Keranos, LLC v. Silicon Storage Technology, Inc., Freescale Semiconductor, Inc., Microchip…

United States Court of Appeals
for the Federal Circuit
______________________
KERANOS, LLC,
Plaintiff-Appellant
UNITED MODULE CORPORATION, PETER
COURTURE, J. NICHOLAS GROSS,
Third Party Defendants
v.
SILICON STORAGE TECHNOLOGY, INC.,
FREESCALE SEMICONDUCTOR, INC.,
MICROCHIP TECHNOLOGY, INC., SAMSUNG
SEMICONDUCTOR, INC., SAMSUNG
ELECTRONICS CO. LTD., TAIWAN
SEMICONDUCTOR MANUFACTURING CO., LTD.,
TSMC NORTH AMERICA,
Defendants-Appellees
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
KERANOS, LLC,
Plaintiff-Appellant
v.
ANALOG DEVICES, INC., INTERNATIONAL
BUSINESS MACHINES CORPORATION, INTEL
CORPORATION, NATIONAL SEMICONDUCTOR
CORPORATION, NXP SEMICONDUCTORS USA,
INC., TEXAS INSTRUMENTS, INC.,
Defendants-Appellees
______________________

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 2
2014-1360, 2014-1500
______________________
Appeals from the United States District Court for the
Eastern District of Texas in No. 2:13-cv-00017-MHS-RSP,
2:13-cv-00018-MHS-RSP, Judge Michael H. Schneider.
______________________
Decided: August 13, 2015
______________________
MICHELLE G. BREIT , Agility IP Law, LLP, Menlo Park,
CA, argued for plaintiff-appellant. Also represented by
J OHN J. EDMONDS , Collins, Edmonds, Pogorzelski,
Schlather & Tower PLLC, Houston, TX.
D ARYL J OSEFFER , King & Spalding LLP, Washington,
DC, argued for defendants-appellees. Also represented by
ADAM C ONRAD, Charlotte, NC; J EFFREY D. MILLS , Austin,
TX; BRUCE W. SLAYDEN II, BRIAN C. BANNER, Slayden
Grubert Beard PLLC, Austin, TX.
______________________
Before CHEN, BRYSON , and HUGHES , Circuit Judges.
CHEN, Circuit Judge.
This appeal involves whether appellant, an exclusive
licensee, has standing to sue for patent infringement and
whether the district court properly applied the local
patent rules to deny appellant’s motions to amend its
infringement contentions. Appellant Keranos, LLC
appeals from the final judgments of the United States
District Court for the Eastern District of Texas entered
after the district court denied Keranos’s motions for leave
to amend infringement contentions. Appellees Silicon
Storage Technology, Inc. (SST), Freescale Semiconductor,
Inc., Microchip Technology, Inc. (Microchip), Samsung

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 3
Semiconductor, Inc. and Samsung Electronics Co., Ltd.
(collectively, Samsung), Taiwan Semiconductor Manufac-
turing Co., Ltd. and TSMC North America (collectively,
TSMC), Analog Devices, Inc., International Business
Machines Corporation, Intel Corporation, National Semi-
conductor Corporation, NXP Semiconductors USA, Inc.,
and Texas Instruments, Inc. assert that Keranos does not
have standing to sue for infringement of U.S. Patent Nos.
4,795,719 (the ’719 patent), 4,868,629 (the ’629 patent),
and 5,042,009 (the ’009 patent).
We agree with the district court that Keranos has
standing to sue for infringement of the asserted patents.
We cannot determine based on the record, however,
whether the district court abused its discretion in denying
Keranos’s motions for leave to amend infringement con-
tentions based on the local patent rules. The court there-
fore vacates and remands for further consideration by the
district court regarding Keranos’s motions for leave to
amend.
BACKGROUND
On June 23, 2010, Keranos sued forty-nine parties,
including all appellees listed above except for SST, in the
Eastern District of Texas for infringing three of its pa-
tents that generally relate to split-gate flash memory.
Keranos accused appellees of using a specific type of flash
memory technology developed by SST, called “Super-
Flash,” that implements a split-gate memory design.
Keranos, which was formed as a Texas corporation on
February 10, 2010, obtained the rights to the asserted
patents from United Module Corporation (UMC) on
February 16, 2010, through an “Exclusive Patent License
and Royalty Agreement.” UMC continued to hold the
legal title to the asserted patents, all of which expired
prior to the filing of the current action; the ’719 and ’629
patents expired in 2006, and the ’009 patent expired in

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 4
2008. Keranos did not join UMC as co-plaintiff in this
action.
In the Northern District of California, SST and cer-
tain defendants from the Texas action then sued Keranos,
UMC, Peter Courture, and J. Nicholas Gross1 in four
separate cases seeking declaratory judgments of nonin-
fringement and invalidity of the same patents. The
California actions were transferred to the Eastern District
of Texas and consolidated into two cases: the original
case filed by Keranos and the consolidated declaratory
judgment case. Following a joint Markman hearing on
December 12, 2012, the district court regrouped the
defendants into two new cases: case number 2:13-cv-
00017 pitting Keranos, UMC, Mr. Courture, and Mr.
Gross against the manufacturers of the accused products,
and case number 2:13-cv-00018, pitting Keranos against
the alleged customers of the accused products who incor-
porated those products into larger products for sale.
In the original Texas action, the defendants moved to
dismiss Keranos’s actions for lack of standing under the
Patent Act, because the patents asserted had expired
before Keranos acquired them and filed suit. The district
court concluded that the license agreement between UMC
1 The California cases named as defendants Peter
Courture, the alleged “sole director, officer, shareholder,
and/or employee of UMC,” and J. Nicholas Gross, the
alleged “president, principal shareholder, and/or sole
employee of Keranos,” based on their alleged tortious
interference. See First Amended Complaint ¶¶ 5, 6, 116–
132, Microchip Tech., Inc. v. United Module Corp., No.
2:11-cv-00332-DF (E.D. Tex. Jan. 27, 2012), ECF No. 108
(Case No. 2:11-cv-00332 was consolidated with Case Nos.
2:11-cv-00331, -333, and -334, which were regrouped as
Case Nos. 2:13-cv-00017 and -18, from which this appeal
was taken.). These claims are not at issue on appeal.

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 5
and Keranos transferred all substantial rights in the
patents, giving Keranos standing to sue for infringement
without joining UMC.
On December 19, 2011, before the cases were re-
grouped, Keranos served its Local Patent Rule 3-1 Disclo-
sure of Asserted Claims and Infringement Contentions
(colloquially, infringement contentions). These original
infringement contentions identified some of defendants’
allegedly infringing products with specificity, by product
name or number, and others more generally, by product
family. After some discovery, on June 20, 2012, Keranos
moved for leave to amend its infringement contentions.
All defendants except Samsung opposed Keranos’s mo-
tion. The cases progressed until August 5, 2013, when the
district court in the case against the manufacturers
denied Keranos’s motion. Keranos unsuccessfully moved
for reconsideration. In its order denying reconsideration,
the district court explained that the local patent rules
required Keranos to identify infringing products by specif-
ic product numbers, rather than by product families, and
that Keranos’s failure to do so led to the denial of its
motion to amend its infringement contentions. The dis-
trict court also found that Keranos had not demonstrated
that it was diligent in “search[ing] for and identify[ing]
infringing products to the extent possible based on public-
ly available information.” J.A. 8.
On January 29, 2014, the magistrate judge held a
hearing where he explained that the only accused prod-
ucts remaining in the case against the manufacturers
were the two products specifically identified by product
number in the original infringement contentions. Kera-
nos agreed to dismiss with prejudice its patent infringe-
ment claims against those products (having determined
that the potential damages recovery for those two prod-
ucts would be de minimis), and stipulated to summary
judgment in favor of the defendants. The district court

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 6
then granted summary judgment for the manufacturers
and entered final judgment against Keranos.
In the case against the customers, the district court
denied Keranos’s motion for leave to amend infringement
contentions and Keranos’s motion to reconsider on similar
grounds. Again, Keranos agreed to dismiss with prejudice
its patent infringement claims against the remaining
products, and the district court granted summary judg-
ment for the customers and entered final judgment
against Keranos.
On appeal, Keranos contends that the district court
abused its discretion in denying Keranos’s motions for
leave to amend infringement contentions. Appellees
disagree, and further contend that Keranos lacked stand-
ing to sue for infringement of the asserted patents.
Because we find Keranos has standing, we have jurisdic-
tion under 28 U.S.C. § 1295(a)(1) to decide whether the
district court abused its discretion in denying Keranos’s
motions for leave to amend infringement contentions.
D ISCUSSION
I. Standing
Appellees contend that Keranos lacks standing to sue
for past infringement of the asserted patents, which
expired before Keranos acquired rights in the patents and
before Keranos filed its complaint for patent infringe-
ment.
A. Legal Framework
“The question of standing to sue is a jurisdictional
one, which we review de novo.” Rite-Hite Corp. v. Kelley
Co., 56 F.3d 1538, 1551 (Fed. Cir. 1995) (en banc) (cita-
tions omitted). If Keranos lacked standing to sue in the
district court, then jurisdiction is not proper on appeal.
Prima Tek II, LLC v. A-Roo Co., 222 F.3d 1372, 1376 (Fed.
Cir. 2000).

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 7
“Standing to sue for patent infringement derives from
the Patent Act, which provides that ‘[a] patentee shall
have remedy by civil action for infringement of his pa-
tent.’” Prima Tek II, 222 F.3d at 1376–77 (quoting 35
U.S.C. § 281). A “patentee” can be the entity to whom the
patent was issued or the successors in title. Id. at 1377
(citing 35 U.S.C. § 100(d)). When the entity that holds
legal title to the patent “makes an assignment of all
substantial rights under the patent,” then that assignee is
“deemed the effective ‘patentee’ under 35 U.S.C. § 281”
with effective title to the patent, and alone has “standing
to maintain an infringement suit in its own name.” Id.
(emphasis added).
“[A]n exclusive license may be tantamount to an as-
signment for purposes of creating standing if it conveys to
the licensee all substantial rights to the patent at issue.”
Aspex Eyewear, Inc. v. Miracle Optics, Inc., 434 F.3d 1336,
1340 (Fed. Cir. 2006) (citing Vaupel Textilmaschinen KG
v. Meccanica Euro Italia SPA, 944 F.2d 870, 875 (Fed.
Cir. 1991)). If an exclusive licensee does not hold all
substantial rights to the patent, however, then it lacks
standing to maintain an infringement suit in its own
name. In such a scenario, the exclusive licensee may have
standing to participate in a patent infringement suit, but
it must join the owner of legal title to satisfy the standing
requirement. Prima Tek II, 222 F.3d at 1377. The patent
owner is a necessary party in a suit brought by an exclu-
sive licensee if “in [the patent owner’s] absence, the court
cannot accord complete relief among existing parties,” or
if the disposition of an action in the patent owner’s ab-
sence may “leave an existing party subject to a substan-
tial risk of incurring double, multiple or otherwise
inconsistent obligations.” Fed. R. Civ. P. 19(a); see Crown
Die & Tool Co. v. Nye Tool & Mach. Works, 261 U.S. 24,
38 (1923).
In this case, UMC entered into an exclusive license
with Keranos. The question for this Court is whether that

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 8
exclusive license assigned to Keranos all substantial
rights to the patents. We look to the provisions of the
exclusive license to determine if all substantial rights
under the patent were assigned such that Keranos has
standing to sue in its own name, or if UMC retained
certain substantial rights such that Keranos should have
joined UMC as a co-plaintiff below. See Prima Tek II, 222
F.3d at 1377–78.
B. All Substantial Rights
After “ascertain[ing] the intention of the parties [to
the license agreement] and examin[ing] the substance of
what was granted,” Vaupel, 944 F.2d at 874, we conclude
that the exclusive license agreement between UMC and
Keranos assigned all substantial rights under the patent
to Keranos, without retaining any substantial rights in
UMC, such that Keranos alone has standing to sue.
First, UMC transferred to Keranos the exclusive past,
present, and future rights to sue and recover for in-
fringement, to make, use, import, and sell products cov-
ered by the patents, and to negotiate and grant
sublicenses.2 The transfer of these rights strongly weighs
in favor of finding Keranos alone has standing. See Aspex,
434 F.3d at 1342 (Transfer of “(1) the exclusive right to
2 Because the patents had expired, when UMC and
Keranos entered into their exclusive license, UMC had no
present or future rights to sue and recover for infringe-
ment, to exclude others from making, using, importing, or
selling products covered by the patents, or to negotiate
and grant sublicenses. See Kimble v. Marvel Entm’t, LLC,
576 U.S. __, 135 S. Ct. 2401, 2407 (2015). But this provi-
sion in the exclusive license further underscores UMC’s
intention to transfer these rights and shows it intended to
transfer to Keranos all substantial rights in the patents-
at-issue.

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 9
make, use, and sell products covered by the patent; (2) the
right to sue for infringement of the patent; and (3) a
virtually unrestricted authority to sublicense its rights
under the agreement . . . strongly favor[s] a finding of an
assignment, not a license.”); Alfred E. Mann Found. for
Scientific Research v. Cochlear Corp., 640 F.3d 1354, 1361
(Fed. Cir. 2010) (“Frequently, though, the nature and
scope of the exclusive licensee’s purported right to bring
suit, together with the nature and scope of any right to
sue purportedly retained by the licensor, is the most
important consideration.”).
Importantly, UMC did not retain the right to sue ac-
cused infringers, which “is the most important factor in
determining whether an exclusive license transfers suffi-
cient rights to render the licensee the owner of the pa-
tent.” Mann, 640 F.3d at 1361. Instead, the agreement
expressly prohibits UMC from instituting or participating
in any law suit related to the patent, or from negotiating
or granting further licenses to the patents, absent written
authorization from Keranos.
Second, in a confidential provision, UMC transferred
to Keranos an exclusive right that gave Keranos a propri-
etary interest in the patents. Cf. Ortho Pharm. Corp. v.
Genetics Inst., Inc., 52 F.3d 1026, 1034 (Fed. Cir. 1995)
(“A patentee may not give a right to sue to a party who
has no proprietary interest in the patent.” (citations
omitted)); Propat Int’l Corp. v. RPost, Inc., 473 F.3d 1187,
1191 (Fed. Cir. 2007) (“The responsibility to maintain a
patent is one of the obligations that has been recognized
by this court as an indication that the party with that
obligation has retained an ownership interest in the
patent.”) (citation omitted).
Finally, the agreement as a whole indicates that UMC
intended to transfer all substantial rights to Keranos. See
Vaupel, 944 F.2d at 874. The agreement includes a catch-
all grant of “any and all other substantial rights . . .

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 10
necessary and sufficient under any applicable law or
precedent to confer standing and permit [Keranos] to
initiate any actions on its own.” The agreement, in a
confidential provision, also placed a certain burden on
UMC to ensure Keranos did not lack standing.
In sum, UMC transferred to Keranos all substantial
rights remaining in the patents and retained no substan-
tial rights for itself. Appellees concede that UMC pos-
sessed no other substantial rights to transfer to Keranos.
Oral Arg. 26:43–27:55, available at http://www.
cafc.uscourts.gov/oral-argument-recordings/2014-1360/all.
C. Mars, Inc. v. Coin Acceptors, Inc.
On appeal, appellees rely on our decision in Mars, Inc.
v. Coin Acceptors, Inc., 527 F.3d 1359 (Fed. Cir. 2008), to
contend that, because UMC did not transfer to Keranos
legal title to the expired patents, Keranos does not have
standing to sue in its own name. Appellees argue that
standing for expired and unexpired patents should be
analyzed differently, because substantial rights no longer
exist once a patent expires. Mars, however, suggests the
opposite conclusion—that the same legal analysis applies
to both expired and unexpired patents to determine
whether an entity has standing to sue for patent in-
fringement. As discussed below, this analysis does not
require the holder of all substantial rights in the patent to
also hold legal title in the patent to have standing when
asserting either expired or unexpired patents.
In Mars, we held that an agreement that transferred
only “any rights in or to past infringement” in a then-
expired patent did not convey standing on the transferee.
527 F.3d at 1363–64, 1371–72. The transferee had ar-
gued that the transfer was “effectively the same as a
transfer of title” because “the right to sue for past in-
fringement is the ‘only remaining right[]’ in an expired
patent.” Id. at 1372. This Court disagreed:

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 11
Title to a patent—even an expired patent—
includes more than merely the right to recover
damages for past infringement. Moreover, the
transfer of the right to sue for past infringement
divorced from title creates a risk of unnecessary
third-party litigation, whether or not the patent
has expired.
Id. (citing Crown Die & Tool, 261 U.S. at 39).
Mars does not, contrary to appellees’ contention, stand
for the proposition that only the person who holds legal
title to an expired patent has standing to sue for past
infringement. Mars’s discussion of “[t]itle to a patent”
does not distinguish between expired and unexpired
patents. Rather, Mars merely reiterates the established
rule that for any patent, expired or not, transferring only
the right to sue for past damages, divorced from title, is
not enough to give the owner of that right standing under
the Patent Act. See Crown Die, 261 U.S. at 44 (“If the
owner of the patent when the infringements took place
has assigned his patent to one, and his claims for damag-
es for infringement to another, then the latter cannot sue
at law at all but must compel his assignor of the claims to
sue for him.”).
Requiring that legal title in an expired patent be
transferred to convey standing on the transferee would
create separate standing rules for expired and unexpired
patents. In other words, if Keranos had entered into the
present exclusive license agreement the day before the
patents expired, then it would have standing based on our
“all substantial rights” rule, but appellees ask us to rule
differently if Keranos acquired the same rights one day
later. We see no reason for a party’s standing to turn on
whether it enters into an exclusive license with a patent
owner before or after the patent expires.
We acknowledge that the patentee has fewer rights to
transfer when the patent has expired; for example, the

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 12
patentee can no longer transfer the right to exclude others
from practicing the patent going forward. But the ab-
sence of some rights in an expired patent does not affect
the standing of a transferee that received all substantial
rights in an expired patent, just as it does not divest of
standing the transferor that did not contract away any
substantial rights. The crux of our standing caselaw has
always been whether a plaintiff has all substantial rights
in the patent-at-issue. Mars asks us to examine whether
the licensor intended to transfer all substantial rights or
merely a subset of those rights. As discussed above, the
title holder, UMC, retained nothing that can be regarded
as a substantial right and nothing in the agreement
suggests it intended to retain any substantial right.
The policy discussed in Mars of avoiding “unnecessary
third-party litigation, whether or not the patent has
expired” further confirms that Keranos alone has stand-
ing because the patent owner, UMC, transferred to Kera-
nos all rights to pursue any infringement litigation. As
explained in Crown Die, if a patentee was allowed to
divide up the existing patent rights in order to “give[] to
many different individuals the right to sue certain named
infringers . . . , it would give the patentee an opportunity
without expense to himself to stir up litigation by third
persons that is certainly contrary to the purpose and
spirit of the statutory provisions for the assigning of
patents.” 261 U.S. at 39; see Vaupel, 944 F.2d at 875
(“The policy underlying the requirement to join the owner
when an exclusive licensee brings suit is to prevent the
possibility of two suits on the same patent against a single
infringer.” (emphasis added) (citing Crown Die, 261 U.S.
at 38)). Our finding that Keranos alone holds all rights to
pursue infringement litigation for the patents-at-issue
advances this policy concern.
In sum, we conclude that Keranos has standing alone
to sue for infringement of the asserted patents and decline
to create one test for establishing standing when an

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 13
unexpired patent has been transferred and a second test
for establishing standing when an expired patent has
been transferred.
II. Compliance with Local Patent Rules
Having determined that Keranos has standing, we
turn to the merits of its appeal: the district court’s denial
of Keranos’s motions for leave to amend infringement
contentions. The district court held that Keranos’s
amended infringement contentions, which “would add
thousands of additional products not specifically disclosed
in [Keranos’s] original infringement contentions,” did not
meet the requirements of the local patent rules. J.A. 6–8.
To justify its identification of new products in its amended
infringement contentions, Keranos argued that it needed
discovery to obtain the information required about those
products, because publicly available information was
insufficient for it to identify products that contained the
allegedly infringing technology. Keranos also argued that
the amended infringement contentions did not add any
new patent claims or infringement theories because each
of the new products fell within the scope of the original
infringement contentions, which generally identified
products that “incorporated the SuperFlash technology.”
J.A. at 6.
The district court disagreed with Keranos that the
type of information in public documents was insufficient
to identify whether the product potentially infringed,
noting that Keranos’s original infringement contentions
used public documents containing that same type of
information to identify the accused products. The district
court also found that, under the local rules, Keranos had
to identify the accused products by specific product name
or number, if known, rejecting Keranos’s contention that
it complied with the local rules by identifying product
families or describing allegedly infringing technology
incorporated in various, unidentified products. The

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 14
district court concluded that Keranos “failed to demon-
strate that it acted diligently in searching for and naming
the additional products that incorporate the accused
technology” when it drafted its original infringement
contentions, given that Keranos had the burden “to search
for and identify infringing products to the extent possible
based on publicly available information.” J.A. 7–8 (citing
Am. Video Graphics, L.P. v. Elec. Arts, Inc., 359 F. Supp.
2d 558, 560 (E.D. Tex. 2005) (“The Patent Rules demon-
strate high expectations as to plaintiffs’ preparedness
before bringing suit, requiring plaintiffs to disclose their
preliminary infringement contentions before discovery
has even begun.”)).
In the Eastern District of Texas, Patent Rule 3-1 re-
quires the patent owner to serve infringement contentions
that, among other things, identify “as specific[ally] as
possible” each accused product. The rule further requires
that the patent owner identify the name or model num-
ber, if known, of each accused product. The purpose of
this rule, and the local patent rules in general, is to
“require parties to crystallize their theories of the case
early in the litigation” so as to “prevent the ‘shifting
sands’ approach to claim construction.” O2 Micro Int’l
Ltd. v. Monolithic Power Sys., Inc., 467 F.3d 1355, 1364
(2006) (quoting Atmel Corp. v. Info. Storage Devices, Inc.,
No. C 95–1987 FMS, 1998 WL 775115, at *2 (N.D. Cal.
Nov. 5, 1998)) (referring to the local patent rules of the
Northern District of California, which are the same as the
local patent rules of the Eastern District of Texas in
relevant part, see STMicroelectronics, Inc. v. Motorola,
Inc., 308 F. Supp. 2d 754, 756 n.1 (E.D. Tex. 2004) (“Alt-
hough the Northern District of California’s opinion is not
binding on this Court, it is persuasive because the rele-
vant portions of the Court’s Patent Rule 3-1 are exactly
the same as that court’s Patent LR 3-1.”)). With one
exception not at issue here, the local rules only allow the
patent owner to amend its infringement contentions by

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 15
order of the court upon a showing of good cause, which
requires diligence in discovering the additional products
and in seeking to amend. Alexsam Inc. v. IDT Corp., No.
2:07-cv-420-CE, 2011 WL 108725, at *1 (E.D. Tex. Jan.
12, 2011). To determine whether the patent owner has
shown good cause to amend its infringement contentions,
the Eastern District of Texas considers “(1) the explana-
tion for the party’s failure to meet the deadline, (2) the
importance of what the Court is excluding, (3) the poten-
tial prejudice if the Court allows that thing that would be
excluded, and (4) the availability of a continuance to cure
such prejudice.” Id.
Local patent rules are essentially a series of case
management orders that fall within a district court’s
broad power to control its docket and enforce its order.
See O2 Micro, 467 F.3d at 1363; STMicroelectronics, Inc.
v. Motorola, Inc., 307 F. Supp. 2d 845, 848 (E.D. Tex.
2004). A district court’s application of its local rules is
reviewed under the standard of abuse of discretion.
AntiCancer, Inc. v. Pfizer, Inc., 769 F.3d 1323, 1328 (Fed.
Cir. 2014). “In reviewing a district court’s exercise of
discretion, this court determines ‘whether (1) the decision
was clearly unreasonable, arbitrary, or fanciful; (2) the
decision was based on an erroneous conclusion of law; (3)
the court’s findings were clearly erroneous; or (4) the
record contains no evidence upon which the court ration-
ally could have based its decision.’” Genentech, Inc. v.
Amgen, Inc., 289 F.3d 761, 774 (Fed. Cir. 2002) (quoting
In re Cambridge Biotech Corp., 186 F.3d 1356, 1369, 51
USPQ2d 1321, 1329 (Fed. Cir. 1999)).
A. Identification of Accused Products
Keranos argues that the district court abused its dis-
cretion in denying Keranos’s motions for leave to amend
infringement contentions because, by identifying the
accused technology (i.e., “SuperFlash”), certain product
families, and certain product numbers in the original

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 16
infringement contentions, Keranos gave appellees suffi-
cient notice of its theory of infringement. Keranos
acknowledges that Patent Rule 3-1(b) requires that it
identify each product by product name or model number,
if known, but Keranos asserts that the local rules allow
for the addition of new products to the infringement
contentions if those products operate in a manner reason-
ably similar to the specific theory of infringement identi-
fied in the original infringement contentions.
Keranos’s infringement contention against Microchip
is representative:
Based on the current investigation, without the
advantage of discovery, Microchip (or foundries on
their behalf) made, used, sold, offered for sale or
imported SuperFlash [integrated circuits] under
license from SST, including but not limited to the
PIC18; PIC24; dsPIC DSCs; PIC32 and related
family of products which are said to include Su-
perFlash memory.
J.A. 21552. According to Keranos, the term “SuperFlash”
refers to a narrow group of products with flash memory,
and the contentions alleged that (1) the manufacturer-
appellees obtained licenses and the know-how to make
SuperFlash memory from SST and (2) the alleged cus-
tomer-appellees selected SuperFlash memory for their
products. Keranos points out that the appellees’ non-
infringement positions analyzed SuperFlash only general-
ly, rather than asserting distinct non-infringement posi-
tions for their specific products. Keranos concludes that
its infringement theory requires only use of the Super-
Flash technology, and that the new products all use
SuperFlash.
Keranos’s infringement contentions also identified
certain product families as infringing the asserted pa-
tents. For example, in the infringement contention ex-
cerpt above, Keranos identified Microchip’s PIC18, PIC24,

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 17
dsPIC DSCs, and PIC32 product families as accused
products. Keranos argues that identifying product family
numbers was sufficient, because appellees referenced
their products by family numbers in responding to discov-
ery requests, and the product family number was the
most specific information Keranos could find in publicly
available documents for some of the appellees.
Appellees disagree that Keranos’s identification of
SuperFlash technology and certain product families
sufficiently disclosed its theory of infringement. Appel-
lees first argue that if Keranos had identified additional
products, it would have further defined Keranos’s theories
of direct infringement because different products allegedly
perform certain steps of the asserted method in different
ways. Second, appellees argue that the identification of
additional products would have in turn prompted inquir-
ies into the specific activities and specific intent required
to prove indirect infringement. Finally, appellees argue
that the identification of additional products could have
revealed Keranos’s specific damages allegations, as Su-
perFlash memory can be incorporated into increasingly
larger products. Additional information about the
amount of potential damages, according to appellees,
would then inform early decisions relating to settlement.
Like the district court, appellees also focus on the re-
quirement of Patent Rule 3-1(b) that the accused products
be identified “as specific[ally] as possible” and “by
name . . . or number, if known.” Appellees argue that
Keranos’s failure to search for and identify products using
information publicly available at the time it filed its
original infringement contentions precludes Keranos from
amending its infringement contentions to add those
products.
We hold that the district court did not abuse its dis-
cretion in requiring Keranos to “demonstrate that it acted
diligently in searching for and naming the additional

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 18
products that incorporate the accused technology” in its
initial infringement contentions. J.A. 7–8 (citing Am.
Video Graphics, 359 F. Supp. 2d at 560). The local patent
rules require that the patent owner identify in its in-
fringement contentions each accused product “of which [it]
is aware . . . as specific[ally] as possible,” which requires
identifying each product “by name or model number, if
known.” Local Patent Rule 3-1(b). In most cases, if the
patent owner wishes to add additional products to its
infringement contentions, it must seek leave of court,
which “shall only be entered upon a showing of good
cause.” Local Patent Rule 3-6(b).
In the Eastern District of Texas, good cause requires
the patent owner to demonstrate, inter alia, that it was
diligent in discovering the products it wishes to add to its
infringement contentions. See J.A. 6 (citing West v.
Jewelry Innovations, Inc., No. C 07-1812 JF, 2008 WL
4532558, at *2 (N.D. Cal. Oct. 8, 2008) (“[T]he Court also
must address whether the party was diligent in discover-
ing the basis for the proposed amendment.”)). Although a
district court, depending on the circumstances, might not
require that the patent owner identify each accused
product by name or model number, a district court is well
within its discretion to refuse the patent owner’s request
to amend infringement contentions if the patent owner
does not show that it acted diligently in its identification
of accused products, which may require the identification
of products by name or model number. Compare Linex
Techs., Inc. v. Belkin Int’l, Inc., 628 F. Supp. 2d 703, 711
(E.D. Tex. 2008) (“[U]sing an exemplary product to outline
infringement contentions can be sufficient.”), with
SmartPhone Techs. LLC v. HTC Corp., No. 6:10-cv-580,
2012 WL 1424173, at *3 (E.D. Tex. Mar. 16, 2012) (deny-
ing-in-part motion for leave to amend infringement con-
tentions as to the products for which the accused infringer
did not dispute that public information was available).

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 19
B. Publicly Available Information
Keranos next argues that its original infringement
contentions identified as specifically as possible each
accused product of which it was aware. To show its
diligence, Keranos submitted a declaration from its prin-
cipal, Nicholas Gross, that detailed the number of hours
spent reviewing datasheets, reverse-engineering products,
and searching public information sources to identify
potentially infringing products. J.A. 1142–43. Keranos
asserts that much of the publicly available information
was insufficient to identify accused products, because it
did not indicate whether the products were available
during the 2004 to 2008 period for which Keranos alleged
damages or whether the products had SuperFlash
memory, instead of the more generic “flash” memory. The
public documents that identified only “flash” memory
were insufficient to accuse the products of infringing the
asserted patents because, according to Keranos, Super-
Flash refers to a narrow subset of flash products, while
Keranos’s efforts to reverse-engineer some “flash” memory
products did not consistently identify the use of Super-
Flash memory. Keranos argues that the local patent
rules do not require that it reverse-engineer all of the
thousands of potentially infringing products. See
STMicroelectronics, 308 F. Supp. 2d at 755 (“[T]he ques-
tion of whether [the disclosing party] conducted ‘reverse
engineering or its equivalent’ is not synonymous with
whether it has complied with Patent [Rule] 3-1, which, as
discussed, requires only to set forth specific theories of
infringement.” (quoting Network Caching Tech., LLC v.
Novell, Inc., No. C-01-2079, 2003 WL 21699799, *4–5
(N.D. Cal. Mar. 21, 2003))).
Keranos further asserts that publicly available infor-
mation did not exist for some of appellees’ products. For
example, the parties agree that TSMC’s product numbers
cannot be identified by public sources. See J.A. 1819
(appellees’ opposition to Keranos’s motions for leave to

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 20
amend infringement contentions, stating that “Keranos
could have identified virtually all of the products it seeks
to add had it exercised diligence in the two years after it
filed the complaint (with TSMC as an exception)”). Kera-
nos also suggests that because Samsung did not oppose its
motions for leave to amend infringement contentions,
there is no evidence that any Samsung product could have
been identified in the original infringement contentions
using publicly available information.
Appellees respond that because Keranos did not per-
form a sufficient search for publicly available information
prior to serving its original infringement contentions, it is
irrelevant whether information was publicly available or
not. To support this contention, appellees point to public
documents for some of the new products in Keranos’s
amended infringement contentions that mention the word
“SuperFlash.” Appellees also point to public documents
for some of the new products that, while they do not
mention SuperFlash technology, contain the same type of
information as the documents Keranos relied on to accuse
the products in its original infringement contention.
In denying Keranos’s motions for leave to amend in-
fringement contentions, the district court found that
Keranos had not shown it diligently searched for and
identified infringing products based on all the publicly
available information. J.A. 8. The record indicates,
however, that publicly available information might not
have been available for the products of some appellees
and, thus, Keranos could not have been more diligent
with respect to those appellees. We therefore vacate and
remand the district court’s order denying Keranos’s
motions for leave to amend infringement contentions. On
remand, the district court should consider, on at least a
party-by-party basis, whether Keranos has shown good
cause to amend its infringement contentions.

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 21
Importantly, we do not hold that the district court
must determine whether Keranos has shown good cause
to amend its infringement contentions on a product-by-
product basis, although the district court may deem it
necessary to do so. We recognize that analyzing docu-
ments on a product-by-product basis might place an
undue strain on the judicial resources of the district court,
particularly here, where thousands of products are at
issue. We also recognize that district courts have broad
discretion to manage their cases, and we therefore limit
our holding to the specific facts of this case. The circum-
stances presented in other cases may require that a
district court look at each new product in proposed
amended infringement contentions to determine whether
a patent owner satisfied the local rules. Here, however, if
a company makes product numbers publicly available as a
general practice, the newly accused product names and
numbers appear to follow this general practice, and public
information accompanying those product numbers would
have allowed Keranos to identify that those products
included the accused technology, the district court may
well be within its discretion to refuse to allow Keranos to
add to its contentions a handful of products for which it
claims there was no publicly available information.
* * *
Because we vacate the district court’s denial of Kera-
nos’s motions to amend infringement contentions, we need
not consider Keranos’s arguments that it had good cause
for amending its infringement contentions, or that the
district court’s denial amounted to improper sanctions.
CONCLUSION
Keranos has standing to sue for infringement of the
asserted patents because it owns all substantial rights in
those patents. Regarding the district court’s order deny-
ing Keranos’s motions for leave to amend infringement
contentions, we cannot determine from the order whether

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KERANOS, LLC v. SILICON STORAGE TECHNOLOGY , INC. 22
the district court exceeded its discretion by denying
Keranos’s motions with respect to all of the differently
situated appellees. We therefore vacate the judgment
below and remand with instructions to determine, on a
party-by-party basis, whether Keranos violated the local
patent rules.
VACATED AND REMANDED
COSTS
Each party shall bear its own costs.

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