Comparable stake leader
Mann Paul Elliot
SEC ownership of ASP Isotopes Inc.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001921865.
Disclosed value leader
Mann Paul Elliot
Comparable rows
50/50
Latest evidence
30 Sep 2026
- Public ticker
- ASPI on Nasdaq
- Parsed ownership sources
-
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
Mann Paul Elliot
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
Mann Paul Elliot
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
30 Sep 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001921865
- Issuer location
- Dallas, TX
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
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
Mann Paul Elliot
Disclosed value leader
Mann Paul Elliot
Comparable rows
50/50
Latest evidence
30 Sep 2026
13D/G
3/4/5
13F
Lead comparable stake: 7%
13D/G row: Mann Paul Elliot
Showing 1-8 of 50 holder rows.
Quick read
Mann Paul Elliot 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 Mann Paul Elliot's linked filing trail.
Comparable ownership
Top 5
Mann Paul Elliot
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 |
|---|---|---|---|---|---|
| Mann Paul Elliot |
13D/G
3/4/5
Chairman and CEO, Director
|
7%
|
$58,118,940
7,759,538 shares
|
+$348,704 | 31 Dec 2025 |
| 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%
|
$9,650,308
2,248,441 shares
|
-$1,477,946 | 08 Sep 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
|
-$60,597 | 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: -$7,913,146.
Buys
$943,264
Insiders: 2
Sells
$8,856,410
Insiders: 7
Net
-$7,913,146
Shares: -1,254,870
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 185,153
Shares: 1,440,023
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 23,000 | 308,391 | $61,800 | $1,225,185 | -$1,163,385 |
| 3-6 | 0 | 570,103 | $0 | $3,933,595 | -$3,933,595 |
| 6-9 | 162,153 | 33,438 | $881,464 | $158,669 | +$722,794 |
| 9-12 | 0 | 528,091 | $0 | $3,538,960 | -$3,538,960 |
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
AK Jensen Investment Management Ltd
Net 12M change
-$7,913,146
Latest report
30 Sep 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| AK Jensen Investment Management Ltd | 10%+ Owner | $40,490,134 | Mixed | 11 Oct 2024 | ||
| Mann Paul Elliot | Chairman and CEO, Director | $38,247,137 | -$4,187,964 | -9.9% | Filing P/S | 02 Sep 2026 |
| Robert Ainscow | Coo | $9,650,308 | -$1,477,946 | -13% | Filing P/S | 08 Sep 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 | -$60,597 | -1.1% | Filing P/S | 12 Nov 2025 |
| Todd Wider | Director | $4,114,151 | -$618,500 | -13% | Filing P/S | 29 Jun 2026 |
| 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 | ||
| Donald George Ainscow | EVP, Gen Counsel, Secretary | $3,019,892 | -$706,107 | -19% | Filing P/S | 02 Sep 2026 |
| Robert John Andrew Ryan | Director | $1,809,594 | +$61,800 | +3.5% | Filing P/S | 30 Sep 2026 |
| Joshua J. Donfeld | Director | $1,060,000 | Filing P/S | 26 Oct 2023 | ||
| Michael Gorley | Director | $551,183 | -$188,100 | -25% | 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Robert John Andrew Ryan | ASPI | Common Stock | Purchase | 2.27% | $40,200 | $2.68 | 15,000 | 675,222 | 30 Sep 2026 | Direct |
| Robert John Andrew Ryan | ASPI | Common Stock | Purchase | 1.23% | $21,600 | $2.70 | 8,000 | 660,222 | 28 Sep 2026 | Direct |
| Robert Ainscow | ASPI | Common Stock | Sale | -0.37% | $36,216 | $4.29 | -8,438 | 2,248,441 | 08 Sep 2026 | Direct |
| Paul Elliot Mann | ASPI | Common Stock | Sale | -0.89% | $343,412 | $4.10 | -83,759 | 9,328,570 | 04 Sep 2026 | Direct |
| Paul Elliot Mann | ASPI | Common Stock | Sale | -0.88% | $328,331 | $3.92 | -83,758 | 9,412,329 | 03 Sep 2026 | Direct |
| Donald George Ainscow | ASPI | Common Stock | Sale | -2.96% | $92,107 | $3.89 | -23,678 | 776,322 | 02 Sep 2026 | Direct |
| Robert Ainscow | ASPI | Common Stock | Sale | -1.1% | $97,625 | $3.90 | -25,000 | 2,256,879 | 02 Sep 2026 | Direct |
| Paul Elliot Mann | ASPI | Common Stock | Sale | -0.87% | $327,494 | $3.91 | -83,758 | 9,496,087 | 02 Sep 2026 | Direct |
| 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 |
* marks a reported price that did not pass the local price check.