0000875657 2025-01-01 2025-12-31 0000875657 2026-04-24 0000875657 2025-06-30 shares iso4217:USD FY 2025 --12-31 true 0000875657 10-K/A true 2025-12-31 false 0-20852 ULTRALIFE CORPORATION DE 2000 Technology Parkway Newark NY 14513 16-1387013 315 332-7100 Common Stock, $0.10 par value per share ULBI NASDAQ No No Yes Yes Accelerated Filer true false true true true false 90469809 16656503 This Amendment No. 1 to the Annual Report on Form 10-K of Ultralife Corporation (the “Company”) for the year ended December 31, 2025 as originally filed with the Securities and Exchange Commission (the “SEC”) on March 23, 2026 (the “Original Form 10-K”), is being filed solely to include the information required by Items 10, 11, 12, 13 and 14 of Part III and to amend Item 15 of Part IV and the Index of Exhibits of Original Form 10-K. This information required by Part III of Form 10-K was omitted from the Original Form 10-K in reliance on General Instruction G(3) to Form 10-K, which permits the information in the above referenced items to be incorporated in the Form 10-K by reference from our definitive proxy statement if such proxy statement is filed no later than 120 days after our fiscal year-end. We are including this Part III information in this Amendment No. 1 to the Original Form 10-K because we will not file a definitive proxy statement containing such information within 120 days after the end of the fiscal year covered by the Original Form 10-K. We plan on filing our definitive proxy statement on or about June 2, 2026 as we are holding our 2026 Annual Stockholders’ Meeting (the “Meeting”) on July 22, 2026.