SEC Form S-8 filed by Plug Power Inc.

As filed with the Securities and Exchange Commission on June 18, 2026

Registration No. 333-_______

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT UNDER

THE SECURITIES ACT OF 1933

PLUG POWER INC.

(Exact Name of Registrant as Specified in Its Charter)

Amendment No. 4 to the Plug Power Inc. 2021 Stock Option and Incentive Plan

(Full Title of the Plan)

Jose Luis Crespo

Chief Executive Officer and President

Plug Power Inc.

125 Vista Boulevard
Slingerlands, New York 12159

(Name and Address of Agent For Service)

(518) 782-7700

(Telephone Number, Including Area Code, of Agent For Service)

With a copy to:

Audrey S. Leigh
Goodwin Procter LLP
620 Eighth Avenue
New York, New York 10018
(212) 813-8800

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12b-2 of the Exchange Act.

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 7(a)(2)(B) of the Securities Act. ¨

EXPLANATORY NOTE

REGISTRATION OF ADDITIONAL SHARES

This Registration Statement on Form S-8 is filed to register an additional 25,000,000 shares of common stock, par value $0.01 per share (“Common Stock”), of Plug Power Inc. (the “Registrant”) authorized to be issued under the Plug Power Inc. 2021 Stock Option and Incentive Plan, as amended (the “2021 Plan”). The stockholders of the Registrant approved an amendment to the 2021 Plan on June 11, 2026 at the Registrant’s 2026 Annual Meeting of Stockholders to, among other things, increase the number of shares of Common Stock available for issuance under the 2021 Plan. These additional shares of Common Stock are securities of the same class as other securities for which the Registration Statements on Forms S-8 (File No. 333-294091, File No. 333-274250, File No. 333-267508 and File No. 333-258797) (the “Prior Registration Statements”) were filed with the Securities and Exchange Commission (the “Commission”) on March 6, 2026, August 29, 2023, September 20, 2022 and August 13, 2021, respectively. After giving effect to this Registration Statement, an aggregate of 116,400,000 shares of the Registrant’s Common Stock have been registered for issuance under the 2021 Plan.

In accordance with General Instruction E to Form S-8, this Registration Statement hereby incorporates by reference the contents of the Prior Registration Statements except as set forth below.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

The following documents filed by the Registrant with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), are incorporated by reference in this Registration Statement:

In addition, all documents (other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) subsequently filed with the Commission by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, on or after the date of this Registration Statement and prior to the filing of a post-effective amendment to this Registration Statement which indicates that all securities offered herein have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of filing of such documents.

Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently filed document which also is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Item 8. Exhibits.

See the Exhibit Index included herein for a list of exhibits filed as part of this Registration Statement, which Exhibit Index is incorporated herein by reference.

EXHIBIT INDEX

*Filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Slingerlands, New York, on this 18^th day of June, 2026.

POWER OF ATTORNEY AND SIGNATURES

We, the undersigned officers and directors of Plug Power Inc., hereby severally constitute and appoint Jose Luis Crespo and Gerard L. Conway Jr., and each of them singly, our true and lawful attorneys with full power to them, and each of them singly, to sign for us and in our names in the capacities indicated below, the Registration Statement on Form S-8 filed herewith and any and all subsequent amendments to said registration statement, and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Plug Power Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or any of them, to said Registration Statement and any and all amendments thereto.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.