Mark C. Fuller - 03 Sep 2025 Form 4 Insider Report for Castellum, Inc. (CTM)

Reporting relationship: Former Officer and Affiliate
Issuer ticker: CTM
Reported as of: 03 Sep 2025
Net transaction value: -$560,000
SEC form: 4
Accepted by SEC: 03 Sep 2025, 17:06:37 UTC
Prior SEC filing: 20 May 2025
Source filing: View source filing
Reporting owner signature: /s/ Mark C. Fuller

Key filing fact

Mark C. Fuller filed Form 4 for Castellum, Inc. (CTM) on 03 Sep 2025.

Key facts

This page summarizes Mark C. Fuller's Form 4 filing for Castellum, Inc. (CTM).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 03 Sep 2025, 17:06.

Change

Previous filing in this sequence was filed on 20 May 2025.
Current net transaction value: -$560,000.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001944544 Primary reporting owner

Fuller Mark C

Relationship: Former Officer and Affiliate
Address: 1934 OLD GALLOWS ROAD, SUITE 350, VIENNA
Signature: /s/ Mark C. Fuller
Signature date: 03 Sep 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

CTM transaction

Common Stock

Sale

Transaction value: $560,000
Shares: -500,000
Change %: -7.6%
Price: $1.12
Shares after: 6,113,659
Date: 03 Sep 2025
Ownership: Direct
Footnotes: F1, F2, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

Mark C. Fuller is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 3 footnotes

Footnote F1

Includes (a) 6,047,519 common shares held by The Mark Chappelle Fuller Revocable Trust, Mark Fuller, TTEE, (b) 50,000 common shares held by Janice Lynn Dudley Revocable Trust, Janice Lynn Dudley TTEE, and (c) 16,140 common shares held by Mark Fuller.

Footnote F2

Effective May 28, 2025, Mr. Fuller ceased to be a member of the Company's board of directors.

Footnote F3

Effective June 12, 2025, Mr. Fuller ceased to be an affiliate of the Company.