No. 26‑1283 itself, so the appearances in that specific docket number are inferred from (a) Proxense's counsel in the companion/consolidated Federal Circuit appeals arising from the same ’954 IPRs and (b) the signature blocks on Proxense's notices of appeal and appellate briefs. I flag each item's confidence level below.

One framing note: No. 26‑1283 is not itself an infringement action — it is a Federal Circuit appeal in which Proxense, LLC (the patent owner and the district-court plaintiff in the underlying W.D. Tex. cases) is the appellant. Proxense's "plaintiff-side" counsel of record is therefore its appellate/PTAB team.

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Counsel of record for Proxense, LLC (plaintiff / appellant-patent owner)

1. David L. Hecht — lead counsel (verified)

• Firm/office: Hecht Partners LLP, 125 Park Avenue, 25th Floor, New York, NY 10017; dhecht@hechtpartners.com; (212) 851‑6821; USPTO Reg. No. 61,618.
• Source/verification: He signed Proxense's notices of appeal as "Lead Counsel" in the companion Proxense IPR appeals (§ 142/§ 90.2 notices filed with the PTAB and the Federal Circuit), e.g. the Oct. 6, 2025 Notice of Appeal in IPR2024‑00573 / IPR2024‑01398 (U.S. 8,646,042). See https://www.docketalarm.com/cases/PTAB/IPR2024-00573/Microsoft_Corporation_v._Proxense_LLC/docs/10-06-2025-Patent_Owner/Notice__notice_of_appeal-28-Notice_of_Appeal.pdf. He also filed the Entry of Appearance as counsel for Appellant Proxense, LLC in the ’954-related Federal Circuit appeal Proxense, LLC v. Microsoft Corp., No. 25‑2131 (Fed. Cir., docketed Oct. 6, 2025). See https://dockets.justia.com/docket/circuit-courts/cafc/25-2131. He is the counsel listed on Proxense's ’954 appellate opening brief (filed Apr. 3, 2026). See https://ipfray.com/wp-content/uploads/2026/04/26-04-03-Proxense-v.-Apple-Microsoft-appellate-opening-brief-1.pdf.
• Experience note: Hecht is the founding partner of Hecht Partners and has been Proxense's principal PTAB/Federal Circuit counsel across its enforcement campaign — e.g., counsel of record for Patent Owner Proxense in Samsung Elecs. Am., Inc. v. Proxense, LLC, IPR2021‑01447 (’905 patent), and in the Microsoft/Apple IPRs on the ’954 family, plus the parallel W.D. Tex. litigations (6:21‑cv‑00210; 6:23‑cv‑00319; 6:24‑cv‑00143).

2. James Zak — of counsel / PTAB-and-appellate team (partially verified)

• Firm/office: Hecht Partners LLP, New York, NY; jzak@hechtpartners.com.
• Source/verification: Listed alongside Hecht as counsel "FOR PATENT OWNER" Proxense in PTAB proceedings, Samsung Electronics America, Inc. v. Proxense, LLC, IPR2021‑01447 (see https://www.docketalarm.com/cases/PTAB/IPR2024-00846/... /2022 WL 683115 excerpt). I did not find a Federal Circuit entry of appearance or brief signature by Zak in the ’954 appeal docket numbers I could check, so his appearance in No. 26‑1283 specifically is unconfirmed.

3. Maxim Price — client-side representative (in-house/technical), role not verified as counsel

• Source: Appears as Proxense's representative in claim-construction correspondence with opposing counsel (Sept. 13, 2024 email regarding Proxense's claim-term identifications, cited in Apple's opening claim construction brief in Proxense v. Apple, 6:24‑cv‑00143‑ADA). See the exhibit reproduced at https://gaeflexstaging-dot-docketupdate.appspot.com/cases/PTAB/IPR2024-00407/Microsoft_Corporation_v._Proxense_LLC/01-07-2025-Petitioner/Exhibit-1019-Apples_Opening_Claim_Construction_Brief/.
• Caveat: I could not verify that Price is an attorney or that he has entered an appearance in the Federal Circuit appeal. Treat as a Proxense-side contact, not confirmed counsel of record.

4. W.D. Tex. trial counsel (context only — different proceeding)

Docket entries quoted in a PTAB exhibit reproduce Proxense's attorney appearances in Proxense, LLC v. Samsung Electronics Co., Ltd., No. 6:21‑cv‑00210‑ADA (W.D. Tex.) (March 22, 2022): Brian D. Melton, Geoffrey L. Harrison, Bryce T. Barcelo, and Meng Xi (all associated with Susman Godfrey LLP's Houston office, based on firm rosters), each "on behalf of Proxense, LLC." See https://www.docketalarm.com/cases/PTAB/IPR2024-00846/Microsoft_Corporation_v._Proxense_LLC/docs/04-26-2024-Petitioner/Exhibit-1022... I have no evidence these attorneys appeared in the Microsoft/Apple cases or on the Federal Circuit appeal; do not treat them as counsel of record in No. 26‑1283 without checking PACER.

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What I could not verify (explicit caveats)

• The No. 26‑1283 docket sheet itself. I could not pull the Federal Circuit docket for 26‑1283, so I cannot confirm the complete list of entries of appearance, whether additional Hecht Partners attorneys (e.g., Zak or others) signed on, or whether any local counsel was designated. (The Federal Circuit does not require local counsel, so an absence would be unsurprising.)
• The precise case-to-docket mapping. The ’954 patent's PTAB appeals I identified are Proxense, LLC v. Apple Inc., No. 25‑2168 (filed Sept. 30, 2025; listed as originating from IPR2024‑00233, IPR2024‑01334, and IPR2024‑00846 — see https://litigation.rpxcorp.com/federal_circuit/[3015503](/patent/3015503)-proxense-v-apple) and Proxense, LLC v. Microsoft Corp., Nos. 25‑2130/25‑2131 (filed Sept. 22, 2025; dockets.justia.com/circuit-courts/cafc/25-2131). The ’954 IPRs are IPR2024‑00233 (Google; Apple joined; FWD June 17, 2025, all challenged claims unpatentable — https://www.docketalarm.com/cases/PTAB/IPR2024-01334/Apple_Inc._v._Proxense_LLC/docs/06-17-2025-Board/Final_Written_Decision...) and IPR2024‑00846 (Microsoft; FWD 2025). Proxense's April 2026 opening brief is captioned as covering the two ’954 final written decisions (https://ipfray.com/ptab-abused-discretion-by-staying-reexamination-that-favored-patentee-proxense-tells-federal-circuit/). No. 26‑1283 is most consistent with one of these ’954 appeals (or a member of a consolidated set), which is how I reached the counsel identification above — but I did not independently confirm that docket number.
• Sealing. Nothing I found indicates that Proxense's counsel identity is under seal; Federal Circuit entries of appearance are public. The district-court record contains sealed orders, but that does not affect counsel identification.
• Appellee side (for contrast, not asked): In the ’954-related appeal 25‑2131, Microsoft's appellee counsel of record are Lauren A. Degnan, W. Karl Renner, Christopher Dryer, and Alex Yu (Fish & Richardson). See https://dockets.justia.com/docket/circuit-courts/cafc/25-2131.

Recommended next step to close the gap: pull the PACER docket for Fed. Cir. No. 26‑1283 (CM/ECF) and read the "Entry of Appearance" filings and the civil appeal docketing statement, which will list every attorney of record for Proxense in that appeal verbatim.

I'll research the counsel of record for the defendants/appellees across the Federal Circuit appeal and the underlying proceedings.

Let me dig into the specific docket and confirm firms for each party.

Counsel of Record — Defendants/Appellees in the Proxense '954 Dispute

Framing note first. The case in the metadata (Fed. Cir. No. 26-1283) is not itself a district-court infringement action — it is Proxense's § 141(c)/§ 319 appeal from the PTAB's '954 final written decisions. So the "defendants" here are the appellees, and their counsel of record sits at two levels: (1) the Federal Circuit appellee teams, and (2) the underlying district-court and PTAB teams in Proxense v. Microsoft, No. 6:23-cv-00319-ADA, and Proxense v. Apple, No. 6:24-cv-00143-ADA. I set out both, because the appellate teams are staffed out of the same firms. I could not retrieve a PACER docket for 26-1283 itself, so the filings I can verify are the related appeals (25-2168, 25-2131) and the district/PTAB records.

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A. Federal Circuit — Appellee Apple Inc.

Source: Justia docket, Proxense, LLC v. Apple Inc., No. 25-2168 (Fed. Cir.), Filing 2 (Oct. 14, 2025) — "Entry of Appearance for Erika H. Arner; Daniel C. Tucker; Taylor Stark as counsel for Appellee Apple Inc." (dockets.justia.com/docket/circuit-courts/cafc/25-2168). The Justia entry does not print firm affiliations; the Finnegan attribution is from firm directories and should be treated as high-confidence-but-not-docket-verified.

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B. Federal Circuit — Appellee Microsoft Corp.

Source: prior-generated section citing Docket Entry 2 in No. 25-2131 (consolidated Proxense v. Microsoft appeal); Renner's Fish & Richardson affiliation is independently confirmed by the IPR2024-00846 exhibit list (MSC-1001 et seq., signed "W. Karl Renner, Reg. No. 41,265, Fish & Richardson P.C., … Minneapolis, MN"). Degnan/Dryer/Yu firms are not shown on the Justia entry and are attributed from firm directories.

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C. Underlying district court — Apple Inc. (No. 6:24-cv-00143-ADA, W.D. Tex., Judge Albright)

Apple is represented in the district court entirely by DLA Piper LLP (US). The team, per the Answer (Dkt. 24), the Rule 7 disclosure (Dkt. 25), and the pro hac vice orders at Dkts. 15–22 (Apr. 19, 2024), is:

Source: Proxense, LLC v. Apple, Inc., No. 6:24-cv-00143-ADA, Dkt. 24 (Answer), Dkt. 25 (Rule 7 disclosure), Dkts. 15–22 (PHV orders) (dockets.justia.com/docket/texas/txwdce/6:2024cv00143/1172779468); Apple's preliminary claim constructions (DLA Piper signature block, Sept. 3, 2024).

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D. Underlying district court — Microsoft Corp. (No. 6:23-cv-00319-ADA, W.D. Tex., Judge Albright)

Microsoft is represented by a Desmarais LLP / Fish & Richardson P.C. combination:

Source: Proxense, LLC v. Microsoft Corp., No. 6:23-cv-00319-ADA, Dkt. 95 (Microsoft brief, signed "Benjamin C. Elacqua / Betty Chen — Counsel for Defendant Microsoft Corporation"); Dkt. 67–68 (Chang PHV), Dkt. 72 (Yang appearance) (CourtListener docket 67312721); Microsoft/Desmarais stipulation letter (Aug. 20, 2024, signed Betty H. Chen, Desmarais LLP, San Francisco).

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E. PTAB — Microsoft's IPR counsel of record (relevant because the appeal arises from these IPRs)

Source: Microsoft Corp. v. Proxense, LLC, IPR2024-00846, Updated Exhibit List (June 24, 2024) (signature block: "W. Karl Renner, Reg. No. 41,265; Roberto J. Devoto, Reg. No. 55,108; Usman Khan, Reg. No. 70,439; Diana Bradley — Fish & Richardson P.C.").

Apple's PTAB counsel for the '954 IPRs (IPR2024-00233/01334, IPR2024-01485) was not capturable from the documents I could reach in this session — Apple's petition counsel names do not appear in the FWD or the exhibit lists I retrieved. The common assumption is that the Finnegan appellate team also handles Apple's PTAB work, but I did not verify that, so I am flagging it rather than asserting it.

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Sourcing caveats and gaps

1. No verified docket for No. 26-1283. I could not pull a PACER/Justia docket for the appeal number in the metadata. All appellate counsel identifications above come from the related appeals (25-2168 for Apple; 25-2131 for Microsoft) and the underlying records. If 26-1283's appellee entries differ from those, this list would need adjustment.
2. Firm affiliations on the Federal Circuit entries are not shown on Justia. Arner/Tucker/Stark (Finnegan) and Degnan/Dryer/Yu (Fish & Richardson) are attributed from firm directories and PTAB records; only Renner's Fish & Richardson affiliation is docket/exhibit-verified in what I retrieved.
3. In-house counsel: no in-house attorney for Apple or Microsoft has appeared in the records I reviewed; the district and appellate teams are outside counsel only.
4. Sealed filings: Apple's transfer motion (Dkt. 30) and related venue papers were filed under seal with a non-confidential exhibit attachment; any counsel appearing only in sealed exhibits would not be captured here.
5. The district-court teams above are the counsel of record as of the last docket activity I could see, and both cases are stayed pending the Federal Circuit/reexam outcomes — so no new district-court appearances are expected in the near term.