1 2 3
4 5 UNITED STATES DISTRICT COURT 6 WESTERN DISTRICT OF WASHINGTON AT SEATTLE 7 DEBORAH FRAME-WILSON ET AL., CASE NO. 2:20-cv-00424-JHC 8
Plaintiffs, ORDER 9 v. 10 AMAZON.COM, INC., 11
Defendant. 12 13
14 I INTRODUCTION 15 This matter comes before the Court on Defendant Amazon.com, Inc.’s “Surreply Motion 16 to Strike or, in the alternative, for Leave to Respond” (Dkt. # 435) and Plaintiffs’ “Motion to 17 Strike Amazon’s February 6 Filings” (Dkt. # 488). The Court has reviewed the materials filed in 18 connection with the motions, the rest of the record, and the governing law. Being fully advised, 19 the Court GRANTS IN PART and DENIES IN PART both motions. 20 21 22 23 24 1 II BACKGROUND 2 In February 2025, Plaintiffs moved to certify a class under Rule 23(b). Dkt. # 266. In 3 connection with their motion, Plaintiffs submitted an Expert Report from Dr. Parag Pathak.1 See 4 Dkt. # 267-1; see also Dkt. # 317-1 (corrected version). In June 2025, Defendant filed its 5 opposition to class certification. Dkt. # 323. It also moved to exclude Dr. Pathak’s expert 6 testimony. See Dkt. # 325. 7 Following various discussions and stipulated motions, the parties and the Court agreed 8 that all contemplated briefing for Plaintiffs’ Motion for Class Certification (Dkt. # 266) and 9 Defendant’s Motion to Exclude Testimony of Parag Pathak, Ph.D. (Dkt. # 325) would be due by 10 November 7, 2025, and January 5, 2026, respectively. See Dkt. ## 350 & 423. The parties 11 complied with these deadlines. See generally Dkt. 12 Five days after Plaintiffs submitted their Reply in Support of Class Certification (Dkt. # 13 429)—the last scheduled filing for the Motion for Class Certification (Dkt. # 266)—Defendant 14 filed a “Surreply Motion to Strike or, in the alternative, for Leave to Respond” (the Surreply 15 Motion). Dkt. # 435.2 This November 12 Surreply Motion contends that Plaintiffs’ Reply at 16 Dkt. # 429 is improper because it: (1) advances new opinions from Prof. Pathak; (2) redefines the 17 class in a way that “makes it entirely unclear what purchases are Class Products”; (3) offers new 18 opinions from a new expert, Dr. David Sunding; (4) includes a misleading discussion of Prof. 19 Ostrovsky’s deposition testimony; and (5) cites “new factual material, including material that 20 became available after Amazon opposed Plaintiffs’ class certification motion.” Dkt. # 435 at 2– 21
22 1 In referring to Dr. Pathak (and the other experts in this case), the parties use “Dr.,” “Prof.,” “Professor,” and “Ph.D.” interchangeably. See generally Dkt. The Court adopts these naming 23 conventions. 2 Defendant later moved for a concurrent expert hearing, which the Court denied on February 26, 24 2026. See Dkt. ## 448 & 491. 1 4. And it asks that the Court give Defendant “the opportunity to file a surreply with expert 2 reports by February 6, 2026 . . . or, alternatively, that the new material described at a high level 3 [in this motion] be stricken.” Id. at 2.
4 The Court did not rule on the Surreply Motion before February 6, 2026. See generally 5 Dkt. Nevertheless, on February 6, 2026, Defendant filed a: (1) “Motion to Exclude Testimony of 6 David Sunding, Ph.D.” (Dkt. ## 472 & 473); (2) “Declaration of Amy J. Mauser in Support of 7 Amazon.com, Inc.’s Motion to Exclude Testimony of David Sunding, Ph.D.” (Dkt. # 474); and 8 (3) “Supplemental Surreply Motion to Strike or, in the alternative, for Leave to Respond” (Dkt. 9 ## 475 & 476). These filings were accompanied by numerous exhibits, including a 3,875-word 10 surreply brief (Dkt. # 476-1), three surrebuttal expert reports (Dkt. ## 476-3–476-5), and 11 hundreds of pages of deposition testimony (Dkt. ## 474-2 & 476-2).3 12 Plaintiffs now move to strike Defendant’s submissions at Dkt. ## 472–476 (the February 13 6 Filings). Dkt. # 488. Plaintiffs argue that these documents should be stricken in their totality 14 because they are “unauthorized, untimely, and overlength.” Id. at 15. They also argue that the 15 February 6 Filings are unnecessary and unjustified, as Plaintiffs do not raise any new arguments 16 or evidence on reply. See generally id.; see also Dkt. # 494. 17 III DISCUSSION 18 A. Legal Standards 19 Generally, “[t]he local rules of this District only allow for a motion, response brief from 20 the party opposing the motion, and a reply brief from the moving party.” Clark v. Washington 21 22
23 3 Although not explicitly stated in the Surreply Motion or the documents themselves, Defendant has since clarified that the documents filed at Dkt. ## 472–476 are “proposed” responses and 24 “conditionally submitted,” pending the Court’s resolution of the Surreply Motion. See Dkt. # 493 at 9. 1 State Dep’t of Health, 735 F. Supp. 3d 1334, 1342 n.1 (W.D. Wash. 2024) (citing LCR 7(b)). 2 There are, however, a few exceptions. 3 First, a party may file a surreply—“that is, a second response from a party in
4 opposition”—without leave of court if they meet the standards of LCR 7(g). Zhai v. Jaddou, 5 2024 WL 1701973, at *1 n.1 (W.D. Wash. Apr. 19, 2024). Under LCR 7(g), a surreply must be 6 filed within five days of the other party’s reply and cannot exceed 1,050 words. See LCR 7 7(g)(2)–(3). The contents are also limited to “requests to strike material contained in or attached 8 to a reply brief[.]” LCR 7(g); see also Zhai, 2024 WL 1701973, at *1 n.1 (“A surreply . . . is not 9 permitted, except for a request to strike material from the moving party’s reply brief.”).4 10 Second, a party may file additional evidence, such as a surrebuttal report, if they obtain 11 permission from the court.5 A court may grant leave to file surreply evidence if: (1) the 12 opposing party raises new evidence or issues in a reply brief or rebuttal report; and (2) the court 13 declines to strike the new materials. See Provenz v. Miller, 102 F.3d 1478, 1483 (9th Cir. 1996) 14 (“Where new evidence is presented in a reply . . . the district court should not consider the new 15 evidence without giving the non-movant an opportunity to respond.”) (citation omitted); see also 16 HDT Bio Corp. v. Emcure Pharms., Ltd., 2022 WL 3018239, at *2 (W.D. Wash. July 29, 2022) 17 (“[W]hen new evidence or issues are raised on reply, courts have discretion to either strike the 18 reply declarations and portions of the reply brief that present new material or consider the new 19 material after affording the nonmoving party an opportunity to respond.”). “Evidence is not 20 4 Although similar, a surreply motion is distinct from a motion to strike under Federal Rule of 21 Civil Procedure 12(f). See LCR (7)(g)(5). Because Defendant filed a surreply, not a Rule 12(f) motion, the Court limits its analysis to whether the Surreply Motion complies with the procedures set forth in 22 LCR 7(g). 5 See, e.g., PUMA SE v. Brooks Sports, Inc., 2024 WL 2091382, at *4 (W.D. Wash. May 9, 2024) (noting that “Rule 26 does not contemplate surrebuttal reports” but that courts will sometimes still 23 entertain them if the party first seeks permission from the court); Morgan v. Rohr, Inc., 2021 WL 4806472, at *2 (S.D. Cal. 2021) (noting that there is no right to a surreply under the local or federal rules 24 but that a court may still permit a surreply at its discretion). 1 ‘new,’ however, if it is submitted in direct response to evidence or arguments raised in the 2 opposition.” Id. at *3 (collecting cases). And surreply evidence typically must respond directly 3 to the new evidence and issues raised in the reply,6 as evidence that could have been submitted 4 with the opposition or that merely seeks to bolster preexisting evidence is an inappropriate use of 5 a surreply.7 6 Last, a party can request permission to file a surreply8 brief to present additional 7 substantive arguments.9 On class certification motions, courts may grant leave to file a surreply 8 brief when the plaintiff has substantively modified the class definition in a reply brief10 or when 9 it believes supplemental information is necessary to ensure that it has a complete record.11 As 10
11 6 See, e.g., McAndie v. Sequim Sch. Dist., 2023 WL 1468469, at *1 (W.D. Wash. Feb. 2, 2023) (permitting the plaintiff to file new evidence in response to the new evidence and arguments raised in the 12 defendant’s reply); Walker v. Conagra Brands, Inc, 2023 WL 3564743, at *4 (C.D. Cal. May 1, 2023) (authorizing a surreply but limiting it “to new evidence and argument raised by [the opposing party] for 13 the first time in Reply”); Butler v. Porsche Cars N. Am., Inc., 2017 WL 1398316, at *3 (N.D. Cal. Apr. 19, 2017) (considering the defendant’s surreply to the extent that it addresses the plaintiff’s new 14 arguments on reply). 7 See, e.g., Pennington v. Providence Seward Health & Servs. - Washington, 2013 WL 12095221, 15 at *12 (D. Alaska Mar. 31, 2013) (denying surreply motion because the proposed surreply “was merely an effort to bolster the evidence contained in the summary judgment record”); MAP Co. v. Lebanese Arak 16 Corp., 2018 WL 3357470, at *5 (C.D. Cal. Jan. 5, 2018) (rejecting declaration because “surreplies must not be used to present matters that could and should have been presented with the opposition”). 8 While court-authorized responses to replies are called “surreplies,” such responses are distinct 17 from the LCR 7(g) surreply motions discussed above. 9 See, e.g., Adamson v. Pierce Cnty., 2024 WL 2723813, at *1 n.1 (W.D. Wash. May 28, 2024), 18 aff’d sub nom. Adamson v. Pierce Cnty. Mun., 2025 WL 2181026 (9th Cir. Aug. 1, 2025) (“Parties wishing to file additional briefing must obtain leave from the Court to do so.”). 19 10 See, e.g., Garcia v. Schlumberger Lift Sols., 2021 WL 1259737, at *3 n.2 (E.D. Cal. 2021) (“[C]ourts have granted leave to file a sur-reply where modified class definitions are presented in reply 20 briefs.”) (collecting cases); Crosby v. Cal. Physicians’ Serv., 498 F. Supp. 3d 1218, 1224 (C.D. Cal. 2020) (permitting a surreply because the defendants “had not yet had an opportunity to address [the 21 plaintiffs’] new class definition”); B.R. v. Cnty. of Orange, 2017 WL 10525878, at *6 (C.D. Cal. Dec. 11, 2017) (permitting a surreply because the plaintiff proposed “an ‘alternative’ class definition in his reply” 22 and surreply was needed to “‘cure[ ]’ any issues impeding class certification”). 11 See, e.g., Torres v. Goddard, 314 F.R.D. 644, 653 (D. Ariz. 2010) (“In order to ‘rule on compliance’ with Rule 23, a court may consider supplemental material provided by the parties in order to 23 make an informed judgement.”) (citation omitted); Morgan, 2021 WL 4806472, at *2 (permitting the defendant to file a surreply “for the Court to consider along with the party’s briefing on the issue of class 24 certification” given the breadth of the plaintiffs’ reply). 1 with surreply evidence, a court will also permit surreply briefs when a party raises new 2 arguments or issues in their reply. See Provenz, 102 F.3d at 1483; HDT, 2022 WL 3018239, at 3 *2. But while a court may permit such briefing, it need not do so.12 And unauthorized surreply 4 briefs, or any unauthorized portions thereof, may be stricken as procedurally improper.13 5 B. Analysis 6 At bottom, the parties advance the same argument: the opposing party has presented new 7 material that is not contemplated by the applicable rules and so the Court must either strike it or 8 give the moving party an opportunity to respond. As the parties’ proposed solution—striking or 9 granting leave to respond—is clearly the appropriate course of action if the Court should find 10 that either party has improperly presented new material, see part III.A above, the only question 11 before the Court is whether either party has in fact presented such material. 12 In the Sureply Motion, Defendant contends that striking or leave to respond is warranted 13 because Plaintiffs’ Reply in Support of Class Certification (Dkt. # 429) raises various new issues 14 and evidence including: (1) new analyses from Dr. Pathak; (2) a new class definition; and (3) a 15 new expert report from Dr. Sunding. See Dkt. # 435 at 2–4. Defendant also contends that a 16 surreply is warranted because Plaintiffs’ Reply includes an incomplete and misleading discussion 17 of Prof. Ostrovsky’s deposition testimony and cites “new factual material” that was unavailable 18 to Defendant when they submitted their class certification opposition. Id. at 4; see also Dkt. ## 19 435-1 & 435-2. In its Response to Plaintiffs’ Motion to Strike, Defendant clarifies that the 20 February 6 Filings are “proposed” responses to Plaintiffs’ purportedly new material, and requests 21
22 12 See, e.g., Vazquez v. Bostock, 349 F.R.D. 333, 355 n.6 (W.D. Wash. 2025) (adopting a narrower class definition without allowing the defendants to submit supplemental briefing). 13 See, e.g., Carr v. Allied Waste Sys. of Alameda Cnty., 419 Fed. App’x 728, 728 (9th Cir. 2011) 23 (unpublished) (affirming the district court’s decision to strike an unauthorized surreply brief); Dasenbrock v. Enenmoh, 2017 WL 1354576, at *1 (E.D. Cal. Apr. 13, 2017) (“Improperly filed surreplies are 24 prohibited and shall be stricken.”). 1 that the Court consider these documents only if it “decides to consider the new material in 2 Plaintiffs’ reply brief.” Dkt. # 493 at 11, 18. 3 Plaintiffs respond that Defendant should not be given leave to respond and instead, that
4 the February 6 Filings should be stricken in their entirety. See generally Dkt. # 488. Plaintiffs’ 5 main argument is that Defendant did not receive permission from the Court to file supplemental 6 documents, and so the February 6 Filings are unauthorized filings in violation of the federal and 7 local rules. Id. at 9–11. But this argument is misguided. Although the Court agrees that it did 8 not provide pre-authorization for the February 6 Filings, it also notes that Defendant filed a 9 proper surreply motion on November 12, 2025, in which Defendant requested leave to respond 10 by February 6, 2026 should the Court decline to strike Plaintiffs’ purportedly new materials. See 11 generally Dkt. # 435. As Defendant’s Surreply Motion remained pending as of February 6, 12 2026, the Court does not believe that it was improper for Defendant to file proposed responses
13 on that date. Thus, the Court DENIES Plaintiffs’ request to strike the February 6 Filings as 14 “unauthorized” and instead, adopts Defendant’s position that the documents at Dkt. ## 472–476 15 are “proposed” filings, subject to the condition that the Court resolve Defendant’s Surreply 16 Motion (Dkt. # 435) by granting leave to respond. 17 As for Plaintiffs’ other arguments, the Court considers them in connection with the five 18 categories of evidence raised in Defendant’s Surreply Motion.14 For the reasons below, it 19 GRANTS IN PART and DENIES IN PART both motions. 20
21 14 The Court finds it appropriate to combine the parties’ arguments related to the two motions because its resolution of Plaintiffs’ Motion to Strike (Dkt. # 488) depends on whether Defendant is 22 permitted to file a surreply. If the Court resolves Defendant’s Surreply Motion by striking Plaintiffs’ purportedly new materials, the February 6 Filings and Plaintiffs’ Motion are moot. In contrast, if the Court grants Defendant leave to respond to Plaintiffs’ purportedly new materials, the February 6 Filings 23 should be permitted and Plaintiffs’ Motion should be denied, so long as the filings fall within the scope of the Court’s leave. On the other hand, if the Court denies Defendant’s Surreply Motion, the February 6 24 Filings must be stricken and Plaintiffs’ Motion granted. 1 1. Dr. Pathak’s “New” Analyses 2 Defendant contends that “[Dr.] Pathak’s opinions have significantly shifted[,]” as he 3 “previously stated he applied his model to transaction data to assess impact/harm” yet he now
4 asserts that “he is relying solely on his theoretic ‘economic’ model to assess impact.” Dkt. # 435 5 at 2. It also states that Dr. Pathak’s Reply (Dkt. # 432-3), which is repeatedly cited in Plaintiffs’ 6 Reply in Support of Class Certification (Dkt. # 429), “makes new claims and performs new 7 analyses relating to pass-through, including (a) a new asymmetric model that Pathak contends 8 demonstrates why PMFNs would result in pass-through of Amazon’s fee changes but not the 9 pass-through of Wal-Mart’s fee changes; (b) new regressions and statistical tests; and (c) a new 10 model of imperfect 3P seller competition that he says shows the pass-through rates he 11 incorporates in his damages model are conservative.” Id. at 3 (internal citations omitted). And 12 Defendant says the Reply is improper because it “hypothesizes that, absent Amazon’s challenged
13 conduct, Wal-Mart would change its pricing policies and no longer have a PMFN” and “claims 14 for the first time that Amazon’s challenged conduct impeded Temu from competing.” Id. 15 Plaintiffs respond that, apart from Defendant’s baseless argument about Prof. Pathak’s 16 supposed “misstatements,” “every issue Amazon seeks to address in its February 6 surreply 17 materials is responsive to issues Amazon and its experts have already raised in opposition to 18 class certification[.]” Dkt. # 488 12–13 (internal citation omitted). Plaintiffs also contend that 19 Defendant “addressed most of these same issues in its reply brief to exclude Prof. Pathak’s 20 testimony, where it had the last word” and thus “suffers no prejudice that would require the 21 extraordinary remedy of permitting it to file supplemental briefing and surreply expert reports.” 22 Id. at 13.
23 The Court does not find that Dr. Pathak’s Reply, or the portions of Plaintiffs’ Reply that 24 cite it, should be stricken for improperly raising new arguments. Still, it does conclude that a 1 surreply is warranted. In reviewing Dr. Pathak’s Reply, the Court finds “that some of Prof. 2 [Pathak’s] more detailed opinions are not simply rebuttal, but bring up new (albeit related) 3 theories and/or explanations for why he came to the conclusions he did.” J.R. Simplot Co. v.
4 McCain Foods USA, Inc., 2021 WL 4899465, at *3 (D. Idaho Oct. 20, 2021). It also finds that 5 by submitting “further evidence and arguments in support of [Plaintiffs’] motion to certify the 6 class,” Prof. Pathak’s Reply has “‘deprived Defendant[ ] of the opportunity to respond.’” 7 Morgan, 2021 WL 4806472, at *2 (quoting Do v. Tri City Healthcare Dist., 2020 WL 6484633, 8 at *2 (S.D. Cal. Nov. 4, 2020)) (emphasis in original); see also City & Cnty. of San Francisco v. 9 Purdue Pharma L.P., 2022 WL 1203075, at *1–2 (N.D. Cal. Apr. 22, 2022) (concluding that an 10 expert presented new arguments on reply because they “offer[ed] a new model based on a new 11 methodology in response to a criticism of [their] opening report”). The Court also agrees with 12 Defendant that there are “obvious efficiencies for the Court to consider this evidence now[,]”
13 Dkt. # 493 at 7, as Dr. Pathak’s opinions and analyses are critical to Plaintiffs’ pending Motion 14 for Class Certification (Dkt. # 266). 15 Accordingly, the Court GRANTS Defendant leave to respond to any new arguments 16 raised in Dr. Pathak’s Reply and DENIES Plaintiffs’ request to strike any portions of the 17 February 6 Filings that purport to respond to such arguments. In granting leave to respond, 18 however, the Court cautions Defendant to limit its surreply to responding to Dr. Pathak’s new 19 arguments and evidence. The Court will not consider surreply arguments that could have been 20 presented in Defendant’s Opposition. The Court will also ignore any surreply arguments that 21 relate to the admissibility of Dr. Pathak’s expert opinions, as the admissibility question has been 22 fully briefed in connection with Defendant’s Motion to Exclude Testimony of Parag Pathak,
23 24 1 Ph.D. (Dkt. # 325), and such arguments do not “respond” to the further evidence and arguments 2 raised by Dr. Pathak’s Reply.15 3 2. Plaintiffs’ “New” Class Definition 4 Defendant contends that Plaintiffs’ Reply in Support of Class Certification (Dkt. # 429) 5 announces a new class definition to which Defendant should be allowed to respond. See Dkt. # 6 435 at 3. In the Surreply Motion, Defendant argues that under the new class definition, it is 7 “entirely unclear what purchases are Class Products.” Id. Defendant’s proposed surreply brief, 8 however, abandons this argument and instead contends that the revised class definition fails 9 because it “includes millions of uninjured class members” and does not “adequately account for 10 seller pricing strategies[.]” Dkt. # 476-1 at 13–15. 11 Plaintiffs respond that a surreply is unwarranted because: (1) “Amazon no longer claims 12 that the class definition is ambiguous, one of the supposed grounds of prejudice to Amazon”; (2)
13 “Amazon does not refute that the percentage of potentially uninjured class members is within the 14 5% range that Olean permits”; and (3) “Amazon is not prejudiced by a modification that results 15 in a narrower class and thus reduces its exposure.” Dkt. ## 488 at 11; 494 at 4. But Plaintiffs’ 16 argument ignores a critical detail: Plaintiffs introduced a new class definition in a reply brief. As 17 the class definition is fundamental to the parties’ arguments on class certification, Plaintiffs’ new 18 class definition can fairly be characterized as a new argument that was improperly raised for the 19 first time on reply. Accordingly, striking the new definition or granting Defendant leave to 20 respond is an appropriate course of action, even if Defendant has not shown prejudice. See 21 Provenz, 102 F.3d at 1483; see also HDT, 2022 WL 3018239, at *2. 22
15 Upon a cursory review, the Court finds that the proposed surreply brief at Dkt. # 476-1 does not 24 currently meet these standards. 1 Because the Court determines that it would be inefficient to strike Plaintiffs’ amended 2 class definition and have Plaintiffs re-move for class certification, it declines to strike the new 3 class definition raised by Plaintiffs’ Reply (Dkt. # 429). Instead, it GRANTS Defendant leave to
4 respond and DENIES Plaintiffs’ request to strike any portions of the February 6 Filings that 5 purport to respond to Plaintiffs’ newly amended class definition. 6 3. Dr. Sunding’s “New” Expert Opinions 7 Defendant contends that Dr. Sunding’s Expert Report (Dkt. # 457-1) presents “new 8 affirmative opinions” to which it is entitled to respond. Dkt. # 435 at 4. It argues that Dr. 9 Sunding’s opinions are new because “Plaintiffs did not offer opinions on how focal point pricing 10 and other pricing strategies affect 3P seller prices on Walmart and eBay until [Dr. Sunding’s] 47- 11 page report[.]” Id. Defendant also separately moves to exclude Dr. Sunding’s report as 12 unreliable expert testimony under Federal Rule of Evidence 702. See Dkt. ## 472 & 473.
13 Plaintiffs respond that Defendant should not be allowed to submit surrebuttal reports or 14 argue for the exclusion of Dr. Sunding’s testimony. See generally Dkt. # 488. They contend that 15 Defendant’s proposed surrebuttal reports are unwarranted because Dr. Sunding’s opinions on 16 focal point pricing are not “new,” as “Prof. Pathak opined on the effects of seller pricing 17 strategies like focal point pricing on sellers’ pass-through of Amazon’s inflated referral fee[.]” 18 Id. at 11. They also argue that Defendant’s Motion to Exclude Testimony of David Sunding, 19 Ph.D. (Dkt. ## 472 & 473) is an unauthorized and untimely Daubert motion, and thus should be 20 stricken. Id. at 14–15. 21 As for the new opinion issue, the Court does not find striking or leave to respond 22 warranted. Although parties may submit rebuttal reports, surrebuttal reports are generally not
23 permitted, absent leave of court. See Fed. R. Civ. P. 26; see also PUMA, 2024 WL 2091382, at 24 *4. In determining whether to grant leave, courts are guided by the standards for rebuttal 1 testimony set forth by Federal Rule of Civil Procedure 26. Under this rule, a party may submit 2 rebuttal expert testimony if it “is intended solely to contradict or rebut evidence on the same 3 subject matter identified by [an initial expert witness.]” Fed. R. Civ. P. 26(a)(2)(D)(ii); see also
4 PUMA, 2024 WL 2091382, at *3 (“A report must satisfy two elements to qualify as a rebuttal 5 report: it must address the same subject matter as another party’s expert report and must be 6 intended solely to contradict or rebut that report.”) (citation and internal quotation marks 7 omitted). And although a party may not slip new arguments into a rebuttal report to sandbag 8 their opponent, see In re Graphics Processing Units Antitrust Litig., 253 F.R.D. 478, 501 (N.D. 9 Cal. 2008), “[n]othing in the text [of Rule 26] prohibits a party from contradicting or rebutting 10 another party’s expert report simply because the report addresses an expected topic.” U.S. Bank, 11 N.A. v. Glogowski L. Firm, PLLC, 339 F.R.D. 579, 581 (W.D. Wash. 2021). 12 If a court determines that the expert’s rebuttal report meets the standards for rebuttal
13 testimony under Rule 26, it generally accepts the report and declines to give the opposing party 14 another opportunity to respond.16 If, however, a court determines that the report does not satisfy 15 these standards, it will strike the report or grant the opposing party leave to file surrebuttal expert 16 reports.17 17 16 See, e.g., In re Cathode Ray Tube Antitrust Litig., 2015 WL 4451579, at *4–5 (N.D. Cal. 2015) 18 (declining to strike rebuttal report from a previously undisclosed expert because the defendants “have not asserted that [the rebuttal] report introduces new rather than rebuttal evidence[,]” although still 19 considering the defendants’ surrebuttals to “cure[ ] any prejudice”); HDT, 2022 WL 3018239, at *3 (declining to strike expert declarations because they “directly respond to the issues and evidence that [the 20 opposing party] submitted”); City of Pomona v. Sociedad Quimica Y Minera De Chile SA, 2018 WL 11714402, at *1 (C.D. Cal. May 1, 2018) (accepting the defendants’ reports as “proper rebuttal reports” 21 and striking the plaintiff’s reports as “improper” surrebuttals). 17 See, e.g., Haldane v. Hammond, 2017 WL 4122545, at *5 (W.D. Wash. 2017) (declining to consider a declaration from a new expert because the expert raised new arguments and evidence that were 22 absent from the plaintiffs’ complaint and motion for class certification); People v. Kinder Morgan Energy Partners, L.P., 159 F. Supp. 3d 1182, 1191–93 (S.D. Cal. 2016) (excluding report of newly introduced 23 expert because he was not properly disclosed as an “expert” under Rule 26 and instead, was disingenuously designated as a “rebuttal expert”); Oracle Am., Inc. v. Google Inc., 2011 WL 5572835, at 24 1 Here, the Court finds that Dr. Sunding’s Expert Report (Dkt. # 457-1) constitutes 2 permissible rebuttal. The Report addresses the same subject matter—focal point pricing—as 3 Defendant’s expert reports. See generally Dkt. # 457-1. It can also be fairly characterized as
4 “intended solely to contradict or rebut” Prof. Berger’s and Prof. Hitt’s reports. See id.; PUMA, 5 2024 WL 2091382, at *3. Defendant also does not argue that Plaintiffs improperly characterized 6 Dr. Sunding as a “rebuttal expert,” that the Report offers new arguments or models that were not 7 contemplated by Dr. Pathak’s report, that Dr. Sunding’s opinions are unresponsive to the issues 8 raised in Defendant’s opposition, or that the Report otherwise exceeds the boundaries of proper 9 rebuttal testimony under Rule 26. See generally Dkt. ## 435 & 493. The Court thus finds no 10 basis to strike Dr. Sunding’s Expert Report (Dkt. # 457-1) or grant Defendant leave to file any 11 surrebuttal reports. Accordingly, it DENIES Defendant’s Surreply Motion as to Dr. Sunding’s 12 rebuttal report and GRANTS Plaintiffs’ request to strike any portions of the February 6 Filings
13 that purport to respond to this report.18 14 *4 (N.D. Cal. Nov. 15, 2011) (striking one of the plaintiff’s two rebuttal reports, as the plaintiff 15 “identified no facts or law that would justify [a second report from a new expert]”); Morgan, 2021 WL 4806472, at *2–3 (granting surreply because the plaintiffs submitted “further evidence and arguments in 16 support of their motion to certify the class,” including a declaration by a “previously-undisclosed expert,” “rather than merely responding to [the defendants’] opposition to the motion”); Century Indem. Co. v. Marine Grp., LLC, 2015 WL 5521986, at *3–6 (D. Or. 2015) (striking rebuttal report because it presented 17 new arguments and evidence that pertained to fundamental issues in the case and so was “not a proper rebuttal report”); Purdue, 2022 WL 1203075, at *1–2 (excluding expert report because it offered “a new 18 model based on a new methodology in response to a criticism of [the expert’s] opening report”); McCain Foods, 2021 WL 4899465, at *3–4 (permitting surrebuttal because the expert’s rebuttal report included 19 opinions that “are not simply rebuttal”). 18 Although the Court strikes these filings as unauthorized surreply materials, nothing in this 20 Order should be read to preclude Defendant from properly re-raising these arguments and/or re- submitting this evidence in connection with its Motion to Exclude Testimony of David Sunding, Ph.D. 21 (Dkt. ## 472 & 473). This Order should also not be read to preclude Defendant’s experts from testifying to their critiques of Dr. Sunding’s opinions, provided that such critiques are limited to true rebuttals and 22 do not propose new arguments or evidence. See, e.g., Cave Consulting Grp., Inc. v. OptumInsight, Inc., 2018 WL 1938555, at *4 (N.D. Cal. Apr. 25, 2018) (striking expert reports but concluding that the experts may “testify at their depositions regarding not only the subject matter of their initial reports but 23 also any critiques of their opinions presented in the rebuttal reports, although they may not present new opinions, arguments, or evidence as alternatives to opinions, arguments, or evidence that [the rebuttal] 24 experts criticized”) (emphasis in original). 1 As for the timeliness issue, the Court does not find that Defendant’s Motion to Exclude 2 Testimony of David Sunding, Ph.D. (Dkt. ## 472 & 473) is untimely. The Court finds nothing in 3 its scheduling orders that would prevent Defendant from filing a Daubert motion in response to a
4 new expert report filed by Plaintiffs. Although the Court ordered the parties to complete briefing 5 on class certification and “Amazon’s Daubert Motion,” i.e., Defendant’ Motion to Exclude 6 Testimony of Parag Pathak, Ph.D (Dkt. # 325), by January 5, 2026, the Court never stated that 7 Defendant was not allowed to file a second Daubert motion should Plaintiffs introduce a new 8 expert. See generally Dkt. ## 350 & 423. The Court also does not find it fair to impose 9 Plaintiffs’ requested June 6, 2025 deadline on Daubert motions where, as here, Plaintiffs did not 10 file the challenged expert report until after the suggested deadline. 11 Thus, rather than penalizing Defendant and striking its motion at Dkt. ## 472 & 473, the 12 Court finds it more appropriate to consider the motion after giving Plaintiffs a reasonable
13 opportunity to respond. See Plexxikon Inc. v. Novartis Pharms. Corp., 2020 WL 1325068, at *1 14 (N.D. Cal. 2020); see also Dkt. # 488 at 15 (Plaintiffs request “an opportunity to respond within 15 a reasonable time” should the Court decline to strike the Motion). Accordingly, the Court 16 DENIES Plaintiffs’ request to strike Defendant’s Motion to Exclude Testimony of David 17 Sunding, Ph.D. (Dkt. ## 472 & 473) and GRANTS Plaintiffs leave to respond. 18 4. Plaintiffs’ “New” Factual Material 19 Defendant contends that Dr. Pathak’s Reply (Dkt. # 432-3) and Plaintiffs’ Reply in 20 Support of Class Certification (Dkt. # 429) “cite new factual material, including material that 21 became available after Amazon opposed Plaintiffs’ class certification motion.” Dkt. # 435 at 4. 22 The Surreply Motion lists many “new” depositions and documents that were cited by Plaintiffs’
23 replies. See Dkt. # 435-2. But it does not specify how or why this evidence is important to the 24 parties’ class certification arguments. See generally Dkt. # 435. Defendant also does not explain 1 why Plaintiffs’ citations to these materials amount to improperly introducing new evidence in a 2 reply rather than “direct[ly] respon[ding] to evidence or arguments raised in the opposition.” 3 HDT, 2022 WL 3018239, at *3. Nor does Defendant advance any meaningful arguments about
4 why it will be prejudiced if it is not allowed to respond to this new material. See generally Dkt. 5 ## 435 & 493. 6 The Court thus does not find a proper basis to strike the newly cited materials or grant 7 Defendant leave to respond. And so it DENIES Defendant’s Surreply Motion as to this evidence 8 and GRANTS Plaintiffs’ request to strike any February 6 Filings that are based on this 9 purportedly new material. 10 5. Plaintiffs’ “Misrepresentation” of Prof. Ostrovsky’s Testimony (& Defendant’s Other Deposition Transcripts) 11 Defendant contends that it “should be permitted to supplement Plaintiffs’ excerpts [of 12 Prof. Ostrovsky’s deposition testimony] so the Court has the complete record.” Dkt. # 435 at 4. 13 While not mentioned in the Surreply Motion, the February 6 Filings also include many other 14 deposition transcripts. See Dkt. ## 474-2 & 476-2 (Exhibits B–P). 15 Plaintiffs do not argue that Defendant is not allowed to submit deposition excerpts to cure 16 any purported misrepresentations in Plaintiffs’ briefings. See generally Dkt. # 488. Instead, they 17 argue that the filing of Prof. Ostrovsky’s deposition testimony on February 6, 2026 was improper 18 because Defendant was required “to submit excerpts of Prof. Ostrovsky’s deposition with its 19 November 12 surreply[.]” Id. at 9, 11. They also argue that the other deposition transcripts filed 20 on February 6, 2026 are “strictly gratuitous” because “Amazon does not even have a colorable 21 ground for filing [them].” Id. at 11. 22 As for Prof. Ostrovsky’s deposition testimony (Dkt. # 476-2 (Exhibit A)), the Court finds 23 no basis to strike. Neither LCR 7(g) nor Plaintiffs’ cited Order from De Coster v. Amazon.com, 24 1 No. 2:21-cv-00693-JHC, state that deposition testimony may be submitted to cure 2 misrepresentations only if it is attached to a surreply motion. See generally LCR 7(g); De 3 Coster, No. 2:21-cv-00693-JHC, Dkt. # 366 at 4 n.3. The Court is also aware of no rule or
4 prudential reason to exclude deposition testimony on this basis, especially where, as here, 5 Defendant raised the misrepresentation issue in a timely surreply motion and stated that it 6 intended to file supplemental deposition excerpts.19 And the Court affirms its decision in De 7 Coster—for the sake of completeness, a party should be allowed to submit further deposition 8 testimony if the opposing party’s reply mischaracterizes the deponent’s testimony. See De 9 Coster, No. 2:21-cv-00693-JHC, Dkt. # 366 at 4 n.3. Accordingly, the Court finds it proper to 10 allow Defendant to supplement Prof. Ostrovsky’s deposition testimony. It thus GRANTS 11 Defendant’s request to submit excerpts of Prof. Ostrovsky’s deposition transcript and DENIES 12 Plaintiffs’ request to strike Dkt. # 476-2 (Exhibit A). 13 The Court does not, however, find any reason to accept the other deposition excerpts filed 14 on February 6, 2026. Unlike with Prof. Ostrovsky’s testimony, Defendant does not claim that 15 Plaintiffs misrepresented these deponents’ statements. See generally Dkt. ## 435 & 493. 16 Defendant also did not call attention to these depositions in the Surreply Motion, nor provide any 17 justification in its Response to Plaintiffs’ Motion to Strike as to why it needed to file, and did 18 file, these deposition transcripts. See generally id. The Court thus concludes that the deposition 19 transcripts at Dkt. # 474-2 and Dkt. # 476-2 (Exhibits B–P) are beyond the scope of the Surreply 20 21 22
23 19 Because the Court finds that Defendant was not required to file these excerpts with its November 12 Surreply Motion, it likewise rejects Plaintiffs’ argument that Defendant’s failure to justify 24 its decision to file on February 6, 2026 is legally significant. See Dkt. ## 488 at 9; 494 at 6. 1 Motion’s request for leave to respond. Accordingly, it GRANTS Plaintiffs’ request to strike 2 these filings as unauthorized surreply materials.20 3 IV CONCLUSION 4 For these reasons, the Court: 5 (1) GRANTS IN PART and DENIES IN PART Defendant’s Surreply Motion (Dkt. # 6 435). Defendant’s request to strike is DENIED. Defendant’s request for leave to 7 respond in the alternative is GRANTED as to Dr. Pathak’s “new” analyses, Plaintiffs’ 8 “new” class definition, and Prof. Ostrovsky’s deposition testimony. Defendant’s 9 Surreply Motion is otherwise DENIED. 10 (2) GRANTS IN PART and DENIES IN PART Plaintiffs’ Motion to Strike (Dkt. # 488). 11 Plaintiffs’ request to strike is GRANTED as to the unexplained deposition transcripts, 12 the portions of the February 6 Filings that purport to respond to Dr. Sunding’s Expert 13 Report, and the portions of the February 6 Filings that purport to respond to 14 Plaintiffs’ newly cited factual material. Plaintiffs’ request to strike is DENIED as to 15 Prof. Ostrovsky’s deposition testimony (Dkt. # 476-2 (Exhibit A)), Defendant’s 16 Motion to Exclude Testimony of David Sunding, Ph.D. (Dkt. ## 472 & 473), and the 17 portions of the February 6 Filings that purport to respond to Dr. Pathak’s “new” 18 analyses and Plaintiffs’ “new” class definition. 19 (3) GRANTS Plaintiffs leave to respond to Defendant’s Motion to Exclude Testimony of 20 David Sunding, Ph.D. (Dkt. ## 472 & 473). The parties are directed to meet and 21 confer within the next five court days to set a briefing schedule and new noting date. 22
23 20 Although the Court strikes these filings as unauthorized surreply materials, nothing in this Order should be read to preclude Defendant from properly resubmitting these deposition transcripts in 24 connection with an authorized filing. 1 (4) STRIKES the remaining, i.e., non-stricken, portions of the February 6 Filings. 2 Defendant is DIRECTED to refile any surreply materials authorized by this Order as 3 a single docket entry by April 1, 2026. Defendant’s surreply brief shall not exceed 4 3,875 words and shall be limited to addressing Plaintiffs’ new class definition and 5 rebutting Dr. Pathak’s new arguments. Extraneous arguments, evidence, and other 6 materials that are not authorized by this Order will be stricken or ignored. 7 Dated this 18th day of March, 2026. 8 □□ eb Char 9 John H. Chun United States District Judge 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24