SEC ownership of ASP Isotopes Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001921865.

Comparable stake leader

Paul Elliot Mann

Disclosed value leader

Paul Elliot Mann

Comparable rows

50/50

Latest evidence

01 Jul 2026

Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 3 signals
Comparable ownership rows
50 of 50
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder
Paul Elliot Mann
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date
01 Jul 2026
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0001921865
Issuer location
Dallas, TX

Ownership snapshot

Top shareholders of ASP Isotopes Inc. (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader
Paul Elliot Mann
Disclosed value leader
Paul Elliot Mann
Comparable rows
50/50
Latest evidence
01 Jul 2026
3/4/5 13D/G 13F Lead comparable stake: 7% 13D/G row: Paul Elliot Mann Showing 1-8 of 50 holder rows.

Quick read

Paul Elliot Mann leads the comparable SEC ownership view at 7%.

50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens Paul Elliot Mann's linked filing trail.
Comparable ownership Top 5
Paul Elliot Mann 7%
BlackRock, Inc. 6.6%
AK Jensen Investment Management Ltd 5.4%
Encompass Capital Advisors LLC 5.1%
BNP Paribas Asset Management UK Ltd 0.9%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 50 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
Paul Elliot Mann
3/4/5 13D/G
Chairman and CEO, Director · Mann Paul Elliot
7%
from 13D/G
$74,339,597
9,579,845 shares
-$4,560,257 28 May 2026
BlackRock, Inc.
13F 13D/G
Company
6.6%
from 13D/G
$57,330,971
9,217,198 shares
30 Jun 2026
AK Jensen Investment Management Ltd
13D/G 3/4/5
10%+ Owner
5.4%
$47,669,611
4,955,261 shares
+$2,373,350 30 Sep 2025
Encompass Capital Advisors LLC
13F 13D/G
Company
5.1%
from 13D/G
$40,814,110
6,561,754 shares
30 Jun 2026
BNP Paribas Asset Management UK Ltd
13D/G
0.9%
$7,073,002
944,326 shares
-$20,102,329 31 Dec 2025
Robert Ainscow
3/4/5
COO
1.8%
$15,970,871
2,281,879 shares
-$1,416,050 08 Jun 2026
Heather Kiessling
3/4/5
Chief Financial Officer
1.2%
$9,584,862
1,526,252 shares
-$735,732 01 Jul 2026
Duncan Moore
3/4/5
Director
0.83%
$5,438,850
1,044,928 shares
-$756,829 12 Nov 2025
How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Forms 3/4/5 flow

Insider trading overview

Net insider flow leans to selling over the last 12 months. Net value: -$10,162,528.

Buys
$881,464
Insiders: 1
Sells
$11,043,992
Insiders: 7
Net
-$10,162,528
Shares: -1,353,178
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 162,153 Shares: 1,515,331
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 0 512,837 $0 $3,629,213 -$3,629,213
3-6 162,153 90,704 $881,464 $463,052 +$418,412
6-9 0 325,591 $0 $1,881,722 -$1,881,722
9-12 0 586,199 $0 $5,070,005 -$5,070,005

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-14 of 14 reporting-owner rows connected to ASP Isotopes Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows
14
Largest Forms 3/4/5 holder
Paul Elliot Mann
Net 12M change
-$10,162,528
Latest report
01 Jul 2026
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
Paul Elliot Mann Chairman and CEO, Director $74,339,597 -$4,560,257 -5.8% Filing P/S 28 May 2026
AK Jensen Investment Management Ltd 10%+ Owner $40,490,134 Mixed 11 Oct 2024
Robert Ainscow Coo $15,970,871 -$1,416,050 -8.1% Filing P/S 08 Jun 2026
Heather Kiessling Chief Financial Officer $9,584,862 -$735,732 -7.1% Filing P/S 01 Jul 2026
Hendrik Strydom Director, 10%+ Owner $7,099,052 Mixed 15 Nov 2022
Duncan Moore Director $5,438,850 -$756,829 -12% Filing P/S 12 Nov 2025
Donald George Ainscow EVP, Gen Counsel, Secretary $4,912,000 -$614,000 -11% Filing P/S 30 Jun 2026
Todd Wider Director $4,114,151 -$1,267,323 -24% Filing P/S 29 Jun 2026
Robert John Andrew Ryan Director $3,861,154 Mixed 18 Dec 2025
Sergey Vasnetsov Director $3,685,063 Mixed 01 Mar 2023
Ph.D. Einar Ronander Chief Scientific Adviser, 10%+ Owner $3,453,527 Mixed 09 Nov 2022
Joshua J. Donfeld Director $1,060,000 Filing P/S 26 Oct 2023
Michael Gorley Director $551,183 -$812,337 -60% Filing P/S 30 Jun 2026
Ralph L. Hunter Jr. Director $278,346 Mixed 18 Dec 2025

Recent insider transactions for ASP Isotopes Inc.

Showing up to 300 recent insider transactions from the last 12 months.

Insider Symbol Class Transaction % SEC-reported value SEC-reported price Shares Shares owned Date Ownership
Heather Kiessling ASPI Common Stock Sale -1.49% $145,219 $6.28 -23,124 1,526,252 01 Jul 2026 Direct
Donald George Ainscow ASPI Common Stock Sale -11.1% $614,000 $6.14 -100,000 800,000 30 Jun 2026 Direct
Todd Wider ASPI Common Stock Sale -6.92% $306,000 $6.12 -50,000 672,247 30 Jun 2026 Direct
Michael Gorley ASPI Common Stock Sale -25.4% $188,100 $6.27 -30,000 87,908 30 Jun 2026 Direct
Todd Wider ASPI Common Stock Sale -6.47% $312,500 $6.25 -50,000 722,247 29 Jun 2026 Direct
Robert Ainscow ASPI Common Stock Sale -0.37% $59,058 $7.00 -8,438 2,281,879 08 Jun 2026 Direct
Paul Elliot Mann ASPI Common Stock Sale -0.87% $649,970 $7.76 -83,759 9,579,845 03 Jun 2026 Direct
Paul Elliot Mann ASPI Common Stock Sale -0.86% $694,354 $8.29 -83,758 9,663,424 02 Jun 2026 Direct
Paul Elliot Mann ASPI Common Stock Sale -0.85% $660,013 $7.88 -83,758 9,747,182 01 Jun 2026 Direct
Paul Elliot Mann ASPI Common Stock Award 29.4% 2,233,555 9,830,940 28 May 2026 Direct
Robert Ainscow ASPI Common Stock Award 53.7% 800,000 2,290,317 28 May 2026 Direct
Donald George Ainscow ASPI Common Stock Award 80% 400,000 900,000 28 May 2026 Direct
Heather Kiessling ASPI Common Stock Award 118.4% 840,000 1,549,376 28 May 2026 Direct
Robert Ainscow ASPI Common Stock Sale -1.49% $117,112 $5.20 -22,500 1,490,317 16 Apr 2026 Direct
Duncan Moore ASPI Common Stock Sale -1.1% $60,597 $5.20 -11,642 1,044,928 16 Apr 2026 Direct
Heather Kiessling ASPI Common Stock Sale -3.16% $126,673 $5.48 -23,124 709,376 15 Apr 2026 Direct
Robert Ainscow ASPI Common Stock Sale -1.63% $112,775 $4.51 -25,000 1,512,817 06 Mar 2026 Direct
Robert Ainscow ASPI Common Stock Sale -0.55% $45,894 $5.44 -8,438 1,537,817 06 Mar 2026 Direct
Paul Elliot Mann ASPI Common Stock Sale 2.18% $881,464 $5.44 162,153 7,597,385 02 Mar 2026 Direct
Duncan Moore ASPI Common Stock Award 3.58% 36,548 1,056,570 18 Dec 2025 Direct
Heather Kiessling ASPI Common Stock Sale -9.85% $463,840 $5.80 -80,000 732,500 18 Dec 2025 Direct
Todd Wider ASPI Common Stock Award 4.97% 36,548 772,247 18 Dec 2025 Direct
Robert John Andrew Ryan ASPI Common Stock Award 5.94% 36,548 652,222 18 Dec 2025 Direct
Ralph L. Hunter Jr. ASPI Common Stock Award 349.1% 36,548 47,018 18 Dec 2025 Direct
Michael Gorley ASPI Common Stock Award 44.9% 36,548 117,908 18 Dec 2025 Direct
Robert Ainscow ASPI Common Stock Sale -0.54% $52,341 $6.20 -8,438 1,546,255 08 Dec 2025 Direct
Paul Elliot Mann ASPI Common Stock Sale -2.05% $932,866 $5.75 -162,153 7,759,538 01 Dec 2025 Direct
Robert Ainscow ASPI Common Stock Sale -1.58% $144,225 $5.77 -25,000 1,554,693 25 Nov 2025 Direct
Paul Elliot Mann ASPI Common Stock Sale -0.63% $288,450 $5.77 -50,000 7,921,691 25 Nov 2025 Direct
Paul Elliot Mann ASPI Common Stock Sale -1.39% $844,538 $7.51 -112,500 7,971,691 17 Nov 2025 Direct
Robert Ainscow ASPI Common Stock Sale -4.1% $506,722 $7.51 -67,500 1,579,693 17 Nov 2025 Direct
Duncan Moore ASPI Common Stock Award 2.56% 25,469 1,020,022 12 Nov 2025 Direct
Todd Wider ASPI Common Stock Award 3.59% 25,469 735,699 12 Nov 2025 Direct
Robert Ainscow ASPI Common Stock Sale -1.35% $305,978 $13.60 -22,500 1,647,193 14 Oct 2025 Direct
Michael Gorley ASPI Common Stock Sale -44% $624,237 $9.75 -64,000 81,360 30 Sep 2025 Direct
Todd Wider ASPI Common Stock Sale -9.45% $648,823 $8.76 -74,108 710,230 15 Sep 2025 Direct
Todd Wider ASPI Common Stock Tax liability -2.72% -21,892 784,338 14 Sep 2025 Direct
Todd Wider ASPI Common Stock Options Exercise 13.5% 96,000 806,230 14 Sep 2025 Direct
Todd Wider ASPI Stock Option (right to buy) Options Exercise -100% -96,000 0 14 Sep 2025 Direct
Robert Ainscow ASPI Common Stock Tax liability -2.43% -38,861 1,557,158 09 Sep 2025 Direct
Robert Ainscow ASPI Common Stock Options Exercise 21.2% 297,000 1,701,345 09 Sep 2025 Direct
Robert Ainscow ASPI Employee Stock Option (right to buy) Options Exercise -100% -297,000 0 09 Sep 2025 Direct
Paul Elliot Mann ASPI Common Stock Sale -0.99% $680,123 $8.39 -81,077 8,084,191 09 Sep 2025 Direct
Paul Elliot Mann ASPI Common Stock Tax liability -3.71% -285,110 7,399,734 09 Sep 2025 Direct
Paul Elliot Mann ASPI Common Stock Options Exercise 16.9% 1,216,000 8,399,734 09 Sep 2025 Direct
Paul Elliot Mann ASPI Employee Stock Option (right to buy) Options Exercise -100% -1,216,000 0 09 Sep 2025 Direct
Robert Ainscow ASPI Common Stock Sale -0.59% $71,945 $8.53 -8,438 1,411,554 08 Sep 2025 Direct
Paul Elliot Mann ASPI Common Stock Sale -1.11% $691,408 $8.53 -81,076 7,234,378 08 Sep 2025 Direct
Ralph L. Hunter Jr. ASPI Common Stock Award 10,470 10,470 06 Sep 2025 Direct
Duncan Moore ASPI Common Stock Sale -7.01% $696,232 $9.28 -75,000 994,553 29 Aug 2025 Direct
* marks a reported price that did not pass the local price check.
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