UNITED STATES SECURITIES AND EXCHANGE COMMISSION Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 11, 2026 EXAGEN INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation) (Commission File Number) Washington, D.C. 20549 FORM 8-K CURRENT REPORT ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule ...