International Business Machines Corporation v. Zillow Group, Inc.; Zillow, Inc.

CourtDistrict Court, W.D. Washington
DecidedJune 30, 2026
Docket2:20-cv-00851
StatusUnknown

This text of International Business Machines Corporation v. Zillow Group, Inc.; Zillow, Inc. (International Business Machines Corporation v. Zillow Group, Inc.; Zillow, Inc.) is published on Counsel Stack Legal Research, covering District Court, W.D. Washington primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
International Business Machines Corporation v. Zillow Group, Inc.; Zillow, Inc., (W.D. Wash. 2026).

Opinion

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3 4 UNITED STATES DISTRICT COURT WESTERN DISTRICT OF WASHINGTON 5 AT SEATTLE 6 INTERNATIONAL BUSINESS MACHINES CORPORATION, 7 Plaintiff, 8 C20-0851 TSZ v. 9 ORDER ZILLOW GROUP, INC.; and 10 ZILLOW, INC., 11 Defendants. 12 THIS MATTER comes before the Court on a motion for summary judgment, 13 docket no. 270, brought by defendants Zillow Group, Inc. and Zillow, Inc. (collectively, 14 “Zillow”), and a related motion to compel discovery, docket no. 272, brought by plaintiff 15 International Business Machines Corporation (“IBM”). Having reviewed all papers filed 16 in support of and in opposition to Zillow’s motion for summary judgment, the Court 17 concludes that the dispositive motion should be denied and that IBM’s related motion to 18 compel discovery may therefore be stricken as moot.1 19

20 1 After considering the parties’ respective views, as set forth in their Joint Status Report dated 21 January 30, 2026, docket no. 264, the Court (i) set a deadline for Zillow to file a motion asserting noninfringement based on the absence of a “single-sign-on operation,” and (ii) allowed IBM to 22 conduct depositions concerning the contents of any declaration or affidavit and/or attachment thereto that Zillow submitted in support of its motion for summary judgment. See Minute Order 1 Background 2 This case has been pending in this District for over six years, and the Court is well

3 acquainted with the remaining patent-in-suit, namely U.S. Patent No. 7,631,346 (“the 4 ’346 Patent”).2 The ’346 Patent survived two separate challenges under 35 U.S.C. § 101, 5 one in the District of Delaware and one in this District, see Int’l Bus. Machs. Corp. v. The 6 Priceline Grp. Inc., No. 15-137, 2016 WL 626495 (D. Del. Feb. 16, 2016), adopted, 2016 7 WL 1253472 (D. Del. Mar. 30, 2016); Int’l Bus. Machs. Corp. v. Zillow Grp., Inc., 549 F. 8 Supp. 3d 1247, 1273–75 (W.D. Wash. 2021), but it was subsequently held unpatentable

9 10 (docket no. 269). In conjunction with its dispositive motion, Zillow submitted the declaration of one of its attorneys, attached to which were several exhibits. See Shih Decl. (docket no. 270-1). 11 IBM sought to depose a Zillow designee pursuant to Federal Rule of Civil Procedure 30(b)(6), but Zillow refused because the exhibits appended to its counsel’s declaration were not Zillow’s 12 documents, but rather (a) materials produced by IBM in this litigation or in connection with patent prosecution or inter partes review proceedings, or (b) public webpages of third parties. See Defs.’ Resp. at 2 (docket no. 274). IBM filed a motion to compel, asking the Court to direct 13 Zillow to submit to a Rule 30(b)(6) deposition and to make its source code available for inspection. See Pl.’s Mot. at 7 (docket no. 272). On June 15, 2026, IBM timely submitted a 14 substantive response to Zillow’s motion for summary judgment. See Pl.’s Resp. (docket nos. 277 & 279). Zillow has filed a reply, docket no. 280, and the motion for summary judgment is fully 15 briefed and ready for consideration. In light of the Court’s ruling on the dispositive motion, which is favorable to IBM, the Court need not address IBM’s related discovery motion. 16 2 This action began in September 2019 in the Central District of California with allegations that 17 Zillow infringed seven (7) different patents. See Compl. (docket no. 1). Two of those patents were declared invalid on the ground that they were not directed to eligible subject matter. Int’l Bus. Machs. Corp. v. Zillow Grp., Inc., 549 F. Supp. 3d 1247, 1260–68 (W.D. Wash. 2021), 18 aff’d, 50 F.4th 1371 (Fed. Cir. 2022). Another patent was declared invalid on the basis of indefiniteness; partial judgment was entered, and the Court’s decision was not appealed. See 19 Int’l Bus. Machs. Corp. v. Zillow Grp., Inc., No. C20-851, 2022 WL 16532550, at *3–4 & 9 (W.D. Wash. Oct. 28, 2022); see also Partial Judgment (docket no. 238). IBM’s claims as to 20 three other patents, one of which was declared invalid in part based on ineligible subject matter, see Chewy, Inc. v. Int’l Bus. Machs. Corp., 94 F.4th 1354, 1364–68 (Fed. Cir. 2024), and another 21 of which was invalidated in toto because of patent-ineligible subject matter, see Int’l Bus. Machs. Corp. v. Zynga Inc., 642 F. Supp. 3d 481 (D. Del. 2022), were dismissed with prejudice upon the 22 parties’ stipulation. Minute Order at ¶ 1 (docket no. 254). 1 in part, with respect to Claims 1–4, 12–16, and 18–19, which were deemed obvious in 2 light of prior art, see Ebates Performance Mktg., Inc. v. Int’l Bus. Machs. Corp.,

3 IPR2022-646, 2023 WL 7358027 (P.T.A.B. Oct. 11, 2023), aff’d sub nom. Int’l Bus. 4 Machs. Corp. v. Zillow Grp., Inc., 160 F.4th 1360 (Fed. Cir. 2025). 5 In this action, IBM asserts that Zillow’s websites (including www.zillow.com and 6 www.zillowgroupmedia.com) and mobile applications (“Apps”) infringe Claims 5, 8, and 7 10 of the ’346 Patent. See 2d Am. Compl. at ¶¶ 156–70 (docket no. 156); see also Joint 8 Status Report at 1:26–27 (docket no. 257). Claim 5 depends from Claim 1, and Claims 8

9 and 10 depend from Claim 5. See ’346 Patent at 45:10, 28, & 34 (docket no. 1-2 at 40). 10 Thus, to prevail on its claim of infringement, IBM must establish, at a minimum, that at 11 least one of Zillow’s platforms (i.e., a website or a mobile application) employs all the 12 elements of the method set forth in independent Claim 1 of the ’346 Patent. In moving 13 for summary judgment, Zillow focuses on only one limitation in Claim 1, namely

14 “single-sign-on operation,” which the Court previously construed as meaning 15 a process by which a user is not required [to] take an action that provides credentials, or that plays a role in launching a provision of credentials on the 16 user’s behalf, to gain access to a second entity’s resources after the user has been authenticated with a first entity. 17 Order at 13 (docket no. 240). Zillow was provided notice and an opportunity to show 18 cause, see Minute Order at ¶ 1(a)(i) (docket no. 269), why the Court should not 19 reconsider its earlier ruling and adopt the interpretation proposed by IBM, namely 20 a process by which a user is authenticated at a first entity and subsequently 21 not required to perform another authentication before accessing a protected resource at a second entity. 22 Pl.’s Opening Br. at 8 (docket no. 203). 1 Having considered the parties’ respective arguments, the Court is persuaded that, 2 under the Court’s prior construction, Zillow has not established it is entitled to judgment

3 as a matter of law and that, given Zillow’s noninfringement analysis, the Court’s earlier 4 definition of “single-sign-on operation” is manifestly erroneous and must be corrected. 5 See Local Civil Rule 7(h)(1).3 6 Discussion 7 A. The ’346 Patent 8 The ’346 Patent is aimed at reducing the burdens on World Wide Web or Internet

9 users who wish to switch between applications controlled by different enterprises that 10 have erected authentication barriers, which are designed to protect their systems, as well 11 as their users’ privacy and/or confidential information. See ’346 Patent at 1:9–2:48 & 12 10:16–20 (docket no. 1-2). The specification4 of the ’346 Patent defines “authentication” 13 as “the process of validating a set of credentials” that are provided by or on behalf of a

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International Business Machines Corporation v. Zillow Group, Inc.; Zillow, Inc., Counsel Stack Legal Research, https://law.counselstack.com/opinion/international-business-machines-corporation-v-zillow-group-inc-zillow-wawd-2026.