Results of Operations · Reg FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549   FORM 8-K   CURRENT REPORT   Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934   Date of Report (Date of earliest event reported): May 18, 2026   SOLUNA HOLDINGS, INC. (Exact name of Registrant as Specified in Its Charter)   Nevada   001-40261   14-1462255 (State or Other Jurisdiction of Incorporation)   (Commission File Number)   (IRS Employer Identification No.)   325 Washington Avenue Extension     Albany , New York   12205 (Address of Principal Executive Offices)   (Zip Code)   Registrant’s Telephone Number, Including Area Code: (516) 216-9257   N/A (Former Name or Former Address, if Changed Since Last Report)   Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:   ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)     ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)     ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))     ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))   Securities registered pursuant to Section 12(b) of the Act:   Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common stock, par value $0.001 per share   SLNH   The Nasdaq Stock Market LLC 9.0% Series A Cumulative Perpetual Preferred Stock, par value $0.001 per share   SLNHP   The Nasdaq Stock Market LLC   Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).   Emerging growth company ☐   If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐             Item 2.02. Results of Operations and Financial Condition.   On May 18, 2026, Soluna Holdings, Inc. (the “Company”) issued a press release announcing its financial results for the three months ended March 31, 2026.   A copy of such press release is attached as Exhibit 99.1 hereto and incorporated herein by reference.   The information in this Item 2.02 of Form 8-K and Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, regardless of any general incorporation language in such filing.   Item 7.01 Regulation FD Disclosure.   On May 18, 2026, the Company posted an updated investor presentation to its investor relations website, which can be found at https://www.solunacomputing.com/investors/updates/. The information on our web site is not incorporated by reference into this Form 8-K and should not be considered to be a part of this Form 8-K. The Company’s web site address is included in this document as an inactive textual reference only.   The information in this Item 7.01 of Form 8-K shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act, regardless of any general incorporation language in such filing.   Item 9.01. Financial Statements and Exhibits.   EXHIBIT INDEX   Exhibit No.   Description       99.1   Press Release, dated May 18, 2026. 104   Cover Page Interactive Data File (embedded within the Inline XBRL document).          SIGNATURES   Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.     SOLUNA HOLDINGS, INC.       Date: May 18, 2026 By: /s/ Michael Picchi     Michael Picchi     Chief Financial Officer     (principal financial officer)