UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANISITON PERIOD FROM _____ TO _____ Commission File Number 0-27512 CSG SYSTEMS INTERNATIONAL, INC. (Exact name of Registrant as specified in its Charter) Delaware 47-0783182 (State or ...