Filer Snapshot

Mark N. Tompkins

CIK 0001455971. SEC filing timeline plus parsed ownership intelligence from 13F, 13D/G, and Forms 3/4/5 where available.

Entity type

Individual

Total filings

36

Latest filing

01 Jun 2026

Industry

n/a

Filing-backed research brief

Start with the SEC data that changes for this CIK

Latest signal: 13D/G stake for Deep Fission, Inc.. Each card links back to the PortfolioSavvy page where the filing evidence is closest.

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Largest parsed holding

—

Populates from the latest parsed 13F information table.

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13D/G large stake

Deep Fission, Inc.

31 Mar 2026 · 5.6% ownership

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Source: SEC Schedule 13D/G

SCHEDULE 13G filed on 01 Jun 2026 for CIK 0001455971.

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Ownership signals CIK-linked ownership evidence from parsed SEC filings. 1 signal
Parsed SEC ownership signals

Parsed SEC ownership coverage

These bars compare filing-backed value available in each disclosure family. Read them as separate lenses, not as one combined ownership total.

Forms 3/4/5 positions$59.58M

Reporting-owner positions with enough filing detail to estimate value.

Forms 3/4/5 position value

3/4/5
$59.58M

Estimated from parsed Forms 3/4/5 when filings include enough share and price data.

Source: Forms 3/4/5Confidence: Estimated when price data is available

Largest linked holdings

Largest issuer positions linked to this CIK across parsed 13F, 13D/G, and Forms 3/4/5 records.

ALMU SERV GUER AMST Venetian-1 Acquisition Corp.

Largest active 13G stakes

Passive or institutional large-stake positions disclosed in parsed Schedule 13G filings.

ALMU PMNT Range Acquisition Corp. Primus Acquisition Inc. Orielle Acquisition Corp. Deep Fission, Inc.
+4 moreVar Acquisition Corp. Deep Isolation Nuclear, Inc. Los Altos Ventures Corp. Lomond Therapeutics Holdings, Inc.
How to read these SEC ownership signals
  • Read each filing family separately: Form 13F, Schedules 13D/G, and Forms 3/4/5 answer different SEC disclosure questions and should not be blended into one ownership total.
  • Use 13F values for visible U.S.-listed equity portfolios, 13D/G rows for large beneficial-owner stakes, and Forms 3/4/5 rows for reporting-owner positions and transactions.
  • Open the linked research path when you need the filing, CIK, issuer, CUSIP, date, or source trail behind a value.
At a glance Names, identifiers, and filing context for this profile. 1 identity field
Business address
App. 1, Via Guidino 23, Lugano Paradiso

Filer intelligence

What SEC filings say about Mark N. Tompkins

A compact read of parsed XML filings. 13F, 13D/G, and Forms 3/4/5 are shown separately because they answer different ownership questions.

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Quick read

  • 5 recent 13D/G stake rows found; top row is Deep Fission, Inc. at 5.6% ownership.
  • Forms 3/4/5 show insider context for ALMU worth $28.73M.

SEC source mix

Counts show available parsed rows, not one combined ownership total.

XML parsed
13F portfolio No rows yet

Quarterly institutional portfolio holdings.

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13D/G stakes 5 rows

Beneficial ownership and large-stake disclosures.

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Forms 3/4/5 5 rows

Officer, director, and 10% owner holdings or transactions.

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13D/G large-stake context

Deep Fission, Inc.

31 Mar 2026 · Common Stock, par value $0.0001 per share

5.6%
Issuer page 13D/G history

Deep Isolation Nuclear, Inc.

31 Mar 2026 · Common Stock, par value $0.0001 per share

5.5%
Issuer page 13D/G history

ALMU

31 Mar 2026 · Common Stock, par value $0.0001 per share

4.8%
Issuer page 13D/G history

Primus Acquisition Inc.

31 Dec 2025 · Common Stock, par value $0.0001 per share

75%
Issuer page 13D/G history

Forms 3/4/5 insider context

ALMU

04 Feb 2026

$28.73M
Issuer page Owner page

SERV

31 Jul 2023

$15.55M
Issuer page Owner page

GUER

12 Nov 2021

$5.4M
Issuer page Owner page

AMST

28 May 2021 · 10% owner

$5.1M
Issuer page Owner page

Latest update

What changed recently for Mark N. Tompkins

Ownership report updated

Latest ownership report period: 22 May 2026. Open the source-backed page to inspect the fresh filing or facts context.

Update date

27 May 2026

Page type

Ownership filings

Latest period

22 May 2026

Ownership context was refreshed from SEC Forms 3/4/5 filed on 27 May 2026.

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SEC filing record

CIK 0001455971 filing coverage

Start with this filing record, then use the linked ownership pages when parsed 13F, 13D/G, Forms 3/4/5, or facts data exists for this CIK.

SEC filings
36
First seen
11 May 2021
Latest filing
01 Jun 2026
Entity
Individual

Observed form types

3 4 SCHEDULE 13G SCHEDULE 13G/A

CIK-linked evidence first

Mark N. Tompkins SEC filings Mark N. Tompkins 13D/G history Mark N. Tompkins owner filings Open SEC filing index

Latest Filings

Showing the latest 12 of 36 SEC filings for Mark N. Tompkins.

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SCHEDULE 13G

SCHEDULE 13G filing

Filing date
01 Jun 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
15 May 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
15 May 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
15 May 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G

SCHEDULE 13G filing

Filing date
17 Feb 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G

SCHEDULE 13G filing

Filing date
17 Feb 2026
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
17 Feb 2026
Reporting date
Not listed
SEC evidence
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4

4 filing

Filing date
05 Feb 2026
Reporting date
04 Feb 2026
SEC evidence
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4

4 filing

Filing date
02 Feb 2026
Reporting date
29 Jan 2026
SEC evidence
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3

3 filing

Filing date
26 Jan 2026
Reporting date
26 Jan 2026
SEC evidence
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SCHEDULE 13G

SCHEDULE 13G filing

Filing date
14 Nov 2025
Reporting date
Not listed
SEC evidence
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SCHEDULE 13G

SCHEDULE 13G filing

Filing date
14 Nov 2025
Reporting date
Not listed
SEC evidence
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