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, 2025 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from_____to _____ Commission File Number: 001-40261 Soluna Holdings, Inc.(Exact name of registrant as specified in its charter) Nevada14-1462255(State or other jurisdiction(I.R.S. Employerof incorporation or organization)Identification No.) 325 Washington Avenue Extension, Albany, New York 12205(Address of principal executive offices) (Zip Code) (516) 216-9257(Registrant’s telephone number, including area code) Securities registered pursuant to Section 12(b) of the Act: Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YesNo Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. YesNo Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the SecuritiesExchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports),and (2) has been subject to such filing requirements for the past 90 days. YesNo Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submittedpursuant to Rule 405 of Regulation S-T (Section 232.405 of this chapter) during the preceding 12 months (or for such shorter periodthat the registrant was required to submit such files). YesNo Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smallerreporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smallerreporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Large accelerated filerNon-accelerated filer If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectivenessof its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registeredpublic accounting firm that prepared or issued its audit report. If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of theregistrant included in the filing reflect the correction of an error to previously issued financial statements. Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-basedcompensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). YesNo The aggregate market value of the voting and non-voting common equity held by non-affiliates as of June30, 2025 (based on theclosing price of $0.58 per share on the Nasdaq Stock Market LLC for that date) was $8,284,532. As of March20, 2026, the Registrant had 111,381,064 shares of common stock outstanding. Documents incorporated by reference: None. TABLE OF CONTENTS PART IItem 1.Business6Item 1A.Risk Factors17Item 1B.Unresolved Staff Comments41Item 1C.Cybersecurity41Item 2.Properties42Item 3.Legal Proceedings42Item 4.Mine Safety Disclosures43PART IIItem 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities44Item 6.[Reserved]44Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations44Item 7A.Quantitative and Qualitative Disclosures About Market Risk65Item 8.Financial Statements and Supplementary Data65Item 9.Changes in and Disagreements with Accountants on Accounting and Financial Disclosure65Item 9A.Controls and Procedures65Item 9B.Other Information67Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections67PART IIIItem 10.Directors, Executive Officers and Corporate Governance68Item 11.Executive Compensation74Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters80Item 13.Certain Relationships and Related Transactions, and Director Independence82Item 14.Principal Accounting Fees and Services84PART IVItem 15.Exhibits, Financial Statement Schedules86 Glossary of Abbreviations and Acronyms for Selected References The following list defines various abbreviations and acronyms used throughout this Annual Report on Form 10-K (this