Companhia de Saneamento Basico do Estado de Sao Paulo–SABESP ADR 2025年年度报告和过渡报告

Washington, D.C. 20549 FORM20-F ¨REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF1934 OR xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FORTHE FISCAL YEAR ENDEDDECEMBER 31, 2024 OR ¨TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934FOR THE TRANSITION PERIOD FROM ________________ TO ________________ OR ¨SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 Date of event requiring this shell company report: ________________ Commission file number001-31317 Companhia de Saneamento Básico do Estado de São Paulo-SABESP(Exact name of Registrant as specified in its charter) Basic Sanitation Company of the State of São Paulo-SABESP(Translation of the Registrant’s name into English) Federative Republic of Brazil(Jurisdiction of incorporation or organization) Rua Costa Carvalho, 30005429-900São Paulo, SP,Brazil(Address of principal executive offices) Daniel Szlakdri@sabesp.com.br(+55 113388 8000)Rua Costa Carvalho, 30005429-900São Paulo, SP,Brazil Securities registered or to be registered pursuant to Section 12(b) of the Act: TradingSymbols(s)Not tradedSBS Common Shares, without par valueAmerican Depositary Shares, evidenced by AmericanDepositary Receipts,each representing one Common Share Shares are not listed for trading, but only in connection with the registration of American Depositary Receipts pursuant to the requirements of the New York StockExchange. Securities registered or to be registered pursuant to Section 12(g) of the Act: None Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act: None Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close of the periodcovered by the annual report. 683,509,868Shares of Common Stock1 Share of Preferred Stock Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YesxNoo If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports pursuant to Section13 or 15(d) of the Securities Exchange Act of 1934 from their obligations under those Sections. YesoNox Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the SecuritiesExchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports)and (2) has been subject to such filing requirements for the past 90 days. YesxNoo Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submittedpursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that theregistrant was required to submit such files). YesxNoo Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or an emerginggrowth company. See the definition of “large accelerated filer,” “accelerated filer,” and “emerging growth company” in Rule 12b-2 ofthe Exchange Act. Accelerated FileroEmerging Growth Company☐ Large Accelerated Filerx Non-accelerated Filero If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if theregistrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards†provided pursuant to Section 13(a) of the Exchange Act.o † The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board toits Accounting Standards Codification after April 5, 2012. Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectivenessof its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registeredpublic accounting firm that prepared or issued its audit report.x If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of theregistrant included in the filing reflect the correction of an error to previously issued financial statements.o Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-basedcompensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).o Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements included in this filing:International Financial ReportingOthero Standardsas issued by theInternational Accounting StandardsBoardx If “Other” has been checke