Form 8-K

8-K — FUELCELL ENERGY INC

Accession: 0001104659-26-085427

Filed: 2026-07-21

Period: 2026-07-21

CIK: 0000886128

SIC: 3620 (ELECTRICAL INDUSTRIAL APPARATUS)

Item: Other Events

Item: Financial Statements and Exhibits

Documents

8-K — tm2616970d4_8k.htm (Primary)

EX-5.1 — EXHIBIT 5.1 (tm2616970d4_ex5-1.htm)

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0000886128

2026-07-21

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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):

July 21, 2026

FUELCELL

ENERGY, INC.

(Exact name of registrant as specified in its

charter)

Delaware

1-14204

06-0853042

(State or other jurisdiction

of incorporation)

(Commission File Number)

(I.R.S. Employer

Identification Number)

Great Pasture Road

Danbury,

Connecticut 06810

(Address of principal executive offices, including zip

code)

(203) 825-6000

(Registrant’s telephone number, including

area code)

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:

¨ 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 13-4(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, $0.0001 par

value per share

FCEL

The Nasdaq Stock Market

LLC

(Nasdaq Global 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 July 21, 2026, FuelCell Energy, Inc. (the “Company”)

filed a prospectus supplement to its automatic shelf registration statement on Form S-3 (Registration No. 333-296607) with

the Securities and Exchange Commission. This Current Report on Form 8-K is being filed solely for the purpose of filing the opinion

of Latham & Watkins LLP relating to the legality of the issuance and sale of the securities set forth in the prospectus supplement,

which opinion is attached as Exhibit 5.1 hereto.

Item 9.01. Financial Statements and Exhibits.

Exhibit

Number

Description

5.1

Opinion

of Latham & Watkins LLP.

23.1

Consent

of Latham & Watkins LLP (contained in the opinion filed as Exhibit 5.1 hereto).

104

Cover

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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.

FUELCELL ENERGY, INC.

Date: July 21, 2026

By:

/s/ Michael

S. Bishop

Michael S. Bishop

Executive Vice President, Chief Financial Officer and

Treasurer

EX-5.1 — EXHIBIT 5.1

EX-5.1

Filename: tm2616970d4_ex5-1.htm · Sequence: 2

Exhibit

5.1

1271 Avenue of the America

New York, New York 10020-1401

Tel: +1.212.906.1200 Fax: +1.212.751.4864

www.lw.com

FIRM

/ AFFILIATE OFFICES

Austin

Milan

Beijing

Munich

Boston

New York

Brussels

Orange County

Chicago

Paris

July 21, 2026

Dubai

Riyadh

Düsseldorf

San Diego

Frankfurt

San Francisco

Hamburg

Seoul

FuelCell Energy, Inc.

Hong

Kong

Silicon Valley

3 Great Pasture Road

Houston

Singapore

Danbury, Connecticut 06810

London

Tel Aviv

Los

Angeles

Tokyo

Madrid

Washington, D.C.

Re: Registration of up to 12,000,000 shares of common stock, par value

$0.0001 per share, of FuelCell Energy, Inc.

To the addressee set forth above:

We have acted as special counsel to FuelCell Energy, Inc.,

a Delaware corporation (the “Company”), in connection with the resale from time to time by the selling stockholder

(the “Selling Stockholder”) named in the Prospectus (as defined below) of up to 12,000,000 shares (the “Shares”)

of the Company’s common stock, $0.0001 par value per share (the “Common Stock”), issuable upon exercise

of outstanding warrants to purchase Common Stock issued to the Selling Stockholder (the “Warrants”) pursuant

to a warrant agreement between the Company and the Selling Stockholder dated June 22, 2026 (the “Warrant Agreement”).

The Shares are included in a registration statement on Form S–3 under the Securities Act of 1933, as amended (the “Act”),

filed with the Securities and Exchange Commission (the “Commission”) on June 8, 2026 (Registration No. 333–296607)

(the “Registration Statement”), a base prospectus, dated June 8, 2026, included in the Registration Statement

at the time it originally became effective (the “Base Prospectus”), and a prospectus supplement, dated July

21, 2026, filed with the Commission pursuant to Rule 424(b) under the Act (together with the Base Prospectus, the “Prospectus”).

This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion

is expressed herein as to any matter pertaining to the contents of the Registration Statement or related Prospectus, other than as expressly

stated herein with respect to the issue of the Shares.

As such counsel, we have examined such matters

of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates

and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters.

We are opining herein as to the General Corporation Law of the State of Delaware (the “DGCL”), and we express

no opinion with respect to any other laws.

July 21, 2026

Page 2

Subject to the foregoing and the other matters

set forth herein, it is our opinion that, as of the date hereof, when the Shares shall have been duly registered on the books of the transfer

agent and registrar therefor in the name or on behalf of the holders of the Warrants and have been issued by the Company against payment

therefor (not less than par value) in the circumstances contemplated by the Warrant Agreement, the issuance of the Shares will have been

duly authorized by all necessary corporate action of the Company, and the Shares will be validly issued, fully paid and nonassessable.

In rendering the foregoing opinion, we have assumed that (i) the Company will comply with all applicable notice requirements regarding

uncertificated shares provided in the DGCL, (ii) the Warrants and the Warrant Agreement have been duly executed and delivered by the Company

and constitute valid and legally binding obligations of the Company, (iii) the relevant Shares will have Vested (as defined in the Warrant

Agreement) pursuant to the terms of the Warrant Agreement prior to the exercise thereof, and (iv) upon the issuance of any of the Shares,

the total number of shares of Common Stock issued and outstanding will not exceed the total number of shares of Common Stock that the

Company is then authorized to issue under its certificate of incorporation, as amended.

This opinion is for your benefit in connection

with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions

of the Act. We consent to your filing this opinion as an exhibit to the Company’s Current Report on Form 8-K dated July 21, 2026

and its incorporation by reference into the Registration Statement and to the reference to our firm in the Prospectus under the heading

“Legal Matters.” In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required

under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Sincerely,

/s/ Latham & Watkins LLP

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