REPORT OF FOREIGN ISSUER Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For the month of December 2025 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 6-K (Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2b under the Securities Exchange Act of 1934.) Yes ¨ No x Eni S.p.A. (If "Yes" is marked, indicate below the file number assigned to ...