Castellum (CTM) COO Andrew Merriman makes open-market share purchase

Rhea-AI Filing Summary

Castellum, Inc. Chief Operating Officer Andrew Merriman reported an open-market purchase of common stock. He bought 2,000 shares at a price of $0.6426 per share. After this transaction, he directly owns 536,000 shares, so the purchase increases an already substantial existing stake by a relatively small amount.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Merriman Andrew

(Last) (First) (Middle)

1934 OLD GALLOWS ROAD

SUITE 350

(Street)

VIENNA VIRGINIA 22182

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Castellum, Inc. [ CTM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Operating Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/27/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/27/2026		P		2,000	A	$0.6426	536,000	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

	/s/ Andrew Merriman	03/27/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Castellum (CTM) report for Andrew Merriman?

Castellum reported that Chief Operating Officer Andrew Merriman bought 2,000 shares of common stock in an open-market transaction. This Form 4 filing shows a direct purchase rather than a sale, modestly increasing his personal equity stake in the company.

At what price did Castellum COO Andrew Merriman buy CTM shares?

Andrew Merriman purchased 2,000 Castellum shares at an average price of $0.6426 per share. This price reflects the cost he paid in the reported open-market transaction and is the only transaction price disclosed in this Form 4 filing.

How many Castellum (CTM) shares does Andrew Merriman own after this trade?

Following the reported purchase, Andrew Merriman directly owns 536,000 shares of Castellum common stock. The 2,000 shares acquired in this transaction represent a small addition to this overall position, as reflected in the Form 4 ownership totals.

Was the Castellum (CTM) insider transaction a buy or a sell?

The insider transaction reported was a buy. The Form 4 classifies it as an open-market purchase of 2,000 common shares, with no corresponding sales reported, indicating a net increase in Andrew Merriman’s directly held Castellum stock.

Does the Castellum (CTM) Form 4 show any derivative or option exercises?

The Form 4 does not report any derivative or option exercises. It shows only a single non-derivative transaction: an open-market purchase of 2,000 shares of common stock, with no options, warrants, or other derivative securities listed in the filing’s transaction details.

Is Andrew Merriman’s Castellum (CTM) purchase a direct or indirect holding?

The filing classifies the 2,000 shares purchased as a direct holding. After the transaction, Merriman directly owns 536,000 shares of Castellum common stock, with no indication in this report of indirect ownership through entities or trusts.