SEC Form S-8 filed by MAIA Biotechnology Inc.

As filed with the Securities and Exchange Commission on April 7, 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

MAIA Biotechnology, Inc.

(Exact Name of Registrant as Specified in Its Charter)

444 West Lake Street, Suite 1700

Chicago, IL 60606

(312) 416-8592

(Address of Principal Executive Offices, Including Zip Code)

MAIA Biotechnology, Inc. 2021 Equity Incentive Plan, as amended

(Full Title of the Plans)

Vlad Vitoc

Chief Executive Officer

c/o MAIA Biotechnology, Inc.

444 West Lake Street, Suite 1700

Chicago, IL 60606

(312) 416-8592

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

With a copy to:

Richard A. Friedman, Esq.
Sheppard, Mullin, Richter & Hampton LLP

30 Rockefeller Plaza

New York, NY 10012

Telephone: (212) 653-8700

Facsimile: (212) 653-8701

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. ☐

This Registration Statement will become effective upon filing in accordance with Rule 462(a) under the Securities Act.

PART I

STATEMENT OF INCORPORATION BY REFERENCE

This Registration Statement on Form S-8, relating to the MAIA Biotechnology 2021 Equity Incentive Plan, as amended (the “2021 Plan”) of MAIA Biotechnology, Inc. (the “Company”), is being filed for the purpose of registering additional securities of the same class as other securities for which Registration Statements on Form S-8 relating to the 2021 Plan have previously been filed and is effective and consists only of those items required by General Instruction E to Form S-8. Accordingly, this Registration Statement incorporates by reference the contents of (i) the Registration Statement on Form S-8, File No. 333-266453, filed with the Securities and Exchange Commission on August 1, 2022, by the Company, relating to the 2021 Plan; (ii) the Registration Statement on Form S-8 File No. 333-273086 filed with the Securities and Exchange Commission on June 30, 2023 relating to the 2021 Plan; (iii) the Registration Statement on Form S-8, File No. 333-278828, filed with the Securities and Exchange Commission on April 19, 2024, by the Company, relating to the 2021 Plan and (iv) the Registration Statement on Form S-8, File No. 333-286225, filed with the Securities and Exchange Commission on March 28, 2025, by the Company, relating to the 2021 Plan (the “Prior Registration Statements”), except for Items 3 and 8, which are being updated by this Registration Statement.

This Registration Statement is being filed for the purpose of registering an additional 6,458,889 shares of common stock, par value $0.0001 per share (“Common Stock”) that were reserved for issuance under the 2021 Plan. In addition, the 2021 Plan provides that shares issued under the 2021 Plan that are forfeit or expire are available for future grants of awards under the 2021 Plan and an additional 645,888 shares of Common Stock are being registered hereunder for that purpose, for an aggregate of 7,104,777 shares of Common Stock being registered hereunder.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of documents by reference.

The following documents filed by the Company with the Securities and Exchange Commission (“SEC”) pursuant to the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), are incorporated herein by reference:

Item 8. Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, 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 the City of Chicago, State of Illinois, on the 7th day of April, 2026.

POWER OF ATTORNEY

We, the undersigned officers and directors of MAIA Biotechnology, Inc., hereby severally constitute and appoint Vlad Vitoc and Jeffrey Himmelreich, and each of them singly (with full power to each of them to act alone), our true and lawful attorneys-in-fact and agents, with full power of substitution and re-substitution in each of them for him or her and in his or her name, place and stead, and in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933), and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as full to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

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 date indicated.