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): September 23, 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 8.01. Other Events.

On September 23, 2025, Soluna Holdings, Inc. (the “Company”) filed a prospectus supplement (the “Prospectus Supplement”) with the Securities and Exchange Commission for the offer and sale of shares of its common stock, par value $0.001 per share, having an aggregate offering price of up to $87,650,000 (the “Shares”), pursuant to that certain At the Market Offering Agreement, dated April 29, 2025, by and between the Company and H.C. Wainwright & Co., LLC (the “Sales Agreement”). The Prospectus Supplement amends and supplements the information in the prospectus dated April 29, 2025 (the “Prior Prospectus”), as previously amended and supplemented by the prospectus supplements dated April 29, 2025 and September 2, 2025 (together with the Prior Prospectus, the “ATM Prospectus”), filed as a part of our registration statement on Form S-3 (File No. 333-286638). The Prospectus Supplement should be read in conjunction with the ATM Prospectus, and is qualified by reference thereto, except to the extent that the information therein amends or supersedes the information contained in the ATM Prospectus. The Prospectus Supplement is not complete without, and may only be delivered or utilized in connection with, the ATM Prospectus and any future amendments or supplements thereto. The Company has previously sold 13,680,483 shares of its common stock for aggregate gross proceeds of approximately $12.3 million under the Sales Agreement. A copy of the opinion of Brownstein Hyatt Farber Schreck, LLP relating to the validity of the Shares is attached as Exhibit 5.1 hereto.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.		Description
5.1		Opinion of Brownstein Hyatt Farber Schreck, LLP
23.1		Consent of Brownstein Hyatt Farber Schreck, LLP (included in Exhibit 5.1)
104		Cover Page Interactive Date 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: September 23, 2025	By:	/s/ David C. Michaels
		David C. Michaels
		Chief Financial Officer
		(principal financial officer)

Soluna Holdings Inc. filed SEC Form 8-K: Other Events, Financial Statements and Exhibits