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

______________________ 
2 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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

JOHN J. EDMONDS, Collins, Edmonds, Pogorzelski, 

Schlather & Tower PLLC, Houston, TX. 

DARYL JOSEFFER, King & Spalding LLP, Washington, 

DC, argued for defendants-appellees. Also represented by

ADAM CONRAD, Charlotte, NC; JEFFREY 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 
KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 3

Semiconductor, Inc. and Samsung Electronics Co., Ltd. 

(collectively, Samsung), Taiwan Semiconductor Manufacturing Co., Ltd. and TSMC North America (collectively, 

TSMC), Analog Devices, Inc., International Business 

Machines Corporation, Intel Corporation, National Semiconductor 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 contentions based on the local patent rules. The court therefore 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 patents that generally relate to split-gate flash memory. 

Keranos accused appellees of using a specific type of flash 

memory technology developed by SST, called “SuperFlash,” 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 
4 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

2008. Keranos did not join UMC as co-plaintiff in this 

action. 

In the Northern District of California, SST and certain defendants from the Texas action then sued Keranos, 

UMC, Peter Courture, and J. Nicholas Gross1 in four 

separate cases seeking declaratory judgments of noninfringement 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-cv00017 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 incorporated 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.

 
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 regrouped, Keranos served its Local Patent Rule 3-1 Disclosure 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 motion. 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 specific 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 district 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 publicly available information.” J.A. 8. 

On January 29, 2014, the magistrate judge held a 

hearing where he explained that the only accused products remaining in the case against the manufacturers 

were the two products specifically identified by product 

number in the original infringement contentions. Keranos agreed to dismiss with prejudice its patent infringement claims against those products (having determined 

that the potential damages recovery for those two products would be de minimis), and stipulated to summary 

judgment in favor of the defendants. The district court 
6 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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 judgment 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 standing to sue for infringement of the asserted patents. 

Because we find Keranos has standing, we have jurisdiction 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. 

DISCUSSION

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 infringement. 

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) (citations 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).
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 patent.’” 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 assignment 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 exclusive 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 absence may “leave an existing party subject to a substantial 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 
8 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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 infringement, to make, use, import, and sell products covered 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 infringement, 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 provision 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 patentsat-issue.

 
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 accused infringers, which “is the most important factor in 

determining whether an exclusive license transfers sufficient rights to render the licensee the owner of the patent.” 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 proprietary 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 catchall grant of “any and all other substantial rights . . . 
10 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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 substantial rights for itself. Appellees concede that UMC possessed 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 infringement. 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 thenexpired patent did not convey standing on the transferee. 

527 F.3d at 1363–64, 1371–72. The transferee had argued that the transfer was “effectively the same as a 

transfer of title” because “the right to sue for past infringement is the ‘only remaining right[]’ in an expired 

patent.” Id. at 1372. This Court disagreed:
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 damages 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 
12 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

patentee can no longer transfer the right to exclude others 

from practicing the patent going forward. But the absence 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 standing because the patent owner, UMC, transferred to Keranos 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 
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 
14 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

district court concluded that Keranos “failed to demonstrate 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 demonstrate 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 requires 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 number, 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) (“Although the Northern District of California’s opinion is not 

binding on this Court, it is persuasive because the relevant 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 
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 explanation for the party’s failure to meet the deadline, (2) the 

importance of what the Court is excluding, (3) the potential 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 rationally 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 discretion 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 
16 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

infringement contentions, Keranos gave appellees sufficient 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 reasonably similar to the specific theory of infringement identified 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 SuperFlash 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 manufacturerappellees obtained licenses and the know-how to make 

SuperFlash memory from SST and (2) the alleged customer-appellees selected SuperFlash memory for their 

products. Keranos points out that the appellees’ noninfringement positions analyzed SuperFlash only generally, rather than asserting distinct non-infringement positions for their specific products. Keranos concludes that 

its infringement theory requires only use of the SuperFlash technology, and that the new products all use 

SuperFlash. 

Keranos’s infringement contentions also identified 

certain product families as infringing the asserted patents. For example, in the infringement contention excerpt above, Keranos identified Microchip’s PIC18, PIC24, 
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 discovery 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. Appellees 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 inquiries 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 SuperFlash 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 requirement 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 discretion in requiring Keranos to “demonstrate that it acted 

diligently in searching for and naming the additional 
18 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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 infringement 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 discovering 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) (denying-in-part motion for leave to amend infringement contentions as to the products for which the accused infringer 

did not dispute that public information was available).
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 principal, 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, SuperFlash 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 SuperFlash 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 question 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 information 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 
20 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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)”). Keranos 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 perform 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 infringement 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. 
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-byproduct basis, although the district court may deem it 

necessary to do so. We recognize that analyzing documents 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 circumstances 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 Keranos’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 denying Keranos’s motions for leave to amend infringement 

contentions, we cannot determine from the order whether 
22 KERANOS, LLC v. SILICON STORAGE TECHNOLOGY, INC. 

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.