8-K

AMERICAN SUPERCONDUCTOR CORPORATION

Date: December 23, 2025

/S/ JOHN W. KOSIBA, JR.

John W. Kosiba, Jr.

Senior Vice President and Chief Financial Officer

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):

December 23, 2025

American Superconductor Corporation

(Exact name of registrant as specified in its charter)

Delaware

000-19672

04-2959321

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

114 East Main Street

Ayer, Massachusetts

01432

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code: (978) 842-3000

Not Applicable

(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 (see General Instruction A.2. below):

☐	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, $0.01 par value per share

AMSC

Nasdaq Global Select Market

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 December 23, 2025, American Superconductor Corporation (the “Company”) filed a prospectus supplement with the Securities and Exchange Commission (the “SEC”) relating to shares of the Company’s common stock to be sold from time to time by certain selling stockholders of the Company. The prospectus supplement forms a part of the Company’s Registration Statement on Form S-3 (Reg. No. 333-281496), which was filed with the SEC and became effective on August 12, 2024.

Latham & Watkins LLP, counsel to the Company, has issued an opinion to the Company, dated December 23, 2025, regarding the validity of such shares. A copy of the opinion is filed as Exhibit 5.1 to this Current Report on Form 8-K.

Item 9.01

Financial Statements and Exhibits

(d) Exhibits:


5.1		Opinion of Latham & Watkins LLP

23.1		Consent of Latham & Watkins LLP (included in Exhibit 5.1)

104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

SEC Form 8-K filed by American Superconductor Corporation