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, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 EOS ENERGY ENTERPRISES, INC. Delaware 001-39291 84-4290188 (State or other jurisdiction (Commission (IRS Employer of incorporation) File Number) Identification No .) 3920 Park Avenue Edison, New Jersey 08820 ...