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Castellum

CTM on NYSEAmerican. Market value $59m.

Watch this stockFree. We tell you when something changes.

Should I look at this?

We have not checked this company yet

This is not advice.

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Who owns it

None of the long-term investors we follow own it. 35 funds in all.

Jun '25
Dec '25
Jun '26
Largest holders overall

From 13F filings for the quarter ended 30 June 2026.

Big holders and activists

No one has reported a stake above 5% since December 2024.

From Schedule 13D and 13G filings: anyone owning more than 5% must file one.

What insiders did

In the last 12 months, 4 insiders bought $48,622 of shares on the open market. 2 sold $769,300.

Cluster buy4 insiders bought within 30 days (9 September 2026 to 1 October 2026).
  • MARTIN TAMMY L
    General Counsel and Secretary
    Bought
    Date
    1 October 2026
    Shares
    1,396
    Price
    $0.54
    Value
    $747
  • Bell David T
    Chief Financial Officer
    Bought
    Date
    1 October 2026
    Shares
    1,396
    Price
    $0.54
    Value
    $747
  • Merriman Andrew
    Chief Operating Officer
    Bought
    Date
    1 October 2026
    Shares
    1,396
    Price
    $0.54
    Value
    $747
  • Ives Glen R
    President, Director
    Bought
    Date
    1 October 2026
    Shares
    1,700
    Price
    $0.54
    Value
    $910
  • Merriman Andrew
    Chief Operating Officer
    Bought
    Date
    9 September 2026
    Shares
    50,000
    Price
    $0.62
    Value
    $30,972
  • Merriman Andrew
    Chief Operating Officer
    Bought
    Date
    1 July 2026
    Shares
    1,202
    Price
    $0.61
    Value
    $736
  • Bell David T
    Chief Financial Officer
    Bought
    Date
    1 July 2026
    Shares
    1,202
    Price
    $0.61
    Value
    $736
  • MARTIN TAMMY L
    General Counsel and Secretary
    Bought
    Date
    1 July 2026
    Shares
    1,202
    Price
    $0.61
    Value
    $736
  • Ives Glen R
    President
    Bought
    Date
    1 July 2026
    Shares
    1,262
    Price
    $0.61
    Value
    $772
  • Merriman Andrew
    Chief Operating Officer
    Bought
    Date
    27 March 2026
    Shares
    2,000
    Price
    $0.64
    Value
    $1,280

From Form 4 filings: insiders must report trades in their own company's shares within two days.

Warning signs in its filings

Problems the company itself reported to the SEC, in its own words.

None of the warning signs we check for were found.

We look for five warning signs: doubt it can keep going, weak checks on its own accounts, a notice that its past accounts can't be relied on, a change of auditor, and one customer bringing in a big share of sales. We don't check lawsuits, investigations or debt yet.

We checked the auditor's report, internal controls, restatement notices, auditor changes and big customers in the 10-K filed 9 Mar 2026, plus the 10-Q filed 6 Aug 2026 and 11 later 8-Ks.

A 10-K is the yearly report every US company files with the SEC. An 8-K is a short notice of a big event.

The deep dive

Everything above is arithmetic on public filings. The deep dive reads the last ten years of annual reports, the proxy statements, and the earnings calls, then argues the case the way Buffett, Klarman, and Hohn would, and checks every claim against the source.

  • What the business is worth, as a range, and the margin of safety at today’s price
  • Prices to start buying, buy, and buy hard
  • The three things that would make this a mistake
  • Every number footnoted to the filing it came from
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What a finished deep dive looks like

Not advice. Numbers on this page come from SEC filings and are updated each night; prices are updated again after the US market closes. The five-year figures are rounded.