Amendment to Annual Report (Form 10-K/A)

This Amendment No. 1 (this "Amendment") on Form amends the Annual Report on Form for the year ended December 31, 2025 of Power Solutions International, Inc. ("PSI" or the "Company") filed with the Securities and Exchange Commission (the "SEC") on March 2, 2026 (the "Original to include the information required by Items 10 through 14 of Part III (the "Part III Disclosure") of the Original This information was previously omitted from the Original in reliance on General Instruction G(3) to Form which permits the information in the above referenced items to be incorporated in the Form by reference to the Company's definitive proxy statement if such statement is filed no later than 120 days after the Company's fiscal

The information included herein as required by the Part III Disclosure is more limited than what is required to be included in the definitive proxy statement to be filed in connection with PSI's 2025 Annual Meeting of Stockholders. Accordingly, the definitive proxy statement to be filed at a later date will include additional information related to the topics herein and additional information not required by the Part III Disclosure.

Pursuant to the SEC rules, Part IV, Item 15 has also been amended to contain the currently dated certificates from the Company's principal executive and financial officers pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. The certificates of the Company's principal executive and financial officers are attached to this Amendment as Exhibits 31.3 and 31.4. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation paragraphs 3, 4 and 5 of the certifications have been omitted. Additionally, PSI is not including the certificates under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment.

Except for the information described above, the Company has not modified or updated disclosures provided in the Original in this Amendment. Accordingly, this Amendment does not reflect events occurring after the filing of the Original or modify or update those disclosures affected by subsequent events, except as noted herein. Information not affected by this Amendment is unchanged and reflects the disclosures made at the time the Original was filed.