Castellum COO buys 50,000 shares in open market

Castellum, Inc. (CTM) reported that its Chief Operating Officer, Andrew Merriman, purchased a total of 50,000 shares of common stock in open-market or private transactions on September 9, 2026.

Rhea-AI Filing Summary

Castellum, Inc. (CTM) reported that its Chief Operating Officer, Andrew Merriman, purchased a total of 50,000 shares of common stock in open-market or private transactions on September 9, 2026. The shares were bought at per-share prices of $0.6193 and $0.62, and are held as direct ownership. No Rule 10b5-1 trading plan is reported for these transactions.

Insider Trade Summary

Net Buyer: 50,000 shares

Net Buy 2 txns

Insider Merriman Andrew

Role Chief Operating Officer

Bought 50,000 shs ($31K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	40,000	$0.6193	$25K
Purchase	Common Stock	10,000	$0.62	$6K

Holdings After Transaction: Common Stock — 588,531 shares (Direct)

Key Figures

Shares purchased (first transaction): 40,000 shares Price per share (first transaction): $0.6193 Shares purchased (second transaction): 10,000 shares +2 more

5 metrics

Shares purchased (first transaction) 40,000 shares Common Stock purchased on September 9, 2026 at $0.6193 per share

Price per share (first transaction) $0.6193 Common Stock purchase by COO on September 9, 2026

Shares purchased (second transaction) 10,000 shares Common Stock purchased on September 9, 2026 at $0.62 per share

Price per share (second transaction) $0.62 Common Stock purchase by COO on September 9, 2026

Total shares purchased 50,000 shares Net insider purchases of CTM common stock reported for September 9, 2026

Key Terms

open market or private transaction, direct ownership, Form 4

3 terms

open market or private transaction financial

"Purchase in open market or private transaction"

direct ownership financial

"the shares are held as direct ownership"

Form 4 regulatory

"insider transaction did CTM report for its Chief Operating Officer"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did CTM report for its Chief Operating Officer?

Castellum reported that Chief Operating Officer Andrew Merriman purchased a total of 50,000 shares of CTM common stock on September 9, 2026 in open-market or private transactions, held as direct ownership.

How many CTM shares did the COO buy and at what prices?

Andrew Merriman bought 40,000 shares at $0.6193 per share and 10,000 shares at $0.62 per share of CTM common stock on September 9, 2026, for a total of 50,000 shares.

Were the CTM insider purchases made under a Rule 10b5-1 trading plan?

No. The filing indicates the Rule 10b5-1 checkbox is not affirmed, so these CTM share purchases by the Chief Operating Officer are not reported as being made under a Rule 10b5-1 trading plan.

What type of ownership does the COO report for these CTM shares?

For these transactions, Andrew Merriman reports direct ownership of the CTM common stock purchased on September 9, 2026. No indirect entities or special ownership structures are indicated for these 50,000 shares.

How many CTM insider buy transactions are disclosed in this Form 4?

The Form 4 discloses two separate insider purchase transactions in CTM common stock by Chief Operating Officer Andrew Merriman on September 9, 2026, together totaling 50,000 shares.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/09/2026 - 04:03 PM Accepted by SEC EDGAR 09/09/2026 - 04:02 PM Learn about SEC filing dates

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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)
09/09/2026

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	09/09/2026		P		40,000	A	$0.6193	578,531	D
Common Stock	09/09/2026		P		10,000	A	$0.62	588,531	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	09/09/2026
	** 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)