Centripetal Networks, LLC v. Palo Alto Networks, Inc., Cisco Systems, Inc., Keysight Technologies, Inc.

United States Court of Appeals
for the Federal Circuit
______________________
CENTRIPETAL NETWORKS, LLC,
Appellant
v.
PALO ALTO NETWORKS, INC., CISCO SYSTEMS,
INC., KEYSIGHT TECHNOLOGIES, INC.,
Appellees
JOHN A. SQUIRES, UNDER SECRETARY OF
COMMERCE FOR INTELLECTUAL PROPERTY
AND DIRECTOR OF THE UNITED STATES
PATENT AND TRADEMARK OFFICE,
Intervenor
______________________
2023-2027
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Nos. IPR2022-
00182, IPR2022-01151, IPR2022-01199.
______________________
Decided: October 22, 2025
______________________
P AUL D. CLEMENT , Clement & Murphy, PLLC, Alexan-
dria, VA, argued for appellant. Also represented by J OSEPH
D EMOTT , MATTHEW ROWEN; MATTHEW J AMES D OWD,
ROBERT J AMES SCHEFFEL , Dowd Scheffel PLLC, Washing-
ton, DC.
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 2
MARK CHRISTOPHER F LEMING, Wilmer Cutler Pickering
Hale and Dorr LLP, Boston, MA, argued for appellees.
Cisco Systems, Inc. also represented by HEATH BROOKS ,
Washington, DC; G ARY M. F OX , New York, NY; T HEODORE
M. F OSTER, Haynes and Boone, LLP, Denver, CO; D EBRA
J ANECE MCC OMAS , D AVID L. MCCOMBS , Dallas, TX;
ANGELA M. O LIVER , Washington, DC.
BRIAN J AMES SPRINGER, Civil Division, United States
Department of Justice, Washington, DC, argued for inter-
venor. Also represented by BRIAN M. BOYNTON; P ETER J.
AYERS , K AKOLI CAPRIHAN, ROBERT J. MCMANUS , F ARHEENA
YASMEEN RASHEED Office of the Solicitor, United States Pa-
tent and Trademark Office, Alexandria, VA.
D OUGLAS H ALLWARD-D RIEMEIER , Ropes & Gray LLP,
Washington, DC, for appellee Palo Alto Networks, Inc.
Also represented by JAMES RICHARD BATCHELDER , ANDREW
T. RADSCH , East Palo Alto, CA.
G ERARD M. D ONOVAN, Reed Smith LLP, Washington,
DC, for appellee Keysight Technologies, Inc. Also repre-
sented by J ONAH D. MITCHELL , San Francisco, CA.
______________________
Before M OORE, Chief Judge, HUGHES and C UNNINGHAM ,
Circuit Judges.
CUNNINGHAM , Circuit Judge.
Centripetal Networks LLC (“Centripetal”) appeals
from a final written decision by the Patent Trial and Ap-
peal Board in an inter partes review (“IPR”) of U.S. Patent
No. 9,917,856, holding claims 1, 24, and 25 of the ’856 pa-
tent unpatentable as obvious. Palo Alto Networks, Inc.
v. Centripetal Networks, Inc., No. IPR2022-00182,
2023 WL 5033832, at *2, *25 (P.T.A.B. May 23, 2023)
(“Merits Decision”). Apart from its arguments on the
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 3
merits, Centripetal argues that the Board’s decision was
tainted by the belated recusal of an administrative patent
judge (“APJ”) only after institution of the IPR. See Palo
Alto Networks, Inc. v. Centripetal Networks, Inc., No.
IPR2022-00182, Paper 55 at 6–22 (P.T.A.B. Feb. 3, 2023)
(“Recusal Decision”).1 While we see no reversible error in
the Board’s recusal analysis, we vacate the Board’s final
written decision for failure to adequately consider evidence
of copying and remand for further proceedings.
I. BACKGROUND
Centripetal owns the ’856 patent, titled “Rule-Based
Network-Threat Detection for Encrypted Communica-
tions.” ’856 patent; Merits Decision at *3. It is directed to
methods and systems for detecting network threats in en-
crypted communications. Merits Decision at *3; see, e.g.,
’856 patent, Abstract; ’856 patent at col. 25 ll. 14–49.
In November 2021, Palo Alto Networks, Inc. (“Palo Alto
Networks”) petitioned for inter partes review of claims 1,
24, and 25 of the ’856 patent. Recusal Decision at 2;
J.A. 353–410. With a panel consisting of APJs McNamara,
Moore, and Amundson, the Board instituted inter partes
review. J.A. 118–209; see Recusal Decision at 3–4. In
June 2022, Centripetal requested rehearing of the institu-
tion decision by either the Board panel or the Precedential
Opinion Panel. Recusal Decision at 3; J.A. 4509–19; see
J.A. 347. The same month, Cisco Systems, Inc. (“Cisco”)
and Keysight Technologies, Inc. (“Keysight”) filed substan-
tively identical petitions to that of Palo Alto Networks and
sought joinder. J.A. 7091–7167; J.A. 7215–28;
J.A. 8809–71; J.A. 9218–34; J.A. 348–49; see Recusal
1 Because this decision is not reported, citations in
this opinion are to the version of the decision included in
the Joint Appendix. See J.A. 61–83. For example, Recusal
Decision at 1 is found at J.A. 61.
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Decision at 4; Appellant’s Br. 18; Appellees’ Br. 14. On De-
cember 6, 2022, the Precedential Opinion Panel declined to
take up Centripetal’s rehearing request. Recusal Decision
at 3; J.A. 6272–73.
By September 29, 2022, Centripetal became aware of
APJ McNamara’s ownership of between $1,001 and
$15,000 in Cisco stock. Recusal Decision at 21 (citing
J.A. 6367); see J.A. 6372–73 (2014 public financial disclo-
sure report disclosing APJ McNamara’s ownership of Cisco
shares). On December 30, 2022, Centripetal filed a motion
seeking recusal of the entire panel and vacatur of the insti-
tution decision, contending that APJ McNamara’s stock
ownership “cast a shadow over the entire panel of judges in
this IPR.”2 J.A. 6360; see J.A. 6344–64; Recusal Decision
at 3. On January 4, 2023, the Board panel (still including
APJ McNamara) denied the rehearing request and granted
the institution and joinder requests related to Cisco’s and
Keysight’s IPR petitions. Recusal Decision at 4;
J.A. 210–342; J.A. 6627–40. Nonetheless, APJ McNamara
withdrew from the Board panel the next day. Recusal De-
cision at 4; J.A. 6650–52; see J.A. 347. He explained that
the governing regulations did not require his recusal be-
cause he had no interest exceeding $15,000 but contended
that his withdrawal would “reduce the number of issues
and simplify the briefing.” Recusal Decision at 4 (quoting
J.A. 6652). APJ Amundson also withdrew, similarly indi-
cating that Centripetal’s motion “lack[ed] merit” but that
his withdrawal would simplify the issues. J.A. 6702; see
Recusal Decision at 4. APJ Moore did not withdraw.
2 Centripetal also argued that APJ McNamara’s re-
ceipt of retirement payments from his prior law firm raised
conflicts concerns. J.A. 6352; see Recusal Decision
at 11–13. Centripetal has abandoned that argument on ap-
peal. See generally Appellant’s Br.
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After two new APJs were assigned to the case, the new
panel denied Centripetal’s motion for vacatur. Recusal De-
cision at 2. The decision noted that APJ McNamara’s par-
ticipation occurred while “Cisco was not a party to th[e]
proceeding,” and that “the value of the holdings falls well
below the $25,000 threshold” that executive branch regu-
lations imposed for matters impacting non-parties. Id.
at 11. The Board held that Centripetal’s “argument that
APJ McNamara’s participation in this case ran afoul of ex-
ecutive-branch ethics regulations [was] frivolous,” and
threatened sanctions if “further baseless arguments” were
raised. Id. at 13–14 (internal quotation marks and citation
omitted). The Board further held that Centripetal’s due
process rights were not violated, noting the expertise of the
Office of Government Ethics (“OGE”) and its factual deter-
mination that interests of below $15,000 for parties and
$25,000 for affected non-parties were “too remote or too in-
consequential to affect the integrity of the services of em-
ployees.” Recusal Decision at 16 (quoting
5 C.F.R. § 2635.402(d)(1)); see 5 C.F.R. § 2640.202(a)–(b).
The Board independently denied the recusal motion as un-
timely, highlighting that Centripetal “sat on” the conflict
for more than three months and that the facts suggested
that Centripetal “was waiting to see if the original panel
would issue a favorable decision on the [rehearing] motion”
or if it would “receive a favorable decision from the Su-
preme Court.” Recusal Decision at 21–22. Centripetal sub-
sequently petitioned this court for a writ of mandamus
directing the Board to vacate the institution decisions. In
re Centripetal Networks, LLC, No. 2023-127, 2023 WL
3477282, at *1 (Fed. Cir. May 16, 2023). We denied the
petition. Id. at *2.
On May 23, 2023, the Board issued a final written de-
cision holding claims 1, 24, and 25 unpatentable as obvious.
Merits Decision at *2, *25. Centripetal timely appealed.
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II. STANDARD OF REVIEW
A judge’s failure to recuse is reviewed for abuse of dis-
cretion. Shell Oil Co. v. United States, 672 F.3d 1283, 1288
(Fed. Cir. 2012). Whether a party forfeited an argument
by failing to timely raise it is also reviewed for abuse of
discretion. Odyssey Logistics & Tech. Corp. v. Stewart,
130 F.4th 973, 979–80 (Fed. Cir. 2025). The court must set
aside the Board’s decision if it is “arbitrary, capricious, an
abuse of discretion, or otherwise not in accordance with
law.” Veritas Techs. LLC v. Veeam Software Corp.,
835 F.3d 1406, 1413 (Fed. Cir. 2016) (quoting 5 U.S.C.
§ 706(2)(A)). “We review the Board’s legal conclusions de
novo and its fact findings for substantial evidence.” Game
& Tech. Co. v. Wargaming Grp. Ltd., 942 F.3d 1343, 1348
(Fed. Cir. 2019).
III. D ISCUSSION
Centripetal contends that the Board’s final written de-
cision must be vacated because APJ McNamara recused be-
latedly after the IPRs were instituted. Appellant’s Br. 28–
39. Centripetal also raises a number of purported deficien-
cies with the Board’s decision on the merits. Appellant’s
Br. 40–59. We begin by addressing our jurisdiction and
then the recusal issue before turning to the merits of the
appeal.
A.
We start by addressing the issue of our jurisdiction
over this case. We “may not rule on the merits of a case
without first determining that [we] ha[ve] jurisdiction.” Si-
nochem Int’l Co. v. Malaysia Int’l Shipping Corp., 549 U.S.
422, 430–31 (2007). We normally have jurisdiction over ap-
peals from the Board under 28 U.S.C. § 1295(a)(4)(A).
However, the America Invents Act “renders ‘final and non-
appealable’ the ‘determination by the Director whether to
institute an inter partes review under this section.’” Thryv,
Inc. v. Click-To-Call Techs., LP, 590 U.S. 45, 52 (2020)
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 7
(quoting 35 U.S.C. § 314(d)). Section 314(d) “bars review
at least of matters ‘closely tied to the application and inter-
pretation of statutes related to’ the institution decision.”
Id. at 53 (quoting Cuozzo Speed Techs., LLC v. Lee,
579 U.S. 261, 275 (2016)). The Supreme Court has re-
served judgment on “the precise effect of § 314(d) on ap-
peals that implicate constitutional questions” or “that
depend on other less closely related statutes.” Cuozzo,
579 U.S. at 275; see id. (declining to “categorically preclude
review of a final decision where . . . there is a due process
problem with the entire proceeding” or where there are
“shenanigans”). In the absence of Supreme Court guid-
ance, we have held that § 314(d) does not bar review of sev-
eral such statutes, such as estoppel and joinder provisions.
See Credit Acceptance Corp. v. Westlake Servs., 859 F.3d
1044, 1050 (Fed. Cir. 2017); Facebook, Inc. v. Windy City
Innovations, LLC, 973 F.3d 1321, 1332 (Fed. Cir. 2020).
Centripetal’s recusal challenge does not turn on the
“interpretation of statutes related to the Patent Office’s de-
cision to initiate inter partes review.” Cuozzo, 579 U.S.
at 275. Instead, it turns on the interpretation of ethics
rules that are “not limited to the institution stage,” Credit
Acceptance, 859 F.3d at 1050, and a constitutional chal-
lenge relevant to the entire proceeding. See Appellant’s
Br. 28–39. Thus, it fits neatly into the categories of cases
over which we have exercised jurisdiction. Indeed, this
case is not the first time we have encountered, and exer-
cised jurisdiction over, a conflict-of-interest challenge to
Board institution procedures. See Mobility Workx, LLC
v. Unified Patents, LLC, 15 F.4th 1146, 1150–56 (Fed. Cir.
2021). Thus, we hold that we have jurisdiction to hear this
appeal.
B.
We turn now to the recusal challenge. As an initial
matter, the Board did not abuse its discretion in holding
Centripetal’s recusal motion to be untimely. See Recusal
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Decision at 21–22. In the analogous context of Article III
judge recusal motions, we have noted that despite “[t]here
being no statute or rule limiting the time within such mo-
tion may be filed,” denying a recusal motion is appropriate
“when the circumstances . . . are such that a grant of the
motion would produce a result inequitable, unjust, and un-
fair.” Polaroid Corp. v. Eastman Kodak Co., 867 F.2d 1415,
1418–19 (Fed. Cir. 1989).3 We have explained that “[t]he
refusal of courts to ‘start over’ has rested not on the mere
passage of time, but on the events that had occurred and
the balancing of equity/fairness considerations in deciding
whether to expunge those events from history’s pages.” Id.
at 1419. Accordingly, we have noted that even a three-
month delay can render a recusal motion untimely when a
party sits on the relevant information while prosecuting
other motions. Id. (citing United States v. Kelley, 712 F.2d
884, 887–88 (1st Cir. 1983)).
The Board did not abuse its discretion in holding that
the circumstances here would make the grant of a recusal
motion inequitable. The Board highlighted that Centripe-
tal was aware of APJ McNamara’s public disclosures more
than three months before the filing of its recusal motion
3 Polaroid applied First Circuit law, but made clear
that its determination did not rest on a unique character-
istic of First Circuit law and noted that this timeliness re-
quirement exists in the vast majority of circuits. 867 F.2d
at 1419; see also Kolon Indus. Inc. v. E.I. DuPont de
Nemours & Co., 748 F.3d 160, 169–170 (4th Cir. 2014) (col-
lecting cases and noting that the overwhelming majority
view of circuits is that there is an inherent timeliness re-
quirement in 28 U.S.C. § 455). Moreover, we have recog-
nized on several occasions that the “principles animating”
district court procedural rules “can be a useful guide” for
examining the Board’s procedures. Odyssey, 130 F.4th
at 978; see, e.g., Facebook, 973 F.3d at 1334.
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and emphasized that Centripetal waited until after it had
received an unfavorable decision on both its motion for re-
hearing and its petition for writ of certiorari to raise its
recusal concerns. Recusal Decision at 22. While Centripe-
tal contends that its delay was justified because it “spent
this time researching the conflict and requesting additional
financial disclosures from the Department of Commerce,”
Appellant’s Br. 37, it concedes that the disclosures it re-
ceived in September 2022 “made clear that a conflicted APJ
was on the instituting panel.” Appellant’s Reply Br. 10.
Having “know[n] of a ground for disqualification” since
then, Centripetal was not “permitted to wait and decide
[whether it] like[d] subsequent treatment that [it] re-
ceive[d]” on its pending motions. Polaroid, 867 F.2d at
1419 (citation omitted).
Moreover, the unique setup of the Board heightens the
need to raise conflicts at the first opportunity. The Board
faces a compressed timeline: It must issue its institution
decision within three months of the patent owner’s prelim-
inary response. 35 U.S.C. § 314(b)(1). For Keysight’s peti-
tion that deadline was January 6, 2023, a mere four
workdays after the recusal motion was filed. See J.A. 8657;
J.A. 9524. Thus, the Board did not abuse its discretion in
holding that the circumstances of this case would make the
grant of a recusal motion inequitable and untimely.
C.
While the Board’s untimeliness finding serves as an in-
dependent ground for affirming the Board’s rejection of
Centripetal’s recusal motion, Centripetal’s recusal argu-
ment also fails on the merits. Government officers and em-
ployees are ordinarily prohibited from participating in
matters in which they have a financial interest. 18 U.S.C.
§ 208(a). However, the Office of Government Ethics is em-
powered to promulgate regulations exempting from ethics
rules financial interests that are “too remote or too incon-
sequential to affect the integrity of the services” of
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executive branch employees. 18 U.S.C. § 208(b)(2). OGE
has done so, promulgating 5 C.F.R. § 2635.402(d),4 which
states, in relevant part, that executive branch employees
“may be permitted to participate in a particular matter
where the otherwise disqualifying financial interest is the
subject of a regulatory exemption,” and identifying “part
2640, subpart B of this chapter” as the source of such reg-
ulatory exemptions that are “based on [OGE’s] determina-
tion that particular interests are too remote or too
inconsequential.” 5 C.F.R. § 2635.402(d). In turn,
5 C.F.R. § 2640.202(a) affirmatively states that “[a]n em-
ployee may participate in any particular matter involving
specific parties in which the disqualifying financial interest
arises from the ownership by the employee” of securities
issued by entities affected by the matter if the securities
are publicly traded and the “aggregate market value of the
holdings of the employee . . . in the securities of all entities
does not exceed $15,000.” See also 5 C.F.R. § 2640.202(b)
(setting a $25,000 de minimis exception for matters affect-
ing nonparties). There is no dispute that, at all times, APJ
McNamara’s stock holding was under $15,000. See
J.A. 6373; J.A. 6651 n.1 (noting that the “value of the stock
is less than 0.04% of the value of the assets reported on the
financial disclosure”).
Centripetal argues that 5 C.F.R. § 2640.202 is a mere
criminal safe harbor and that 5 C.F.R. §§ 2635.101 and
2638.102 set out a more stringent standard executive
4 Several of the regulations discussed were revised
after the Board issued its final written decision. See Legal
Expense Fund Regulation, 88 Fed. Reg. 33799 (May 25,
2023); Modernization Updates to Standards of Ethical Con-
duct for Employees of the Executive Branch, 89 Fed. Reg.
43686 (May 17, 2024). Unless otherwise specified, we refer
to and cite the versions of these regulations that were in
effect while this case was ongoing before the Board.
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branch employees must follow.5 Appellant’s Br. 29–30.
Section 2635.101 sets out “general principles” that apply
“[w]here a situation is not covered by the standards set
forth in this part.” 5 C.F.R. § 2635.101(b); see, e.g., id.
§ 2635.101(b)(2) (“Employees shall not hold financial inter-
ests that conflict with the conscientious performance of
duty.”). Thus, rather than raising the standard set forth in
5 C.F.R. §§ 2635.402 and 2640.202, 5 C.F.R. § 2635.101
merely acts as a catch-all and a general principle that
“form[s] the basis” for the more specific standards in those
provisions. Similarly, 5 C.F.R. § 2638.102 sets out a “fun-
damental principle that public service is a public trust,”
and states that “[a]s provided in the Standards of Conduct
at part 2635 of this chapter, employees must . . . avoid los-
ing impartiality or appearing to lose impartiality in carry-
ing out official duties.” Thus, it is clear from the text of the
regulations that 5 C.F.R. § 2640.202 is not a mere criminal
safe harbor.
Centripetal also argues that APJ McNamara violated
5 C.F.R. §§ 2635.501 and 2635.502 by failing to recuse. Ap-
pellant’s Br. 29–31. Section 2635.501 states that “[u]nder
§ 2635.502, unless he receives prior authorization, an em-
ployee should not participate in a particular matter involv-
ing specific parties which he knows is likely to affect the
financial interests of a member of his household” if “a rea-
sonable person with knowledge of the relevant facts would
question his impartiality in the matter.”
5 Because it does not affect our ultimate disposition
regarding the recusal issue, we assume without deciding
that these regulations are enforceable. But see
5 C.F.R. § 2635.106(c) (“A violation of this part or of sup-
plemental agency regulations, as such, does not create any
right or benefit, substantive or procedural, enforceable at
law by any person against the United States, its agencies,
its officers or employees, or any other person.”).
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5 C.F.R. § 2635.501. In turn, 5 C.F.R. § 2635.502 states
that where “a reasonable person with knowledge of the rel-
evant facts [would] question his impartiality in the matter,
the employee should not participate in the matter unless
he has informed the agency designee of the appearance
problem and received authorization from the agency de-
signee.”
Centripetal’s argument with respect to
5 C.F.R. §§ 2635.501 and 2635.502 fails because these reg-
ulations do not apply to an employee’s own financial hold-
ings. Section 2635.501 provides an overview of the subpart
and section 2635.502 concerns “[p]ersonal and business re-
lationships,” 5 C.F.R. § 2635.502, and are directed to con-
flicts relating to financial interests of “member[s] of his
household” or “person[s] with whom he has a covered rela-
tionship,” not an employee’s own financial interests.
5 C.F.R. § 2635.502(a); see, e.g., 5 C.F.R. § 2635.502(b), Ex-
amples 1–5 (discussing different hypothetical scenarios in-
volving personal or business relationships). By contrast,
5 C.F.R. § 2640.202 governs the specific situation at issue
here—ownership of publicly owned securities by the em-
ployee. Indeed, the note accompanying 5 C.F.R. § 2635.501
states that “when an employee’s official duties impact upon
the employee’s own financial interests . . . the standards
set forth in subparts D or F of this part apply and only a
statutory waiver or exemption, as described in
§§ 2635.402(d) and 2635.605(a), will enable the employee
to participate in that matter.” 5 C.F.R. § 2635.501 Note.
The note also expressly indicates that the “authorization
procedures in § 2635.502(d) may not be used” when consid-
ering an employee’s own financial interests, and that in-
stead “the application of one of the exemptions set forth in
subpart B of part 2640 of this chapter,” which would in-
clude the de minimis exception in 5 C.F.R. § 2640.202,
“constitutes a determination that the interest of the Gov-
ernment in the employee’s participation outweighs” the
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appearance of impropriety concern.6 Id. Thus, on their
face, 5 C.F.R. §§ 2635.501 and 2635.502 do not cover an em-
ployee’s own financial holdings. Instead, §§ 2635.402 and
2640.202 address this situation. Because APJ McNamara
at all times complied with those regulations, he did not vi-
olate the executive branch ethics rules.
D.
Independent of its argument regarding the executive
branch ethics rules, Centripetal contends that its funda-
mental due process rights were violated and that it was
treated unfairly. Appellant’s Br. 25, 28–35. Centripetal
argues that (1) the Board’s language was improperly
harsh, id. at 28–29, 31–32; (2) APJs should be held to the
same standards as Article III judges, because of the height-
ened need for impartiality, id. at 32–34; and (3) because
the Patent and Trademark Office (“PTO”) has enacted
guidance that future similar conflicts should give rise to
recusal, to be fair such guidance should be retroactive, id.
at 34–35. We disagree on all counts.
6 When 5 C.F.R. § 2635.501 was amended, this lan-
guage was expressly moved from the note to
§ 2635.501(b)(3). 5 C.F.R. § 2635.501(b)(3) (2025); see
Modernization Updates to Standards of Ethical Conduct
for Employees of the Executive Branch, 88 Fed. Reg. 10774,
10776 (Feb. 21, 2023) (noting that Section 2635.501 was
“restructure[d] . . . to organize the current text and the text
of the current Note into new paragraphs” and that “[n]o
substantive change is intended”). The new version of the
regulation also states that “[a]n applicable waiver or ex-
emption under part 2640 of this chapter also authorizes an
employee’s participation in particular matters that would
otherwise be restricted by § 2635.502.” 5 C.F.R.
§ 2635.501(b)(3) (2025).
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The Board did not violate Centripetal’s due process
rights by criticizing the merits of its recusal arguments.
Centripetal focuses on the Board’s description of Centripe-
tal’s “argument that APJ McNamara’s participation in this
case ran afoul of ‘executive-branch ethics regulations’” as
“frivolous” and the Board’s characterization of Centripe-
tal’s delay as “highly inappropriate.” Recusal Decision
at 13, 22; see Appellant’s Br. 28. Having reviewed the
Board’s decision, we disagree; the Board’s statements
merely reflect its candid, independent judgment of the ar-
guments raised and the circumstances of the case. We cer-
tainly do not conclude that the Board’s statements show
this case to be one of the rare cases where “opinions formed
by the judge[s] on the basis of facts introduced or events
occurring in the course of the current proceedings . . . dis-
play a deep-seated favoritism or antagonism that would
make fair judgment impossible.” Liteky v. United States,
510 U.S. 540, 555 (1994). Thus, the Board did not violate
Centripetal’s due process rights by criticizing its argu-
ments.
The Board did not violate Centripetal’s due process
rights by declining to apply the ethics rules for Article III
judges to APJs. See Recusal Decision at 20–21. While pro-
ceedings before APJs may have many of the trappings of
Article III proceedings, the two are subject to separate stat-
utory and regulatory schemes. Compare 28 U.S.C. § 455
(applying only to Article III judges and magistrate judges),
with 5 C.F.R. § 2640.102(b) (defining “employee” as “an of-
ficer or employee of the executive branch of the United
States, or of any independent agency of the United States”).
Centripetal provides no support for the proposition that the
statutory ethics rules for Article III judges are coextensive
with constitutional due process. Compare Gibson v. Ber-
ryhill, 411 U.S. 564, 579 (1973) (“[T]hose with substantial
pecuniary interest in legal proceedings should not adjudi-
cate these disputes.” (emphasis added)), with 28 U.S.C.
§ 455(d) (defining a disqualifying “financial interest” as a
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 15
“legal or equitable interest, however small”), and
5 C.F.R. § 2635.402(d)(1) (indicating that the de minimis
exception implemented by OGE is “based on its determina-
tion that particular interests are too remote or too inconse-
quential to affect the integrity of the services of
employees”). Centripetal does not identify either a statu-
tory or constitutional provision that would require the ex-
act same ethics rules for Article III judges and APJs with
respect to disqualifying financial interests.7
Centripetal argues that it is unfair that the PTO has
now directed Board management “to avoid empaneling
cases to judges who hold stock or bonds . . . in any of the
disclosed parties or real parties in interest, regardless of
the dollar value.” Appellant’s Br. 34 (citing Memorandum
from Katherine K. Vidal, Under Sec’y of Commerce for In-
tellectual Prop. & Dir. of the USPTO, to the Members of the
Patent Trial & Appeal Bd. & the Trademark Trial & Ap-
peal Bd. at 2 (Sep. 22, 2023) (“Memorandum”),
https://perma.cc/4FJQ-B69C). However, that guidance is
(1) explicitly not retroactive, Memorandum at 4; (2) “sepa-
rate from existing ethics standards,” id. at 3; and (3) pur-
suant to the Director’s authority “to set policy and to
designate panels of the [Board].” Id. at 2. We are aware of
no due process principle that prohibits an agency from im-
posing stricter procedural rules that only apply prospec-
tively. Cf. Gen. Motors Corp. v. Romein, 503 U.S. 181, 191
(1992) (“Retroactive legislation presents problems of un-
fairness that are more serious than those posed by prospec-
tive legislation, because it can deprive citizens of legitimate
expectations and upset settled transactions.”).
7 In Centripetal Networks, Inc. v. Cisco Systems, Inc.,
38 F.4th 1025, 1033–34 (Fed. Cir. 2022), we held that a dis-
trict court judge was disqualified from further proceedings
in the case under 28 U.S.C. § 455 because of stock owner-
ship in a party. Section 455 does not apply to APJs.
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Accordingly, Centripetal has not shown that its due process
rights were violated by the PTO only prospectively impos-
ing its new procedure.
E.
Even if Centripetal’s recusal motion were timely and
meritorious, it would still not justify vacatur. “[M]anda-
tory recusal does not require mandatory vacatur.” Shell
Oil Co. v. United States, 672 F.3d 1283, 1293 (Fed. Cir.
2012). Instead, courts apply a three-factor test to deter-
mine whether any error was harmless: (1) “the risk of in-
justice to the parties in the particular case;” (2) “the risk
that the denial of relief will produce injustice in other
cases;” and (3) “the risk of undermining the public’s confi-
dence in the judicial process.” Liljeberg v. Health Servs.
Acquisition Corp., 486 U.S. 847, 864 (1988); see also Cen-
tripetal Networks, Inc. v. Cisco Sys., Inc., 38 F.4th 1025,
1034 (Fed. Cir. 2022) (“Cisco”). Here, each of those factors
weighs against vacatur.
The risk of injustice to the parties in this case is low.
Centripetal’s delay in raising recusal concerns, see Sec-
tion III.B, supra, also decreases the risk of injustice to
them. See Cisco, 38 F.4th at 1034–35. Moreover, the insti-
tution decision at issue was issued before Cisco became in-
volved in the litigation. J.A. 118–209. Centripetal received
a final written decision on the merits by three disinterested
judges, including two judges who were never on the panel
with APJ McNamara. See generally Merits Decision. To
the extent that Centripetal argues that APJ McNamara
should have recused before voting on the joinder motion,
Centripetal has not demonstrated any prejudice from Cisco
joining as an “understudy” to Palo Alto Networks and
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 17
making no new arguments.8 See J.A. 270–71 (conditioning
Cisco’s joinder on it not raising new evidence, arguments,
or unpatentability grounds). Moreover, because we ulti-
mately vacate the final written decision on the merits, the
Board will have another opportunity to consider this case.
Accordingly, Centripetal has not demonstrated any preju-
dice requiring vacatur.
The risk of injustice in other cases is similarly low. As
noted above, the PTO has changed its assignment method-
ology to prevent cases like this one from reoccurring. See
Memorandum. While there remains the general interest
in “encouraging a judge or litigant to more carefully exam-
ine possible grounds for disqualification and to promptly
disclose them when discovered,” Liljeberg, 486 U.S. at 868,
the PTO’s change in rules decreases the risk of injustice in
other cases.
The public confidence factor also does not support va-
catur. APJ McNamara properly disclosed his financial in-
formation and then recused following the discovery of a
potential conflict. See J.A. 6372–73; J.A. 6650–52. Cen-
tripetal’s theory of harm is simply too attenuated; it re-
quires that APJ McNamara have been biased while
deciding institution of the Palo Alto Networks IPR based
on a relatively small stock holding in Cisco, a non-party at
the time; that he then influenced the non-conflicted APJ
Moore; that APJ Moore then overcame the two disinter-
ested APJs who later joined the case; and that this chain of
events ultimately tainted the entire proceeding. Cf. Wil-
liams v. Pennsylvania, 579 U.S. 1, 16 (2016) (“Allowing an
appellate panel to reconsider a case without the participa-
tion of the interested member will permit judges to probe
8 Centripetal concedes that Cisco and Keysight filed
substantively identical petitions and motions for joinder
and raises no challenge as to Keysight’s participation in the
case. See Appellant’s Br. 18.
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 18
lines of analysis or engage in discussions they may have
felt constrained to avoid in their first deliberations.”). Nor
does Centripetal present evidence showing that there is a
common problem of APJs improperly influencing other
APJs by using overly harsh language in their prudent
recusal decisions, or that the public is deeply concerned
about APJs having sat on a panel with a conflicted judge
before that judge recused.9 Cf. Cisco, 38 F.4th at 1038–39
(noting the “increasingly common problem” of, and the pub-
lic outcry over, judges presiding over cases while they or
9 Contrary to Centripetal’s assertion that “an en-
tirely new panel of APJs is . . . necessary,” Appellant’s
Br. 36, a recused judge’s conflict does not infect the remain-
ing panel members. We note that in the analogous Article
III setting, when a panel member recuses himself midway
through a case, it is standard practice in many courts to
replace only the recused judge as the Board did here. See,
e.g., Fed. Cir. R. 47.11 (“If a judge of a panel that has heard
oral argument or taken under submission any appeal, pe-
tition, or motion is unable to continue with consideration of
the matter because of . . . recusal, the remaining judges
will determine the matter if they are in agreement and no
remaining judge requests the designation of another
judge.”); D.C. Cir. Handbook of Practice and Internal Pro-
cedures X.D (When “a judge discovers the basis for recusal
only after the case has been scheduled before a particular
panel . . . a replacement judge is assigned to hear the case
on that date.”); 5th Cir. Rules and Internal Operating Pro-
cedures at 47 (“If a judge recuses, . . . he or she immediately
notifies the other members of the panel, and arrangements
are made for a substitute judge.”); 1st Cir. Internal Operat-
ing Procedure VII.D (A case may be assigned to a panel in-
cluding a particular judge “where a case has been assigned
to a panel, but the subsequent recusal of a judge . . . makes
it appropriate to transfer the case . . . to find a replacement
judge.”).
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 19
their family members hold stock in parties). Thus, none of
the relevant factors indicate that vacatur is justified based
on recusal concerns.
F.
Turning to the merits of the appeal, we conclude that
the Board erred by not properly considering evidence of
copying. Before the Board, Centripetal indicated that “the
district court” in Cisco “found that the ’856 Patent had been
copied by Cisco.” J.A. 4680. Centripetal also introduced
into the record some of the evidence from the Cisco litiga-
tion. That evidence includes (1) testimony that Centripetal
executives met with Cisco in 2016 and presented infor-
mation about the ’856 patent, J.A. 4937–44 at 1215:13–
1222:25; (2) testimony regarding internal Cisco communi-
cations showing that Cisco intended to study Centripetal’s
patents, J.A. 4849–50 at 1128:8–1129:5; and (3) expert tes-
timony contending that Cisco plausibly copied Centripe-
tal’s technology, J.A. 3523–24 at 3223:7–3224:16.
The Board did not discuss any of this evidence in its
final written decision. Instead, it noted that the district
court’s decision had been vacated and stated that it was
“not in a position to evaluate the entirety of the litigation
record, weigh witness testimony, and make a factual find-
ing about copying.” Merits Decision at *24. The Board did
not have to go searching throughout the entire litigation
record to find the evidence of copying, but it had an obliga-
tion to consider the specific evidence that was put before it.
See Stratoflex, Inc. v. Aeroquip Corp., 713 F.2d 1530, 1539
(Fed. Cir. 1983) (“Enroute to a conclusion on obviousness,
a court must not stop until all pieces of evidence on that
issue have been fully considered and each has been given
its appropriate weight. . . . It is error to exclude that evi-
dence [on secondary considerations] from consideration.”);
Knoll Pharm. Co. v. Teva Pharms. USA, Inc., 367 F.3d
1381, 1385 (Fed. Cir. 2004) (“The so-called ‘objective’ crite-
ria must always be considered and given whatever weight
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CENTRIPETAL NETWORKS, LLC v. PALO ALTO NETWORKS, INC. 20
is warranted by the evidence presented.” (citation omit-
ted)). Because the Board failed to properly consider evi-
dence of copying, we vacate and remand for the Board to
conduct the proper analysis in the first instance.
IV. CONCLUSION
We vacate the Board’s final written decision and re-
mand to the Board for further proceedings consistent with
this opinion. At oral argument, Appellees expressly stated
that they did not object to a new panel of APJs hearing this
case if remanded. See Oral Arg. 48:45–49:10.10 Given this
concession, on remand, the Director should consider
whether to assign this case to new APJs.
VACATED AND REMANDED
COSTS
No costs.
10 Available at https://oralarguments.cafc.uscourts.
gov/default.aspx?fl=23-2027_02062025.mp3.
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