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 fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 000-51734 Calumet Specialty Products Partners, L.P. (Exact Name of Registrant as Specified in Its Charter) Delaware 35-1811116 (State or Other Jurisdiction of (I.R.S. Employer Incorp ...