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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): November 17, 2025

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 November 17, 2025, Soluna Holdings, Inc. (the “Company”) issued a press release announcing its financial results for the quarter ended September 30, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 7.01 Regulation FD Disclosure.

See “Item 2.02 Results of Operations and Financial Condition” above.

In connection with the release of the Company’s financial results for the quarter ended September 30, 2025, on November 17, 2025, the Company made available an updated investor presentation on the investor relations portion of its website. A copy of the investor presentation is attached hereto as Exhibit 99.2 and is incorporated herein by reference.

The information in this Current Report on Form 8-K under Items 2.02 and 7.01, including the information contained in Exhibits 99.1 and 99.2, is being furnished to the Securities and Exchange Commission, and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by a specific reference in such filing.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits.

99.1 |  | Press Release, dated November 17, 2025
99.2 |  | Investor Presentation, dated November 17, 2025
104 |  | Cover Page Interactive Data File (embedded with 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: November 17, 2025 | By: | /s/ David C. Michaels
|  | David C. Michaels
|  | Chief Financial Officer
|  | (principal financial officer)