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 For the Annual Period Ended December 31, 2022 or ☐ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to Commission file number 001-35662 QUALYS, INC. (Exact name of registrant as specified in its charter) Delaware 77-0534145 (State or other jurisdiction of (I.R.S. Employer ...