Page 1

( Mark One ) X UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , DC 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 FORM 10 - K TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Delaware ( State or Other Jurisdiction of Incorporation or Organization ) For the fiscal year ended December 31 , 2020 OR 2777 Orchard Parkway San Jose , California ( Address of Principal Executive Offices ) For the transition period from Calix , Inc. ( Exact Name of Registrant as Specified in Its Charter ) Title of each class Common Stock , $ 0.025 par value to Commission File Number : 001-34674 Securities registered pursuant to Section 12 ( b ) of the Act : Trading symbol CALX Registrant's telephone number , including area code ( 408 ) 514-3000 68-0438710 ( I.R.S. Employer Identification No. ) 95134 ( Zip Code ) Securities registered pursuant to section 12 ( g ) of the Act : None ( Title of class ) Name of each exchange on which registered The New York Stock Exchange Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes : o No : x Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes : o No : X Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange 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 . Yes : x No : o Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes : x No : 0 Indicate by ch mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accel ated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , ” “ smaller reporting company , ” and “ emerging growth company " in Rule 12b - 2 of the Exchange Act . Large Accelerated Filer Non - accelerated filer Accelerated Filer Smaller Reporting Company X Emerging Growth Company If an emerging growth company , indicate by check mark if the registrant 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