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Table of Contents □ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K Annual Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 Transition Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 For the transition period from Commission file number 001-35662 Delaware ( State or other jurisdiction of incorporation or organization ) For Annual Period Ended December 31 , 2020 or Title of each class Common stock , $ 0.001 par value per share to QUALYS , INC . ( Exact name of registrant as specified in its charter ) 919 E. Hillsdale Boulevard , 4th Floor , Foster City , California 94404 ( Address of principal executive offices , including zip code ) ( 650 ) 801-6100 ( Registrant's telephone number , including area code ) Securities registered pursuant to section 12 ( b ) of the Act : Trading Symbol ( s ) QLYS 77-0534145 ( I.R.S. Employer Identification Number ) Name of exchange on which registered NASDAQ Stock Market No Securities registered pursuant to section 12 ( g ) of the Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes 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 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 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 during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated 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 Accelerated filer Non - accelerated filer Smaller reporting company 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 . Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . < Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes ☐ No 区 As of June 30 , 2020 , the aggregate market value of voting shares of common stock held by non - affiliates of the registrant was $ 3,501 million based on the last reported sale price of the registrant's common stock on June 30 , 2020. Shares of common stock held by each executive officer and director and by each person who owns 10 % or more of the outstanding common stock have been excluded in that such persons may be deemed to be affiliates . This determination of affiliate status is not necessarily a conclusive determination for other purposes . The number of shares of the registrant's common stock outstanding as of February 12 , 2021 was 39,207,735 shares . ☐ NO □ No DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's Proxy Statement for its 2021 Annual Meeting of Stockholders are incorporated by reference in Part III of this Annual Report on Form 10 - K where indicated . Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant's fiscal year ended December 31 , 2020 .