Form 8-K

8-K — Castellum, Inc.

Accession: 0001877939-26-000044

Filed: 2026-05-20

Period: 2026-05-19

CIK: 0001877939

SIC: 8742 (SERVICES-MANAGEMENT CONSULTING SERVICES)

Item: Submission of Matters to a Vote of Security Holders

Documents

8-K — ctm-20260519.htm (Primary)

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8-K

8-K (Primary)

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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 and Exchange Act of 1934

Date of Report (Date of earliest event reported): 5/19/2026

CASTELLUM, INC.

(Exact name of Registrant as specified in its charter)

Nevada 001-41526 27-4079982

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

1934 Old Gallows Road, Suite 350

Vienna, VA 22182

(Address of principal executive offices, including zip code)

703-752-6157

(Registrant’s telephone number, including area code)

Check the appropriate box below if the 8-K filing is intended to simultaneously satisfy the filing obligations of the registrant under any of the following provisions:

☐ Written communication 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 240.13(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 $0.0001 per share CTM NYSE American LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

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 5.07 Submission of Matters to a Vote of Security Holders.

The Company held its annual meeting of stockholders on May 19, 2026 (the “2026 Annual Meeting”), at which three proposals were submitted to the Company’s stockholders. The proposals are described in detail in the Company’s proxy statement for the 2026 Annual Meeting filed with the Securities and Exchange Commission on April 7, 2026 (the “2026 Proxy Statement”). A quorum of the Company’s common shares was present for the 2026 Annual Meeting, and the final results for the votes regarding the proposals are set forth below.

Proposal 1 - Stockholders elected five directors of the Company to hold office until the next Annual Meeting of Stockholders and until their successors are duly elected and qualify. The name of each director elected, and the votes cast for such individuals are set forth below:

Name For Withheld Broker Non-Votes

Mark S. Alarie 26,773,763 6,942,753 22,789,172

John F. Campbell 26,063,019 7,653,497 22,789,172

Bernard S. Champoux 26,970,017 6,746,499 22,789,172

Glen R. Ives 29,097,115 4,619,401 22,789,172

C. Thomas McMillen 26,288,648 7,427,868 22,789,172

Proposal 2 - Stockholders approved a proposal to ratify the Company’s appointment of RSM US LLP as the Company’s independent registered public accounting firm for the fiscal year ended December 31, 2026. The votes regarding Proposal 2 are set forth below:

For Against Abstentions

53,771,662 2,553,667 180,359

Proposal 3 - Stockholders approved an amendment to the Castellum, Inc. Second Amended 2021 Stock Incentive Plan to increase the aggregate number of shares reserved for issuance under the plan to 13,000,000. The votes regarding Proposal 3 are set forth below:

For Against Abstentions Broker Non-Votes

19,780,876 13,632,126 303,514 22,789,172

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No. Exhibit Title

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.

CASTELLUM, INC.

Date: May 20, 2026 By: /s/ Glen R. Ives

Name: Glen R. Ives

Title: Chief Executive Officer (Principal Executive Officer)

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