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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 20 - F o REGISTRATION STATEMENT PURSUANT TO SECTION 12 ( b ) OR ( g ) OF THE SECURITIES EXCHANGE ACT OF 1934 OR þ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE FISCAL YEAR ENDED DECEMBER 31 , 2020 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from OR 0 SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Title of each class Date of event requiring this shell company report¸ Commission file number 001-31317 Companhia de Saneamento Básico do Estado de São Paulo - SABESP ( Exact name of Registrant as specified in its charter ) Common Shares , without par value 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 , 300 05429-900 São Paulo , SP , Brazil ( Address of principal executive offices ) Rui de Britto Álvares Affonso raffonso@sabesp.com.br ( +55 11 3388 8247 ) Rua Costa Carvalho , 300 05429-900 São Paulo , SP , Brazil Securities registered or to be registered pursuant to Section 12 ( b ) of the Act : American Depositary Shares , evidenced by American Depositary Receipts , each representing one Common Share Trading Symbols ( s ) Not traded SBS Name of each exchange on which registered New York Stock Exchange * New York Stock Exchange 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 Stock Exchange . to